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• Implementing a robust async stream reader

  - by Jon

  I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output, but that is a detail and does not play an important role. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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• Form Loop Error

  - by JM4

  I have a form which loops if the value indicated is less than or equal the number of 'enrollee's needed. The while loop works perfectly with one exception, I use DOB fields which ALSO use FOR loops to display their values. If I remove the DOB fields, the form loop works fine, when left in, it errors out. Any ideas? <form id="Enroll_Form" action="<?php $_SERVER['PHP_SELF']; ?>" method="post" name="Enroll_Form" > <?php $i=1; while ($i <= ($_SESSION['Num_Members'])): {?> <table class="demoTable"> <tr> <td>First Name: </td> <td><input type="text" name="F1FirstName" value="<?php echo $fields['F1FirstName']; ?>" /></td> </tr> <tr> <td>Middle Initial: </td> <td><input type="text" name="F1MI" size="2" maxlength="1" value="<?php echo $fields['F1MI']; ?>" /></td> </tr> <tr> <td>Last Name: </td> <td><input type="text" name="F1LastName" value="<?php echo $fields['F1LastName']; ?>" /></td> </tr> <tr> <td>Federation No: </td> <td><input type="text" name="F1FedNum" maxlength="10" value="<?php echo $fields['F1FedNum']; ?>" /></td> </tr> <tr> <td>SSN: </td> <td><input type="text" name="F1SSN1" size="3" maxlength="3" value="<?php echo $fields['F1SSN1']; ?>" /> - <input type="text" name="F1SSN2" size="2" maxlength="2" value="<?php echo $fields['F1SSN2']; ?>" /> - <input type="text" name="F1SSN3" size="4" maxlength="4" value="<?php echo $fields['F1SSN3']; ?>" /> </td> </tr> <tr> <td>Date of Birth</td> <td> <select name="F1DOB1"> <option value="">Month</option> <?php for ($i=1; $i<=12; $i++) { echo "<option value='$i'"; if ($fields["F1DOB1"] == $i) echo " selected"; echo ">$i</option>"; } ?> </select> / <select name="F1DOB2"> <option value="">Day</option> <?php for ($i=1; $i<=31; $i++) { echo "<option value='$i'"; if ($fields["F1DOB2"] == $i) echo " selected"; echo ">$i</option>"; } ?> </select> / <select name="F1DOB3"> <option value="">Year</option> <?php for ($i=date('Y'); $i>=1900; $i--) { echo "<option value='$i'"; if ($fields["F1DOB3"] == $i) echo " selected"; echo ">$i</option>"; } ?> </select> </td> </tr> <tr> <td>Address: </td> <td><input type="text" name="F1Address" value="<?php echo $fields['F1Address']; ?>" /></td> </tr> <tr> <td>City: </td> <td><input type="text" name="F1City" value="<?php echo $fields['F1City']; ?>" /></td> </tr> <tr> <td>State: </td> <td><select name="F1State"><option value="">Choose a State</option><?php showOptionsDrop($states_arr, null, true); ?></select></td> </tr> <tr> <td>Zip Code: </td> <td><input type="text" name="F1Zip" size="6" maxlength="5" value="<?php echo $fields['F1Zip']; ?>" /></td> </tr> <tr> <td>Contact Telephone No: </td> <td>( <input type="text" name="F1Phone1" size="3" maxlength="3" value="<?php echo $fields['F1Phone1']; ?>" /> ) <input type="text" name="F1Phone2" size="3" maxlength="3" value="<?php echo $fields['F1Phone2']; ?>" /> - <input type="text" name="F1Phone3" size="4" maxlength="4" value="<?php echo $fields['F1Phone3']; ?>" /> </td> </tr> <tr> <td>Email:</td> <td><input type="text" name="F1Email" value="<?php echo $fields['F1Email']; ?>" /></td> </tr> </table> <br /> <?php } $i++; endwhile; ?> <div align="right"><input class="enrbutton" type="submit" name="submit" value="Continue" /></div> </form>

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• How to know if the client has terminated in sockets

  - by shadyabhi

  Suppose, I have a connected socket after writing this code.. if ((sd = accept(socket_d, (struct sockaddr *)&client_addr, &alen)) < 0) { perror("accept failed\n"); exit(1); } How can I know at the server side that client has exited. My whole program actually does the following.. Accepts a connection from client Starts a new thread that reads messages from that particular client and then broadcast this message to all the connected clients. If you want to see the whole code... In this whole code. I am also struggling with one more problem that whenever I kill a client with Ctrl+C, my server terminates abruptly.. It would be nice if anyone could suggest what the problem is.. #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <signal.h> #include <errno.h> #include <pthread.h> /*CONSTANTS*/ #define DEFAULT_PORT 10000 #define LISTEN_QUEUE_LIMIT 6 #define TOTAL_CLIENTS 10 #define CHAR_BUFFER 256 /*GLOBAL VARIABLE*/ int current_client = 0; int connected_clients[TOTAL_CLIENTS]; extern int errno; void *client_handler(void * socket_d); int main(int argc, char *argv[]) { struct sockaddr_in server_addr;/* structure to hold server's address*/ int socket_d; /* listening socket descriptor */ int port; /* protocol port number */ int option_value; /* needed for setsockopt */ pthread_t tid[TOTAL_CLIENTS]; port = (argc > 1)?atoi(argv[1]):DEFAULT_PORT; /* Socket Server address structure */ memset((char *)&server_addr, 0, sizeof(server_addr)); server_addr.sin_family = AF_INET; /* set family to Internet */ server_addr.sin_addr.s_addr = INADDR_ANY; /* set the local IP address */ server_addr.sin_port = htons((u_short)port); /* Set port */ /* Create socket */ if ( (socket_d = socket(PF_INET, SOCK_STREAM, 0)) < 0) { fprintf(stderr, "socket creation failed\n"); exit(1); } /* Make listening socket's port reusable */ if (setsockopt(socket_d, SOL_SOCKET, SO_REUSEADDR, (char *)&option_value, sizeof(option_value)) < 0) { fprintf(stderr, "setsockopt failure\n"); exit(1); } /* Bind a local address to the socket */ if (bind(socket_d, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) { fprintf(stderr, "bind failed\n"); exit(1); } /* Specify size of request queue */ if (listen(socket_d, LISTEN_QUEUE_LIMIT) < 0) { fprintf(stderr, "listen failed\n"); exit(1); } memset(connected_clients,0,sizeof(int)*TOTAL_CLIENTS); for (;;) { struct sockaddr_in client_addr; /* structure to hold client's address*/ int alen = sizeof(client_addr); /* length of address */ int sd; /* connected socket descriptor */ if ((sd = accept(socket_d, (struct sockaddr *)&client_addr, &alen)) < 0) { perror("accept failed\n"); exit(1); } else printf("\n I got a connection from (%s , %d)\n",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port)); if (pthread_create(&tid[current_client],NULL,(void *)client_handler,(void *)sd) != 0) { perror("pthread_create error"); continue; } connected_clients[current_client]=sd; current_client++; /*Incrementing Client number*/ } return 0; } void *client_handler(void *connected_socket) { int sd; sd = (int)connected_socket; for ( ; ; ) { ssize_t n; char buffer[CHAR_BUFFER]; for ( ; ; ) { if (n = read(sd, buffer, sizeof(char)*CHAR_BUFFER) == -1) { perror("Error reading from client"); pthread_exit(1); } int i=0; for (i=0;i<current_client;i++) { if (write(connected_clients[i],buffer,sizeof(char)*CHAR_BUFFER) == -1) perror("Error sending messages to a client while multicasting"); } } } } My client side is this (Maye be irrelevant while answering my question) #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <string.h> #include <stdlib.h> void error(char *msg) { perror(msg); exit(0); } void *listen_for_message(void * fd) { int sockfd = (int)fd; int n; char buffer[256]; bzero(buffer,256); printf("YOUR MESSAGE: "); fflush(stdout); while (1) { n = read(sockfd,buffer,256); if (n < 0) error("ERROR reading from socket"); if (n == 0) pthread_exit(1); printf("\nMESSAGE BROADCAST: %sYOUR MESSAGE: ",buffer); fflush(stdout); } } int main(int argc, char *argv[]) { int sockfd, portno, n; struct sockaddr_in serv_addr; struct hostent *server; pthread_t read_message; char buffer[256]; if (argc < 3) { fprintf(stderr,"usage %s hostname port\n", argv[0]); exit(0); } portno = atoi(argv[2]); sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd < 0) error("ERROR opening socket"); server = gethostbyname(argv[1]); if (server == NULL) { fprintf(stderr,"ERROR, no such host\n"); exit(0); } bzero((char *) &serv_addr, sizeof(serv_addr)); serv_addr.sin_family = AF_INET; bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length); serv_addr.sin_port = htons(portno); if (connect(sockfd,&serv_addr,sizeof(serv_addr)) < 0) error("ERROR connecting"); bzero(buffer,256); if (pthread_create(&read_message,NULL,(void *)listen_for_message,(void *)sockfd) !=0 ) { perror("error creating thread"); } while (1) { fgets(buffer,255,stdin); n = write(sockfd,buffer,256); if (n < 0) error("ERROR writing to socket"); bzero(buffer,256); } return 0; }

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• Inserting Records in Ascending Order function- C homework assignment

  - by Aaron McRuer

  Good day, Stack Overflow. I have a homework assignment that I'm working on this weekend that I'm having a bit of a problem with. We have a struct "Record" (which contains information about cars for a dealership) that gets placed in a particular spot in a linked list according to 1) its make and 2) according to its model year. This is done when initially building the list, when a "int insertRecordInAscendingOrder" function is called in Main. In "insertRecordInAscendingOrder", a third function, "createRecord" is called, where the linked list is created. The function then goes to the function "compareCars" to determine what elements get put where. Depending on the value returned by this function, insertRecordInAscendingOrder then places the record where it belongs. The list is then printed out. There's more to the assignment, but I'll cross that bridge when I come to it. Ideally, and for the assignment to be considered correct, the linked list must be ordered as: Chevrolet 2012 25 Chevrolet 2013 10 Ford 2010 5 Ford 2011 3 Ford 2012 15 Honda 2011 9 Honda 2012 3 Honda 2013 12 Toyota 2009 2 Toyota 2011 7 Toyota 2013 20 from the a text file that has the data ordered the following way: Ford 2012 15 Ford 2011 3 Ford 2010 5 Toyota 2011 7 Toyota 2012 20 Toyota 2009 2 Honda 2011 9 Honda 2012 3 Honda 2013 12 Chevrolet 2013 10 Chevrolet 2012 25 Notice that the alphabetical order of the "make" field takes precedence, then, the model year is arranged from oldest to newest. However, the program produces this as the final list: Chevrolet 2012 25 Chevrolet 2013 10 Honda 2011 9 Honda 2012 3 Honda 2013 12 Toyota 2009 2 Toyota 2011 7 Toyota 2012 20 Ford 2010 5 Ford 2011 3 Ford 2012 15 I sat down with a grad student and tried to work out all of this yesterday, but we just couldn't figure out why it was kicking the Ford nodes down to the end of the list. Here's the code. As you'll notice, I included a printList call at each instance of the insertion of a node. This way, you can see just what is happening when the nodes are being put in "order". It is in ANSI C99. All function calls must be made as they are specified, so unfortunately, there's no real way of getting around this problem by creating a more efficient algorithm. #include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX_LINE 50 #define MAX_MAKE 20 typedef struct record { char *make; int year; int stock; struct record *next; } Record; int compareCars(Record *car1, Record *car2); void printList(Record *head); Record* createRecord(char *make, int year, int stock); int insertRecordInAscendingOrder(Record **head, char *make, int year, int stock); int main(int argc, char **argv) { FILE *inFile = NULL; char line[MAX_LINE + 1]; char *make, *yearStr, *stockStr; int year, stock, len; Record* headRecord = NULL; /*Input and file diagnostics*/ if (argc!=2) { printf ("Filename not provided.\n"); return 1; } if((inFile=fopen(argv[1], "r"))==NULL) { printf("Can't open the file\n"); return 2; } /*obtain values for linked list*/ while (fgets(line, MAX_LINE, inFile)) { make = strtok(line, " "); yearStr = strtok(NULL, " "); stockStr = strtok(NULL, " "); year = atoi(yearStr); stock = atoi(stockStr); insertRecordInAscendingOrder(&headRecord,make, year, stock); } printf("The original list in ascending order: \n"); printList(headRecord); } /*use strcmp to compare two makes*/ int compareCars(Record *car1, Record *car2) { int compStrResult; compStrResult = strcmp(car1->make, car2->make); int compYearResult = 0; if(car1->year > car2->year) { compYearResult = 1; } else if(car1->year == car2->year) { compYearResult = 0; } else { compYearResult = -1; } if(compStrResult == 0 ) { if(compYearResult == 1) { return 1; } else if(compYearResult == -1) { return -1; } else { return compStrResult; } } else if(compStrResult == 1) { return 1; } else { return -1; } } int insertRecordInAscendingOrder(Record **head, char *make, int year, int stock) { Record *previous = *head; Record *newRecord = createRecord(make, year, stock); Record *current = *head; int compResult; if(*head == NULL) { *head = newRecord; printf("Head is null, list was empty\n"); printList(*head); return 1; } else if ( compareCars(newRecord, *head)==-1) { *head = newRecord; (*head)->next = current; printf("New record was less than the head, replacing\n"); printList(*head); return 1; } else { printf("standard case, searching and inserting\n"); previous = *head; while ( current != NULL &&(compareCars(newRecord, current)==1)) { printList(*head); previous = current; current = current->next; } printList(*head); previous->next = newRecord; previous->next->next = current; } return 1; } /*creates records from info passed in from main via insertRecordInAscendingOrder.*/ Record* createRecord(char *make, int year, int stock) { printf("CreateRecord\n"); Record *theRecord; int len; if(!make) { return NULL; } theRecord = malloc(sizeof(Record)); if(!theRecord) { printf("Unable to allocate memory for the structure.\n"); return NULL; } theRecord->year = year; theRecord->stock = stock; len = strlen(make); theRecord->make = malloc(len + 1); strncpy(theRecord->make, make, len); theRecord->make[len] = '\0'; theRecord->next=NULL; return theRecord; } /*prints list. lists print.*/ void printList(Record *head) { int i; int j = 50; Record *aRecord; aRecord = head; for(i = 0; i < j; i++) { printf("-"); } printf("\n"); printf("%20s%20s%10s\n", "Make", "Year", "Stock"); for(i = 0; i < j; i++) { printf("-"); } printf("\n"); while(aRecord != NULL) { printf("%20s%20d%10d\n", aRecord->make, aRecord->year, aRecord->stock); aRecord = aRecord->next; } printf("\n"); } The text file you'll need for a command line argument can be saved under any name you like; here are the contents you'll need: Ford 2012 15 Ford 2011 3 Ford 2010 5 Toyota 2011 7 Toyota 2012 20 Toyota 2009 2 Honda 2011 9 Honda 2012 3 Honda 2013 12 Chevrolet 2013 10 Chevrolet 2012 25 Thanks in advance for your help. I shall continue to plow away at it myself.

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• Why my shell program wont open the file got as argument in function "cat"

  - by anna karenina

  I included the code below, sorry to bother you with so much code. Argument parsing is ok, i checked it out with watches. I've put some printfs to check out where the problem may be and it seems that it wont open the file cat receives as argument. i called from shell like "cat -b file" #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #define TRUE 0 #define FALSE 1 void yes(int argc, char *argv[]); int cat(int argc, char *argv[]); //#include "cat.h" //#include "yes.h" //#include"tee.h" char buf[50],c[10], *p2,*p, *pch; int count; char *matrix[20]; void yes(int argc, char *argv[]) { int i; // if (argc >= 2 && *argv[1] == '-') // { //printf("ERROR!"); //} //if (argc == 1) // { while (1) if (puts("y") == EOF) { perror("yes"); exit(FALSE); } // } while (1) for (i = 1; i < argc; i++) if (fputs(argv[i], stdout) == EOF || putchar(i == argc - 1 ? '\n' : ' ') == EOF) { perror("yes"); exit(FALSE); } //exit(TRUE); } int main(int argc, char *argv[]) { //p=(char *)malloc(sizeof(char)*50); do { fprintf (stderr, "$ "); fgets (buf,50,stdin); p=buf; fprintf (stderr, "Comanda primita de la tastatura: "); fputs (buf, stderr); int i=0,j=0; //strcpy(p,buf); strcpy(c,"\0"); while (buf[i] == ' ') { i++; p++; } if (buf[i] == '#') fprintf (stderr, "Nici o comanda, ci e un comentariu!\n"); else { j=0; while (buf[i] != ' ' && buf[i] != '\n') { i++; j++; } strncpy (c,p,j); fprintf (stderr, "%s\n",c); if (strcmp (c,"yes") == 0) { p2 = p+j+1; pch = strtok (p2," "); count = 0; while (pch != NULL) { //printf ("%s\n",pch); matrix[count] = strdup(pch); pch = strtok (NULL, " "); count++; } yes(count, matrix); fprintf (stderr, "Aici se va executa comanda yes\n"); } else if (strcmp (c,"cat") == 0) { p2 = p+j+1; pch = strtok (p2," "); count = 0; while (pch != NULL) { //printf ("%s\n",pch); matrix[count] = strdup(pch); pch = strtok (NULL, " "); count++; } cat(count,matrix); fprintf (stderr, "Aici se va executa comanda cat \n"); } else if (strcmp (c,"tee") == 0) { //tee(); fprintf(stderr, "Aici se va executa comanda tee\n"); } fprintf (stderr, "Aici se va executa comanda basename\n"); strcpy(buf,"\0"); } } while (strcmp(c, "exit") != 0); fprintf (stderr, "Terminat corect!\n"); return 0; } int cat(int argc, char *argv[]) { int c ; opterr = 0 ; optind = 0 ; char number = 0; char squeeze = 0; char marker = 0; fprintf(stderr,"SALUT< SUNT IN FUNCTIZE>\n"); while ((c = getopt (argc, argv, "bnsE")) != -1) switch (c) { case 'b' : number = 1; break; case 'n' : number = 2; break; case 'm' : marker = 1; break; case 's' : squeeze = 1; break; case 'E' : marker = 1; break; } if (optind + 1 != argc) { fprintf (stderr, "\tWrong arguments!\n") ; return -1 ; } FILE * fd = fopen (argv[optind], "r"); printf("am deschis fisierul %s ",argv[optind]); if (fd == NULL) { printf("FISIER NULL asdasdasdasdasd"); return 1; } char line[1025]; int line_count = 1; while (!feof(fd)) { fgets(line, 1025, fd); printf("sunt in while :> %s",line); int len = strlen(line); if (line[len - 1] == '\n') { if(len - 2 >= 0) { if(line[len - 2] == '\r') { line[len - 2] = '\0'; len -= 2; } else { line[len - 1] = '\0'; len -= 1; } } else { line[len - 1] = '\0'; len -= 1; } } if (squeeze == 1 && len == 0) continue; if (number == 1) { fprintf (stdout, "%4d ", line_count); line_count++; } else if (number == 2) { if (len > 0) { fprintf (stdout, "%4d ", line_count); line_count++; } else fprintf (stdout, " "); } fprintf(stdout, "%s", line); if (marker == 1) fprintf(stdout, "$"); fprintf(stdout, "\n"); } fclose (fd); return 0 ; }

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• Implementing a robust async stream reader for a console

  - by Jon

  I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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• Probelm with String.split() in java

  - by Matt

  What I am trying to do is read a .java file, and pick out all of the identifiers and store them in a list. My problem is with the .split() method. If you run this code the way it is, you will get ArrayOutOfBounds, but if you change the delimiter from "." to anything else, the code works. But I need to lines parsed by "." so is there another way I could accomplish this? import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.*; public class MyHash { private static String[] reserved = new String[100]; private static List list = new LinkedList(); private static List list2 = new LinkedList(); public static void main (String args[]){ Hashtable hashtable = new Hashtable(997); makeReserved(); readFile(); String line; ListIterator itr = list.listIterator(); int listIndex = 0; while (listIndex < list.size()) { if (itr.hasNext()){ line = itr.next().toString(); //PROBLEM IS HERE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! String[] words = line.split("."); //CHANGE THIS AND IT WILL WORK System.out.println(words[0]); //TESTING TO SEE IF IT WORKED } listIndex++; } } public static void readFile() { String text; String[] words; BufferedReader in = null; try { in = new BufferedReader(new FileReader("MyHash.java")); //NAME OF INPUT FILE } catch (FileNotFoundException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } try { while ((text = in.readLine()) != null){ text = text.trim(); words = text.split("\\s+"); for (int i = 0; i < words.length; i++){ list.add(words[i]); } for (int j = 0; j < reserved.length; j++){ if (list.contains(reserved[j])){ list.remove(reserved[j]); } } } } catch (IOException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } try { in.close(); } catch (IOException ex) { Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, null, ex); } } public static int keyIt (int x) { int key = x % 997; return key; } public static int horner (String word){ int length = word.length(); char[] letters = new char[length]; for (int i = 0; i < length; i++){ letters[i]=word.charAt(i); } char[] alphabet = new char[26]; String abc = "abcdefghijklmnopqrstuvwxyz"; for (int i = 0; i < 26; i++){ alphabet[i]=abc.charAt(i); } int[] numbers = new int[length]; int place = 0; for (int i = 0; i < length; i++){ for (int j = 0; j < 26; j++){ if (alphabet[j]==letters[i]){ numbers[place]=j+1; place++; } } } int hornered = numbers[0] * 32; for (int i = 1; i < numbers.length; i++){ hornered += numbers[i]; if (i == numbers.length -1){ return hornered; } hornered = hornered % 997; hornered *= 32; } return hornered; } public static String[] makeReserved (){ reserved[0] = "abstract"; reserved[1] = "assert"; reserved[2] = "boolean"; reserved[3] = "break"; reserved[4] = "byte"; reserved[5] = "case"; reserved[6] = "catch"; reserved[7] = "char"; reserved[8] = "class"; reserved[9] = "const"; reserved[10] = "continue"; reserved[11] = "default"; reserved[12] = "do"; reserved[13] = "double"; reserved[14] = "else"; reserved[15] = "enum"; reserved[16] = "extends"; reserved[17] = "false"; reserved[18] = "final"; reserved[19] = "finally"; reserved[20] = "float"; reserved[21] = "for"; reserved[22] = "goto"; reserved[23] = "if"; reserved[24] = "implements"; reserved[25] = "import"; reserved[26] = "instanceof"; reserved[27] = "int"; reserved[28] = "interface"; reserved[29] = "long"; reserved[30] = "native"; reserved[31] = "new"; reserved[32] = "null"; reserved[33] = "package"; reserved[34] = "private"; reserved[35] = "protected"; reserved[36] = "public"; reserved[37] = "return"; reserved[38] = "short"; reserved[39] = "static"; reserved[40] = "strictfp"; reserved[41] = "super"; reserved[42] = "switch"; reserved[43] = "synchronize"; reserved[44] = "this"; reserved[45] = "throw"; reserved[46] = "throws"; reserved[47] = "trasient"; reserved[48] = "true"; reserved[49] = "try"; reserved[50] = "void"; reserved[51] = "volatile"; reserved[52] = "while"; reserved[53] = "="; reserved[54] = "=="; reserved[55] = "!="; reserved[56] = "+"; reserved[57] = "-"; reserved[58] = "*"; reserved[59] = "/"; reserved[60] = "{"; reserved[61] = "}"; return reserved; } }

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• How to convert this procedural programming to object-oriented programming?

  - by manus91

  I have a source code that is needed to be converted by creating classes, objects and methods. So far, I've just done by converting the initial main into a separate class. But I don't know what to do with constructor and which variables are supposed to be private. This is the code : import java.util.*; public class Card{ private static void shuffle(int[][] cards){ List<Integer> randoms = new ArrayList<Integer>(); Random randomizer = new Random(); for(int i = 0; i < 8;) { int r = randomizer.nextInt(8)+1; if(!randoms.contains(r)) { randoms.add(r); i++; } } List<Integer> clonedList = new ArrayList<Integer>(); clonedList.addAll(randoms); Collections.shuffle(clonedList); randoms.addAll(clonedList); Collections.shuffle(randoms); int i=0; for(int r=0; r < 4; r++){ for(int c=0; c < 4; c++){ cards[r][c] = randoms.get(i); i++; } } } public static void play() throws InterruptedException { int ans = 1; int preview; int r1,c1,r2,c2; int[][] cards = new int[4][4]; boolean[][] cardstatus = new boolean[4][4]; boolean gameover = false; int moves; Scanner input = new Scanner(System.in); do{ moves = 0; shuffle(cards); System.out.print("Enter the time(0 to 5) in seconds for the preview of the answer : "); preview = input.nextInt(); while((preview<0) || (preview>5)){ System.out.print("Invalid time!! Re-enter time(0 - 5) : "); preview = input.nextInt(); } preview = 1000*preview; System.out.println(" "); for (int i =0; i<4;i++){ for (int j=0;j<4;j++){ System.out.print(cards[i][j]); System.out.print(" "); } System.out.println(""); System.out.println(""); } Thread.sleep(preview); for(int b=0;b<25;b++){ System.out.println(" "); } for(int r=0;r<4;r++){ for(int c=0;c<4;c++){ System.out.print("*"); System.out.print(" "); cardstatus[r][c] = false; } System.out.println(""); System.out.println(" "); } System.out.println(""); do{ do{ System.out.print("Please insert the first card row : "); r1 = input.nextInt(); while((r1<1) || (r1>4)){ System.out.print("Invalid coordinate!! Re-enter first card row : "); r1 = input.nextInt(); } System.out.print("Please insert the first card column : "); c1 = input.nextInt(); while((c1<1) || (c1>4)){ System.out.print("Invalid coordinate!! Re-enter first card column : "); c1 = input.nextInt(); } if(cardstatus[r1-1][c1-1] == true){ System.out.println("The card is already flipped!! Select another card."); System.out.println(""); } }while(cardstatus[r1-1][c1-1] != false); do{ System.out.print("Please insert the second card row : "); r2 = input.nextInt(); while((r2<1) || (r2>4)){ System.out.print("Invalid coordinate!! Re-enter second card row : "); r2 = input.nextInt(); } System.out.print("Please insert the second card column : "); c2 = input.nextInt(); while((c2<1) || (c2>4)){ System.out.print("Invalid coordinate!! Re-enter second card column : "); c2 = input.nextInt(); } if(cardstatus[r2-1][c2-1] == true){ System.out.println("The card is already flipped!! Select another card."); } if((r1==r2)&&(c1==c2)){ System.out.println("You can't select the same card twice!!"); continue; } }while(cardstatus[r2-1][c2-1] != false); r1--; c1--; r2--; c2--; System.out.println(""); System.out.println(""); System.out.println(""); for(int r=0;r<4;r++){ for(int c=0;c<4;c++){ if((r==r1)&&(c==c1)){ System.out.print(cards[r][c]); System.out.print(" "); } else if((r==r2)&&(c==c2)){ System.out.print(cards[r][c]); System.out.print(" "); } else if(cardstatus[r][c] == true){ System.out.print(cards[r][c]); System.out.print(" "); } else{ System.out.print("*"); System.out.print(" "); } } System.out.println(" "); System.out.println(" "); } System.out.println(""); if(cards[r1][c1] == cards[r2][c2]){ System.out.println("Cards Matched!!"); cardstatus[r1][c1] = true; cardstatus[r2][c2] = true; } else{ System.out.println("No cards match!!"); } Thread.sleep(2000); for(int b=0;b<25;b++){ System.out.println(""); } for(int r=0;r<4;r++){ for(int c=0;c<4;c++){ if(cardstatus[r][c] == true){ System.out.print(cards[r][c]); System.out.print(" "); } else{ System.out.print("*"); System.out.print(" "); } } System.out.println(""); System.out.println(" "); } System.out.println(""); System.out.println(""); System.out.println(""); gameover = true; for(int r=0;r<4;r++){ for( int c=0;c<4;c++){ if(cardstatus[r][c]==false){ gameover = false; break; } } if(gameover==false){ break; } } moves++; }while(gameover != true); System.out.println("Congratulations, you won!!"); System.out.println("It required " + moves + " moves to finish it."); System.out.println(""); System.out.print("Would you like to play again? (1=Yes / 0=No) : "); ans = input.nextInt(); }while(ans == 1); } } The main class is: import java.util.*; public class PlayCard{ public static void main(String[] args) throws InterruptedException{ Card game = new Card(); game.play(); } } Should I simplify the Card class by creating other classes? Through this code, my javadoc has no constructtor. So i need help on this!

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• File using .net sockets, transferring problem

  - by Sergei

  I have a client and server, client sending file to server. When i transfer files on my computer(in local) everything is ok(try to sen file over 700mb). When i try to sent file use Internet to my friend in the end of sending appears error on server "Input string is not in correct format".This error appears in this expression fSize = Convert::ToUInt64(tokenes[0]); - and i don't mind wht it's appear. File should be transfered and wait other transferring ps: sorry for too much code, but i want to find solution private: void CreateServer() { try{ IPAddress ^ipAddres = IPAddress::Parse(ipAdress); listener = gcnew System::Net::Sockets::TcpListener(ipAddres, port); listener->Start(); clientsocket =listener->AcceptSocket(); bool keepalive = true; array<wchar_t,1> ^split = gcnew array<wchar_t>(1){ '\0' }; array<wchar_t,1> ^split2 = gcnew array<wchar_t>(1){ '|' }; statusBar1->Text = "Connected" ; // while (keepalive) { array<Byte>^ size1 = gcnew array<Byte>(1024); clientsocket->Receive(size1); System::String ^notSplited = System::Text::Encoding::GetEncoding(1251)->GetString(size1); array<String^> ^ tokenes = notSplited->Split(split2); System::String ^fileName = tokenes[1]->ToString(); statusBar1->Text = "Receiving file" ; unsigned long fSize = 0; //IN THIS EXPRESSIN APPEARS ERROR fSize = Convert::ToUInt64(tokenes[0]); if (!Directory::Exists("Received")) Directory::CreateDirectory("Received"); System::String ^path = "Received\\"+ fileName; while (File::Exists(path)) { int dotPos = path->LastIndexOf('.'); if (dotPos == -1) { path += "[1]"; } else { path = path->Insert(dotPos, "[1]"); } } FileStream ^fs = gcnew FileStream(path, FileMode::CreateNew, FileAccess::Write); BinaryWriter ^f = gcnew BinaryWriter(fs); //bytes received unsigned long processed = 0; pBarFilesTr->Visible = true; pBarFilesTr->Minimum = 0; pBarFilesTr->Maximum = (int)fSize; // Set the initial value of the ProgressBar. pBarFilesTr->Value = 0; pBarFilesTr->Step = 1024; //loop for receive file array<Byte>^ buffer = gcnew array<Byte>(1024); while (processed < fSize) { if ((fSize - processed) < 1024) { int bytes ; array<Byte>^ buf = gcnew array<Byte>(1024); bytes = clientsocket->Receive(buf); if (bytes != 0) { f->Write(buf, 0, bytes); processed = processed + (unsigned long)bytes; pBarFilesTr->PerformStep(); } break; } else { int bytes = clientsocket->Receive(buffer); if (bytes != 0) { f->Write(buffer, 0, 1024); processed = processed + 1024; pBarFilesTr->PerformStep(); } else break; } } statusBar1->Text = "File was received" ; array<Byte>^ buf = gcnew array<Byte>(1); clientsocket->Send(buf,buf->Length,SocketFlags::None); f->Close(); fs->Close(); SystemSounds::Beep->Play(); } }catch(System::Net::Sockets::SocketException ^es) { MessageBox::Show(es->ToString()); } catch(System::Exception ^es) { MessageBox::Show(es->ToString()); } } private: void CreateClient() { clientsock = gcnew System::Net::Sockets::TcpClient(ipAdress, port); ns = clientsock->GetStream(); sr = gcnew StreamReader(ns); statusBar1->Text = "Connected" ; } private:void Send() { try{ OpenFileDialog ^openFileDialog1 = gcnew OpenFileDialog(); System::String ^filePath = ""; System::String ^fileName = ""; //file choose dialog if (openFileDialog1->ShowDialog() == System::Windows::Forms::DialogResult::OK) { filePath = openFileDialog1->FileName; fileName = openFileDialog1->SafeFileName; } else { MessageBox::Show("You must select a file", "Error", MessageBoxButtons::OK, MessageBoxIcon::Exclamation); return; } statusBar1->Text = "Sending file" ; NetworkStream ^writerStream = clientsock->GetStream(); System::Runtime::Serialization::Formatters::Binary::BinaryFormatter ^format = gcnew System::Runtime::Serialization::Formatters::Binary::BinaryFormatter(); array<Byte>^ buffer = gcnew array<Byte>(1024); FileStream ^fs = gcnew FileStream(filePath, FileMode::Open); BinaryReader ^br = gcnew BinaryReader(fs); //file size unsigned long fSize = (unsigned long)fs->Length; //transfer file size + name bFSize = Encoding::GetEncoding(1251)->GetBytes(Convert::ToString(fs->Length+"|"+fileName+"|")); writerStream->Write(bFSize, 0, bFSize->Length); //status bar pBarFilesTr->Visible = true; pBarFilesTr->Minimum = 0; pBarFilesTr->Maximum = (int)fSize; pBarFilesTr->Value = 0; // Set the initial value of the ProgressBar. pBarFilesTr->Step = 1024; //bytes transfered unsigned long processed = 0; int bytes = 1024; //loop for transfer while (processed < fSize) { if ((fSize - processed) < 1024) { bytes = (int)(fSize - processed); array<Byte>^ buf = gcnew array<Byte>(bytes); br->Read(buf, 0, bytes); writerStream->Write(buf, 0, buf->Length); pBarFilesTr->PerformStep(); processed = processed + (unsigned long)bytes; break; } else { br->Read(buffer, 0, 1024); writerStream->Write(buffer, 0, buffer->Length); pBarFilesTr->PerformStep(); processed = processed + 1024; } } array<Byte>^ bufsss = gcnew array<Byte>(100); writerStream->Read(bufsss,0,bufsss->Length); statusBar1->Text = "File was sent" ; btnSend->Enabled = true; fs->Close(); br->Close(); SystemSounds::Beep->Play(); newThread->Abort(); } catch(System::Net::Sockets::SocketException ^es) { MessageBox::Show(es->ToString()); } } UPDATE: ok, i can add checking if clientsocket->Receive(size1); equal zero, but why he begin receiving data again , in the ending of receiving. UPDATE:After adding this checking problem remains. AND WIN RAR SAY TO OPENING ARCHIVE - unexpected end of file! UPDATE:http://img153.imageshack.us/img153/3760/erorr.gif I think it continue receiving some bytes from client(that remains in the stream), but why existes cicle while (processed < fSize)

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• Uploading multiple files using Spring MVC 3.0.2 after HiddenHttpMethodFilter has been enabled

  - by Tiny

  I'm using Spring version 3.0.2. I need to upload multiple files using the multiple="multiple" attribute of a file browser such as, <input type="file" id="myFile" name="myFile" multiple="multiple"/> (and not using multiple file browsers something like the one stated by this answer, it indeed works I tried). Although no versions of Internet Explorer supports this approach unless an appropriate jQuery plugin/widget is used, I don't care about it right now (since most other browsers support this). This works fine with commons fileupload but in addition to using RequestMethod.POST and RequestMethod.GET methods, I also want to use other request methods supported and suggested by Spring like RequestMethod.PUT and RequestMethod.DELETE in their own appropriate places. For this to be so, I have configured Spring with HiddenHttpMethodFilter which goes fine as this question indicates. but it can upload only one file at a time even though multiple files in the file browser are chosen. In the Spring controller class, a method is mapped as follows. @RequestMapping(method={RequestMethod.POST}, value={"admin_side/Temp"}) public String onSubmit(@RequestParam("myFile") List<MultipartFile> files, @ModelAttribute("tempBean") TempBean tempBean, BindingResult error, Map model, HttpServletRequest request, HttpServletResponse response) throws IOException, FileUploadException { for(MultipartFile file:files) { System.out.println(file.getOriginalFilename()); } } Even with the request parameter @RequestParam("myFile") List<MultipartFile> files which is a List of type MultipartFile (it can always have only one file at a time). I could find a strategy which is likely to work with multiple files on this blog. I have gone through it carefully. The solution below the section SOLUTION 2 – USE THE RAW REQUEST says, If however the client insists on using the same form input name such as ‘files[]‘ or ‘files’ and then populating that name with multiple files then a small hack is necessary as follows. As noted above Spring 2.5 throws an exception if it detects the same form input name of type file more than once. CommonsFileUploadSupport – the class which throws that exception is not final and the method which throws that exception is protected so using the wonders of inheritance and subclassing one can simply fix/modify the logic a little bit as follows. The change I’ve made is literally one word representing one method invocation which enables us to have multiple files incoming under the same form input name. It attempts to override the method protected MultipartParsingResult parseFileItems(List fileItems, String encoding) {} of the abstract class CommonsFileUploadSupport by extending the class CommonsMultipartResolver such as, package multipartResolver; import java.io.UnsupportedEncodingException; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import javax.servlet.ServletContext; import org.apache.commons.fileupload.FileItem; import org.springframework.util.StringUtils; import org.springframework.web.multipart.MultipartException; import org.springframework.web.multipart.MultipartFile; import org.springframework.web.multipart.commons.CommonsMultipartFile; import org.springframework.web.multipart.commons.CommonsMultipartResolver; final public class MultiCommonsMultipartResolver extends CommonsMultipartResolver { public MultiCommonsMultipartResolver() { } public MultiCommonsMultipartResolver(ServletContext servletContext) { super(servletContext); } @Override @SuppressWarnings("unchecked") protected MultipartParsingResult parseFileItems(List fileItems, String encoding) { Map<String, MultipartFile> multipartFiles = new HashMap<String, MultipartFile>(); Map multipartParameters = new HashMap(); // Extract multipart files and multipart parameters. for (Iterator it = fileItems.iterator(); it.hasNext();) { FileItem fileItem = (FileItem) it.next(); if (fileItem.isFormField()) { String value = null; if (encoding != null) { try { value = fileItem.getString(encoding); } catch (UnsupportedEncodingException ex) { if (logger.isWarnEnabled()) { logger.warn("Could not decode multipart item '" + fileItem.getFieldName() + "' with encoding '" + encoding + "': using platform default"); } value = fileItem.getString(); } } else { value = fileItem.getString(); } String[] curParam = (String[]) multipartParameters.get(fileItem.getFieldName()); if (curParam == null) { // simple form field multipartParameters.put(fileItem.getFieldName(), new String[] { value }); } else { // array of simple form fields String[] newParam = StringUtils.addStringToArray(curParam, value); multipartParameters.put(fileItem.getFieldName(), newParam); } } else { // multipart file field CommonsMultipartFile file = new CommonsMultipartFile(fileItem); if (multipartFiles.put(fileItem.getName(), file) != null) { throw new MultipartException("Multiple files for field name [" + file.getName() + "] found - not supported by MultipartResolver"); } if (logger.isDebugEnabled()) { logger.debug("Found multipart file [" + file.getName() + "] of size " + file.getSize() + " bytes with original filename [" + file.getOriginalFilename() + "], stored " + file.getStorageDescription()); } } } return new MultipartParsingResult(multipartFiles, multipartParameters); } } What happens is that the last line in the method parseFileItems() (the return statement) i.e. return new MultipartParsingResult(multipartFiles, multipartParameters); causes a compile-time error because the first parameter multipartFiles is a type of Map implemented by HashMap but in reality, it requires a parameter of type MultiValueMap<String, MultipartFile> It is a constructor of a static class inside the abstract class CommonsFileUploadSupport, public abstract class CommonsFileUploadSupport { protected static class MultipartParsingResult { public MultipartParsingResult(MultiValueMap<String, MultipartFile> mpFiles, Map<String, String[]> mpParams) { } } } The reason might be - this solution is about the Spring version 2.5 and I'm using the Spring version 3.0.2 which might be inappropriate for this version. I however tried to replace the Map with MultiValueMap in various ways such as the one shown in the following segment of code, MultiValueMap<String, MultipartFile>mul=new LinkedMultiValueMap<String, MultipartFile>(); for(Entry<String, MultipartFile>entry:multipartFiles.entrySet()) { mul.add(entry.getKey(), entry.getValue()); } return new MultipartParsingResult(mul, multipartParameters); but no success. I'm not sure how to replace Map with MultiValueMap and even doing so could work either. After doing this, the browser shows the Http response, HTTP Status 400 - type Status report message description The request sent by the client was syntactically incorrect (). Apache Tomcat/6.0.26 I have tried to shorten the question as possible as I could and I haven't included unnecessary code. How could be made it possible to upload multiple files after Spring has been configured with HiddenHttpMethodFilter? That blog indicates that It is a long standing, high priority bug. If there is no solution regarding the version 3.0.2 (3 or higher) then I have to disable Spring support forever and continue to use commons-fileupolad as suggested by the third solution on that blog omitting the PUT, DELETE and other request methods forever. Just curiously waiting for a solution and/or suggestion. Very little changes to the code in the parseFileItems() method inside the class MultiCommonsMultipartResolver might make it to upload multiple files but I couldn't succeed in my attempts (again with the Spring version 3.0.2 (3 or higher)).

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• Script to create a table and fields in SQL wont work

  - by Jacksta

  Warning this is lenghty! attack if you knowledagble. well at least more then a newb beginner like me. This script uses three files as detailed below. It is suppoed to create the database and fields from the form input. It gets to the end and shows my_contacts has been created!. But when i go into phpMyadmin the table has not been created. I have a file named show_createtable.html which is used to create a table in MySQL <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Untitled Document</title> </head> <body> <h1>Step 1: Name and Number</h1> <form method="post" action="do_showfielddef.php" /> <p><strong>Table Name:</strong><br /> <input type="text" name="table_name" size="30" /></p> <p><strong>Number of fields:</strong><br /> <input type="text" name="num_fields" size="30" /></p> <p><input type="submit" name="submit" value="go to step2" /></p> </form> </body> </html> This Form Posts to do_showfielddef.php <?php //validate important input if ((!$_POST[table_name]) || (!$_POST[num_fields])) { header( "location: show_createtable.html"); exit; } //begin creating form for display $form_block = " <form action=\"do_createtable.php\" method=\"post\"> <input name=\"table_name\" type=\"hidden\" value=\"$_POST[table_name]\"> <table cellspacing=\"5\" cellpadding=\"5\"> <tr> <th>Field Name</th><th>Field Type</th><th>Table Length</th><th>Primary Key?</th><th>Auto-Increment?</th> </tr>"; //count from 0 until you reach the number fo fields for ($i = 0; $i <$_POST[num_fields]; $i++) { $form_block .=" <tr> <td align=center><input type=\"texr\" name=\"field name[]\" size=\"30\"></td> <td align=center> <select name=\"field_type[]\"> <option value=\"char\">char</option> <option value=\"date\">date</option> <option value=\"float\">float</option> <option value=\"int\">int</option> <option value=\"text\">text</option> <option value=\"varchar\">varchar</option> </select> </td> <td align=center><input type=\"text\" name=\"field_length[]\" size=\"5\"></td> <td aligh=center><input type=\"checkbox\" name=\"primary[]\" value=\"Y\"></td> <td aligh=center><input type=\"checkbox\" name=\"auto_increment[]\" value=\"Y\"></td> </tr>"; } //finish up the form $form_block .= " <tr> <td align=center colspan=3><input type =\"submit\" value=\"create table\"> </td> </tr> </table> </form>"; ?> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Create a database table: Step 2</title> </head> <body> <h1>defnie fields for <? echo "$_POST[table_name]"; ?> </h1> <? echo "$form_block"; ?> </body> </html> Which in turn creates the table and fields with this file do_showfielddef.php //connect to database $connection = @mysql_connect("localhost", "user", "pass") or die(mysql_error()); $db = @mysql_select_db($db_name, $connection) or die(mysql_error()); //start creating the SQL statement $sql = "CREATE TABLE $_POST[table_name]("; //continue the SQL statement for each new field for ($i = 0; $i < count($_POST[field_name]); $i++) { $sql .= $_POST[field_name][$i]." ".$_POST[field_type][$i]; if ($_POST[auto_increment][$i] =="Y") { $additional = "NOT NULL auto_increment"; } else { $additional = ""; } if ($_POST[primary][$i] =="Y") { $additional .= ", primary key (".$_POST[field_name][$i].")"; } else { $additional = ""; } if ($_POST[field_length][$i] !="") { $sql .= " (".$_POST[field_length][$i].") $additional ,"; } else { $sql .=" $additional ,"; } } //clean up the end of the string $sql = substr($sql, 0, -1); $sql .= ")"; //execute the query $result = mysql_query($sql, $connection) or die(mysql_error()); //get a giid message for display upon success if ($result) { $msg = "<p>" .$_POST[table_name]." has been created!</p>"; } ?> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Create A Database Table: Step 3</title> </head> <body> <h1>Adding table to <? echo "$db_name"; ?>...</h1> <? echo "$msg"; ?> </body> </html>

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• questions regarding the use of A* with the 15-square puzzle

  - by Cheeso

  I'm trying to build an A* solver for a 15-square puzzle. The goal is to re-arrange the tiles so that they appear in their natural positions. You can only slide one tile at a time. Each possible state of the puzzle is a node in the search graph. For the h(x) function, I am using an aggregate sum, across all tiles, of the tile's dislocation from the goal state. In the above image, the 5 is at location 0,0, and it belongs at location 1,0, therefore it contributes 1 to the h(x) function. The next tile is the 11, located at 0,1, and belongs at 2,2, therefore it contributes 3 to h(x). And so on. EDIT: I now understand this is what they call "Manhattan distance", or "taxicab distance". I have been using a step count for g(x). In my implementation, for any node in the state graph, g is just +1 from the prior node's g. To find successive nodes, I just examine where I can possibly move the "hole" in the puzzle. There are 3 neighbors for the puzzle state (aka node) that is displayed: the hole can move north, west, or east. My A* search sometimes converges to a solution in 20s, sometimes 180s, and sometimes doesn't converge at all (waited 10 mins or more). I think h is reasonable. I'm wondering if I've modeled g properly. In other words, is it possible that my A* function is reaching a node in the graph via a path that is not the shortest path? Maybe have I not waited long enough? Maybe 10 minutes is not long enough? For a fully random arrangement, (assuming no parity problems), What is the average number of permutations an A* solution will examine? (please show the math) I'm going to look for logic errors in my code, but in the meantime, Any tips? (ps: it's done in Javascript). Also, no, this isn't CompSci homework. It's just a personal exploration thing. I'm just trying to learn Javascript. EDIT: I've found that the run-time is highly depend upon the heuristic. I saw the 10x factor applied to the heuristic from the article someone mentioned, and it made me wonder - why 10x? Why linear? Because this is done in javascript, I could modify the code to dynamically update an html table with the node currently being considered. This allowd me to peek at the algorithm as it was progressing. With a regular taxicab distance heuristic, I watched as it failed to converge. There were 5's and 12's in the top row, and they kept hanging around. I'd see 1,2,3,4 creep into the top row, but then they'd drop out, and other numbers would move up there. What I was hoping to see was 1,2,3,4 sort of creeping up to the top, and then staying there. I thought to myself - this is not the way I solve this personally. Doing this manually, I solve the top row, then the 2ne row, then the 3rd and 4th rows sort of concurrently. So I tweaked the h(x) function to more heavily weight the higher rows and the "lefter" columns. The result was that the A* converged much more quickly. It now runs in 3 minutes instead of "indefinitely". With the "peek" I talked about, I can see the smaller numbers creep up to the higher rows and stay there. Not only does this seem like the right thing, it runs much faster. I'm in the process of trying a bunch of variations. It seems pretty clear that A* runtime is very sensitive to the heuristic. Currently the best heuristic I've found uses the summation of dislocation * ((4-i) + (4-j)) where i and j are the row and column, and dislocation is the taxicab distance. One interesting part of the result I got: with a particular heuristic I find a path very quickly, but it is obviously not the shortest path. I think this is because I am weighting the heuristic. In one case I got a path of 178 steps in 10s. My own manual effort produce a solution in 87 moves. (much more than 10s). More investigation warranted. So the result is I am seeing it converge must faster, and the path is definitely not the shortest. I have to think about this more. Code: var stop = false; function Astar(start, goal, callback) { // start and goal are nodes in the graph, represented by // an array of 16 ints. The goal is: [1,2,3,...14,15,0] // Zero represents the hole. // callback is a method to call when finished. This runs a long time, // therefore we need to use setTimeout() to break it up, to avoid // the browser warning like "Stop running this script?" // g is the actual distance traveled from initial node to current node. // h is the heuristic estimate of distance from current to goal. stop = false; start.g = start.dontgo = 0; // calcHeuristic inserts an .h member into the array calcHeuristicDistance(start); // start the stack with one element var closed = []; // set of nodes already evaluated. var open = [ start ]; // set of nodes to evaluate (start with initial node) var iteration = function() { if (open.length==0) { // no more nodes. Fail. callback(null); return; } var current = open.shift(); // get highest priority node // update the browser with a table representation of the // node being evaluated $("#solution").html(stateToString(current)); // check solution returns true if current == goal if (checkSolution(current,goal)) { // reconstructPath just records the position of the hole // through each node var path= reconstructPath(start,current); callback(path); return; } closed.push(current); // get the set of neighbors. This is 3 or fewer nodes. // (nextStates is optimized to NOT turn directly back on itself) var neighbors = nextStates(current, goal); for (var i=0; i<neighbors.length; i++) { var n = neighbors[i]; // skip this one if we've already visited it if (closed.containsNode(n)) continue; // .g, .h, and .previous get assigned implicitly when // calculating neighbors. n.g is nothing more than // current.g+1 ; // add to the open list if (!open.containsNode(n)) { // slot into the list, in priority order (minimum f first) open.priorityPush(n); n.previous = current; } } if (stop) { callback(null); return; } setTimeout(iteration, 1); }; // kick off the first iteration iteration(); return null; }

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• Logic error for Gauss elimination

  - by iwanttoprogram

  Logic error problem with the Gaussian Elimination code...This code was from my Numerical Methods text in 1990's. The code is typed in from the book- not producing correct output... Sample Run: SOLUTION OF SIMULTANEOUS LINEAR EQUATIONS USING GAUSSIAN ELIMINATION This program uses Gaussian Elimination to solve the system Ax = B, where A is the matrix of known coefficients, B is the vector of known constants and x is the column matrix of the unknowns. Number of equations: 3 Enter elements of matrix [A] A(1,1) = 0 A(1,2) = -6 A(1,3) = 9 A(2,1) = 7 A(2,2) = 0 A(2,3) = -5 A(3,1) = 5 A(3,2) = -8 A(3,3) = 6 Enter elements of [b] vector B(1) = -3 B(2) = 3 B(3) = -4 SOLUTION OF SIMULTANEOUS LINEAR EQUATIONS The solution is x(1) = 0.000000 x(2) = -1.#IND00 x(3) = -1.#IND00 Determinant = -1.#IND00 Press any key to continue . . . The code as copied from the text... //Modified Code from C Numerical Methods Text- June 2009 #include <stdio.h> #include <math.h> #define MAXSIZE 20 //function prototype int gauss (double a[][MAXSIZE], double b[], int n, double *det); int main(void) { double a[MAXSIZE][MAXSIZE], b[MAXSIZE], det; int i, j, n, retval; printf("\n \t SOLUTION OF SIMULTANEOUS LINEAR EQUATIONS"); printf("\n \t USING GAUSSIAN ELIMINATION \n"); printf("\n This program uses Gaussian Elimination to solve the"); printf("\n system Ax = B, where A is the matrix of known"); printf("\n coefficients, B is the vector of known constants"); printf("\n and x is the column matrix of the unknowns."); //get number of equations n = 0; while(n <= 0 || n > MAXSIZE) { printf("\n Number of equations: "); scanf ("%d", &n); } //read matrix A printf("\n Enter elements of matrix [A]\n"); for (i = 0; i < n; i++) for (j = 0; j < n; j++) { printf(" A(%d,%d) = ", i + 1, j + 1); scanf("%lf", &a[i][j]); } //read {B} vector printf("\n Enter elements of [b] vector\n"); for (i = 0; i < n; i++) { printf(" B(%d) = ", i + 1); scanf("%lf", &b[i]); } //call Gauss elimination function retval = gauss(a, b, n, &det); //print results if (retval == 0) { printf("\n\t SOLUTION OF SIMULTANEOUS LINEAR EQUATIONS\n"); printf("\n\t The solution is"); for (i = 0; i < n; i++) printf("\n \t x(%d) = %lf", i + 1, b[i]); printf("\n \t Determinant = %lf \n", det); } else printf("\n \t SINGULAR MATRIX \n"); return 0; } /* Solves the system of equations [A]{x} = {B} using */ /* the Gaussian elimination method with partial pivoting. */ /* Parameters: */ /* n - number of equations */ /* a[n][n] - coefficient matrix */ /* b[n] - right-hand side vector */ /* *det - determinant of [A] */ int gauss (double a[][MAXSIZE], double b[], int n, double *det) { double tol, temp, mult; int npivot, i, j, l, k, flag; //initialization *det = 1.0; tol = 1e-30; //initial tolerance value npivot = 0; //mult = 0; //forward elimination for (k = 0; k < n; k++) { //search for max coefficient in pivot row- a[k][k] pivot element for (i = k + 1; i < n; i++) { if (fabs(a[i][k]) > fabs(a[k][k])) { //interchange row with maxium element with pivot row npivot++; for (l = 0; l < n; l++) { temp = a[i][l]; a[i][l] = a[k][l]; a[k][l] = temp; } temp = b[i]; b[i] = b[k]; b[k] = temp; } } //test for singularity if (fabs(a[k][k]) < tol) { //matrix is singular- terminate flag = 1; return flag; } //compute determinant- the product of the pivot elements *det = *det * a[k][k]; //eliminate the coefficients of X(I) for (i = k; i < n; i++) { mult = a[i][k] / a[k][k]; b[i] = b[i] - b[k] * mult; //compute constants for (j = k; j < n; j++) //compute coefficients a[i][j] = a[i][j] - a[k][j] * mult; } } //adjust the sign of the determinant if(npivot % 2 == 1) *det = *det * (-1.0); //backsubstitution b[n] = b[n] / a[n][n]; for(i = n - 1; i > 1; i--) { for(j = n; j > i + 1; j--) b[i] = b[i] - a[i][j] * b[j]; b[i] = b[i] / a[i - 1][i]; } flag = 0; return flag; } The solution should be: 1.058824, 1.823529, 0.882353 with det as -102.000000 Any insight is appreciated...

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• C socket programming: select() is returning 0 despite messages sent from server

  - by Fantastic Fourier

  Hey all, I'm using select() to recv() messages from server, using TCP/IP. When I send() messages from the server, it returns a reasonable number of bytes, saying it's sent successful. And it does get to the client successfully when I use while loop to just recv(). Everything is fine and dandy. while(1) recv() // obviously pseudocode However, when I try to use select(), select() returns 0 from timeout (which is set to 1 second) and for the life of me I cannot figure out why it doesn't see the messages sent from the server. I should also mention that when the server disconnects, select() doesn't see that either, where as if I were to use recv(), it would return 0 to indicate that the connection using the socket has been closed. Any inputs or thoughts are deeply appreciated. #include <arpa/inet.h> #include <errno.h> #include <fcntl.h> #include <netdb.h> #include <netinet/in.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <strings.h> #include <sys/select.h> #include <sys/socket.h> #include <sys/time.h> #include <sys/types.h> #include <time.h> #include <unistd.h> #define SERVER_PORT 10000 #define MAX_CONNECTION 20 #define MAX_MSG 50 struct client { char c_name[MAX_MSG]; char g_name[MAX_MSG]; int csock; int host; // 0 = not host of a multicast group struct sockaddr_in client_address; struct client * next_host; struct client * next_client; }; struct fd_info { char c_name[MAX_MSG]; int socks_inuse[MAX_CONNECTION]; int sock_fd, max_fd; int exit; struct client * c_sys; struct sockaddr_in c_address[MAX_CONNECTION]; struct sockaddr_in server_address; struct sockaddr_in client_address; fd_set read_set; }; struct message { char c_name[MAX_MSG]; char g_name[MAX_MSG]; char _command[3][MAX_MSG]; char _payload[MAX_MSG]; struct sockaddr_in client_address; struct client peer; }; int main(int argc, char * argv[]) { char * host; char * temp; int i, sockfd; int msg_len, rv, ready; int connection, management, socketread; int sockfds[MAX_CONNECTION]; // for three threads that handle new connections, user inputs and select() for sockets pthread_t connection_handler, manager, socket_reader; struct sockaddr_in server_address, client_address; struct hostent * hserver, cserver; struct timeval timeout; struct message msg; struct fd_info info; info.exit = 0; // exit information: if exit = 1, threads quit info.c_sys = NULL; // looking up from the host database if (argc == 3) { host = argv[1]; // server address strncpy(info.c_name, argv[2], strlen(argv[2])); // client name } else { printf("plz read the manual, kthxbai\n"); exit(1); } printf("host is %s and hp is %p\n", host, hserver); hserver = gethostbyname(host); if (hserver) { printf("host found: %s\n", hserver->h_name ); } else { printf("host not found\n"); exit(1); } // setting up address and port structure information on serverside bzero((char * ) &server_address, sizeof(server_address)); // copy zeroes into string server_address.sin_family = AF_INET; memcpy(&server_address.sin_addr, hserver->h_addr, hserver->h_length); server_address.sin_port = htons(SERVER_PORT); bzero((char * ) &client_address, sizeof(client_address)); // copy zeroes into string client_address.sin_family = AF_INET; client_address.sin_addr.s_addr = htonl(INADDR_ANY); client_address.sin_port = htons(SERVER_PORT); // opening up socket sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd < 0) exit(1); else { printf("socket is opened: %i \n", sockfd); info.sock_fd = sockfd; } // sets up time out option for the bound socket timeout.tv_sec = 1; // seconds timeout.tv_usec = 0; // micro seconds ( 0.5 seconds) setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timeval)); // binding socket to a port rv = bind(sockfd, (struct sockaddr *) &client_address, sizeof(client_address)); if (rv < 0) { printf("MAIN: ERROR bind() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("socket is bound\n"); printf("MAIN: %li \n", client_address.sin_addr.s_addr); // connecting rv = connect(sockfd, (struct sockaddr *) &server_address, sizeof(server_address)); info.server_address = server_address; info.client_address = client_address; info.sock_fd = sockfd; info.max_fd = sockfd; printf("rv = %i\n", rv); if (rv < 0) { printf("MAIN: ERROR connect() %i: %s\n", errno, strerror(errno)); exit(1); } else printf("connected\n"); fd_set readset; FD_ZERO(&readset); FD_ZERO(&info.read_set); FD_SET(info.sock_fd, &info.read_set); while(1) { readset = info.read_set; printf("MAIN: %i \n", readset); ready = select((info.max_fd)+1, &readset, NULL, NULL, &timeout); if(ready == -1) { sleep(2); printf("TEST: MAIN: ready = -1. %s \n", strerror(errno)); } else if (ready == 0) { sleep(2); printf("TEST: MAIN: ready = 0. %s \n", strerror(errno)); } else if (ready > 0) { printf("TEST: MAIN: ready = %i. %s at socket %i \n", ready, strerror(errno), i); for(i = 0; i < ((info.max_fd)+1); i++) { if(FD_ISSET(i, &readset)) { rv = recv(sockfd, &msg, 500, 0); if(rv < 0) continue; else if(rv > 0) printf("MAIN: TEST: %s %s \n", msg._command[0], msg._payload); else if (rv == 0) { sleep(3); printf("MAIN: TEST: SOCKET CLOSEDDDDDD \n"); } FD_CLR(i, &readset); } } } info.read_set = readset; } // close connection close(sockfd); printf("socket closed. BYE! \n"); return(0); }

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• How Should I Generate Trade Statistics For CouchDB/Rails3 Application?

  - by James

  My Problem: I am trying to developing a web application for currency traders. The application allows traders to enter or upload information about their trades and I want to calculate a wide variety of statistics based on what the user entered. Now, normally I would use a relational database for this, but I have two requirements that don't fit well with a relational database so I am attempting to use couchdb. Those two problems are: 1) Primarily, I have a companion desktop application that users will be able to work with and replicate to the site using couchdb's awesome replication feature and 2) I would like to allow users to be able to define their own custom things to track about trades and generate results based off of what they enter. The schema less nature of couch seems perfect here, but it may end up being harder than it sounds. (I already know couch requires you to define views in advance and such so I was just planning on sticking all the custom attributes in an array and then emitting the array in the view and further processing from there.) What I Am Doing: Right now I am just emitting each trade in couch keyed by each user's system and querying with the key of the system to get an array of trades per system. Simple. I am not using a reduce function currently to calculate any stats because I couldn't figure out how to get everything I need without getting a reduce overflow error. Here is an example of rows that are getting emitted from couch: {"total_rows":134,"offset":0,"rows":[ {"id":"5b1dcd47221e160d8721feee4ccc64be", "key":["80e40ba2fa43589d57ec3f1d19db41e6","2010/05/14 04:32:37 +0000"], null, "doc":{ "_id":"5b1dcd47221e160d8721feee4ccc64be", "_rev":"1-bc9fe763e2637694df47d6f5efb58e5b", "couchrest-type":"Trade", "system":"80e40ba2fa43589d57ec3f1d19db41e6", "pair":"EUR/USD", "direction":"Buy", "entry":12600, "exit":12700, "stop_loss":12500, "profit_target":12700, "status":"Closed", "slug":"101332132375", "custom_tracking": [{"name":"signal", "value":"Pin Bar"}] "updated_at":"2010/05/14 04:32:37 +0000", "created_at":"2010/05/14 04:32:37 +0000", "result":100}} ]} In my rails 3 controller I am basically just populating an array of trades such as the one above and then extracting out the relevant data into smaller arrays that I can compute my statistics on. Here is my show action for the page that I want to display the stats and all the trades: def show @trades = Trade.by_system(:startkey => [@system.id], :endkey => [@system.id, Time.now ]) @trades.each do |trade| if trade.result > 0 @winning_trades << trade.result elsif trade.result < 0 @losing_trades << trade.result else @breakeven_trades << trade.result end if trade.direction == "Buy" @long_trades << trade.result else @short_trades << trade.result end if trade["custom_tracking"] != nil @custom_tracking << {"result" => trade.result, "variables" => trade["custom_tracking"]} end end end I am omitting some other stuff that is going on, but that is the gist of what I am doing. Then I am calculating stuff in the view layer to produce some results: <% winning_long_trades = @long_trades.reject {|trade| trade <= 0 } %> <% winning_short_trades = @short_trades.reject {|trade| trade <= 0 } %> <ul> <li>Total Trades: <%= @trades.count %></li> <li>Winners: <%= @winning_trades.size %></li> <li>Biggest Winner (Pips): <%= @winning_trades.max %></li> <li>Average Win(Pips): <%= @winning_trades.sum/@winning_trades.size %></li> <li>Losers: <%= @losing_trades.size %></li> <li>Biggest Loser (Pips): <%= @losing_trades.min %></li> <li>Average Loss(Pips): <%= @losing_trades.sum/@losing_trades.size %></li> <li>Breakeven Trades: <%= @breakeven_trades.size %></li> <li>Long Trades: <%= @long_trades.size %></li> <li>Winning Long Trades: <%= winning_long_trades.size %></li> <li>Short Trades: <%= @short_trades.size %></li> <li>Winning Short Trades: <%= winning_short_trades.size %></li> <li>Total Pips: <%= @winning_trades.sum + @losing_trades.sum %></li> <li>Win Rate (%): <%= @winning_trades.size/@trades.count.to_f * 100 %></li> </ul> This produces the following results, which aside from a few things is exactly what I want: Total Trades: 134 Winners: 70 Biggest Winner (Pips): 1488 Average Win(Pips): 440 Losers: 58 Biggest Loser (Pips): -516 Average Loss(Pips): -225 Breakeven Trades: 6 Long Trades: 125 Winning Long Trades: 67 Short Trades: 9 Winning Short Trades: 3 Total Pips: 17819 Win Rate (%): 52.23880597014925 What I Am Wondering- Finally The Actual Questions: I am starting to get really skeptical of how well this method will work when a user has 5,000 trades instead of just 134 like in this example. I anticipate most users will only have somewhere under 200 per year, but some users may have a couple thousand trades per year. Probably no more than 5,000 per year. It seems to work ok now, but the page load times are already getting a tad high for my tastes. (About 800ms to generate the page according to rails logs with about a 250ms of that spent in the view layer.) I will end up caching this page I am sure, but I still need the regenerate the page each time a trade is updated and I can't afford to have this be too slow. Sooo..... Is doing something similar here possible with a straight couchdb reduce function? I am assuming handing this off to couch would possibly help with larger data sets. I couldn't figure out how, but I suppose that doesn't mean it isn't possible. If possible, any hints will be helpful. Could I use a list function if a reduce was not available due to reduce constraints? Are couchdb list functions suitable for this type of calculations? Anyone have any idea of whether or not list functions perform well? Any hints what one would look like for the type of calculations I am trying to achieve? I thought about other options such as running the calculations at the time each trade was saved or nightly if I had to and saving the results to a statistics doc that I could then query so that all the processing was done ahead of time. I would like this to be the last resort because then I can't really filter out trades by time periods dynamically like I would really like to. (I want to have a slider that a user can slide to only show trades from that time period using the startkey and endkey in couchdb if I can.) If I should continue running the calculations inside the rails app at the time of the page view, what can I do to improve my current implementation. I am new to rails, couch and programming in general. I am sure that I could be doing something better here. Do I need to create an array for each stat or is there a better way to do that. I guess I just would really like some advice on how to tackle this problem. I want to keep the page generation time minimal since I anticipate these being some of the highest trafficked pages. My gut is that I will need to offload the statistics calculation to either couch or run the stats in advance of when they are called, but I am not sure. Lastly: Like I mentioned above, one of the primary reasons for using couch is to allow users to define their own things to track per trade. Getting the data into couch is no problem, but how would I be able to take the custom_tracking array and find how many winning trades for each named tracking attribute. If anyone can give me any hints to the possibility of doing this that would be great. Thanks a bunch. Would really appreciate any help. Willing to fork out some $$$ if someone wants to take on the problem for me. (Don't know if that is allowed on stack overflow or not.)

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• c# Unable to open file for reading

  - by Maks

  I'm writing a program that uses FileSystemWatcher to monitor changes to a given directory, and when it recieves OnCreated or OnChanged event, it copies those created/changed files to a specified directorie(s). At first I had problems with the fact that OnChanged/OnCreated events can be sent twice (not acceptable in case it needed to process 500MB file) but I made a way around this and with what I'm REALLY STUCKED with is getting the following IOException: The process cannot access the file 'C:\Where are Photos\bookmarks (11).html' because it is being used by another process. Thus, preventing the program from copying all the files it should. So as I mentioned, when user uses this program he/she specifes monitored directory, when user copies/creates/changes file in that directory, program should get OnCreated/OnChanged event and then copy that file to few other directories. Above error happens in all casess, if user copies few files that needs to owerwrite other ones in folder being monitored or when copying bulk of several files or even sometimes when copying one file in a monitored directory. Whole program is quite big so I'm sending the most important parts. OnCreated: private void OnCreated(object source, FileSystemEventArgs e) { AddLogEntry(e.FullPath, "created", ""); // Update last access data if it's file so the same file doesn't // get processed twice because of sending another event. if (fileType(e.FullPath) == 2) { lastPath = e.FullPath; lastTime = DateTime.Now; } // serves no purpose now, it will be remove soon string fileName = GetFileName(e.FullPath); // copies file from source to few other directories Copy(e.FullPath, fileName); Console.WriteLine("OnCreated: " + e.FullPath); } OnChanged: private void OnChanged(object source, FileSystemEventArgs e) { // is it directory if (fileType(e.FullPath) == 1) return; // don't mind directory changes itself // Only if enough time has passed or if it's some other file // because two events can be generated int timeDiff = ((TimeSpan)(DateTime.Now - lastTime)).Seconds; if ((timeDiff < minSecsDiff) && (e.FullPath.Equals(lastPath))) { Console.WriteLine("-- skipped -- {0}, timediff: {1}", e.FullPath, timeDiff); return; } // Update last access data for above to work lastPath = e.FullPath; lastTime = DateTime.Now; // Only if size is changed, the rest will handle other handlers if (e.ChangeType == WatcherChangeTypes.Changed) { AddLogEntry(e.FullPath, "changed", ""); string fileName = GetFileName(e.FullPath); Copy(e.FullPath, fileName); Console.WriteLine("OnChanged: " + e.FullPath); } } fileType: private int fileType(string path) { if (Directory.Exists(path)) return 1; // directory else if (File.Exists(path)) return 2; // file else return 0; } Copy: private void Copy(string srcPath, string fileName) { foreach (string dstDirectoy in paths) { string eventType = "copied"; string error = "noerror"; string path = ""; string dirPortion = ""; // in case directory needs to be made if (srcPath.Length > fsw.Path.Length) { path = srcPath.Substring(fsw.Path.Length, srcPath.Length - fsw.Path.Length); int pos = path.LastIndexOf('\\'); if (pos != -1) dirPortion = path.Substring(0, pos); } if (fileType(srcPath) == 1) { try { Directory.CreateDirectory(dstDirectoy + path); //Directory.CreateDirectory(dstDirectoy + fileName); eventType = "created"; } catch (IOException e) { eventType = "error"; error = e.Message; } } else { try { if (!overwriteFile && File.Exists(dstDirectoy + path)) continue; // create new dir anyway even if it exists just to be sure Directory.CreateDirectory(dstDirectoy + dirPortion); // copy file from where event occured to all specified directories using (FileStream fsin = new FileStream(srcPath, FileMode.Open, FileAccess.Read, FileShare.Read)) { using (FileStream fsout = new FileStream(dstDirectoy + path, FileMode.Create, FileAccess.Write)) { byte[] buffer = new byte[32768]; int bytesRead = -1; while ((bytesRead = fsin.Read(buffer, 0, buffer.Length)) > 0) fsout.Write(buffer, 0, bytesRead); } } } catch (Exception e) { if ((e is IOException) && (overwriteFile == false)) { eventType = "skipped"; } else { eventType = "error"; error = e.Message; // attempt to find and kill the process locking the file. // failed, miserably System.Diagnostics.Process tool = new System.Diagnostics.Process(); tool.StartInfo.FileName = "handle.exe"; tool.StartInfo.Arguments = "\"" + srcPath + "\""; tool.StartInfo.UseShellExecute = false; tool.StartInfo.RedirectStandardOutput = true; tool.Start(); tool.WaitForExit(); string outputTool = tool.StandardOutput.ReadToEnd(); string matchPattern = @"(?<=\s+pid:\s+)\b(\d+)\b(?=\s+)"; foreach (Match match in Regex.Matches(outputTool, matchPattern)) { System.Diagnostics.Process.GetProcessById(int.Parse(match.Value)).Kill(); } Console.WriteLine("ERROR: {0}: [ {1} ]", e.Message, srcPath); } } } AddLogEntry(dstDirectoy + path, eventType, error); } } I checked everywhere in my program and whenever I use some file I use it in using block so even writing event to log (class for what I ommited since there is probably too much code already in post) wont lock the file, that is it shouldn't since all operations are using using statement block. I simply have no clue who's locking the file if not my program "copy" process from user through Windows or something else. Right now I have two possible "solutions" (I can't say they are clean solutions since they are hacks and as such not desireable). Since probably the problem is with fileType method (what else could lock the file?) I tried changing it to this, to simulate "blocking-until-ready-to-open" operation: fileType: private int fileType(string path) { FileStream fs = null; int ret = 0; bool run = true; if (Directory.Exists(path)) ret = 1; else { while (run) { try { fs = new FileStream(path, FileMode.Open); ret = 2; run = false; } catch (IOException) { } finally { if (fs != null) { fs.Close(); fs.Dispose(); } } } } return ret; } This is working as much as I could tell (test), but... it's hack, not to mention other deficients. The other "solution" I could try (I didn't test it yet) is using GC.Collect() somewhere at the end of fileType() method. Maybe even worse "solution" than previous one. Can someone pleas tell me, what on earth is locking the file, preventing it from opening and how can I fix that? What am I missing to see? Thanks in advance.

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• StringIndexOutOfBoundsException error in main method

  - by Ro Siv

  I am obtaining a StringIndexOutOfBoundsError when running my main method. Here is the output of my program in the command line. "Please enter the shift, 1 for day, 2 for night" 1 "you entered a number for the shift" "Please enter the hourly pay Rate" 2 "you entered a number for the pay Rate" "Please enter the employees name" brenda "cat6b" "your value you entered is correct 0-9 or a - z" "Please enter the employee number" 100e "cat41" "your value you entered is correct 0-9 or a - z" "Please enter current date in XXYYZZZZ format, X is day, Y is month, Z is year" 10203933 "cat81 " "your value you entered is correct 0-9 or a - z" 90 1 valye of array is 1 81 0 value of array is 0 82 2 value of array is 2 83 0 value of array is 0 84 3 value of array is 3 85 9 value of array is 9 86 3 value of array is 3 87 3 value of array is 3 "Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 8 at java.lang.String.charAt(String.java:658) at ProductionWorker<init>(ProductionWorker.java:66) at labBookFiftyFour.main(labBookFiftyFour.java:58)" "Press any key to continue . . ." Ignore the cat parts in the code, i was using a println statement to test the code. Ignore the value of array output as well, as i wanted to use an array in the program later on. Here is my main method. import java.math.*; import java.text.DecimalFormat; import java.io.*; import java.util.*; public class labBookFiftyFour { public static void main(String[] args) { Scanner myInput = new Scanner(System.in); int shift = -1; double pRate = -2; String name = " "; String number = " "; String date = " "; while(shift < 0 || pRate < 0 ) { System.out.println("Please enter the shift, 1 for day, 2 for night"); if(myInput.hasNextInt()){ System.out.println("you entered a number for the shift"); shift = myInput.nextInt(); } System.out.println("Please enter the hourly pay Rate"); if(myInput.hasNextDouble()){ System.out.println("you entered a number for the pay Rate"); pRate = myInput.nextDouble(); } else if (myInput.hasNext()) { System.out.println("Please enter a proper value"); myInput.next(); } else { System.err.println("No more input"); System.exit(1); } } myInput.nextLine(); //consume newLine System.out.println("Please enter the employees name"); name = myInput.nextLine(); //use your isValid method if(isValid(name)) { System.out.println("your value you entered is correct 0-9 or a - z "); } System.out.println("Please enter the employee number"); number = myInput.nextLine(); //use your isValid method if(isValid(number)) { System.out.println("your value you entered is correct 0-9 or a - z "); } System.out.println("Please enter current date in XXYYZZZZ format, X is day, Y is month, Z is year"); date = myInput.nextLine(); //use your isValid method if(isValid(date)) { System.out.println("your value you entered is correct 0-9 or a - z "); } ProductionWorker myWorker = new ProductionWorker(shift, pRate, name, number, date); //int day and night , double payRate System.out.println("THis is the shift " + myWorker.getShift() + " This is the pay Rate " + myWorker.getPRate() + " " + myWorker.getName() + " " + myWorker.getNumber() + " " + myWorker.getDate()); } //Made this method for testing String input for 0-9 or a - z values , put AFTER main method, but before end of class public static boolean isValid(String stringName) //This method has to be static, for some reason? { System.out.println("cat" + stringName.length() + stringName.charAt(0)); boolean flag = true; int index = 0; while(index < stringName.length()) { if(Character.isLetterOrDigit(stringName.charAt(index))) { flag = true; } else { flag = false; } ++index; } return flag; } } Here is my employeeOne. java Superclass public class employeeOne { private String name; private String number; private String date; public employeeOne(String name, String number, String date) { this.name = name; this.number = number; this.date = date; } public String getName() { return name; } public String getNumber() { return number; } public String getDate() { return date; } } Here is my ProductionWorker.java subclass, which extends employeeOne public class ProductionWorker extends employeeOne { private int shift; //shift represents day or night, day = 1, night = 2 private double pRate; //hourly pay rate public ProductionWorker(int shift, double pRate, String name, String number, String date) { super(name, number, date); this.shift = shift; if(this.shift >= 3 || this.shift <= 0) { System.out.println("You entered an out of bounds shift date, enter 1 for day or 2 for night, else shift will be day"); this.shift = 1; } this.pRate = pRate; boolean goodSoFar = true; int indexNum = 0; int indexDate = 0; if(name.length() <= 10 && number.length() <= 4 && date.length() < 9 ) { goodSoFar = true; } else { goodSoFar = false; } while(goodSoFar && indexNum < 3) //XXXL XXX digits 1-9, L is a letter A -M { if(Character.isDigit(number.charAt(indexNum))) { goodSoFar = true; } else { goodSoFar = false; } ++indexNum; } while(goodSoFar && indexNum < 4) { if(Character.isLetter(number.charAt(indexNum))) { goodSoFar = true; } else if(Character.isDigit(number.charAt(indexNum))) { goodSoFar = false; } else if(Character.isDigit(number.charAt(indexNum)) == false && Character.isLetter(number.charAt(indexNum)) == false) { goodSoFar = false; } ++indexNum; } int[] dateValues = new int[date.length()]; while(goodSoFar && indexDate <= date.length()) //XXYYZZZZ { System.out.println("" + date.length() + indexDate + " " + date.charAt(indexDate)); if(Character.isDigit(date.charAt(indexDate))) { dateValues[indexDate] = Character.getNumericValue(date.charAt(indexDate)); System.out.println("value of array is " + dateValues[indexDate]); ++indexDate; } else { goodSoFar = false; } } if(goodSoFar) { System.out.println("your input is good so far"); } else { System.out.println("your input is wrong for name or number or date"); } } public int getShift() { return shift; } public double getPRate() { return pRate; } }

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• Strange (Undefined?) Behavior of Free in C

  - by Chris Cirefice

  This is really strange... and I can't debug it (tried for about two hours, debugger starts going haywire after a while...). Anyway, I'm trying to do something really simple: Free an array of strings. The array is in the form: char **myStrings. The array elements are initialized as: myString[index] = malloc(strlen(word)); myString[index] = word; and I'm calling a function like this: free_memory(myStrings, size); where size is the length of the array (I know this is not the problem, I tested it extensively and everything except this function is working). free_memory looks like this: void free_memory(char **list, int size) { for (int i = 0; i < size; i ++) { free(list[i]); } free(list); } Now here comes the weird part. if (size> strlen(list[i])) then the program crashes. For example, imagine that I have a list of strings that looks something like this: myStrings[0] = "Some"; myStrings[1] = "random"; myStrings[2] = "strings"; And thus the length of this array is 3. If I pass this to my free_memory function, strlen(myStrings[0]) > 3 (4 3), and the program crashes. However, if I change myStrings[0] to be "So" instead, then strlen(myStrings[0]) < 3 (2 < 3) and the program does not crash. So it seems to me that free(list[i]) is actually going through the char[] that is at that location and trying to free each character, which I imagine is undefined behavior. The only reason I say this is because I can play around with the size of the first element of myStrings and make the program crash whenever I feel like it, so I'm assuming that this is the problem area. Note: I did try to debug this by stepping through the function that calls free_memory, noting any weird values and such, but the moment I step into the free_memory function, the debugger crashes, so I'm not really sure what is going on. Nothing is out of the ordinary until I enter the function, then the world explodes. Another note: I also posted the shortened version of the source for this program (not too long; Pastebin) here. I am compiling on MinGW with the c99 flag on. PS - I just thought of this. I am indeed passing numUniqueWords to the free function, and I know that this does not actually free the entire piece of memory that I allocated. I've called it both ways, that's not the issue. And I left it how I did because that is the way that I will be calling it after I get it to work in the first place, I need to revise some of my logic in that function. Source, as per request (on-site): #include <stdio.h> #include <string.h> #include <ctype.h> #include <stdlib.h> #include "words.h" int getNumUniqueWords(char text[], int size); int main(int argc, char* argv[]) { setvbuf(stdout, NULL, 4, _IONBF); // For Eclipse... stupid bug. --> does NOT affect the program, just the output to console! int nbr_words; char text[] = "Some - \"text, a stdin\". We'll have! also repeat? We'll also have a repeat!"; int length = sizeof(text); nbr_words = getNumUniqueWords(text, length); return 0; } void free_memory(char **list, int size) { for (int i = 0; i < size; i ++) { // You can see that printing the values is fine, as long as free is not called. // When free is called, the program will crash if (size > strlen(list[i])) //printf("Wanna free value %d w/len of %d: %s\n", i, strlen(list[i]), list[i]); free(list[i]); } free(list); } int getNumUniqueWords(char text[], int length) { int numTotalWords = 0; char *word; printf("Length: %d characters\n", length); char totalWords[length]; strcpy(totalWords, text); word = strtok(totalWords, " ,.-!?()\"0123456789"); while (word != NULL) { numTotalWords ++; printf("%s\n", word); word = strtok(NULL, " ,.-!?()\"0123456789"); } printf("Looks like we counted %d total words\n\n", numTotalWords); char *uniqueWords[numTotalWords]; char *tempWord; int wordAlreadyExists = 0; int numUniqueWords = 0; char totalWordsCopy[length]; strcpy(totalWordsCopy, text); for (int i = 0; i < numTotalWords; i++) { uniqueWords[i] = NULL; } // Tokenize until all the text is consumed. word = strtok(totalWordsCopy, " ,.-!?()\"0123456789"); while (word != NULL) { // Look through the word list for the current token. for (int j = 0; j < numTotalWords; j ++) { // Just for clarity, no real meaning. tempWord = uniqueWords[j]; // The word list is either empty or the current token is not in the list. if (tempWord == NULL) { break; } //printf("Comparing (%s) with (%s)\n", tempWord, word); // If the current token is the same as the current element in the word list, mark and break if (strcmp(tempWord, word) == 0) { printf("\nDuplicate: (%s)\n\n", word); wordAlreadyExists = 1; break; } } // Word does not exist, add it to the array. if (!wordAlreadyExists) { uniqueWords[numUniqueWords] = malloc(strlen(word)); uniqueWords[numUniqueWords] = word; numUniqueWords ++; printf("Unique: %s\n", word); } // Reset flags and continue. wordAlreadyExists = 0; word = strtok(NULL, " ,.-!?()\"0123456789"); } // Print out the array just for funsies - make sure it's working properly. for (int x = 0; x <numUniqueWords; x++) { printf("Unique list %d: %s\n", x, uniqueWords[x]); } printf("\nNumber of unique words: %d\n\n", numUniqueWords); // Right below is where things start to suck. free_memory(uniqueWords, numUniqueWords); return numUniqueWords; }

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• depth first search graph by using linked list

  - by programmerwannabe

  im using mac book and i cannot read the text file using this code. moreover, can you guys please add function(graph is connected?, and is this graph tree?) inputA.txt consist 1 2 1 6 1 5 2 3 2 6 3 4 3 6 4 5 4 6 5 6 #include <stdio.h> #include <memory.h> #include <stdlib.h> #define MAX 10 #define TRUE 1 #define FALSE 0 typedef struct Graph{ int vertex; struct Graph* link; } g_node; typedef struct graphType{ int x; int visited[MAX]; g_node* adjList_H[MAX]; } graphType; typedef struct stack{ int data; struct stack* link; } s_node; s_node* top; void push(int item){ s_node* n=(s_node*)malloc(sizeof(s_node)); n->data = item; n->link = top; top = n; } int pop(){ int item; s_node* n=top; if(top == NULL){ puts("\nstack is empty!\n"); return 0; } else { item = n-> data; top = n->link; free(n); return item; } } void createGraph(graphType* g){ int v; g->x = 1; for(v=1 ; v < MAX ; v++){ g -> visited[v] = FALSE; g -> adjList_H[v] = NULL; } } void insertVertex(graphType* g, int v){ if(((g->x)) > MAX){ puts("\n it has been overed the number of vertex\n"); return ; } g -> x++; } void insertEdge(graphType* g, int u, int v){ g_node* node; if(u >= g -> x || v >= g -> x){ puts("\n no vertex in the graph\n"); return ; } node = (g_node*)malloc(sizeof(g_node)); node -> vertex = v; node -> link = g -> adjList_H[u]; g-> adjList_H[u] = node; } void print_adjList(graphType* g){ int i; g_node *p; for(i=1 ; i<g -> x ; i++){ printf("\n\t\t vertex %d adjacency list ", i); p = g -> adjList_H[i]; while(p){ printf("-> %d", p-> vertex); p = p-> link; } } } void DFS_adjList(graphType* g, int v) { g_node* w; top = NULL; push(v); g->visited[v] = TRUE; printf(" %d", v); while(top != NULL){ w=g->adjList_H[v]; while(w){ if (!g->visited[w->vertex]){ push(w->vertex); g->visited[w->vertex] = TRUE; printf(" %d", w->vertex); v = w->vertex; w=g->adjList_H[v]; } else w= w->link; } v = pop(); } } int main (int argc, const char * argv[]) { FILE *fp; char mychar; char arr[][2]={0, }; int j, k; int i; graphType *G9; G9 = (graphType*)malloc(sizeof(graphType)); createGraph(G9); for(i=1; i<7 ; i++) insertVertex(G9, i); fp = fopen("inputD.txt", "r"); for(j = 0 ; j< 10 ; j++){ for(k = 0 ; k < 2 ; k++){ mychar = fgetc(fp); if(mychar = EOF){ j=10; break; } else if(mychar == ' ') continue; else if(mychar <= '9' || mychar >= '1'){ arr[j][k] = mychar; printf("%d%d", arr[i][k]); } } } insertEdge(G9, 1, 2); insertEdge(G9, 1, 6); insertEdge(G9, 1, 5); insertEdge(G9, 2, 3); insertEdge(G9, 2, 6); insertEdge(G9, 3, 4); insertEdge(G9, 3, 6); insertEdge(G9, 4, 5); insertEdge(G9, 4, 6); insertEdge(G9, 5, 6); insertEdge(G9, 6, 5); insertEdge(G9, 6, 4); insertEdge(G9, 5, 4); insertEdge(G9, 6, 3); insertEdge(G9, 4, 3); insertEdge(G9, 6, 2); insertEdge(G9, 3, 2); insertEdge(G9, 5, 1); insertEdge(G9, 6, 1); insertEdge(G9, 2, 1); printf("\n graph adjacency list "); print_adjList(G9); printf("\n \n//////////////////////////////////////////////\n\n depth fist search >> "); DFS_adjList(G9, 1); return 0; }

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• What's New in ASP.NET 4

  - by Navaneeth

  The .NET Framework version 4 includes enhancements for ASP.NET 4 in targeted areas. Visual Studio 2010 and Microsoft Visual Web Developer Express also include enhancements and new features for improved Web development. This document provides an overview of many of the new features that are included in the upcoming release. This topic contains the following sections: ASP.NET Core Services ASP.NET Web Forms ASP.NET MVC Dynamic Data ASP.NET Chart Control Visual Web Developer Enhancements Web Application Deployment with Visual Studio 2010 Enhancements to ASP.NET Multi-Targeting ASP.NET Core Services ASP.NET 4 introduces many features that improve core ASP.NET services such as output caching and session state storage. Extensible Output Caching Since the time that ASP.NET 1.0 was released, output caching has enabled developers to store the generated output of pages, controls, and HTTP responses in memory. On subsequent Web requests, ASP.NET can serve content more quickly by retrieving the generated output from memory instead of regenerating the output from scratch. However, this approach has a limitation — generated content always has to be stored in memory. On servers that experience heavy traffic, the memory requirements for output caching can compete with memory requirements for other parts of a Web application. ASP.NET 4 adds extensibility to output caching that enables you to configure one or more custom output-cache providers. Output-cache providers can use any storage mechanism to persist HTML content. These storage options can include local or remote disks, cloud storage, and distributed cache engines. Output-cache provider extensibility in ASP.NET 4 lets you design more aggressive and more intelligent output-caching strategies for Web sites. For example, you can create an output-cache provider that caches the "Top 10" pages of a site in memory, while caching pages that get lower traffic on disk. Alternatively, you can cache every vary-by combination for a rendered page, but use a distributed cache so that the memory consumption is offloaded from front-end Web servers. You create a custom output-cache provider as a class that derives from the OutputCacheProvider type. You can then configure the provider in the Web.config file by using the new providers subsection of the outputCache element For more information and for examples that show how to configure the output cache, see outputCache Element for caching (ASP.NET Settings Schema). For more information about the classes that support caching, see the documentation for the OutputCache and OutputCacheProvider classes. By default, in ASP.NET 4, all HTTP responses, rendered pages, and controls use the in-memory output cache. The defaultProvider attribute for ASP.NET is AspNetInternalProvider. You can change the default output-cache provider used for a Web application by specifying a different provider name for defaultProvider attribute. In addition, you can select different output-cache providers for individual control and for individual requests and programmatically specify which provider to use. For more information, see the HttpApplication.GetOutputCacheProviderName(HttpContext) method. The easiest way to choose a different output-cache provider for different Web user controls is to do so declaratively by using the new providerName attribute in a page or control directive, as shown in the following example: <%@ OutputCache Duration="60" VaryByParam="None" providerName="DiskCache" %> Preloading Web Applications Some Web applications must load large amounts of data or must perform expensive initialization processing before serving the first request. In earlier versions of ASP.NET, for these situations you had to devise custom approaches to "wake up" an ASP.NET application and then run initialization code during the Application_Load method in the Global.asax file. To address this scenario, a new application preload manager (autostart feature) is available when ASP.NET 4 runs on IIS 7.5 on Windows Server 2008 R2. The preload feature provides a controlled approach for starting up an application pool, initializing an ASP.NET application, and then accepting HTTP requests. It lets you perform expensive application initialization prior to processing the first HTTP request. For example, you can use the application preload manager to initialize an application and then signal a load-balancer that the application was initialized and ready to accept HTTP traffic. To use the application preload manager, an IIS administrator sets an application pool in IIS 7.5 to be automatically started by using the following configuration in the applicationHost.config file: <applicationPools> <add name="MyApplicationPool" startMode="AlwaysRunning" /> </applicationPools> Because a single application pool can contain multiple applications, you specify individual applications to be automatically started by using the following configuration in the applicationHost.config file: <sites> <site name="MySite" id="1"> <application path="/" serviceAutoStartEnabled="true" serviceAutoStartProvider="PrewarmMyCache" > <!-- Additional content --> </application> </site> </sites> <!-- Additional content --> <serviceAutoStartProviders> <add name="PrewarmMyCache" type="MyNamespace.CustomInitialization, MyLibrary" /> </serviceAutoStartProviders> When an IIS 7.5 server is cold-started or when an individual application pool is recycled, IIS 7.5 uses the information in the applicationHost.config file to determine which Web applications have to be automatically started. For each application that is marked for preload, IIS7.5 sends a request to ASP.NET 4 to start the application in a state during which the application temporarily does not accept HTTP requests. When it is in this state, ASP.NET instantiates the type defined by the serviceAutoStartProvider attribute (as shown in the previous example) and calls into its public entry point. You create a managed preload type that has the required entry point by implementing the IProcessHostPreloadClient interface, as shown in the following example: public class CustomInitialization : System.Web.Hosting.IProcessHostPreloadClient { public void Preload(string[] parameters) { // Perform initialization. } } After your initialization code runs in the Preload method and after the method returns, the ASP.NET application is ready to process requests. Permanently Redirecting a Page Content in Web applications is often moved over the lifetime of the application. This can lead to links to be out of date, such as the links that are returned by search engines. In ASP.NET, developers have traditionally handled requests to old URLs by using the Redirect method to forward a request to the new URL. However, the Redirect method issues an HTTP 302 (Found) response (which is used for a temporary redirect). This results in an extra HTTP round trip. ASP.NET 4 adds a RedirectPermanent helper method that makes it easy to issue HTTP 301 (Moved Permanently) responses, as in the following example: RedirectPermanent("/newpath/foroldcontent.aspx"); Search engines and other user agents that recognize permanent redirects will store the new URL that is associated with the content, which eliminates the unnecessary round trip made by the browser for temporary redirects. Session State Compression By default, ASP.NET provides two options for storing session state across a Web farm. The first option is a session state provider that invokes an out-of-process session state server. The second option is a session state provider that stores data in a Microsoft SQL Server database. Because both options store state information outside a Web application's worker process, session state has to be serialized before it is sent to remote storage. If a large amount of data is saved in session state, the size of the serialized data can become very large. ASP.NET 4 introduces a new compression option for both kinds of out-of-process session state providers. By using this option, applications that have spare CPU cycles on Web servers can achieve substantial reductions in the size of serialized session state data. You can set this option using the new compressionEnabled attribute of the sessionState element in the configuration file. When the compressionEnabled configuration option is set to true, ASP.NET compresses (and decompresses) serialized session state by using the .NET Framework GZipStreamclass. The following example shows how to set this attribute. <sessionState mode="SqlServer" sqlConnectionString="data source=dbserver;Initial Catalog=aspnetstate" allowCustomSqlDatabase="true" compressionEnabled="true" /> ASP.NET Web Forms Web Forms has been a core feature in ASP.NET since the release of ASP.NET 1.0. Many enhancements have been in this area for ASP.NET 4, such as the following: The ability to set meta tags. More control over view state. Support for recently introduced browsers and devices. Easier ways to work with browser capabilities. Support for using ASP.NET routing with Web Forms. More control over generated IDs. The ability to persist selected rows in data controls. More control over rendered HTML in the FormView and ListView controls. Filtering support for data source controls. Enhanced support for Web standards and accessibility Setting Meta Tags with the Page.MetaKeywords and Page.MetaDescription Properties Two properties have been added to the Page class: MetaKeywords and MetaDescription. These two properties represent corresponding meta tags in the HTML rendered for a page, as shown in the following example: <head id="Head1" runat="server"> <title>Untitled Page</title> <meta name="keywords" content="keyword1, keyword2' /> <meta name="description" content="Description of my page" /> </head> These two properties work like the Title property does, and they can be set in the @ Page directive. For more information, see Page.MetaKeywords and Page.MetaDescription. Enabling View State for Individual Controls A new property has been added to the Control class: ViewStateMode. You can use this property to disable view state for all controls on a page except those for which you explicitly enable view state. View state data is included in a page's HTML and increases the amount of time it takes to send a page to the client and post it back. Storing more view state than is necessary can cause significant decrease in performance. In earlier versions of ASP.NET, you could reduce the impact of view state on a page's performance by disabling view state for specific controls. But sometimes it is easier to enable view state for a few controls that need it instead of disabling it for many that do not need it. For more information, see Control.ViewStateMode. Support for Recently Introduced Browsers and Devices ASP.NET includes a feature that is named browser capabilities that lets you determine the capabilities of the browser that a user is using. Browser capabilities are represented by the HttpBrowserCapabilities object which is stored in the HttpRequest.Browser property. Information about a particular browser's capabilities is defined by a browser definition file. In ASP.NET 4, these browser definition files have been updated to contain information about recently introduced browsers and devices such as Google Chrome, Research in Motion BlackBerry smart phones, and Apple iPhone. Existing browser definition files have also been updated. For more information, see How to: Upgrade an ASP.NET Web Application to ASP.NET 4 and ASP.NET Web Server Controls and Browser Capabilities. The browser definition files that are included with ASP.NET 4 are shown in the following list: •blackberry.browser •chrome.browser •Default.browser •firefox.browser •gateway.browser •generic.browser •ie.browser •iemobile.browser •iphone.browser •opera.browser •safari.browser A New Way to Define Browser Capabilities ASP.NET 4 includes a new feature referred to as browser capabilities providers. As the name suggests, this lets you build a provider that in turn lets you write custom code to determine browser capabilities. In ASP.NET version 3.5 Service Pack 1, you define browser capabilities in an XML file. This file resides in a machine-level folder or an application-level folder. Most developers do not need to customize these files, but for those who do, the provider approach can be easier than dealing with complex XML syntax. The provider approach makes it possible to simplify the process by implementing a common browser definition syntax, or a database that contains up-to-date browser definitions, or even a Web service for such a database. For more information about the new browser capabilities provider, see the What's New for ASP.NET 4 White Paper. Routing in ASP.NET 4 ASP.NET 4 adds built-in support for routing with Web Forms. Routing is a feature that was introduced with ASP.NET 3.5 SP1 and lets you configure an application to use URLs that are meaningful to users and to search engines because they do not have to specify physical file names. This can make your site more user-friendly and your site content more discoverable by search engines. For example, the URL for a page that displays product categories in your application might look like the following example: http://website/products.aspx?categoryid=12 By using routing, you can use the following URL to render the same information: http://website/products/software The second URL lets the user know what to expect and can result in significantly improved rankings in search engine results. the new features include the following: The PageRouteHandler class is a simple HTTP handler that you use when you define routes. You no longer have to write a custom route handler. The HttpRequest.RequestContext and Page.RouteData properties make it easier to access information that is passed in URL parameters. The RouteUrl expression provides a simple way to create a routed URL in markup. The RouteValue expression provides a simple way to extract URL parameter values in markup. The RouteParameter class makes it easier to pass URL parameter values to a query for a data source control (similar to FormParameter). You no longer have to change the Web.config file to enable routing. For more information about routing, see the following topics: ASP.NET Routing Walkthrough: Using ASP.NET Routing in a Web Forms Application How to: Define Routes for Web Forms Applications How to: Construct URLs from Routes How to: Access URL Parameters in a Routed Page Setting Client IDs The new ClientIDMode property makes it easier to write client script that references HTML elements rendered for server controls. Increasing use of Microsoft Ajax makes the need to do this more common. For example, you may have a data control that renders a long list of products with prices and you want to use client script to make a Web service call and update individual prices in the list as they change without refreshing the entire page. Typically you get a reference to an HTML element in client script by using the document.GetElementById method. You pass to this method the value of the id attribute of the HTML element you want to reference. In the case of elements that are rendered for ASP.NET server controls earlier versions of ASP.NET could make this difficult or impossible. You were not always able to predict what id values ASP.NET would generate, or ASP.NET could generate very long id values. The problem was especially difficult for data controls that would generate multiple rows for a single instance of the control in your markup. ASP.NET 4 adds two new algorithms for generating id attributes. These algorithms can generate id attributes that are easier to work with in client script because they are more predictable and that are easier to work with because they are simpler. For more information about how to use the new algorithms, see the following topics: ASP.NET Web Server Control Identification Walkthrough: Making Data-Bound Controls Easier to Access from JavaScript Walkthrough: Making Controls Located in Web User Controls Easier to Access from JavaScript How to: Access Controls from JavaScript by ID Persisting Row Selection in Data Controls The GridView and ListView controls enable users to select a row. In previous versions of ASP.NET, row selection was based on the row index on the page. For example, if you select the third item on page 1 and then move to page 2, the third item on page 2 is selected. In most cases, is more desirable not to select any rows on page 2. ASP.NET 4 supports Persisted Selection, a new feature that was initially supported only in Dynamic Data projects in the .NET Framework 3.5 SP1. When this feature is enabled, the selected item is based on the row data key. This means that if you select the third row on page 1 and move to page 2, nothing is selected on page 2. When you move back to page 1, the third row is still selected. This is a much more natural behavior than the behavior in earlier versions of ASP.NET. Persisted selection is now supported for the GridView and ListView controls in all projects. You can enable this feature in the GridView control, for example, by setting the EnablePersistedSelection property, as shown in the following example: <asp:GridView id="GridView2" runat="server" PersistedSelection="true"> </asp:GridView> FormView Control Enhancements The FormView control is enhanced to make it easier to style the content of the control with CSS. In previous versions of ASP.NET, the FormView control rendered it contents using an item template. This made styling more difficult in the markup because unexpected table row and table cell tags were rendered by the control. The FormView control supports RenderOuterTable, a property in ASP.NET 4. When this property is set to false, as show in the following example, the table tags are not rendered. This makes it easier to apply CSS style to the contents of the control. <asp:FormView ID="FormView1" runat="server" RenderTable="false"> For more information, see FormView Web Server Control Overview. ListView Control Enhancements The ListView control, which was introduced in ASP.NET 3.5, has all the functionality of the GridView control while giving you complete control over the output. This control has been made easier to use in ASP.NET 4. The earlier version of the control required that you specify a layout template that contained a server control with a known ID. The following markup shows a typical example of how to use the ListView control in ASP.NET 3.5. <asp:ListView ID="ListView1" runat="server"> <LayoutTemplate> <asp:PlaceHolder ID="ItemPlaceHolder" runat="server"></asp:PlaceHolder> </LayoutTemplate> <ItemTemplate> <% Eval("LastName")%> </ItemTemplate> </asp:ListView> In ASP.NET 4, the ListView control does not require a layout template. The markup shown in the previous example can be replaced with the following markup: <asp:ListView ID="ListView1" runat="server"> <ItemTemplate> <% Eval("LastName")%> </ItemTemplate> </asp:ListView> For more information, see ListView Web Server Control Overview. Filtering Data with the QueryExtender Control A very common task for developers who create data-driven Web pages is to filter data. This traditionally has been performed by building Where clauses in data source controls. This approach can be complicated, and in some cases the Where syntax does not let you take advantage of the full functionality of the underlying database. To make filtering easier, a new QueryExtender control has been added in ASP.NET 4. This control can be added to EntityDataSource or LinqDataSource controls in order to filter the data returned by these controls. Because the QueryExtender control relies on LINQ, but you do not to need to know how to write LINQ queries to use the query extender. The QueryExtender control supports a variety of filter options. The following lists QueryExtender filter options. Term Definition SearchExpression Searches a field or fields for string values and compares them to a specified string value. RangeExpression Searches a field or fields for values in a range specified by a pair of values. PropertyExpression Compares a specified value to a property value in a field. If the expression evaluates to true, the data that is being examined is returned. OrderByExpression Sorts data by a specified column and sort direction. CustomExpression Calls a function that defines custom filter in the page. For more information, see QueryExtenderQueryExtender Web Server Control Overview. Enhanced Support for Web Standards and Accessibility Earlier versions of ASP.NET controls sometimes render markup that does not conform to HTML, XHTML, or accessibility standards. ASP.NET 4 eliminates most of these exceptions. For details about how the HTML that is rendered by each control meets accessibility standards, see ASP.NET Controls and Accessibility. CSS for Controls that Can be Disabled In ASP.NET 3.5, when a control is disabled (see WebControl.Enabled), a disabled attribute is added to the rendered HTML element. For example, the following markup creates a Label control that is disabled: <asp:Label id="Label1" runat="server"   Text="Test" Enabled="false" /> In ASP.NET 3.5, the previous control settings generate the following HTML: <span id="Label1" disabled="disabled">Test</span> In HTML 4.01, the disabled attribute is not considered valid on span elements. It is valid only on input elements because it specifies that they cannot be accessed. On display-only elements such as span elements, browsers typically support rendering for a disabled appearance, but a Web page that relies on this non-standard behavior is not robust according to accessibility standards. For display-only elements, you should use CSS to indicate a disabled visual appearance. Therefore, by default ASP.NET 4 generates the following HTML for the control settings shown previously: <span id="Label1" class="aspNetDisabled">Test</span> You can change the value of the class attribute that is rendered by default when a control is disabled by setting the DisabledCssClass property. CSS for Validation Controls In ASP.NET 3.5, validation controls render a default color of red as an inline style. For example, the following markup creates a RequiredFieldValidator control: <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"   ErrorMessage="Required Field" ControlToValidate="RadioButtonList1" /> ASP.NET 3.5 renders the following HTML for the validator control: <span id="RequiredFieldValidator1"   style="color:Red;visibility:hidden;">RequiredFieldValidator</span> By default, ASP.NET 4 does not render an inline style to set the color to red. An inline style is used only to hide or show the validator, as shown in the following example: <span id="RequiredFieldValidator1"   style"visibility:hidden;">RequiredFieldValidator</span> Therefore, ASP.NET 4 does not automatically show error messages in red. For information about how to use CSS to specify a visual style for a validation control, see Validating User Input in ASP.NET Web Pages. CSS for the Hidden Fields Div Element ASP.NET uses hidden fields to store state information such as view state and control state. These hidden fields are contained by a div element. In ASP.NET 3.5, this div element does not have a class attribute or an id attribute. Therefore, CSS rules that affect all div elements could unintentionally cause this div to be visible. To avoid this problem, ASP.NET 4 renders the div element for hidden fields with a CSS class that you can use to differentiate the hidden fields div from others. The new classvalue is shown in the following example: <div class="aspNetHidden"> CSS for the Table, Image, and ImageButton Controls By default, in ASP.NET 3.5, some controls set the border attribute of rendered HTML to zero (0). The following example shows HTML that is generated by the Table control in ASP.NET 3.5: <table id="Table2" border="0"> The Image control and the ImageButton control also do this. Because this is not necessary and provides visual formatting information that should be provided by using CSS, the attribute is not generated in ASP.NET 4. CSS for the UpdatePanel and UpdateProgress Controls In ASP.NET 3.5, the UpdatePanel and UpdateProgress controls do not support expando attributes. This makes it impossible to set a CSS class on the HTMLelements that they render. In ASP.NET 4 these controls have been changed to accept expando attributes, as shown in the following example: <asp:UpdatePanel runat="server" class="myStyle"> </asp:UpdatePanel> The following HTML is rendered for this markup: <div id="ctl00_MainContent_UpdatePanel1" class="expandoclass"> </div> Eliminating Unnecessary Outer Tables In ASP.NET 3.5, the HTML that is rendered for the following controls is wrapped in a table element whose purpose is to apply inline styles to the entire control: FormView Login PasswordRecovery ChangePassword If you use templates to customize the appearance of these controls, you can specify CSS styles in the markup that you provide in the templates. In that case, no extra outer table is required. In ASP.NET 4, you can prevent the table from being rendered by setting the new RenderOuterTable property to false. Layout Templates for Wizard Controls In ASP.NET 3.5, the Wizard and CreateUserWizard controls generate an HTML table element that is used for visual formatting. In ASP.NET 4 you can use a LayoutTemplate element to specify the layout. If you do this, the HTML table element is not generated. In the template, you create placeholder controls to indicate where items should be dynamically inserted into the control. (This is similar to how the template model for the ListView control works.) For more information, see the Wizard.LayoutTemplate property. New HTML Formatting Options for the CheckBoxList and RadioButtonList Controls ASP.NET 3.5 uses HTML table elements to format the output for the CheckBoxList and RadioButtonList controls. To provide an alternative that does not use tables for visual formatting, ASP.NET 4 adds two new options to the RepeatLayout enumeration: UnorderedList. This option causes the HTML output to be formatted by using ul and li elements instead of a table. OrderedList. This option causes the HTML output to be formatted by using ol and li elements instead of a table. For examples of HTML that is rendered for the new options, see the RepeatLayout enumeration. Header and Footer Elements for the Table Control In ASP.NET 3.5, the Table control can be configured to render thead and tfoot elements by setting the TableSection property of the TableHeaderRow class and the TableFooterRow class. In ASP.NET 4 these properties are set to the appropriate values by default. CSS and ARIA Support for the Menu Control In ASP.NET 3.5, the Menu control uses HTML table elements for visual formatting, and in some configurations it is not keyboard-accessible. ASP.NET 4 addresses these problems and improves accessibility in the following ways: The generated HTML is structured as an unordered list (ul and li elements). CSS is used for visual formatting. The menu behaves in accordance with ARIA standards for keyboard access. You can use arrow keys to navigate menu items. (For information about ARIA, see Accessibility in Visual Studio and ASP.NET.) ARIA role and property attributes are added to the generated HTML. (Attributes are added by using JavaScript instead of included in the HTML, to avoid generating HTML that would cause markup validation errors.) Styles for the Menu control are rendered in a style block at the top of the page, instead of inline with the rendered HTML elements. If you want to use a separate CSS file so that you can modify the menu styles, you can set the Menu control's new IncludeStyleBlock property to false, in which case the style block is not generated. Valid XHTML for the HtmlForm Control In ASP.NET 3.5, the HtmlForm control (which is created implicitly by the <form runat="server"> tag) renders an HTML form element that has both name and id attributes. The name attribute is deprecated in XHTML 1.1. Therefore, this control does not render the name attribute in ASP.NET 4. Maintaining Backward Compatibility in Control Rendering An existing ASP.NET Web site might have code in it that assumes that controls are rendering HTML the way they do in ASP.NET 3.5. To avoid causing backward compatibility problems when you upgrade the site to ASP.NET 4, you can have ASP.NET continue to generate HTML the way it does in ASP.NET 3.5 after you upgrade the site. To do so, you can set the controlRenderingCompatibilityVersion attribute of the pages element to "3.5" in the Web.config file of an ASP.NET 4 Web site, as shown in the following example: <system.web>   <pages controlRenderingCompatibilityVersion="3.5"/> </system.web> If this setting is omitted, the default value is the same as the version of ASP.NET that the Web site targets. (For information about multi-targeting in ASP.NET, see .NET Framework Multi-Targeting for ASP.NET Web Projects.) ASP.NET MVC ASP.NET MVC helps Web developers build compelling standards-based Web sites that are easy to maintain because it decreases the dependency among application layers by using the Model-View-Controller (MVC) pattern. MVC provides complete control over the page markup. It also improves testability by inherently supporting Test Driven Development (TDD). Web sites created using ASP.NET MVC have a modular architecture. This allows members of a team to work independently on the various modules and can be used to improve collaboration. For example, developers can work on the model and controller layers (data and logic), while the designer work on the view (presentation). For tutorials, walkthroughs, conceptual content, code samples, and a complete API reference, see ASP.NET MVC 2. Dynamic Data Dynamic Data was introduced in the .NET Framework 3.5 SP1 release in mid-2008. This feature provides many enhancements for creating data-driven applications, such as the following: A RAD experience for quickly building a data-driven Web site. Automatic validation that is based on constraints defined in the data model. The ability to easily change the markup that is generated for fields in the GridView and DetailsView controls by using field templates that are part of your Dynamic Data project. For ASP.NET 4, Dynamic Data has been enhanced to give developers even more power for quickly building data-driven Web sites. For more information, see ASP.NET Dynamic Data Content Map. Enabling Dynamic Data for Individual Data-Bound Controls in Existing Web Applications You can use Dynamic Data features in existing ASP.NET Web applications that do not use scaffolding by enabling Dynamic Data for individual data-bound controls. Dynamic Data provides the presentation and data layer support for rendering these controls. When you enable Dynamic Data for data-bound controls, you get the following benefits: Setting default values for data fields. Dynamic Data enables you to provide default values at run time for fields in a data control. Interacting with the database without creating and registering a data model. Automatically validating the data that is entered by the user without writing any code. For more information, see Walkthrough: Enabling Dynamic Data in ASP.NET Data-Bound Controls. New Field Templates for URLs and E-mail Addresses ASP.NET 4 introduces two new built-in field templates, EmailAddress.ascx and Url.ascx. These templates are used for fields that are marked as EmailAddress or Url using the DataTypeAttribute attribute. For EmailAddress objects, the field is displayed as a hyperlink that is created by using the mailto: protocol. When users click the link, it opens the user's e-mail client and creates a skeleton message. Objects typed as Url are displayed as ordinary hyperlinks. The following example shows how to mark fields. [DataType(DataType.EmailAddress)] public object HomeEmail { get; set; } [DataType(DataType.Url)] public object Website { get; set; } Creating Links with the DynamicHyperLink Control Dynamic Data uses the new routing feature that was added in the .NET Framework 3.5 SP1 to control the URLs that users see when they access the Web site. The new DynamicHyperLink control makes it easy to build links to pages in a Dynamic Data site. For information, see How to: Create Table Action Links in Dynamic Data Support for Inheritance in the Data Model Both the ADO.NET Entity Framework and LINQ to SQL support inheritance in their data models. An example of this might be a database that has an InsurancePolicy table. It might also contain CarPolicy and HousePolicy tables that have the same fields as InsurancePolicy and then add more fields. Dynamic Data has been modified to understand inherited objects in the data model and to support scaffolding for the inherited tables. For more information, see Walkthrough: Mapping Table-per-Hierarchy Inheritance in Dynamic Data. Support for Many-to-Many Relationships (Entity Framework Only) The Entity Framework has rich support for many-to-many relationships between tables, which is implemented by exposing the relationship as a collection on an Entity object. New field templates (ManyToMany.ascx and ManyToMany_Edit.ascx) have been added to provide support for displaying and editing data that is involved in many-to-many relationships. For more information, see Working with Many-to-Many Data Relationships in Dynamic Data. New Attributes to Control Display and Support Enumerations The DisplayAttribute has been added to give you additional control over how fields are displayed. The DisplayNameAttribute attribute in earlier versions of Dynamic Data enabled you to change the name that is used as a caption for a field. The new DisplayAttribute class lets you specify more options for displaying a field, such as the order in which a field is displayed and whether a field will be used as a filter. The attribute also provides independent control of the name that is used for the labels in a GridView control, the name that is used in a DetailsView control, the help text for the field, and the watermark used for the field (if the field accepts text input). The EnumDataTypeAttribute class has been added to let you map fields to enumerations. When you apply this attribute to a field, you specify an enumeration type. Dynamic Data uses the new Enumeration.ascx field template to create UI for displaying and editing enumeration values. The template maps the values from the database to the names in the enumeration. Enhanced Support for Filters Dynamic Data 1.0 had built-in filters for Boolean columns and foreign-key columns. The filters did not let you specify the order in which they were displayed. The new DisplayAttribute attribute addresses this by giving you control over whether a column appears as a filter and in what order it will be displayed. An additional enhancement is that filtering support has been rewritten to use the new QueryExtender feature of Web Forms. This lets you create filters without requiring knowledge of the data source control that the filters will be used with. Along with these extensions, filters have also been turned into template controls, which lets you add new ones. Finally, the DisplayAttribute class mentioned earlier allows the default filter to be overridden, in the same way that UIHint allows the default field template for a column to be overridden. For more information, see Walkthrough: Filtering Rows in Tables That Have a Parent-Child Relationship and QueryableFilterRepeater. ASP.NET Chart Control The ASP.NET chart server control enables you to create ASP.NET pages applications that have simple, intuitive charts for complex statistical or financial analysis. The chart control supports the following features: Data series, chart areas, axes, legends, labels, titles, and more. Data binding. Data manipulation, such as copying, splitting, merging, alignment, grouping, sorting, searching, and filtering. Statistical formulas and financial formulas. Advanced chart appearance, such as 3-D, anti-aliasing, lighting, and perspective. Events and customizations. Interactivity and Microsoft Ajax. Support for the Ajax Content Delivery Network (CDN), which provides an optimized way for you to add Microsoft Ajax Library and jQuery scripts to your Web applications. For more information, see Chart Web Server Control Overview. Visual Web Developer Enhancements The following sections provide information about enhancements and new features in Visual Studio 2010 and Visual Web Developer Express. The Web page designer in Visual Studio 2010 has been enhanced for better CSS compatibility, includes additional support for HTML and ASP.NET markup snippets, and features a redesigned version of IntelliSense for JScript. Improved CSS Compatibility The Visual Web Developer designer in Visual Studio 2010 has been updated to improve CSS 2.1 standards compliance. The designer better preserves HTML source code and is more robust than in previous versions of Visual Studio. HTML and JScript Snippets In the HTML editor, IntelliSense auto-completes tag names. The IntelliSense Snippets feature auto-completes whole tags and more. In Visual Studio 2010, IntelliSense snippets are supported for JScript, alongside C# and Visual Basic, which were supported in earlier versions of Visual Studio. Visual Studio 2010 includes over 200 snippets that help you auto-complete common ASP.NET and HTML tags, including required attributes (such as runat="server") and common attributes specific to a tag (such as ID, DataSourceID, ControlToValidate, and Text). You can download additional snippets, or you can write your own snippets that encapsulate the blocks of markup that you or your team use for common tasks. For more information on HTML snippets, see Walkthrough: Using HTML Snippets. JScript IntelliSense Enhancements In Visual 2010, JScript IntelliSense has been redesigned to provide an even richer editing experience. IntelliSense now recognizes objects that have been dynamically generated by methods such as registerNamespace and by similar techniques used by other JavaScript frameworks. Performance has been improved to analyze large libraries of script and to display IntelliSense with little or no processing delay. Compatibility has been significantly increased to support almost all third-party libraries and to support diverse coding styles. Documentation comments are now parsed as you type and are immediately leveraged by IntelliSense. Web Application Deployment with Visual Studio 2010 For Web application projects, Visual Studio now provides tools that work with the IIS Web Deployment Tool (Web Deploy) to automate many processes that had to be done manually in earlier versions of ASP.NET. For example, the following tasks can now be automated: Creating an IIS application on the destination computer and configuring IIS settings. Copying files to the destination computer. Changing Web.config settings that must be different in the destination environment. Propagating changes to data or data structures in SQL Server databases that are used by the Web application. For more information about Web application deployment, see ASP.NET Deployment Content Map. Enhancements to ASP.NET Multi-Targeting ASP.NET 4 adds new features to the multi-targeting feature to make it easier to work with projects that target earlier versions of the .NET Framework. Multi-targeting was introduced in ASP.NET 3.5 to enable you to use the latest version of Visual Studio without having to upgrade existing Web sites or Web services to the latest version of the .NET Framework. In Visual Studio 2008, when you work with a project targeted for an earlier version of the .NET Framework, most features of the development environment adapt to the targeted version. However, IntelliSense displays language features that are available in the current version, and property windows display properties available in the current version. In Visual Studio 2010, only language features and properties available in the targeted version of the .NET Framework are shown. For more information about multi-targeting, see the following topics: .NET Framework Multi-Targeting for ASP.NET Web Projects ASP.NET Side-by-Side Execution Overview How to: Host Web Applications That Use Different Versions of the .NET Framework on the Same Server How to: Deploy Web Site Projects Targeted for Earlier Versions of the .NET Framework

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• 26 Days: Countdown to Oracle OpenWorld 2012

  - by Michael Snow

  Welcome to our countdown to Oracle OpenWorld! Oracle OpenWorld 2012 is just around the corner. In less than 26 days, San Francisco will be invaded by an expected 50,000 people from all over the world. Here on the Oracle WebCenter team, we’ve all been working to help make the experience a great one for all our WebCenter customers. For a sneak peak  – we’ll be spending this week giving you a teaser of what to look forward to if you are joining us in San Francisco from September 30th through October 4th. We have Oracle WebCenter sessions covering all topics imaginable. Take a look and use the tools we provide to build out your schedule in advance and reserve your seats in your favorite sessions.  That gives you plenty of time to plan for your week with us in San Francisco. If unfortunately, your boss denied your request to attend - there are still some ways that you can join in the experience virtually On-Demand. This year - we are expanding even more up North of Market Street and will be taking over Union Square as well. Check out this map of San Francisco to get a sense of how much of a footprint Oracle OpenWorld has grown to this year. With so much to see and so many sessions to learn from - its no wonder that people get excited. Add to that a good mix of fun and all of the possible WebCenter sessions you could attend - you won't want to sleep at all to take full advantage of such an opportunity. We'll also have our annual WebCenter Customer Appreciation reception - stay tuned this week for some more info on registration to make sure you'll be able to join us. If you've been following the America's Cup at all and believe in EXTREME PERFORMANCE you'll definitely want to take a look at this video from last year's OpenWorld Keynote. 12.00 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Important OpenWorld Links:  Attendee / Presenters Toolkit Oracle Schedule Builder WebCenter Sessions (listed in the catalog under Fusion Middleware as "Portals, Sites, Content, and Collaboration" ) Oracle Music Festival - AMAZING Line up!!  Oracle Customer Appreciation Night -LOOK HERE!! Oracle OpenWorld LIVE On-Demand Here are all the WebCenter sessions broken down by day for your viewing pleasure. Monday, October 1st CON8885 - Simplify CRM Engagement with Contextual Collaboration Are your sales teams disconnected and disengaged? Do you want a tool for easily connecting expertise across your organization and providing visibility into the complete sales process? Do you want a way to enhance and retain organization knowledge? Oracle Social Network is the answer. Attend this session to learn how to make CRM easy, effective, and efficient for use across virtual sales teams. Also learn how Oracle Social Network can drive sales force collaboration with natural conversations throughout the sales cycle, promote sales team productivity through purposeful social networking without the noise, and build cross-team knowledge by integrating conversations with CRM and other business applications. CON8268 - Oracle WebCenter Strategy: Engaging Your Customers. Empowering Your Business Oracle WebCenter is a user engagement platform for social business, connecting people and information. Attend this session to learn about the Oracle WebCenter strategy, and understand where Oracle is taking the platform to help companies engage customers, empower employees, and enable partners. Business success starts with ensuring that everyone is engaged with the right people and the right information and can access what they need through the channel of their choice—Web, mobile, or social. Are you giving customers, employees, and partners the best-possible experience? Come learn how you can! ¶ HOL10208 - Add Social Capabilities to Your Enterprise Applications Oracle Social Network enables you to add real-time collaboration capabilities into your enterprise applications, so that conversations can happen directly within your business systems. In this hands-on lab, you will try out the Oracle Social Network product to collaborate with other attendees, using real-time conversations with document sharing capabilities. Next you will embed social capabilities into a sample Web-based enterprise application, using embedded UI components. Experts will also write simple REST-based integrations, using the Oracle Social Network API to programmatically create social interactions. ¶ CON8893 - Improve Employee Productivity with Intuitive and Social Work Environments Social technologies have already transformed the ways customers, employees, partners, and suppliers communicate and stay informed. Forward-thinking organizations today need technologies and infrastructures to help them advance to the next level and integrate social activities with business applications to deliver a user experience that simplifies business processes and enterprise application engagement. Attend this session to hear from an innovative Oracle Social Network customer and learn how you can improve productivity with intuitive and social work environments and empower your employees with innovative social tools to enable contextual access to content and dynamic personalization of solutions. ¶ CON8270 - Oracle WebCenter Content Strategy and Vision Oracle WebCenter provides a strategic content infrastructure for managing documents, images, e-mails, and rich media files. With a single repository, organizations can address any content use case, such as accounts payable, HR onboarding, document management, compliance, records management, digital asset management, or Website management. In this session, learn about future plans for how Oracle WebCenter will address new use cases as well as new integrations with Oracle Fusion Middleware and Oracle Applications, leveraging your investments by making your users more productive and error-free. ¶ CON8269 - Oracle WebCenter Sites Strategy and Vision Oracle’s Web experience management solution, Oracle WebCenter Sites, enables organizations to use the online channel to drive customer acquisition and brand loyalty. It helps marketers and business users easily create and manage contextually relevant, social, interactive online experiences across multiple channels on a global scale. In this session, learn about future plans for how Oracle WebCenter Sites will provide you with the tools, capabilities, and integrations you need in order to continue to address your customers’ evolving requirements for engaging online experiences and keep moving your business forward. ¶ CON8896 - Living with SharePoint SharePoint is a popular platform, but it’s not always the best fit for Oracle customers. In this session, you’ll discover the technical and nontechnical limitations and pitfalls of SharePoint and learn about Oracle alternatives for collaboration, portals, enterprise and Web content management, social computing, and application integration. The presentation shows you how to integrate with SharePoint when business or IT requirements dictate and covers cloud-based (Office 365) and on-premises versions of SharePoint. Presented by a former Microsoft director of SharePoint product management and backed by independent customer research, this session will prepare you to answer the question “Why don’t we just use SharePoint for that?’ the next time it comes up in your organization. ¶ CON7843 - Content-Enabling Enterprise Processes with Oracle WebCenter Organizations today continually strive to automate business processes, reduce costs, and improve efficiency. Many business processes are content-intensive and unstructured, requiring ad hoc collaboration, and distributed in nature, requiring many approvals and generating huge volumes of paper. In this session, learn how Oracle and SYSTIME have partnered to help a customer content-enable its enterprise with Oracle WebCenter Content and Oracle WebCenter Imaging 11g and integrate them with Oracle Applications. ¶ CON6114 - Tape Robotics’ Newest Superhero: Now Fueled by Oracle Software For small, midsize, and rapidly growing businesses that want the most energy-efficient, scalable storage infrastructure to meet their rapidly growing data demands, Oracle’s most recent addition to its award-winning tape portfolio leverages several pieces of Oracle software. With Oracle Linux, Oracle WebLogic, and Oracle Fusion Middleware tools, the library achieves a higher level of usability than previous products while offering customers a familiar interface for management, plus ease of use. This session examines the competitive advantages of the tape library and how Oracle software raises customer satisfaction. Learn how the combination of Oracle engineered systems, Oracle Secure Backup, and Oracle’s StorageTek tape libraries provide end-to-end coverage of your data. ¶ CON9437 - Mobile Access Management With more than five billion mobile devices on the planet and an increasing number of users using their own devices to access corporate data and applications, securely extending identity management to mobile devices has become a hot topic. This session focuses on how to extend your existing identity management infrastructure and policies to securely and seamlessly enable mobile user access. CON7815 - Customer Experience Online in Cloud: Oracle WebCenter Sites, Oracle ATG Apps, Oracle Exalogic Oracle WebCenter Sites and Oracle’s ATG product line together can provide a compelling marketing and e-commerce experience. When you couple them with the extreme performance of Oracle Exalogic, you’ll see unmatched scalability that provides you with a true cloud-based solution. In this session, you’ll learn how running Oracle WebCenter Sites and ATG applications on Oracle Exalogic delivers both a private and a public cloud experience. Find out what it takes to get these systems working together and delivering engaging Web experiences. Even if you aren’t considering Oracle Exalogic today, the rich Web experience of Oracle WebCenter, paired with the depth of the ATG product line, can provide your business full support, from merchandising through sale completion. ¶ CON8271 - Oracle WebCenter Portal Strategy and Vision To innovate and keep a competitive edge, organizations need to leverage the power of agile and responsive Web applications. Oracle WebCenter Portal enables you to do just that, by delivering intuitive user experiences for enterprise applications to drive innovation with composite applications and mashups. Attend this session to learn firsthand from customers how Oracle WebCenter Portal extends the value of existing enterprise applications, business processes, and content; delivers a superior business user experience; and maximizes limited IT resources. ¶ CON8880 - The Connected Customer Experience Begins with the Online Channel There’s a lot of talk these days about how to connect the customer journey across various touchpoints—from Websites and e-commerce to call centers and in-store—to provide experiences that are more relevant and engaging and ultimately gain competitive edge. Doing it all at once isn’t a realistic objective, so where do you start? Come to this session, and hear about three steps you can take that can help you begin your journey toward delivering the connected customer experience. You’ll hear how Oracle now has an integrated digital marketing platform for your corporate Website, your e-commerce site, your self-service portal, and your marketing and loyalty campaigns, and you’ll learn what you can do today to begin executing on your customer experience initiatives. ¶ GEN11451 - General Session: Building Mobile Applications with Oracle Cloud With the prevalence of smart mobile devices, companies are facing an increased demand to provide access to data and applications from new channels. However, developing applications for mobile devices poses some unique challenges. Come to this session to learn how Oracle addresses these challenges, offering a simpler way to develop and deploy cross-device mobile applications. See how Oracle Cloud enables you to access applications, data, and services from mobile channels in an easier way.  CON8272 - Oracle Social Network Strategy and Vision One key way of increasing employee productivity is by bringing people, processes, and information together—providing new social capabilities to enable business users to quickly correspond and collaborate on business activities. Oracle WebCenter provides a user engagement platform with social and collaborative technologies to empower business users to focus on their key business processes, applications, and content in the context of their role and process. Attend this session to hear how the latest social capabilities in Oracle Social Network are enabling organizations to transform themselves into social businesses.  --- Tuesday, October 2nd HOL10194 - Enterprise Content Management Simplified: Oracle WebCenter Content’s Next-Generation UI Regardless of the nature of your business, unstructured content underpins many of its daily functions. Whether you are working with traditional presentations, spreadsheets, or text documents—or even with digital assets such as images and multimedia files—your content needs to be accessible and manageable in convenient and intuitive ways to make working with the content easier. Additionally, you need the ability to easily share documents with coworkers to facilitate a collaborative working environment. Come to this session to see how Oracle WebCenter Content’s next-generation user interface helps modern knowledge workers easily manage personal and enterprise documents in a collaborative environment.¶ CON8877 - Develop a Mobile Strategy with Oracle WebCenter: Engage Customers, Employees, and Partners Mobile technology has gone from nice-to-have to a cornerstone of user engagement. Mobile access enables users to have information available at their fingertips, enabling them to take action the moment they make a decision, interact in the moment of convenience, and take advantage of new service offerings in their preferred channels. All your employees have your mobile applications in their pocket; now what are you going to do? It is a critical step for companies to think through what their employees, customers, and partners really need on their devices. Attend this session to see how Oracle WebCenter enables you to better engage your customers, employees, and partners by providing a unified experience across multiple channels. ¶ CON9447 - Enabling Access for Hundreds of Millions of Users How do you grow your business by identifying, authenticating, authorizing, and federating users on the Web, leveraging social identity and the open source OAuth protocol? How do you scale your access management solution to support hundreds of millions of users? With social identity support out of the box, Oracle’s access management solution is also benchmarked for 250-million-user deployment according to real-world customer scenarios. In this session, you will learn about the social identity capability and the 250-million-user benchmark testing of Oracle Access Manager and Oracle Adaptive Access Manager running on Oracle Exalogic and Oracle Exadata. ¶ HOL10207 - Build an Intranet Portal with Oracle WebCenter In this hands-on lab, you’ll work with Oracle WebCenter Portal and Oracle WebCenter Content to build out an enterprise portal that maximizes the productivity of teams and individual contributors. Using browser-based tools, you’ll manage site resources such as page styles, templates, and navigation. You’ll edit content stored in Oracle WebCenter Content directly from your portal. You’ll also experience the latest features that promote collaboration, social networking, and personal productivity. ¶ CON2906 - Get Proactive: Best Practices for Maintaining Oracle Fusion Middleware You chose Oracle Fusion Middleware products to help your organization deliver superior business results. Now learn how to take full advantage of your software with all the great tools, resources, and product updates you’re entitled to through Oracle Support. In this session, Oracle product experts provide proven best practices to help you work more efficiently, plan and prepare for upgrades and patching more effectively, and manage risk. Topics include configuration management tools, remote diagnostics, My Oracle Support Community, and My Oracle Support Lifecycle Advisors. New users and Oracle Fusion Middleware experts alike are guaranteed to leave with fresh ideas and practical, easy-to-implement next steps. ¶ CON8878 - Oracle WebCenter’s Cloud Strategy: From Social and Platform Services to Mashups Cloud computing represents a paradigm shift in how we build applications, automate processes, collaborate, and share and in how we secure our enterprise. Additionally, as you adopt cloud-based services in your organization, it’s likely that you will still have many critical on-premises applications running. With these mixed environments, multiple user interfaces, different security, and multiple datasources and content sources, how do you start evolving your strategy to account for these challenges? Oracle WebCenter offers a complete array of technologies enabling you to solve these challenges and prepare you for the cloud. Attend this session to learn how you can use Oracle WebCenter in the cloud as well as create on-premises and cloud application mash-ups. ¶ CON8901 - Optimize Enterprise Business Processes with Oracle WebCenter and Oracle BPM Do you have business processes that span multiple applications? Are you grappling with how to have visibility across these business processes; how to manage content that is associated with these processes; and, most importantly, how to model and optimize these business processes? Attend this session to hear how Oracle WebCenter and Oracle Business Process Management provide a unique set of integrated solutions to provide a composite application dashboard across these business processes and offer a solution for content-centric business processes. ¶ CON8883 - Deliver Engaging Interfaces to Oracle Applications with Oracle WebCenter Critical business processes live within enterprise applications, and application users need to manage and execute these processes as effectively as possible. Oracle provides a comprehensive user engagement platform to increase user productivity and optimize overall processes within Oracle Applications—Oracle E-Business Suite and Oracle’s Siebel, PeopleSoft, and JD Edwards product families—and third-party applications. Attend this session to learn how you can integrate these applications with Oracle WebCenter to deliver composite application dashboards to your end users—whether they are your customers, partners, or employees—for enhanced usability and Web 2.0–enabled enterprise portals.¶ Wednesday, October 3rd CON8895 - Future-Ready Intranets: How Aramark Re-engineered the Application Landscape There are essential techniques and technologies you can use to deliver employee portals that garner higher productivity, improve business efficiency, and increase user engagement. Attend this session to learn how you can leverage Oracle WebCenter Portal as a user engagement platform for bringing together business process management, enterprise content management, and business intelligence into a highly relevant and integrated experience. Hear how Aramark has leveraged Oracle WebCenter Portal and Oracle WebCenter Content to deliver a unified workspace providing simpler navigation and processing, consolidation of tools, easy access to information, integrated search, and single sign-on. ¶ CON8886 - Content Consolidation: Save Money, Increase Efficiency, and Eliminate Silos Organizations are looking for ways to save money and be more efficient. With content in many different places, it’s difficult to know where to look for a document and whether the document is the most current version. With Oracle WebCenter, content can be consolidated into one best-of-breed repository that is secure, scalable, and integrated with your business processes and applications. Users can find the content they need, where they need it, and ensure that it is the right content. This session covers content challenges that affect your business; content consolidation that can lead to savings in storage and administration costs and can lower risks; and how companies are realizing savings. ¶ CON8911 - Improve Online Experiences for Customers and Partners with Self-Service Portals Are you able to provide your customers and partners an easy-to-use online self-service experience? Are you processing high-volume transactions and struggling with call center bottlenecks or back-end systems that won’t integrate, causing order delays and customer frustration? Are you looking to target content such as product and service offerings to your end users? This session shares approaches to providing targeted delivery as well as strategies and best practices for transforming your business by providing an intuitive user experience for your customers and partners. ¶ CON6156 - Top 10 Ways to Integrate Oracle WebCenter Content This session covers 10 common ways to integrate Oracle WebCenter Content with other enterprise applications and middleware. It discusses out-of-the-box modules that provide expanded features in Oracle WebCenter Content—such as enterprise search, SOA, and BPEL—as well as developer tools you can use to create custom integrations. The presentation also gives guidance on which integration option may work best in your environment. ¶ HOL10207 - Build an Intranet Portal with Oracle WebCenter In this hands-on lab, you’ll work with Oracle WebCenter Portal and Oracle WebCenter Content to build out an enterprise portal that maximizes the productivity of teams and individual contributors. Using browser-based tools, you’ll manage site resources such as page styles, templates, and navigation. You’ll edit content stored in Oracle WebCenter Content directly from your portal. You’ll also experience the latest features that promote collaboration, social networking, and personal productivity. ¶ CON7817 - Migration to Oracle WebCenter Imaging 11g Customers today continually strive to automate business processes, reduce costs, and improve efficiency. The accounts payable process—which is often distributed in nature, requires many approvals, and generates huge volumes of paper invoices—is automated by many customers. In this session, learn how Oracle and SYSTIME have partnered to help a customer migrate its existing Oracle Imaging and Process Management Release 7.6 to the latest Oracle WebCenter Imaging 11g and integrate it with Oracle’s JD Edwards family of products. ¶ CON8910 - How to Engage Customers Across Web, Mobile, and Social Channels Whether on desktops at the office, on tablets at home, or on mobile phones when on the go, today’s customers are always connected. To engage today’s customers, you need to make the online customer experience connected and consistent across a host of devices and multiple channels, including Web, mobile, and social networks. Managing this multichannel environment can result in lots of headaches without the right tools. Attend this session to learn how Oracle WebCenter Sites solves the challenge of multichannel customer engagement. ¶ HOL10206 - Oracle WebCenter Sites 11g: Transforming the Content Contributor Experience Oracle WebCenter Sites 11g makes it easy for marketers and business users to contribute to and manage Websites with the new visual, contextual, and intuitive Web authoring interface. In this hands-on lab, you will create and manage content for a sports-themed Website, using many of the new and enhanced features of the 11g release. ¶ CON8900 - Building Next-Generation Portals: An Interactive Customer Panel Discussion Social and collaborative technologies have changed how people interact, learn, and collaborate, and providing a modern, social Web presence is imperative to remain competitive in today’s market. Can your business benefit from a more collaborative and interactive portal environment for employees, customers, and partners? Attend this session to hear from Oracle WebCenter Portal customers as they share their strategies and best practices for providing users with a modern experience that adapts to their needs and includes personalized access to content in context. The panel also addresses how customers have benefited from creating next-generation portals by migrating from older portal technologies to Oracle WebCenter Portal. ¶ CON9625 - Taking Control of Oracle WebCenter Security Organizations are increasingly looking to extend their Oracle WebCenter portal for social business, to serve external users and provide seamless access to the right information. In particular, many organizations are extending Oracle WebCenter in a business-to-business scenario requiring secure identification and authorization of business partners and their users. This session focuses on how customers are leveraging, securing, and providing access control to Oracle WebCenter portal and mobile solutions. You will learn best practices and hear real-world examples of how to provide flexible and granular access control for Oracle WebCenter deployments, using Oracle Platform Security Services and Oracle Access Management Suite product offerings. ¶ CON8891 - Extending Social into Enterprise Applications and Business Processes Oracle Social Network is an extensible social platform that enables contextual collaboration within enterprise applications and business processes, providing relevant data from across various enterprise systems in one place. Attend this session to see how an Oracle Social Network customer is integrating multiple applications—such as CRM, HCM, and business processes—into Oracle Social Network and Oracle WebCenter to enable individuals and teams to solve complex cross-organizational business problems more effectively by utilizing the social enterprise. ¶ Thursday, October 4th CON8899 - Becoming a Social Business: Stories from the Front Lines of Change What does it really mean to be a social business? How can you change our organization to embrace social approaches? What pitfalls do you need to avoid? In this lively panel discussion, customer and industry thought leaders in social business explore these topics and more as they share their stories of the good, the bad, and the ugly that can happen when embracing social methods and technologies to improve business success. Using moderated questions and open Q&A from the audience, the panel discusses vital topics such as the critical factors for success, the major issues to avoid, how to gain senior executive support for social efforts, how to handle undesired behavior, and how to measure business impact. It takes a thought-provoking look at becoming a social business from the inside. ¶ CON6851 - Oracle WebCenter and Oracle Business Intelligence Enterprise Edition to Create Vendor Portals Large manufacturers of grocery items routinely find themselves depending on the inventory management expertise of their wholesalers and distributors. Inventory costs can be managed more efficiently by the manufacturers if they have better insight into the inventory levels of items carried by their distributors. This creates a unique opportunity for distributors and wholesalers to leverage this knowledge into a revenue-generating subscription service. Oracle Business Intelligence Enterprise Edition and Oracle WebCenter Portal play a key part in enabling creation of business-managed business intelligence portals for vendors. This session discusses one customer that implemented this by leveraging Oracle WebCenter and Oracle Business Intelligence Enterprise Edition. ¶ CON8879 - Provide a Personalized and Consistent Customer Experience in Your Websites and Portals Your customers engage with your company online in different ways throughout their journey—from prospecting by acquiring information on your corporate Website to transacting through self-service applications on your customer portal—and then the cycle begins again when they look for new products and services. Ensuring that the customer experience is consistent and personalized across online properties—from branding and content to interactions and transactions—can be a daunting task. Oracle WebCenter enables you to speak and interact with your customers with one voice across your Websites and portals by providing an integrated platform for delivery of self-service and engagement that unifies and personalizes the online experience. Learn more in this session. ¶ CON8898 - Land Mines, Potholes, and Dirt Roads: Navigating the Way to ECM Nirvana Ten years ago, people were predicting that by this time in history, we’d be some kind of utopian paperless society. As we all know, we’re not there yet, but are we getting closer? What is keeping companies from driving down the road to enterprise content management bliss? Most people understand that using ECM as a central platform enables organizations to expedite document-centric processes, but most business processes in organizations are still heavily paper-based. Many of these processes could be automated and improved with an ECM platform infrastructure. In this panel discussion, you’ll hear from Oracle WebCenter customers that have already solved some of these challenges as they share their strategies for success and roads to avoid along your journey. ¶ CON8908 - Oracle WebCenter Portal: Creating and Using Content Presenter Templates Oracle WebCenter Portal applications use task flows to display and integrate content stored in the Oracle WebCenter Content server. Among the most flexible task flows is Content Presenter, which renders various types of content on an Oracle WebCenter Portal page. Although Oracle WebCenter Portal comes with a set of predefined Content Presenter templates, developers can create their own templates for specific rendering needs. This session shows the lifecycle of developing Content Presenter task flows, including how to create, package, import, modify at runtime, and use such templates. In addition to simple examples with Oracle Application Development Framework (Oracle ADF) UI elements to render the content, it shows how to use other UI technologies, CSS files, and JavaScript libraries. ¶ CON8897 - Using Web Experience Management to Drive Online Marketing Success Every year, the online channel becomes more imperative for driving organizational top-line revenue, but for many companies, mastering how to best market their products and services in a fast-evolving online world with high customer expectations for personalized experiences can be a complex proposition. Come to this panel discussion, and hear directly from online marketers how they are succeeding today by using Web experience management to drive marketing success, using capabilities such as targeting and optimization, user-generated content, mobile site publishing, and site visitor personalization to deliver engaging online experiences. ¶ CON8892 - Oracle’s Journey to Social Business Social business is a revolution, one that is causing rapidly accelerating change in how companies and customers engage with one another and how employees work together. Oracle’s goal in becoming a social business is to create a socially connected organization in which working collaboratively across geographical locations, lines of business, and management chains is second nature, enabling innovative solutions to business challenges. We can achieve this by connecting the right people, finding the right content, communicating with the right people, collaborating at the right time, and building the right communities in the right context—all ready in the CLOUD. Attend this session to see how Oracle is transforming itself into a social business. ¶  ------------ If you've read all the way to the end here - we are REALLY looking forward to seeing you in San Francisco.

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• New features of C# 4.0

  This article covers New features of C# 4.0. Article has been divided into below sections. Introduction. Dynamic Lookup. Named and Optional Arguments. Features for COM interop. Variance. Relationship with Visual Basic. Resources. Other interested readings… 22 New Features of Visual Studio 2008 for .NET Professionals 50 New Features of SQL Server 2008 IIS 7.0 New features Introduction It is now close to a year since Microsoft Visual C# 3.0 shipped as part of Visual Studio 2008. In the VS Managed Languages team we are hard at work on creating the next version of the language (with the unsurprising working title of C# 4.0), and this document is a first public description of the planned language features as we currently see them. Please be advised that all this is in early stages of production and is subject to change. Part of the reason for sharing our plans in public so early is precisely to get the kind of feedback that will cause us to improve the final product before it rolls out. Simultaneously with the publication of this whitepaper, a first public CTP (community technology preview) of Visual Studio 2010 is going out as a Virtual PC image for everyone to try. Please use it to play and experiment with the features, and let us know of any thoughts you have. We ask for your understanding and patience working with very early bits, where especially new or newly implemented features do not have the quality or stability of a final product. The aim of the CTP is not to give you a productive work environment but to give you the best possible impression of what we are working on for the next release. The CTP contains a number of walkthroughs, some of which highlight the new language features of C# 4.0. Those are excellent for getting a hands-on guided tour through the details of some common scenarios for the features. You may consider this whitepaper a companion document to these walkthroughs, complementing them with a focus on the overall language features and how they work, as opposed to the specifics of the concrete scenarios. C# 4.0 The major theme for C# 4.0 is dynamic programming. Increasingly, objects are “dynamic” in the sense that their structure and behavior is not captured by a static type, or at least not one that the compiler knows about when compiling your program. Some examples include a. objects from dynamic programming languages, such as Python or Ruby b. COM objects accessed through IDispatch c. ordinary .NET types accessed through reflection d. objects with changing structure, such as HTML DOM objects While C# remains a statically typed language, we aim to vastly improve the interaction with such objects. A secondary theme is co-evolution with Visual Basic. Going forward we will aim to maintain the individual character of each language, but at the same time important new features should be introduced in both languages at the same time. They should be differentiated more by style and feel than by feature set. The new features in C# 4.0 fall into four groups: Dynamic lookup Dynamic lookup allows you to write method, operator and indexer calls, property and field accesses, and even object invocations which bypass the C# static type checking and instead gets resolved at runtime. Named and optional parameters Parameters in C# can now be specified as optional by providing a default value for them in a member declaration. When the member is invoked, optional arguments can be omitted. Furthermore, any argument can be passed by parameter name instead of position. COM specific interop features Dynamic lookup as well as named and optional parameters both help making programming against COM less painful than today. On top of that, however, we are adding a number of other small features that further improve the interop experience. Variance It used to be that an IEnumerable<string> wasn’t an IEnumerable<object>. Now it is – C# embraces type safe “co-and contravariance” and common BCL types are updated to take advantage of that. Dynamic Lookup Dynamic lookup allows you a unified approach to invoking things dynamically. With dynamic lookup, when you have an object in your hand you do not need to worry about whether it comes from COM, IronPython, the HTML DOM or reflection; you just apply operations to it and leave it to the runtime to figure out what exactly those operations mean for that particular object. This affords you enormous flexibility, and can greatly simplify your code, but it does come with a significant drawback: Static typing is not maintained for these operations. A dynamic object is assumed at compile time to support any operation, and only at runtime will you get an error if it wasn’t so. Oftentimes this will be no loss, because the object wouldn’t have a static type anyway, in other cases it is a tradeoff between brevity and safety. In order to facilitate this tradeoff, it is a design goal of C# to allow you to opt in or opt out of dynamic behavior on every single call. The dynamic type C# 4.0 introduces a new static type called dynamic. When you have an object of type dynamic you can “do things to it” that are resolved only at runtime: dynamic d = GetDynamicObject(…); d.M(7); The C# compiler allows you to call a method with any name and any arguments on d because it is of type dynamic. At runtime the actual object that d refers to will be examined to determine what it means to “call M with an int” on it. The type dynamic can be thought of as a special version of the type object, which signals that the object can be used dynamically. It is easy to opt in or out of dynamic behavior: any object can be implicitly converted to dynamic, “suspending belief” until runtime. Conversely, there is an “assignment conversion” from dynamic to any other type, which allows implicit conversion in assignment-like constructs: dynamic d = 7; // implicit conversion int i = d; // assignment conversion Dynamic operations Not only method calls, but also field and property accesses, indexer and operator calls and even delegate invocations can be dispatched dynamically: dynamic d = GetDynamicObject(…); d.M(7); // calling methods d.f = d.P; // getting and settings fields and properties d[“one”] = d[“two”]; // getting and setting thorugh indexers int i = d + 3; // calling operators string s = d(5,7); // invoking as a delegate The role of the C# compiler here is simply to package up the necessary information about “what is being done to d”, so that the runtime can pick it up and determine what the exact meaning of it is given an actual object d. Think of it as deferring part of the compiler’s job to runtime. The result of any dynamic operation is itself of type dynamic. Runtime lookup At runtime a dynamic operation is dispatched according to the nature of its target object d: COM objects If d is a COM object, the operation is dispatched dynamically through COM IDispatch. This allows calling to COM types that don’t have a Primary Interop Assembly (PIA), and relying on COM features that don’t have a counterpart in C#, such as indexed properties and default properties. Dynamic objects If d implements the interface IDynamicObject d itself is asked to perform the operation. Thus by implementing IDynamicObject a type can completely redefine the meaning of dynamic operations. This is used intensively by dynamic languages such as IronPython and IronRuby to implement their own dynamic object models. It will also be used by APIs, e.g. by the HTML DOM to allow direct access to the object’s properties using property syntax. Plain objects Otherwise d is a standard .NET object, and the operation will be dispatched using reflection on its type and a C# “runtime binder” which implements C#’s lookup and overload resolution semantics at runtime. This is essentially a part of the C# compiler running as a runtime component to “finish the work” on dynamic operations that was deferred by the static compiler. Example Assume the following code: dynamic d1 = new Foo(); dynamic d2 = new Bar(); string s; d1.M(s, d2, 3, null); Because the receiver of the call to M is dynamic, the C# compiler does not try to resolve the meaning of the call. Instead it stashes away information for the runtime about the call. This information (often referred to as the “payload”) is essentially equivalent to: “Perform an instance method call of M with the following arguments: 1. a string 2. a dynamic 3. a literal int 3 4. a literal object null” At runtime, assume that the actual type Foo of d1 is not a COM type and does not implement IDynamicObject. In this case the C# runtime binder picks up to finish the overload resolution job based on runtime type information, proceeding as follows: 1. Reflection is used to obtain the actual runtime types of the two objects, d1 and d2, that did not have a static type (or rather had the static type dynamic). The result is Foo for d1 and Bar for d2. 2. Method lookup and overload resolution is performed on the type Foo with the call M(string,Bar,3,null) using ordinary C# semantics. 3. If the method is found it is invoked; otherwise a runtime exception is thrown. Overload resolution with dynamic arguments Even if the receiver of a method call is of a static type, overload resolution can still happen at runtime. This can happen if one or more of the arguments have the type dynamic: Foo foo = new Foo(); dynamic d = new Bar(); var result = foo.M(d); The C# runtime binder will choose between the statically known overloads of M on Foo, based on the runtime type of d, namely Bar. The result is again of type dynamic. The Dynamic Language Runtime An important component in the underlying implementation of dynamic lookup is the Dynamic Language Runtime (DLR), which is a new API in .NET 4.0. The DLR provides most of the infrastructure behind not only C# dynamic lookup but also the implementation of several dynamic programming languages on .NET, such as IronPython and IronRuby. Through this common infrastructure a high degree of interoperability is ensured, but just as importantly the DLR provides excellent caching mechanisms which serve to greatly enhance the efficiency of runtime dispatch. To the user of dynamic lookup in C#, the DLR is invisible except for the improved efficiency. However, if you want to implement your own dynamically dispatched objects, the IDynamicObject interface allows you to interoperate with the DLR and plug in your own behavior. This is a rather advanced task, which requires you to understand a good deal more about the inner workings of the DLR. For API writers, however, it can definitely be worth the trouble in order to vastly improve the usability of e.g. a library representing an inherently dynamic domain. Open issues There are a few limitations and things that might work differently than you would expect. · The DLR allows objects to be created from objects that represent classes. However, the current implementation of C# doesn’t have syntax to support this. · Dynamic lookup will not be able to find extension methods. Whether extension methods apply or not depends on the static context of the call (i.e. which using clauses occur), and this context information is not currently kept as part of the payload. · Anonymous functions (i.e. lambda expressions) cannot appear as arguments to a dynamic method call. The compiler cannot bind (i.e. “understand”) an anonymous function without knowing what type it is converted to. One consequence of these limitations is that you cannot easily use LINQ queries over dynamic objects: dynamic collection = …; var result = collection.Select(e => e + 5); If the Select method is an extension method, dynamic lookup will not find it. Even if it is an instance method, the above does not compile, because a lambda expression cannot be passed as an argument to a dynamic operation. There are no plans to address these limitations in C# 4.0. Named and Optional Arguments Named and optional parameters are really two distinct features, but are often useful together. Optional parameters allow you to omit arguments to member invocations, whereas named arguments is a way to provide an argument using the name of the corresponding parameter instead of relying on its position in the parameter list. Some APIs, most notably COM interfaces such as the Office automation APIs, are written specifically with named and optional parameters in mind. Up until now it has been very painful to call into these APIs from C#, with sometimes as many as thirty arguments having to be explicitly passed, most of which have reasonable default values and could be omitted. Even in APIs for .NET however you sometimes find yourself compelled to write many overloads of a method with different combinations of parameters, in order to provide maximum usability to the callers. Optional parameters are a useful alternative for these situations. Optional parameters A parameter is declared optional simply by providing a default value for it: public void M(int x, int y = 5, int z = 7); Here y and z are optional parameters and can be omitted in calls: M(1, 2, 3); // ordinary call of M M(1, 2); // omitting z – equivalent to M(1, 2, 7) M(1); // omitting both y and z – equivalent to M(1, 5, 7) Named and optional arguments C# 4.0 does not permit you to omit arguments between commas as in M(1,,3). This could lead to highly unreadable comma-counting code. Instead any argument can be passed by name. Thus if you want to omit only y from a call of M you can write: M(1, z: 3); // passing z by name or M(x: 1, z: 3); // passing both x and z by name or even M(z: 3, x: 1); // reversing the order of arguments All forms are equivalent, except that arguments are always evaluated in the order they appear, so in the last example the 3 is evaluated before the 1. Optional and named arguments can be used not only with methods but also with indexers and constructors. Overload resolution Named and optional arguments affect overload resolution, but the changes are relatively simple: A signature is applicable if all its parameters are either optional or have exactly one corresponding argument (by name or position) in the call which is convertible to the parameter type. Betterness rules on conversions are only applied for arguments that are explicitly given – omitted optional arguments are ignored for betterness purposes. If two signatures are equally good, one that does not omit optional parameters is preferred. M(string s, int i = 1); M(object o); M(int i, string s = “Hello”); M(int i); M(5); Given these overloads, we can see the working of the rules above. M(string,int) is not applicable because 5 doesn’t convert to string. M(int,string) is applicable because its second parameter is optional, and so, obviously are M(object) and M(int). M(int,string) and M(int) are both better than M(object) because the conversion from 5 to int is better than the conversion from 5 to object. Finally M(int) is better than M(int,string) because no optional arguments are omitted. Thus the method that gets called is M(int). Features for COM interop Dynamic lookup as well as named and optional parameters greatly improve the experience of interoperating with COM APIs such as the Office Automation APIs. In order to remove even more of the speed bumps, a couple of small COM-specific features are also added to C# 4.0. Dynamic import Many COM methods accept and return variant types, which are represented in the PIAs as object. In the vast majority of cases, a programmer calling these methods already knows the static type of a returned object from context, but explicitly has to perform a cast on the returned value to make use of that knowledge. These casts are so common that they constitute a major nuisance. In order to facilitate a smoother experience, you can now choose to import these COM APIs in such a way that variants are instead represented using the type dynamic. In other words, from your point of view, COM signatures now have occurrences of dynamic instead of object in them. This means that you can easily access members directly off a returned object, or you can assign it to a strongly typed local variable without having to cast. To illustrate, you can now say excel.Cells[1, 1].Value = "Hello"; instead of ((Excel.Range)excel.Cells[1, 1]).Value2 = "Hello"; and Excel.Range range = excel.Cells[1, 1]; instead of Excel.Range range = (Excel.Range)excel.Cells[1, 1]; Compiling without PIAs Primary Interop Assemblies are large .NET assemblies generated from COM interfaces to facilitate strongly typed interoperability. They provide great support at design time, where your experience of the interop is as good as if the types where really defined in .NET. However, at runtime these large assemblies can easily bloat your program, and also cause versioning issues because they are distributed independently of your application. The no-PIA feature allows you to continue to use PIAs at design time without having them around at runtime. Instead, the C# compiler will bake the small part of the PIA that a program actually uses directly into its assembly. At runtime the PIA does not have to be loaded. Omitting ref Because of a different programming model, many COM APIs contain a lot of reference parameters. Contrary to refs in C#, these are typically not meant to mutate a passed-in argument for the subsequent benefit of the caller, but are simply another way of passing value parameters. It therefore seems unreasonable that a C# programmer should have to create temporary variables for all such ref parameters and pass these by reference. Instead, specifically for COM methods, the C# compiler will allow you to pass arguments by value to such a method, and will automatically generate temporary variables to hold the passed-in values, subsequently discarding these when the call returns. In this way the caller sees value semantics, and will not experience any side effects, but the called method still gets a reference. Open issues A few COM interface features still are not surfaced in C#. Most notably these include indexed properties and default properties. As mentioned above these will be respected if you access COM dynamically, but statically typed C# code will still not recognize them. There are currently no plans to address these remaining speed bumps in C# 4.0. Variance An aspect of generics that often comes across as surprising is that the following is illegal: IList<string> strings = new List<string>(); IList<object> objects = strings; The second assignment is disallowed because strings does not have the same element type as objects. There is a perfectly good reason for this. If it were allowed you could write: objects[0] = 5; string s = strings[0]; Allowing an int to be inserted into a list of strings and subsequently extracted as a string. This would be a breach of type safety. However, there are certain interfaces where the above cannot occur, notably where there is no way to insert an object into the collection. Such an interface is IEnumerable<T>. If instead you say: IEnumerable<object> objects = strings; There is no way we can put the wrong kind of thing into strings through objects, because objects doesn’t have a method that takes an element in. Variance is about allowing assignments such as this in cases where it is safe. The result is that a lot of situations that were previously surprising now just work. Covariance In .NET 4.0 the IEnumerable<T> interface will be declared in the following way: public interface IEnumerable<out T> : IEnumerable { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> : IEnumerator { bool MoveNext(); T Current { get; } } The “out” in these declarations signifies that the T can only occur in output position in the interface – the compiler will complain otherwise. In return for this restriction, the interface becomes “covariant” in T, which means that an IEnumerable<A> is considered an IEnumerable<B> if A has a reference conversion to B. As a result, any sequence of strings is also e.g. a sequence of objects. This is useful e.g. in many LINQ methods. Using the declarations above: var result = strings.Union(objects); // succeeds with an IEnumerable<object> This would previously have been disallowed, and you would have had to to some cumbersome wrapping to get the two sequences to have the same element type. Contravariance Type parameters can also have an “in” modifier, restricting them to occur only in input positions. An example is IComparer<T>: public interface IComparer<in T> { public int Compare(T left, T right); } The somewhat baffling result is that an IComparer<object> can in fact be considered an IComparer<string>! It makes sense when you think about it: If a comparer can compare any two objects, it can certainly also compare two strings. This property is referred to as contravariance. A generic type can have both in and out modifiers on its type parameters, as is the case with the Func<…> delegate types: public delegate TResult Func<in TArg, out TResult>(TArg arg); Obviously the argument only ever comes in, and the result only ever comes out. Therefore a Func<object,string> can in fact be used as a Func<string,object>. Limitations Variant type parameters can only be declared on interfaces and delegate types, due to a restriction in the CLR. Variance only applies when there is a reference conversion between the type arguments. For instance, an IEnumerable<int> is not an IEnumerable<object> because the conversion from int to object is a boxing conversion, not a reference conversion. Also please note that the CTP does not contain the new versions of the .NET types mentioned above. In order to experiment with variance you have to declare your own variant interfaces and delegate types. COM Example Here is a larger Office automation example that shows many of the new C# features in action. using System; using System.Diagnostics; using System.Linq; using Excel = Microsoft.Office.Interop.Excel; using Word = Microsoft.Office.Interop.Word; class Program { static void Main(string[] args) { var excel = new Excel.Application(); excel.Visible = true; excel.Workbooks.Add(); // optional arguments omitted excel.Cells[1, 1].Value = "Process Name"; // no casts; Value dynamically excel.Cells[1, 2].Value = "Memory Usage"; // accessed var processes = Process.GetProcesses() .OrderByDescending(p =&gt; p.WorkingSet) .Take(10); int i = 2; foreach (var p in processes) { excel.Cells[i, 1].Value = p.ProcessName; // no casts excel.Cells[i, 2].Value = p.WorkingSet; // no casts i++; } Excel.Range range = excel.Cells[1, 1]; // no casts Excel.Chart chart = excel.ActiveWorkbook.Charts. Add(After: excel.ActiveSheet); // named and optional arguments chart.ChartWizard( Source: range.CurrentRegion, Title: "Memory Usage in " + Environment.MachineName); //named+optional chart.ChartStyle = 45; chart.CopyPicture(Excel.XlPictureAppearance.xlScreen, Excel.XlCopyPictureFormat.xlBitmap, Excel.XlPictureAppearance.xlScreen); var word = new Word.Application(); word.Visible = true; word.Documents.Add(); // optional arguments word.Selection.Paste(); } } The code is much more terse and readable than the C# 3.0 counterpart. Note especially how the Value property is accessed dynamically. This is actually an indexed property, i.e. a property that takes an argument; something which C# does not understand. However the argument is optional. Since the access is dynamic, it goes through the runtime COM binder which knows to substitute the default value and call the indexed property. Thus, dynamic COM allows you to avoid accesses to the puzzling Value2 property of Excel ranges. Relationship with Visual Basic A number of the features introduced to C# 4.0 already exist or will be introduced in some form or other in Visual Basic: · Late binding in VB is similar in many ways to dynamic lookup in C#, and can be expected to make more use of the DLR in the future, leading to further parity with C#. · Named and optional arguments have been part of Visual Basic for a long time, and the C# version of the feature is explicitly engineered with maximal VB interoperability in mind. · NoPIA and variance are both being introduced to VB and C# at the same time. VB in turn is adding a number of features that have hitherto been a mainstay of C#. As a result future versions of C# and VB will have much better feature parity, for the benefit of everyone. Resources All available resources concerning C# 4.0 can be accessed through the C# Dev Center. Specifically, this white paper and other resources can be found at the Code Gallery site. Enjoy! span.fullpost {display:none;}

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• PSTN Trunk TDM400P Install on Asterisk / Trixbox

  - by Jona

  Hey All, I'm trying to get a TDM400P card with FXO module to connect to our PSTN line. The card is correctly detected by Linux: [trixbox1.localdomain asterisk]# lspci 00:09.0 Communication controller: Tiger Jet Network Inc. Tiger3XX Modem/ISDN interface I've run setup-pstn which produces the following output trixbox1.localdomain ~]# setup-pstn -------------------------------------------------------------- Detecting PSTN cards and USB PSTN Devices -------------------------------------------------------------- Hardware present! STOPPING ASTERISK Asterisk Stopped STOPPING FOP SERVER FOP Server Stopped Unloading DAHDI hardware modules: done Loading DAHDI hardware modules: wct4xxp: [ OK ] wcte12xp: [ OK ] wct1xxp: [ OK ] wcte11xp: [ OK ] wctdm24xxp: [ OK ] opvxa1200: [ OK ] wcfxo: [ OK ] wctdm: [ OK ] wcb4xxp: [ OK ] wctc4xxp: [ OK ] xpp_usb: [ OK ] Running dahdi_cfg: [ OK ] SETTING FILE PERMISSIONS Permissions OK STARTING ASTERISK Asterisk Started STARTING FOP SERVER FOP Server Started Chan Extension Context Language MOH Interpret Blocked State pseudo default en default In Service 1 from-pstn en default In Service dahdi_scan returns: dahdi_scan [1] active=yes alarms=OK description=Wildcard TDM400P REV I Board 5 name=WCTDM/4 manufacturer=Digium devicetype=Wildcard TDM400P REV I location=PCI Bus 00 Slot 10 basechan=1 totchans=4 irq=209 type=analog port=1,FXO port=2,none port=3,none port=4,none And asterisk can see the channel: > trixbox1*CLI> dahdi show channel 1 > Channel: 1LI> File Descriptor: 14 > Span: 11*CLI> Extension: I> Dialing: > noI> Context: from-pstn Caller ID: I> > Calling TON: 0 Caller ID name: > Mailbox: none Destroy: 0LI> InAlarm: > 1LI> Signalling Type: FXS Kewlstart > Radio: 0*CLI> Owner: <None> Real: > <None>> Callwait: <None> Threeway: > <None> Confno: -1LI> Propagated > Conference: -1 Real in conference: 0 > DSP: no1*CLI> Busy Detection: no TDD: > no1*CLI> Relax DTMF: no > Dialing/CallwaitCAS: 0/0 Default law: > ulaw Fax Handled: no Pulse phone: no > DND: no1*CLI> Echo Cancellation: > trixbox1128 taps trixbox1(unless TDM > bridged) currently OFF Actual > Confinfo: Num/0, Mode/0x0000 Actual > Confmute: No > Hookstate (FXS only): Onhook A cat of /etc/asterisk/dahdi.conf shows: [trixbox1.localdomain ~]# cat /etc/asterisk/dahdi-channels.conf ; Autogenerated by /usr/sbin/dahdi_genconf on Tue May 25 17:45:13 2010 ; If you edit this file and execute /usr/sbin/dahdi_genconf again, ; your manual changes will be LOST. ; Dahdi Channels Configurations (chan_dahdi.conf) ; ; This is not intended to be a complete chan_dahdi.conf. Rather, it is intended ; to be #include-d by /etc/chan_dahdi.conf that will include the global settings ; ; Span 1: WCTDM/4 "Wildcard TDM400P REV I Board 5" (MASTER) ;;; line="1 WCTDM/4/0 FXSKS (SWEC: MG2)" signalling=fxs_ks callerid=asreceived group=0 context=from-pstn channel => 1 callerid= group= context=default I have configured a "ZAP Trunk (DAHDI compatibility Mode)" with the ZAP identifier 1 and an outbound route, but when ever I try to make an external call via it I get the "All Circuits are busy now, please try your call again later message". I have one outbound route which uses the dial pattern 9|. and the Trunk Zap/1 and one Zap Trunk which uses Zap Identifier (trunk name): 1 and has no Dial Rules. The FXO module is directly connected to our phone line from BT via a BT-RJ11 cable. When running tail -f /var/log/asterisk/full and placing a call I get the following output: [May 26 11:10:52] VERBOSE[2723] logger.c: == Using SIP RTP TOS bits 184 [May 26 11:10:52] VERBOSE[2723] logger.c: == Using SIP RTP CoS mark 5 [May 26 11:10:52] VERBOSE[2723] logger.c: == Using SIP VRTP TOS bits 136 [May 26 11:10:52] VERBOSE[2723] logger.c: == Using SIP VRTP CoS mark 6 [May 26 11:10:52] WARNING[2661] pbx.c: FONALITY: This thread has already held the conlock, skip locking [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [901483890915@from-internal:1] Macro("SIP/801-b7ce8c28", "user-callerid,SKIPTTL,") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:1] Set("SIP/801-b7ce8c28", "AMPUSER=801") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:2] GotoIf("SIP/801-b7ce8c28", "0?report") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:3] ExecIf("SIP/801-b7ce8c28", "1?Set(REALCALLERIDNUM=801)") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:4] Set("SIP/801-b7ce8c28", "AMPUSER=801") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:5] Set("SIP/801-b7ce8c28", "AMPUSERCIDNAME=Jona") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:6] GotoIf("SIP/801-b7ce8c28", "0?report") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:7] Set("SIP/801-b7ce8c28", "AMPUSERCID=801") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:8] Set("SIP/801-b7ce8c28", "CALLERID(all)="Jona" <801>") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:9] Set("SIP/801-b7ce8c28", "REALCALLERIDNUM=801") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:10] ExecIf("SIP/801-b7ce8c28", "0?Set(CHANNEL(language)=)") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:11] GotoIf("SIP/801-b7ce8c28", "1?continue") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Goto (macro-user-callerid,s,20) [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-user-callerid:20] NoOp("SIP/801-b7ce8c28", "Using CallerID "Jona" <801>") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [901483890915@from-internal:2] Set("SIP/801-b7ce8c28", "_NODEST=") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [901483890915@from-internal:3] Macro("SIP/801-b7ce8c28", "record-enable,801,OUT,") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-record-enable:1] GotoIf("SIP/801-b7ce8c28", "1?check") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Goto (macro-record-enable,s,4) [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-record-enable:4] AGI("SIP/801-b7ce8c28", "recordingcheck,20100526-111052,1274868652.1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Launched AGI Script /var/lib/asterisk/agi-bin/recordingcheck [May 26 11:10:52] VERBOSE[2858] logger.c: recordingcheck,20100526-111052,1274868652.1: Outbound recording not enabled [May 26 11:10:52] VERBOSE[2858] logger.c: -- <SIP/801-b7ce8c28>AGI Script recordingcheck completed, returning 0 [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-record-enable:5] MacroExit("SIP/801-b7ce8c28", "") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [901483890915@from-internal:4] Macro("SIP/801-b7ce8c28", "dialout-trunk,1,01483890915,") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:1] Set("SIP/801-b7ce8c28", "DIAL_TRUNK=1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:2] GosubIf("SIP/801-b7ce8c28", "0?sub-pincheck,s,1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:3] GotoIf("SIP/801-b7ce8c28", "0?disabletrunk,1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:4] Set("SIP/801-b7ce8c28", "DIAL_NUMBER=01483890915") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:5] Set("SIP/801-b7ce8c28", "DIAL_TRUNK_OPTIONS=tr") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:6] Set("SIP/801-b7ce8c28", "OUTBOUND_GROUP=OUT_1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:7] GotoIf("SIP/801-b7ce8c28", "1?nomax") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Goto (macro-dialout-trunk,s,9) [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:9] GotoIf("SIP/801-b7ce8c28", "0?skipoutcid") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:10] Set("SIP/801-b7ce8c28", "DIAL_TRUNK_OPTIONS=") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:11] Macro("SIP/801-b7ce8c28", "outbound-callerid,1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:1] ExecIf("SIP/801-b7ce8c28", "0?Set(CALLERPRES()=)") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:2] ExecIf("SIP/801-b7ce8c28", "0?Set(REALCALLERIDNUM=801)") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:3] GotoIf("SIP/801-b7ce8c28", "1?normcid") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Goto (macro-outbound-callerid,s,6) [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:6] Set("SIP/801-b7ce8c28", "USEROUTCID=") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:7] Set("SIP/801-b7ce8c28", "EMERGENCYCID=") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:8] Set("SIP/801-b7ce8c28", "TRUNKOUTCID=") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:9] GotoIf("SIP/801-b7ce8c28", "1?trunkcid") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Goto (macro-outbound-callerid,s,12) [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:12] ExecIf("SIP/801-b7ce8c28", "0?Set(CALLERID(all)=)") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:13] ExecIf("SIP/801-b7ce8c28", "0?Set(CALLERID(all)=)") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outbound-callerid:14] ExecIf("SIP/801-b7ce8c28", "0?Set(CALLERPRES()=prohib_passed_screen)") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:12] ExecIf("SIP/801-b7ce8c28", "0?AGI(fixlocalprefix)") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:13] Set("SIP/801-b7ce8c28", "OUTNUM=01483890915") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:14] Set("SIP/801-b7ce8c28", "custom=DAHDI/1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:15] ExecIf("SIP/801-b7ce8c28", "0?Set(DIAL_TRUNK_OPTIONS=M(setmusic^))") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:16] Macro("SIP/801-b7ce8c28", "dialout-trunk-predial-hook,") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk-predial-hook:1] MacroExit("SIP/801-b7ce8c28", "") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:17] GotoIf("SIP/801-b7ce8c28", "0?bypass,1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:18] GotoIf("SIP/801-b7ce8c28", "0?customtrunk") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:19] Dial("SIP/801-b7ce8c28", "DAHDI/1/01483890915,300,") in new stack [May 26 11:10:52] WARNING[2858] app_dial.c: Unable to create channel of type 'DAHDI' (cause 0 - Unknown) [May 26 11:10:52] VERBOSE[2858] logger.c: == Everyone is busy/congested at this time (1:0/0/1) [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-dialout-trunk:20] Goto("SIP/801-b7ce8c28", "s-CHANUNAVAIL,1") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Goto (macro-dialout-trunk,s-CHANUNAVAIL,1) [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s-CHANUNAVAIL@macro-dialout-trunk:1] GotoIf("SIP/801-b7ce8c28", "1?noreport") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Goto (macro-dialout-trunk,s-CHANUNAVAIL,3) [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s-CHANUNAVAIL@macro-dialout-trunk:3] NoOp("SIP/801-b7ce8c28", "TRUNK Dial failed due to CHANUNAVAIL (hangupcause: 0) - failing through to other trunks") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [901483890915@from-internal:5] Macro("SIP/801-b7ce8c28", "outisbusy,") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- Executing [s@macro-outisbusy:1] Playback("SIP/801-b7ce8c28", "all-circuits-busy-now,noanswer") in new stack [May 26 11:10:52] VERBOSE[2858] logger.c: -- <SIP/801-b7ce8c28> Playing 'all-circuits-busy-now.ulaw' (language 'en') [May 26 11:10:54] VERBOSE[2858] logger.c: -- Executing [s@macro-outisbusy:2] Playback("SIP/801-b7ce8c28", "pls-try-call-later,noanswer") in new stack [May 26 11:10:54] VERBOSE[2858] logger.c: -- <SIP/801-b7ce8c28> Playing 'pls-try-call-later.ulaw' (language 'en') [May 26 11:10:54] WARNING[2661] pbx.c: FONALITY: This thread has already held the conlock, skip locking [May 26 11:10:54] VERBOSE[2858] logger.c: == Spawn extension (macro-outisbusy, s, 2) exited non-zero on 'SIP/801-b7ce8c28' in macro 'outisbusy' [May 26 11:10:54] VERBOSE[2858] logger.c: == Spawn extension (from-internal, 901483890915, 5) exited non-zero on 'SIP/801-b7ce8c28' [May 26 11:10:54] VERBOSE[2858] logger.c: -- Executing [h@from-internal:1] Macro("SIP/801-b7ce8c28", "hangupcall") in new stack [May 26 11:10:54] VERBOSE[2858] logger.c: -- Executing [s@macro-hangupcall:1] ResetCDR("SIP/801-b7ce8c28", "vw") in new stack [May 26 11:10:54] VERBOSE[2858] logger.c: -- Executing [s@macro-hangupcall:2] NoCDR("SIP/801-b7ce8c28", "") in new stack [May 26 11:10:54] VERBOSE[2858] logger.c: -- Executing [s@macro-hangupcall:3] GotoIf("SIP/801-b7ce8c28", "1?skiprg") in new stack [May 26 11:10:54] VERBOSE[2858] logger.c: -- Goto (macro-hangupcall,s,6) [May 26 11:10:55] VERBOSE[2858] logger.c: -- Executing [s@macro-hangupcall:6] GotoIf("SIP/801-b7ce8c28", "1?skipblkvm") in new stack [May 26 11:10:55] VERBOSE[2858] logger.c: -- Goto (macro-hangupcall,s,9) [May 26 11:10:55] VERBOSE[2858] logger.c: -- Executing [s@macro-hangupcall:9] GotoIf("SIP/801-b7ce8c28", "1?theend") in new stack [May 26 11:10:55] VERBOSE[2858] logger.c: -- Goto (macro-hangupcall,s,11) [May 26 11:10:55] VERBOSE[2858] logger.c: -- Executing [s@macro-hangupcall:11] Hangup("SIP/801-b7ce8c28", "") in new stack [May 26 11:10:55] VERBOSE[2858] logger.c: == Spawn extension (macro-hangupcall, s, 11) exited non-zero on 'SIP/801-b7ce8c28' in macro 'hangupcall' [May 26 11:10:55] VERBOSE[2858] logger.c: == Spawn extension (from-internal, h, 1) exited non-zero on 'SIP/801-b7ce8c28' I'm guessing I've missed a configuration step somewhere but no idea where, any help greatly appreciated.

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• Oracle Support Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1)

  - by faye.todd(at)oracle.com

  Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1) Copyright (c) 2010, Oracle Corporation. All Rights Reserved. In this Document  Purpose  Last Review Date  Instructions for the Reader  Troubleshooting Details     1. Scope and Application      2. Definitions and Classifications     3. How to Use This Guide     4. Basic AQ Propagation Troubleshooting     5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages     6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment     7. Performance Issues  References Applies to: Oracle Server - Enterprise Edition - Version: 8.1.7.0 to 11.2.0.2 - Release: 8.1.7 to 11.2Information in this document applies to any platform. Purpose This document presents a step-by-step methodology for troubleshooting and resolving problems with Advanced Queuing Propagation in both Streams and basic Advanced Queuing environments. It also serves as a master reference for other more specific notes on Oracle Streams Propagation and Advanced Queuing Propagation issues. Last Review Date December 20, 2010 Instructions for the Reader A Troubleshooting Guide is provided to assist in debugging a specific issue. When possible, diagnostic tools are included in the document to assist in troubleshooting. Troubleshooting Details 1. Scope and Application This note is intended for Database Administrators of Oracle databases where issues are being encountered with propagating messages between advanced queues, whether the queues are used for user-created messaging systems or for Oracle Streams. It contains troubleshooting steps and links to notes for further problem resolution.It can also be used a template to document a problem when it is necessary to engage Oracle Support Services. Knowing what is NOT happening can frequently speed up the resolution process by focusing solely on the pertinent problem area. This guide is divided into five parts: Section 2: Definitions and Classifications (discusses the different types and features of propagations possible - helpful for understanding the rest of the guide) Section 3: How to Use this Guide (to be used as a start part for determining the scope of the problem and what sections to consult) Section 4. Basic AQ propagation troubleshooting (applies to both AQ propagation of user enqueued and dequeued messages as well as Oracle Streams propagations) Section 5. Additional troubleshooting steps for AQ propagation of user enqueued and dequeued messages Section 6. Additional troubleshooting steps for Oracle Streams propagation Section 7. Performance issues 2. Definitions and Classifications Given the potential scope of issues that can be encountered with AQ propagation, the first recommended step is to do some basic diagnosis to determine the type of problem that is being encountered. 2.1. What Type of Propagation is Being Used? 2.1.1. Buffered Messaging For an advanced queue, messages can be maintained on disk (persistent messaging) or in memory (buffered messaging). To determine if a queue is buffered or not, reference the GV_$BUFFERED_QUEUES view. If the queue does not appear in this view, it is persistent. 2.1.2. Propagation mode - queue-to-dblink vs queue-to-queue As of 10.2, an AQ propagation can also be defined as queue-to-dblink, or queue-to-queue: queue-to-dblink: The propagation delivers messages or events from the source queue to all subscribing queues at the destination database identified by the dblink. A single propagation schedule is used to propagate messages to all subscribing queues. Hence any changes made to this schedule will affect message delivery to all the subscribing queues. This mode does not support multiple propagations from the same source queue to the same target database. queue-to-queue: Added in 10.2, this propagation mode delivers messages or events from the source queue to a specific destination queue identified on the database link. This allows the user to have fine-grained control on the propagation schedule for message delivery. This new propagation mode also supports transparent failover when propagating to a destination Oracle RAC system. With queue-to-queue propagation, you are no longer required to re-point a database link if the owner instance of the queue fails on Oracle RAC. This mode supports multiple propagations to the same target database if the target queues are different. The default is queue-to-dblink. To verify if queue-to-queue propagation is being used, in non-Streams environments query DBA_QUEUE_SCHEDULES.DESTINATION - if a remote queue is listed along with the remote database link, then queue-to-queue propagation is being used. For Streams environments, the DBA_PROPAGATION.QUEUE_TO_QUEUE column can be checked.See the following note for a method to switch between the two modes:Document 827473.1 How to alter propagation from queue-to-queue to queue-to-dblink 2.1.3. Combined Capture and Apply (CCA) for Streams In 11g Oracle Streams environments, an optimization called Combined Capture and Apply (CCA) is implemented by default when possible. Although a propagation is configured in this case, Streams does not use it; instead it passes information directly from capture to an apply receiver. To see if CCA is in use: COLUMN CAPTURE_NAME HEADING 'Capture Name' FORMAT A30COLUMN OPTIMIZATION HEADING 'CCA Mode?' FORMAT A10SELECT CAPTURE_NAME, DECODE(OPTIMIZATION,0, 'No','Yes') OPTIMIZATIONFROM V$STREAMS_CAPTURE; Also, see the following note:Document 463820.1 Streams Combined Capture and Apply in 11g 2.2. Queue Table Compatibility There are three types of queue table compatibility. In more recent databases, queue tables may be present in all three modes of compatibility: 8.0 - earliest version, deprecated in 10.2 onwards 8.1 - support added for RAC, asynchronous notification, secure queues, queue level access control, rule-based subscribers, separate storage of history information 10.0 - if the database is in 10.1-compatible mode, then the default value for queue table compatibility is 10.0 2.3. Single vs Multiple Consumer Queue Tables If more than one recipient can dequeue a message from a queue, then its queue table is multiple consumer. You can propagate messages from a multiple-consumer queue to a single-consumer queue. Propagation from a single-consumer queue to a multiple-consumer queue is not possible. 3. How to Use This Guide 3.1. Are Messages Being Propagated at All, or is the Propagation Just Slow? Run the following query on the source database for the propagation (assuming that it is running): select TOTAL_NUMBER from DBA_QUEUE_SCHEDULES where QNAME='<source_queue_name>'; If TOTAL_NUMBER is increasing, then propagation is most likely functioning, although it may be slow. For performance issues, see Section 7. 3.2. Propagation Between Persistent User-Created Queues See Sections 4 and 5 (and optionally Section 6 if performance is an issue). 3.3. Propagation Between Buffered User-Created Queues See Sections 4, 5, and 6 (and optionally Section 7 if performance is an issue). 3.4. Propagation between Oracle Streams Queues (without Combined Capture and Apply (CCA) Optimization) See Sections 4 and 6 (and optionally Section 7 if performance is an issue). 3.5. Propagation between Oracle Streams Queues (with Combined Capture and Apply (CCA) Optimization) Although an AQ propagation is not used directly in this case, some characteristics of the message transfer are inferred from the propagation parameters used. Some parts of Sections 4 and 6 still apply. 3.6. Messaging Gateway Propagations This note does not apply to Messaging Gateway propagations. 4. Basic AQ Propagation Troubleshooting 4.1. Double-check Your Code Make sure that you are consistent in your usage of the database link(s) names, queue names, etc. It may be useful to plot a diagram of which queues are connected via which database links to make sure that the logical structure is correct. 4.2. Verify that Job Queue Processes are Running 4.2.1. Versions 10.2 and Lower - DBA_JOBS Package For versions 10.2 and lower, a scheduled propagation is managed by DBMS_JOB package. The propagation is performed by job queue process background processes. Therefore we need to verify that there are sufficient processes available for the propagation process. We should have at least 4 job queue processes running and preferably more depending on the number of other jobs running in the database. It should be noted that for AQ specific work, AQ will only ever use half of the job queue processes available.An issue caused by an inadequate job queue processes parameter setting is described in the following note:Document 298015.1 Kwqjswproc:Excep After Loop: Assigning To Self 4.2.1.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; 4.2.1.2. Job Queue Processes in Memory The following command will show how many job queue processes are currentlyin use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.1.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (spids) of job queue processes involved in propagation via select p.SPID, p.PROGRAM from V$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOBand j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%'; and these SPIDs can be used to check at the operating system level that they exist.In 8i a job queue process will have a name similar to: ora_snp1_<instance_name>.In 9i onwards you will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.2.2. Version 11.1 and Above - Oracle Scheduler In version 11.1 and above, Oracle Scheduler is used to perform AQ and Streams propagations. Oracle Scheduler automatically tunes the number of slave processes for these jobs based on the load on the computer system, and the JOB_QUEUE_PROCESSES initialization parameter is only used to specify the maximum number of slave processes. Therefore, the JOB_QUEUE_PROCESSES initialization parameter does not need to be set (it defaults to a very high number), unless you want to limit the number of slaves that can be created. If JOB_QUEUE_PROCESSES = 0, no propagation jobs will run.See the following note for a discussion of Oracle Streams 11g and Oracle Scheduler:Document 1083608.1 11g Streams and Oracle Scheduler 4.2.2.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0, and preferably be left at its default value. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; To set the JOB_QUEUE_PROCESSES parameter to its default value, run: connect / as sysdbaalter system reset JOB_QUEUE_PROCESSES; and then bounce the instance. 4.2.2.2. Job Queue Processes in Memory The following command will show how many job queue processes are currently in use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.2.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (SPIDs) of job queue processes involved in propagation via col PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_namefrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDRand jr.JOB_name=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%'; and these SPIDs can be used to check at the operating system level that they exist.You will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.3. Check the Alert Log and Any Associated Trace Files The first place to check for propagation failures is the alert logs at all sites (local and if relevant all remote sites). When a job queue process attempts to execute a schedule and fails it will always write an error stack to the alert log. This error stack will also be written in a job queue process trace file, which will be written to the BACKGROUND_DUMP_DEST location for 10.2 and below, and in the DIAGNOSTIC_DEST location for 11g. The fact that errors are written to the alert log demonstrates that the schedule is executing. This means that the problem could be with the set up of the schedule. In this example the ORA-02068 demonstrates that the failure was at the remote site. Further investigation revealed that the remote database was not open, hence the ORA-03114 error. Starting the database resolved the problem. Thu Feb 14 10:40:05 2002 Propagation Schedule for (AQADM.MULTIPLEQ, SHANE816.WORLD) encountered following error:ORA-04052: error occurred when looking up Remote object [email protected]: error occurred at recursive SQL level 4ORA-02068: following severe error from SHANE816ORA-03114: not connected to ORACLEORA-06512: at "SYS.DBMS_AQADM_SYS", line 4770ORA-06512: at "SYS.DBMS_AQADM", line 548ORA-06512: at line 1 Other potential errors that may be written to the alert log can be found in the following notes:Document 827184.1 AQ Propagation with CLOB data types Fails with ORA-22990 (11.1)Document 846297.1 AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn] (10.2, 11.1)Document 731292.1 ORA-25215 Reported on Local Propagation When Using Transformation with ANYDATA queue tables (10.2, 11.1, 11.2)Document 365093.1 ORA-07445 [kwqppay2aqe()+7360] Reported on Propagation of a Transformed Message (10.1, 10.2)Document 219416.1 Advanced Queuing Propagation Fails with ORA-22922 (9.0)Document 1203544.1 AQ Propagation Aborted with ORA-600 [ociksin: invalid status] on SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE After Upgrade (11.1, 11.2)Document 1087324.1 ORA-01405 ORA-01422 reported by Advanced Queuing Propagation schedules after RAC reconfiguration (10.2)Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370 incorrect usage of method" (9.2, 10.2, 11.1, 11.2)Document 332792.1 ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up Statspack (8.1, 9.0, 9.2, 10.1)Document 353325.1 ORA-24056: Internal inconsistency for QUEUE <queue_name> and destination <dblink> (8.1, 9.0, 9.2, 10.1, 10.2, 11.1, 11.2)Document 787367.1 ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2 (10.1, 10.2)Document 566622.1 ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1 (9.2, 10.1)Document 731539.1 ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTP (9.0, 9.2, 10.1, 10.2, 11.1)Document 253131.1 Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555) (9.2)Document 118884.1 How to unschedule a propagation schedule stuck in pending stateDocument 222992.1 DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 1204080.1 AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.Document 1233675.1 AQ Propagation stops after upgrade to 11.2.0.1 ORA-30757 4.3.1. Errors Related to Incorrect Network Configuration The most common propagation errors result from an incorrect network configuration. The list below contains common errors caused by tnsnames.ora file or database links being configured incorrectly: - ORA-12154: TNS:could not resolve service name- ORA-12505: TNS:listener does not currently know of SID given in connect descriptor- ORA-12514: TNS:listener could not resolve SERVICE_NAME - ORA-12541: TNS-12541 TNS:no listener 4.4. Check the Database Links Exist and are Functioning Correctly For schedules to remote databases confirm the database link exists via. SQL> col DBLINK for a45SQL> select QNAME, NVL(REGEXP_SUBSTR(DESTINATION, '[^@]+', 1, 2), DESTINATION) dblink2 from DBA_QUEUE_SCHEDULES3 where MESSAGE_DELIVERY_MODE = 'PERSISTENT';QNAME DBLINK------------------------------ ---------------------------------------------MY_QUEUE ORCL102B.WORLD Connect as the owner of the link and select across it to verify it works and connects to the database we expect. i.e. select * from ALL_QUEUES@ ORCL102B.WORLD; You need to ensure that the userid that scheduled the propagation (using DBMS_AQADM.SCHEDULE_PROPAGATION or DBMS_PROPAGATION_ADM.CREATE_PROPAGATION if using Streams) has access to the database link for the destination. 4.5. Has Propagation Been Correctly Scheduled? Check that the propagation schedule has been created and that a job queue process has been assigned. Look for the entry in DBA_QUEUE_SCHEDULES and SYS.AQ$_SCHEDULES for your schedule. For 10g and below, check that it has a JOBNO entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_JOBS with that JOBNO. For 11g and above, check that the schedule has a JOB_NAME entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_SCHEDULER_JOBS with that JOB_NAME. Check the destination is as intended and spelled correctly. SQL> select SCHEMA, QNAME, DESTINATION, SCHEDULE_DISABLED, PROCESS_NAME from DBA_QUEUE_SCHEDULES;SCHEMA QNAME DESTINATION S PROCESS------- ---------- ------------------ - -----------AQADM MULTIPLEQ AQ$_LOCAL N J000 AQ$_LOCAL in the destination column shows that the queue to which we are propagating to is in the same database as the source queue. If the propagation was to a remote (different) database, a database link will be in the DESTINATION column. The entry in the SCHEDULE_DISABLED column, N, means that the schedule is NOT disabled. If Y (yes) appears in this column, propagation is disabled and the schedule will not be executed. If not using Oracle Streams, propagation should resume once you have enabled the schedule by invoking DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE (for 10.2 Oracle Streams and above, the DBMS_PROPAGATION_ADM.START_PROPAGATION procedure should be used). The PROCESS_NAME is the name of the job queue process currently allocated to execute the schedule. This process is allocated dynamically at execution time. If the PROCESS_NAME column is null (empty) the schedule is not currently executing. You may need to execute this statement a number of times to verify if a process is being allocated. If a process is at some time allocated to the schedule, it is attempting to execute. SQL> select SCHEMA, QNAME, LAST_RUN_DATE, NEXT_RUN_DATE from DBA_QUEUE_SCHEDULES;SCHEMA QNAME LAST_RUN_DATE NEXT_RUN_DATE------ ----- ----------------------- ----------------------- AQADM MULTIPLEQ 13-FEB-2002 13:18:57 13-FEB-2002 13:20:30 In 11g, these dates are expressed in TIMESTAMP WITH TIME ZONE datatypes. If the NEXT_RUN_DATE and NEXT_RUN_TIME columns are null when this statement is executed, the scheduled propagation is currently in progress. If they never change it would suggest that the schedule itself is never executing. If the next scheduled execution is too far away, change the NEXT_TIME parameter of the schedule so that schedules are executed more frequently (assuming that the window is not set to be infinite). Parameters of a schedule can be changed using the DBMS_AQADM.ALTER_PROPAGATION_SCHEDULE call. In 10g and below, scheduling propagation posts a job in the DBA_JOBS view. The columns are more or less the same as DBA_QUEUE_SCHEDULES so you just need to recognize the job and verify that it exists. SQL> select JOB, WHAT from DBA_JOBS where WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';JOB WHAT---- ----------------- 720 next_date := sys.dbms_aqadm.aq$_propaq(job); For 11g, scheduling propagation posts a job in DBA_SCHEDULER_JOBS instead: SQL> select JOB_NAME from DBA_SCHEDULER_JOBS where JOB_NAME like 'AQ_JOB$_%';JOB_NAME------------------------------AQ_JOB$_41 If no job exists, check DBA_QUEUE_SCHEDULES to make sure that the schedule has not been disabled. For 10g and below, the job number is dynamic for AQ propagation schedules. The procedure that is executed to expedite a propagation schedule runs, removes itself from DBA_JOBS, and then reposts a new job for the next scheduled propagation. The job number should therefore always increment unless the schedule has been set up to run indefinitely. 4.6. Is the Schedule Executing but Failing to Complete? Run the following query: SQL> select FAILURES, LAST_ERROR_MSG from DBA_QUEUE_SCHEDULES;FAILURES LAST_ERROR_MSG------------ -----------------------1 ORA-25207: enqueue failed, queue AQADM.INQ is disabled from enqueueingORA-02063: preceding line from SHANE816 The failures column shows how many times we have attempted to execute the schedule and failed. Oracle will attempt to execute the schedule 16 times after which it will be removed from the DBA_JOBS or DBA_SCHEDULER_JOBS view and the schedule will become disabled. The column DBA_QUEUE_SCHEDULES.SCHEDULE_DISABLED will show 'Y'. For 11g and above, the DBA_SCHEDULER_JOBS.STATE column will show 'BROKEN' for the job corresponding to DBA_QUEUE_SCHEDULES.JOB_NAME. Prior to 10g the back off algorithm for failures was exponential, whereas from 10g onwards it is linear. The propagation will become disabled on the 17th attempt. Only the last execution failure will be reflected in the LAST_ERROR_MSG column. That is, if the schedule fails 5 times for 5 different reasons, only the last set of errors will be recorded in DBA_QUEUE_SCHEDULES. Any errors need to be resolved to allow propagation to continue. If propagation has also become disabled due to 17 failures, first resolve the reason for the error and then re-enable the schedule using the DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE procedure, or DBMS_PROPAGATION_ADM.START_PROPAGATION if using 10.2 or above Oracle Streams. As soon as the schedule executes successfully the error message entries will be deleted. Oracle does not keep a history of past failures. However, when using Oracle Streams, the errors will be retained in the DBA_PROPAGATION view even after the schedule resumes successfully. See the following note for instructions on how to clear out the errors from the DBA_PROPAGATION view:Document 808136.1 How to clear the old errors from DBA_PROPAGATION view?If a schedule is active and no errors are being reported then the source queue may not have any messages to be propagated. 4.7. Do the Propagation Notification Queue Table and Queue Exist? Check to see that the propagation notification queue table and queue exist and are enabled for enqueue and dequeue. Propagation makes use of the propagation notification queue for handling propagation run-time events, and the messages in this queue are stored in a SYS-owned queue table. This queue should never be stopped or dropped and the corresponding queue table never be dropped. 10g and belowThe propagation notification queue table is of the format SYS.AQ$_PROP_TABLE_n, where 'n' is the RAC instance number, i.e. '1' for a non-RAC environment. This queue and queue table are created implicitly when propagation is first scheduled. If propagation has been scheduled and these objects do not exist, try unscheduling and rescheduling propagation. If they still do not exist contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ$_PROP_TABLE_1SQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ$_PROP_NOTIFY_1 YES YESAQ$_AQ$_PROP_TABLE_1_E NO NO If the AQ$_PROP_NOTIFY_1 queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_1_E should not be enabled for enqueue or dequeue.11g and aboveThe propagation notification queue table is of the format SYS.AQ_PROP_TABLE, and is created when the database is created. If they do not exist, contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ_PROP_TABLESQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ_PROP_NOTIFY YES YESAQ$_AQ_PROP_TABLE_E NO NO If the AQ_PROP_NOTIFY queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_E should not be enabled for enqueue or dequeue. 4.8. Does the Remote Queue Exist and is it Enabled for Enqueueing? Check that the remote queue the propagation is transferring messages to exists and is enabled for enqueue: SQL> select DESTINATION from USER_QUEUE_SCHEDULES where QNAME = 'OUTQ';DESTINATION-----------------------------------------------------------------------------"AQADM"."INQ"@M2V102.ESSQL> select OWNER, NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED from [email protected];OWNER NAME ENQUEUE DEQUEUE-------- ------ ----------- -----------AQADM INQ YES YES 4.9. Do the Target and Source Database Charactersets Differ? If a message fails to propagate, check the database charactersets of the source and target databases. Investigate whether the same message can propagate between the databases with the same characterset or it is only a particular combination of charactersets which causes a problem. 4.10. Check the Queue Table Type Agreement Propagation is not possible between queue tables which have types that differ in some respect. One way to determine if this is the case is to run the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure for the two queues that the propagation operates on. If the types do not agree, DBMS_AQADM.VERIFY_QUEUE_TYPES will return '0'.For AQ propagation between databases which have different NLS_LENGTH_SEMANTICS settings, propagation will not work, unless the queues are Oracle Streams ANYDATA queues.See the following notes for issues caused by lack of type agreement:Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 353754.1 Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT 4.11. Enable Propagation Tracing 4.11.1. System Level This is set it in the init.ora/spfile as follows: event="24040 trace name context forever, level 10" and restart the instanceThis event cannot be set dynamically with an alter system command until version 10.2: SQL> alter system set events '24040 trace name context forever, level 10'; To unset the event: SQL> alter system set events '24040 trace name context off'; Debugging information will be logged to job queue trace file(s) (jnnn) as propagation takes place. You can check the trace file for errors, and for statements indicating that messages have been sent. For the most part the trace information is understandable. This trace should also be uploaded to Oracle Support if a service request is created. 4.11.2. Attaching to a Specific Process We can also attach to an existing job queue processes that is running a propagation schedule and trace it individually using the oradebug utility, as follows:10.2 and below connect / as sysdbaselect p.SPID, p.PROGRAM from v$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 11g connect / as sysdbacol PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_NAMEfrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 4.11.3. Further Tracing The previous tracing steps only trace the job queue process executing the propagation on the source. At times it is useful to trace the propagation receiver process (the session which is enqueueing the messages into the target queue) on the target database which is associated with the job queue process on the source database.These following queries provide ways of identifying the processes involved in propagation so that you can attach to them via oradebug to generate trace information.In order to identify the propagation receiver process you need to execute the query as a user with privileges to access the v$ views in both the local and remote databases so the database link must connect as a user with those privileges in the remote database. The <DBLINK> in the queries should be replaced by the appropriate database link.The queries have two forms due to the differences between operating systems. The value returned by 'Rem Process' is the operating system identifier of the propagation receiver on the remote database. Once identified, this process can be attached to and traced on the remote database using the commands given in Section 4.11.2.10.2 and below - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from v$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 10.2 and below - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=sr.PROCESS; 11g - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 11g - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=sr.PROCESS;   5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages 5.1. Check the Privileges of All Users Involved Ensure that the owner of the database link has the necessary privileges on the aq packages. SQL> select TABLE_NAME, PRIVILEGE from USER_TAB_PRIVS;TABLE_NAME PRIVILEGE------------------------------ ----------------------------------------DBMS_LOCK EXECUTEDBMS_AQ EXECUTEDBMS_AQADM EXECUTEDBMS_AQ_BQVIEW EXECUTEQT52814_BUFFER SELECT Note that when queue table is created, a view called QT<nnn>_BUFFER is created in the SYS schema, and the queue table owner is given SELECT privileges on it. The <nnn> corresponds to the object_id of the associated queue table. SQL> select * from USER_ROLE_PRIVS;USERNAME GRANTED_ROLE ADM DEF OS_------------------------------ ------------------------------ ---- ---- ---AQ_USER1 AQ_ADMINISTRATOR_ROLE NO YES NOAQ_USER1 CONNECT NO YES NOAQ_USER1 RESOURCE NO YES NO It is good practice to configure central AQ administrative user. All admin and processing jobs are created, executed and administered as this user. This configuration is not mandatory however, and the database link can be owned by any existing queue user. If this latter configuration is used, ensure that the connecting user has the necessary privileges on the AQ packages and objects involved. Privileges for an AQ Administrative user Execute on DBMS_AQADM Execute on DBMS_AQ Granted the AQ_ADMINISTRATOR_ROLE Privileges for an AQ user Execute on DBMS_AQ Execute on the message payload Enqueue privileges on the remote queue Dequeue privileges on the originating queue Privileges need to be confirmed on both sites when propagation is scheduled to remote destinations. Verify that the user ID used to login to the destination through the database link has been granted privileges to use AQ. 5.2. Verify Queue Payload Types AQ will not propagate messages from one queue to another if the payload types of the two queues are not verified to be equivalent. An AQ administrator can verify if the source and destination's payload types match by executing the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure. The results of the type checking will be stored in the SYS.AQ$_MESSAGE_TYPES table. This table can be accessed using the object identifier OID of the source queue and the address database link of the destination queue, i.e. [schema.]queue_name[@destination]. Prior to Oracle 9i the payload (message type) had to be the same for all the queue tables involved in propagation. From Oracle9i onwards a transformation can be used so that payloads can be converted from one type to another. The following procedural call made on the source database can verify whether we can propagate between the source and the destination queue tables. connect aq_user1/[email protected] serverout onDECLARErc_value number;BEGINDBMS_AQADM.VERIFY_QUEUE_TYPES(src_queue_name => 'AQ_USER1.Q_1', dest_queue_name => 'AQ_USER2.Q_2',destination => 'dbl_aq_user2.es',rc => rc_value);dbms_output.put_line('rc_value code is '||rc_value);END;/ If propagation is possible then the return code value will be 1. If it is 0 then propagation is not possible and further investigation of the types and transformations used by and in conjunction with the queue tables is required. With regard to comparison of the types the following sql can be used to extract the DDL for a specific type with' %' changed appropriately on the source and target. This can then be compared for the source and target. SET LONG 20000 set pagesize 50 EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'STORAGE',false); SELECT DBMS_METADATA.GET_DDL('TYPE',t.type_name) from user_types t WHERE t.type_name like '%'; EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'DEFAULT'); 5.3. Check Message State and Destination The first step in this process is to identify the queue table associated with the problem source queue. Although you schedule propagation for a specific queue, most of the meta-data associated with that queue is stored in the underlying queue table. The following statement finds the queue table for a given queue (note that this is a multiple-consumer queue table). SQL> select QUEUE_TABLE from DBA_QUEUES where NAME = 'MULTIPLEQ';QUEUE_TABLE --------------------MULTIPLEQTABLE For a small amount of messages in a multiple-consumer queue table, the following query can be run: SQL> select MSG_STATE, CONSUMER_NAME, ADDRESS from AQ$MULTIPLEQTABLE where QUEUE = 'MULTIPLEQ';MSG_STATE CONSUMER_NAME ADDRESS-------------- ----------------------- -------------READY AQUSER2 [email protected] AQUSER1READY AQUSER3 AQADM.INQ In this example we see 2 messages ready to be propagated to remote queues and 1 that is not. If the address column is blank, the message is not scheduled for propagation and can only be dequeued from the queue upon which it was enqueued. The MSG_STATE column values are discussed in Document 102330.1 Advanced Queueing MSG_STATE Values and their Interpretation. If the address column has a value, the message has been enqueued for propagation to another queue. The first row in the example includes a database link (@M2V102.ES). This demonstrates that the message should be propagated to a queue at a remote database. The third row does not include a database link so will be propagated to a queue that resides on the same database as the source queue. The consumer name is the intended recipient at the target queue. Note that we are not querying the base queue table directly; rather, we are querying a view that is available on top of every queue table, AQ$<queue_table_name>.A more realistic query in an environment where the queue table contains thousands of messages is8.0.3-compatible multiple-consumer queue table and all compatibility single-consumer queue tables select count(*), MSG_STATE, QUEUE from AQ$<queue_table_name>  group by MSG_STATE, QUEUE; 8.1.3 and 10.0-compatible queue tables select count(*), MSG_STATE, QUEUE, CONSUMER_NAME from AQ$<queue_table_name>group by MSG_STATE, QUEUE, CONSUMER_NAME; For multiple-consumer queue tables, if you did not see the expected CONSUMER_NAME , check the syntax of the enqueue code and verify the recipients are declared correctly. If a recipients list is not used on enqueue, check the subscriber list in the AQ$_<queue_table_name>_S view (note that a single-consumer queue table does not have a subscriber view. This view records all members of the default subscription list which were added using the DBMS_AQADM.ADD_SUBSCRIBER procedure and also those enqueued using a recipient list. SQL> select QUEUE, NAME, ADDRESS from AQ$MULTIPLEQTABLE_S;QUEUE NAME ADDRESS---------- ----------- -------------MULTIPLEQ AQUSER2 [email protected] AQUSER1 In this example we have 2 subscribers registered with the queue. We have a local subscriber AQUSER1, and a remote subscriber AQUSER2, on the queue INQ, owned by AQADM, at M2V102.ES. Unless overridden with a recipient list during enqueue every message enqueued to this queue will be propagated to INQ at M2V102.ES.For 8.1 style and above multiple consumer queue tables, you can also check the following information at the target: select CONSUMER_NAME, DEQ_TXN_ID, DEQ_TIME, DEQ_USER_ID, PROPAGATED_MSGID from AQ$<queue_table_name> where QUEUE = '<QUEUE_NAME>'; For 8.0 style queues, if the queue table supports multiple consumers you can obtain the same information from the history column of the queue table: select h.CONSUMER, h.TRANSACTION_ID, h.DEQ_TIME, h.DEQ_USER, h.PROPAGATED_MSGIDfrom AQ$<queue_table_name> t, table(t.history) h where t.Q_NAME = '<QUEUE_NAME>'; A non-NULL TRANSACTION_ID indicates that the message was successfully propagated. Further, the DEQ_TIME indicates the time of propagation, the DEQ_USER indicates the userid used for propagation, and the PROPAGATED_MSGID indicates the message ID of the message that was enqueued at the destination. 6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment 6.1. Is the Propagation Enabled? For a propagation job to propagate messages, the propagation must be enabled. For Streams, a special view called DBA_PROPAGATION exists to convey information about Streams propagations. If messages are not being propagated by a propagation as expected, then the propagation might not be enabled. To query for this: SELECT p.PROPAGATION_NAME, DECODE(s.SCHEDULE_DISABLED, 'Y', 'Disabled','N', 'Enabled') SCHEDULE_DISABLED, s.PROCESS_NAME, s.FAILURES, s.LAST_ERROR_MSGFROM DBA_QUEUE_SCHEDULES s, DBA_PROPAGATION pWHERE p.DESTINATION_DBLINK = NVL(REGEXP_SUBSTR(s.DESTINATION, '[^@]+', 1, 2), s.DESTINATION) AND s.SCHEMA = p.SOURCE_QUEUE_OWNER AND s.QNAME = p.SOURCE_QUEUE_NAME AND MESSAGE_DELIVERY_MODE = 'PERSISTENT' order by PROPAGATION_NAME; At times, the propagation job may become "broken" or fail to start after an error has been encountered or after a database restart. If an error is indicated by the above query, an attempt to disable the propagation and then re-enable it can be made. In the examples below, for the propagation named STRMADMIN_PROPAGATE where the queue name is STREAMS_QUEUE owned by STRMADMIN and the destination database link is ORCL2.WORLD, the commands would be:10.2 and above exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE'); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); If the above does not fix the problem, stop the propagation specifying the force parameter (2nd parameter on stop_propagation) as TRUE: exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE',true); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); The statistics for the propagation as well as any old error messages are cleared when the force parameter is set to TRUE. Therefore if the propagation schedule is stopped with FORCE set to TRUE, and upon restart there is still an error message in DBA_PROPAGATION, then the error message is current.9.2 or 10.1 exec dbms_aqadm.disable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms.aqadm.enable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); If the above does not fix the problem, perform an unschedule of propagation and then schedule_propagation: exec dbms_aqadm.unschedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms_aqadm.schedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); Typically if the error from the first query in Section 6.1 recurs after restarting the propagation as shown above, further troubleshooting of the error is needed. 6.2. Check Propagation Rule Sets and Transformations Inspect the configuration of the rules in the rule set that is associated with the propagation process to make sure that they evaluate to TRUE as expected. If not, then the object or schema will not be propagated. Remember that when a negative rule evaluates to TRUE, the specified object or schema will not be propagated. Finally inspect any rule-based transformations that are implemented with propagation to make sure they are changing the data in the intended way.The following query shows what rule sets are assigned to a propagation: select PROPAGATION_NAME, RULE_SET_OWNER||'.'||RULE_SET_NAME "Positive Rule Set",NEGATIVE_RULE_SET_OWNER||'.'||NEGATIVE_RULE_SET_NAME "Negative Rule Set"from DBA_PROPAGATION; The next two queries list the propagation rules and their conditions. The first is for the positive rule set, the second is for the negative rule set: set long 4000select rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES rwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER and RULE_SET_NAME in(select RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME;   set long 4000select c.PROPAGATION_NAME, rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES r ,DBA_PROPAGATION cwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER andrsr.RULE_SET_OWNER=c.NEGATIVE_RULE_SET_OWNER and rsr.RULE_SET_NAME=c.NEGATIVE_RULE_SET_NAMEand rsr.RULE_SET_NAME in(select NEGATIVE_RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME; 6.3. Determining the Total Number of Messages and Bytes Propagated As in Section 3.1, determining if messages are flowing can be instructive to see whether the propagation is entirely hung or just slow. If the propagation is not in flow control (see Section 6.5.2), but the statistics are incrementing slowly, there may be a performance issue. For Streams implementations two views are available that can assist with this that can show the number of messages sent by a propagation, as well as the number of acknowledgements being returned from the target site: the V$PROPAGATION_SENDER view at the Source site and the V$PROPAGATION_RECEIVER view at the destination site. It is helpful to query both to determine if messages are being delivered to the target. Look for the statistics to increase.Source: select QUEUE_SCHEMA, QUEUE_NAME, DBLINK,HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS, TOTAL_BYTESfrom V$PROPAGATION_SENDER; Target: select SRC_QUEUE_SCHEMA, SRC_QUEUE_NAME, SRC_DBNAME, DST_QUEUE_SCHEMA, DST_QUEUE_NAME, HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS from V$PROPAGATION_RECEIVER; 6.4. Check Buffered Subscribers The V$BUFFERED_SUBSCRIBERS view displays information about subscribers for all buffered queues in the instance. This view can be queried to make sure that the site that the propagation is propagating to is listed as a subscriber address for the site being propagated from: select QUEUE_SCHEMA, QUEUE_NAME, SUBSCRIBER_ADDRESS from V$BUFFERED_SUBSCRIBERS; The SUBSCRIBER_ADDRESS column will not be populated when the propagation is local (between queues on the same database). 6.5. Common Streams Propagation Errors 6.5.1. ORA-02082: A loopback database link must have a connection qualifier. This error can occur if you use the Streams Setup Wizard in Oracle Enterprise Manager without first configuring the GLOBAL_NAME for your database. 6.5.2. ORA-25307: Enqueue rate too high. Enable flow control DBA_QUEUE_SCHEDULES will display this informational message for propagation when the automatic flow control (10g feature of Streams) has been invoked.Similar to Streams capture processes, a Streams propagation process can also go into a state of 'flow control. This is an informative message that indicates flow control has been automatically enabled to reduce the rate at which messages are being enqueued into at target queue.This typically occurs when the target site is unable to keep up with the rate of messages flowing from the source site. Other than checking that the apply process is running normally on the target site, usually no action is required by the DBA. Propagation and the capture process will be resumed automatically when the target site is able to accept more messages.The following document contains more information:Document 302109.1 Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlSee the following document for one potential cause of this situation:Document 1097115.1 Oracle Streams Apply Reader is in 'Paused' State 6.5.3. ORA-25315 unsupported configuration for propagation of buffered messages This error typically occurs when the target database is RAC and usually indicates that an attempt was made to propagate buffered messages with the database link pointing to an instance in the destination database which is not the owner instance of the destination queue. To resolve the problem, use queue-to-queue propagation for buffered messages. 6.5.4. ORA-600 [KWQBMCRCPTS101] after dropping / recreating propagation For cause/fixes refer to:Document 421237.1 ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams Propagation 6.5.5. Stopping or Dropping a Streams Propagation Hangs See the following note:Document 1159787.1 Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It Hang 6.6. Streams Propagation-Related Notes for Common Issues Document 437838.1 Streams Specific PatchesDocument 749181.1 How to Recover Streams After Dropping PropagationDocument 368912.1 Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentDocument 564649.1 ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveDocument 553017.1 Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201Document 944846.1 Streams Propagation Fails Ora-7445 [kohrsmc]Document 745601.1 ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'Document 333068.1 ORA-23603: Streams Enqueue Aborted Eue To Low SGADocument 363496.1 Ora-25315 Propagating on RAC StreamsDocument 368237.1 Unable to Unschedule Propagation. Streams Queue is InvalidDocument 436332.1 dbms_propagation_adm.stop_propagation hangsDocument 727389.1 Propagation Fails With ORA-12528Document 730911.1 ORA-4063 Is Reported After Dropping Negative Prop.RulesetDocument 460471.1 Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsDocument 1165583.1 ORA-600 [kwqpuspse0-ack] In Streams EnvironmentDocument 1059029.1 Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationDocument 556309.1 Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedDocument 839568.1 Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''Document 311021.1 Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredDocument 359971.1 STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068Document 1101616.1 DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747 7. Performance Issues A propagation may seem to be slow if the queries from Sections 3.1 and 6.3 show that the message statistics are not changing quickly. In Oracle Streams, this more usually is due to a slow apply process at the target rather than a slow propagation. Propagation could be inferred to be slow if the message statistics are changing, and the state of a capture process according to V$STREAMS_CAPTURE.STATE is PAUSED FOR FLOW CONTROL, but an ORA-25307 'Enqueue rate too high. Enable flow control' warning is NOT observed in DBA_QUEUE_SCHEDULES per Section 6.5.2. If this is the case, see the following notes / white papers for suggestions to increase performance:Document 335516.1 Master Note for Streams Performance RecommendationsDocument 730036.1 Overview for Troubleshooting Streams Performance IssuesDocument 780733.1 Streams Propagation Tuning with Network ParametersWhite Paper: http://www.oracle.com/technetwork/database/features/availability/maa-wp-10gr2-streams-performance-130059.pdfWhite Paper: Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2, http://www.oracle.com/technetwork/database/features/availability/maa-10gr2-streams-configuration-132039.pdf, See APPENDIX A: USING STREAMS CONFIGURATIONS OVER A NETWORKFor basic AQ propagation, the network tuning in the aforementioned Appendix A of the white paper 'Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2' is applicable. References NOTE:102330.1 - Advanced Queueing MSG_STATE Values and their InterpretationNOTE:102771.1 - Advanced Queueing Propagation using PL/SQLNOTE:1059029.1 - Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationNOTE:1079577.1 - Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"NOTE:1083608.1 - 11g Streams and Oracle SchedulerNOTE:1087324.1 - ORA-01405 ORA-01422 reported by Adavanced Queueing Propagation schedules after RAC reconfigurationNOTE:1097115.1 - Oracle Streams Apply Reader is in 'Paused' StateNOTE:1101616.1 - DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747NOTE:1159787.1 - Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It HangNOTE:1165583.1 - ORA-600 [kwqpuspse0-ack] In Streams EnvironmentNOTE:118884.1 - How to unschedule a propagation schedule stuck in pending stateNOTE:1203544.1 - AQ PROPAGATION ABORTED WITH ORA-600[OCIKSIN: INVALID STATUS] ON SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE AFTER UPGRADENOTE:1204080.1 - AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.NOTE:219416.1 - Advanced Queuing Propagation fails with ORA-22922NOTE:222992.1 - DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082NOTE:253131.1 - Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555)NOTE:282987.1 - Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueNOTE:298015.1 - Kwqjswproc:Excep After Loop: Assigning To SelfNOTE:302109.1 - Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlNOTE:311021.1 - Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredNOTE:332792.1 - ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up StatspackNOTE:333068.1 - ORA-23603: Streams Enqueue Aborted Eue To Low SGANOTE:335516.1 - Master Note for Streams Performance RecommendationsNOTE:353325.1 - ORA-24056: Internal inconsistency for QUEUE and destination NOTE:353754.1 - Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT.NOTE:359971.1 - STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068NOTE:363496.1 - Ora-25315 Propagating on RAC StreamsNOTE:365093.1 - ORA-07445 [kwqppay2aqe()+7360] reported on Propagation of a Transformed MessageNOTE:368237.1 - Unable to Unschedule Propagation. Streams Queue is InvalidNOTE:368912.1 - Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentNOTE:421237.1 - ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams PropagationNOTE:436332.1 - dbms_propagation_adm.stop_propagation hangsNOTE:437838.1 - Streams Specific PatchesNOTE:460471.1 - Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsNOTE:463820.1 - Streams Combined Capture and Apply in 11gNOTE:553017.1 - Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201NOTE:556309.1 - Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedNOTE:564649.1 - ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveNOTE:566622.1 - ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1NOTE:727389.1 - Propagation Fails With ORA-12528NOTE:730036.1 - Overview for Troubleshooting Streams Performance IssuesNOTE:730911.1 - ORA-4063 Is Reported After Dropping Negative Prop.RulesetNOTE:731292.1 - ORA-25215 Reported On Local Propagation When Using Transformation with ANYDATA queue tablesNOTE:731539.1 - ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTPNOTE:745601.1 - ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'NOTE:749181.1 - How to Recover Streams After Dropping PropagationNOTE:780733.1 - Streams Propagation Tuning with Network ParametersNOTE:787367.1 - ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2NOTE:808136.1 - How to clear the old errors from DBA_PROPAGATION view ?NOTE:827184.1 - AQ Propagation with CLOB data types Fails with ORA-22990NOTE:827473.1 - How to alter propagation from queue_to_queue to queue_to_dblinkNOTE:839568.1 - Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''NOTE:846297.1 - AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn]NOTE:944846.1 - Streams Propagation Fails Ora-7445 [kohrsmc]

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• Red Gate Coder interviews: Alex Davies

  - by Michael Williamson

  Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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