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  • Why i cannot get the frame of a UIView in order to move it? The view is defined.

    - by Jann
    I am creating a nav-based app with a view that floats at the bottom of the screen (Alpha .7 most of the time). I create it like this... // stuff to create the tabbar/nav bar. // THIS ALL WORKS... // then add it to subview. [window addSubview:tabBarController.view]; // need this last line to display the window (and tab bar controller) [window makeKeyAndVisible]; // Okay, here is the code i am using to create a grey-ish strip exactly `zlocationAccuracyHeight` pixels high at `zlocationAccuracyVerticalStartPoint` starting point vertically. CGRect locationManagerAccuracyUIViewFrame = CGRectMake(0,zlocationAccuracyVerticalStartPoint,[[UIScreen mainScreen] bounds].size.width,zlocationAccuracyHeight); self.locationManagerAccuracyUIView = [[UIView alloc] initWithFrame:locationManagerAccuracyUIViewFrame]; self.locationManagerAccuracyUIView.autoresizingMask = (UIViewAutoresizingFlexibleWidth); self.locationManagerAccuracyUIView.backgroundColor = [UIColor darkGrayColor]; [self.locationManagerAccuracyUIView setAlpha:0]; CGRect locationManagerAccuracyLabelFrame = CGRectMake(0, 0,[[UIScreen mainScreen] bounds].size.width,zlocationAccuracyHeight); locationManagerAccuracyLabel = [[UILabel alloc] initWithFrame:locationManagerAccuracyLabelFrame]; if ([myGizmoClass useLocationServices] == 0) { locationManagerAccuracyLabel.text = @"GPS Accuracy: Using Manual Location"; } else { locationManagerAccuracyLabel.text = @"GPS Accuracy: One Moment Please..."; } locationManagerAccuracyLabel.font = [UIFont boldSystemFontOfSize:12]; locationManagerAccuracyLabel.textAlignment = UITextAlignmentCenter; locationManagerAccuracyLabel.textColor = [UIColor whiteColor]; locationManagerAccuracyLabel.backgroundColor = [UIColor clearColor]; [locationManagerAccuracyLabel setAlpha:0]; [self.locationManagerAccuracyUIView addSubview: locationManagerAccuracyLabel]; [window addSubview: self.locationManagerAccuracyUIView]; this all works (i am not sure about the order i create the uiview in ... meaning i am creating the frame, the view, creating the "accuracy text" and adding that to the view, then adding the uiview as a subview of the window . It works and seems correct in my logic. So, here is the tough part. I have a timer that i am testing with. I am trying to float the uiview up by 30 pix. here is that code: [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.3]; CGRect rect = [ self.locationManagerAccuracyUIView frame]; NSLog(@"ORIGIN: %d x %d (%@)\n",rect.origin.x,rect.origin.y,rect); rect.origin.y -= 30; [UIView commitAnimations]; The problem? rect is nill, rect.origin.x and rect.origin.y are both zero. Can anyone tell me why? Here is how i set up self.locationManagerAccuracyUIView in my files: Delegate.h UIView *locationManagerAccuracyUIView; UILabel *locationManagerAccuracyLabel; ... @property (nonatomic, retain) IBOutlet UIView *locationManagerAccuracyUIView; @property (nonatomic, retain) IBOutlet UILabel *locationManagerAccuracyLabel; Delegate.m ... @synthesize locationManagerAccuracyUIView; @synthesize locationManagerAccuracyLabel; ... BTW: Other places in another timer i DO set the alpha to fade in and out and THAT works! So locationManagerAccuracyUIView is valid and defined as a view... For instance: [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.5]; [locationManagerAccuracyLabel setAlpha:1]; [UIView commitAnimations]; [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.5]; [self.locationManagerAccuracyUIView setAlpha:.7]; [UIView commitAnimations]; ...and it DOES work. Can anyone help me? As an aside: I know, when typing this I used self.locationManagerAccuracyUIView and locationManagerAccuracyUIView interchangeably to see if for some reason that was the issue. It is not. :) Thx

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  • I asked this yesterday, after the input given I'm still having trouble implementing..

    - by Josh
    I'm not sure how to fix this or what I did wrong, but whenever I enter in a value it just closes out the run prompt. So, seems I do have a problem somewhere in my coding. Whenever I run the program and input a variable, it always returns the same answer.."The content at location 76 is 0." On that note, someone told me that "I don't know, but I suspect that Program A incorrectly has a fixed address being branched to on instructions 10 and 11." - mctylr but I'm not sure how to fix that.. I'm trying to figure out how to incorporate this idea from R Samuel Klatchko.. I'm still not sure what I'm missing but I can't get it to work.. const int OP_LOAD = 3; const int OP_STORE = 4; const int OP_ADD = 5; ... const int OP_LOCATION_MULTIPLIER = 100; mem[0] = OP_LOAD * OP_LOCATION_MULTIPLIER + ...; mem[1] = OP_ADD * OP_LOCATION_MULTIPLIER + ...; operand = memory[ j ] % OP_LOCATION_MULTIPLIER; operation = memory[ j ] / OP_LOCATION_MULTIPLIER; I'm new to programming, I'm not the best, so I'm going for simplicity. Also this is an SML program. Anyway, this IS a homework assignment and I'm wanting a good grade on this. So I was looking for input and making sure this program will do what I'm hoping they are looking for. Anyway, here are the instructions: Write SML (Simpletron Machine language) programs to accomplish each of the following task: A) Use a sentinel-controlled loop to read positive number s and compute and print their sum. Terminate input when a neg number is entered. B) Use a counter-controlled loop to read seven numbers, some positive and some negative, and compute + print the avg. C) Read a series of numbers, and determine and print the largest number. The first number read indicates how many numbers should be processed. Without further a due, here is my program. All together. int main() { const int READ = 10; const int WRITE = 11; const int LOAD = 20; const int STORE = 21; const int ADD = 30; const int SUBTRACT = 31; const int DIVIDE = 32; const int MULTIPLY = 33; const int BRANCH = 40; const int BRANCHNEG = 41; const int BRANCHZERO = 41; const int HALT = 43; int mem[100] = {0}; //Making it 100, since simpletron contains a 100 word mem. int operation; //taking the rest of these variables straight out of the book seeing as how they were italisized. int operand; int accum = 0; // the special register is starting at 0 int j; // This is for part a, it will take in positive variables in a sent-controlled loop and compute + print their sum. Variables from example in text. memory [0] = 1010; memory [01] = 2009; memory [02] = 3008; memory [03] = 2109; memory [04] = 1109; memory [05] = 4300; memory [06] = 1009; j = 0; //Makes the variable j start at 0. while ( true ) { operand = memory[ j ]%100; // Finds the op codes from the limit on the memory (100) operation = memory[ j ]/100; //using a switch loop to set up the loops for the cases switch ( operation ){ case 10: //reads a variable into a word from loc. Enter in -1 to exit cout <<"\n Input a positive variable: "; cin >> memory[ operand ]; break; case 11: // takes a word from location cout << "\n\nThe content at location " << operand << "is " << memory[operand]; break; case 20:// loads accum = memory[ operand ]; break; case 21: //stores memory[ operand ] = accum; break; case 30: //adds accum += mem[operand]; break; case 31: // subtracts accum-= memory[ operand ]; break; case 32: //divides accum /=(memory[ operand ]); break; case 33: // multiplies accum*= memory [ operand ]; break; case 40: // Branches to location j = -1; break; case 41: //branches if acc. is < 0 if (accum < 0) j = 5; break; case 42: //branches if acc = 0 if (accum == 0) j = 5; break; case 43: // Program ends exit(0); break; } j++; } return 0; }

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  • RSA encryption/ Decryption in a client server application

    - by user308806
    Hi guys, probably missing something very straight forward on this, but please forgive me, I'm very naive! Have a client server application where the client identifies its self with an RSA encrypted username & password. Unfortunately I'm getting a "bad padding exception: data must start with zero" when i try to decrypt with the public key on the client side. I'm fairly sure the key is correct as I have tested encrypting with public key then decrypting with private key on the client side with no problems at all. Just seems when I transfer it over the connection it messses it up somehow?! Using PrintWriter & BufferedReader on the sockets if thats of importance. EncodeBASE64 & DecodeBASE64 encode byte[] to 64base and vice versa respectively. Any ideas guys?? Client side: Socket connectionToServer = new Socket("127.0.0.1", 7050); InputStream in = connectionToServer.getInputStream(); DataInputStream dis = new DataInputStream(in); int length = dis.readInt(); byte[] data = new byte[length]; // dis.readFully(data); dis.read(data); System.out.println("The received Data*****************************************"); System.out.println("The length of bits "+ length); System.out.println(data); System.out.println("***********************************************************"); Decryption d = new Decryption(); byte [] ttt = d.decrypt(data); System.out.print(data); String ss = new String(ttt); System.out.println("***********************"); System.out.println(ss); System.out.println("************************"); Server Side: in = connectionFromClient.getInputStream(); OutputStream out = connectionFromClient.getOutputStream(); DataOutputStream dataOut = new DataOutputStream(out); LicenseList licenses = new LicenseList(); String ValidIDs = licenses.getAllIDs(); System.out.println(ValidIDs); Encryption enc = new Encryption(); byte[] encrypted = enc.encrypt(ValidIDs); byte[] dd = enc.encrypt(ValidIDs); String tobesent = new String(dd); //byte[] rsult = enc.decrypt(dd); //String tt = String(rsult); System.out.println("The sent data**********************************************"); System.out.println(dd); String temp = new String(dd); System.out.println(temp); System.out.println("*************************************************************"); //BufferedWriter bf = new BufferedWriter(OutputStreamWriter(out)); //dataOut.write(ValidIDs.getBytes().length); dataOut.writeInt(ValidIDs.getBytes().length); dataOut.flush(); dataOut.write(encrypted); dataOut.flush(); System.out.println("********Testing**************"); System.out.println("Here are the ids:::"); System.out.println(licenses.getAllIDs()); System.out.println("**********************"); //bw.write("it is working well\n");

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  • Jquery autocomplete UI - No results on multiple fields

    - by pjammer
    Andrew's answer to my comment has sparked this question. According to his awesome answer in the link above, the code at the bottom of the question will only work for ONE widget. But it's killer nice code and makes sense... I guess I want the best of both worlds. Nice JS, (if that is possible) and to have the zero results show() just the element that we're using at the time. This code snippet is the main crux of my problem, as I see it: source: function (request, response) { jQuery.ajax({ url: "/autocomplete.json", data: { term: request.term }, success: function (data) { if (data.length == 0) { jQuery('span.guest_investor_email').show(); jQuery('span.investor_field_delete_button').show(); } response(data); } }); Currently: I have a button on my page that says "Add more Information" and each time you click it, a new instance of the autocomplete text field appears, complete with some hidden fields and a display:none; on guest_investor_email. If I use the autocomplete text field, say 3 times, and i have 3 autocomplete instances on the page and the third one finds 0 results: The code will show() all 3 instances of the guest_investor_email text field, instead of just this one that is blank. QUESTION: How do i get something like jQuery(this).siblings(('span.guest_investor_email').show(); to work? this is an Object and not an array of elements to select. If it isn't with this I don't mind, as long as I know how to get at it. Thanks. Full Code: jQuery(".auto_search_complete").live("click", function() { jQuery(this).autocomplete({ minLength: 3, source: function (request, response) { jQuery.ajax({ url: "/autocomplete.json", data: { term: request.term }, success: function (data) { if (data.length == 0) { jQuery('span.guest_investor_email').show(); jQuery('span.investor_field_delete_button').show(); } response(data); } }); }, focus: function(event, ui) { jQuery(this).val(ui.item.user ? ui.item.user.name : ui.item.pitch.name); return false; }, select: function(event, ui) { jQuery(this).val(ui.item.user ? ui.item.user.name : ui.item.pitch.name); jQuery(this).siblings('div.hidden_fields').children('.poly_id').val(ui.item.user ? ui.item.user.id : ui.item.pitch.id); jQuery(this).siblings('div.hidden_fields').children('.poly_type').val(ui.item.user ? "User" : "Pitch"); jQuery(this).siblings('span.guest_investor_email').hide(); jQuery(this).siblings('span.investor_field_delete_button').show(); jQuery(this).attr('readonly','readonly'); jQuery(this).attr('id', "investor-selected"); return false; } }).each(function() { jQuery(this).data( "autocomplete" )._renderItem = function( ul, item ) { return jQuery( "" ) .data( "item.autocomplete", item ) .append("" + (item.user ? item.user.name : item.pitch.name) + "" + (item.user ? item.user.investor_type : item.pitch.investor_type) + " - " + (item.user ? item.user.city : item.pitch.city) + "" ) .appendTo( ul ); }; }); });

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  • Odd C++ template behaviour with static member vars

    - by jon hanson
    This piece of code is supposed to calculate an approximation to e (i.e. the mathematical constant ~ 2.71828183) at compile-time, using the following approach; e1 = 2 / 1 e2 = (2 * 2 + 1) / (2 * 1) = 5 / 2 = 2.5 e3 = (3 * 5 + 1) / (3 * 2) = 16 / 6 ~ 2.67 e4 = (4 * 16 + 1) / (4 * 6) = 65 / 24 ~ 2.708 ... e(i) = (e(i-1).numer * i + 1) / (e(i-1).denom * i) The computation is returned via the result static member however, after 2 iterations it yields zero instead of the expected value. I've added a static member function f() to compute the same value and that doesn't exhibit the same problem. #include <iostream> #include <iomanip> // Recursive case. template<int ITERS, int NUMERATOR = 2, int DENOMINATOR = 1, int I = 2> struct CalcE { static const double result; static double f () {return CalcE<ITERS, NUMERATOR * I + 1, DENOMINATOR * I, I + 1>::f ();} }; template<int ITERS, int NUMERATOR, int DENOMINATOR, int I> const double CalcE<ITERS, NUMERATOR, DENOMINATOR, I>::result = CalcE<ITERS, NUMERATOR * I + 1, DENOMINATOR * I, I + 1>::result; // Base case. template<int ITERS, int NUMERATOR, int DENOMINATOR> struct CalcE<ITERS, NUMERATOR, DENOMINATOR, ITERS> { static const double result; static double f () {return result;} }; template<int ITERS, int NUMERATOR, int DENOMINATOR> const double CalcE<ITERS, NUMERATOR, DENOMINATOR, ITERS>::result = static_cast<double>(NUMERATOR) / DENOMINATOR; // Test it. int main (int argc, char* argv[]) { std::cout << std::setprecision (8); std::cout << "e2 ~ " << CalcE<2>::result << std::endl; std::cout << "e3 ~ " << CalcE<3>::result << std::endl; std::cout << "e4 ~ " << CalcE<4>::result << std::endl; std::cout << "e5 ~ " << CalcE<5>::result << std::endl; std::cout << std::endl; std::cout << "e2 ~ " << CalcE<2>::f () << std::endl; std::cout << "e3 ~ " << CalcE<3>::f () << std::endl; std::cout << "e4 ~ " << CalcE<4>::f () << std::endl; std::cout << "e5 ~ " << CalcE<5>::f () << std::endl; return 0; } I've tested this with VS 2008 and VS 2010, and get the same results in each case: e2 ~ 2 e3 ~ 2.5 e4 ~ 0 e5 ~ 0 e2 ~ 2 e3 ~ 2.5 e4 ~ 2.6666667 e5 ~ 2.7083333 Why does result not yield the expected values whereas f() does? According to Rotsor's comment below, this does work with GCC, so I guess the question is, am i relying on some type of undefined behaviour with regards to static initialisation order, or is this a bug with Visual Studio?

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  • Overloading '-' for array subtraction

    - by Chris Wilson
    I am attempting to subtract two int arrays, stored as class members, using an overloaded - operator, but I'm getting some peculiar output when I run tests. The overload definition is Number& Number :: operator-(const Number& NumberObject) { for (int count = 0; count < NumberSize; count ++) { Value[count] -= NumberObject.Value[count]; } return *this; } Whenever I run tests on this, NumberObject.Value[count] always seems to be returning a zero value. Can anyone see where I'm going wrong with this? The line in main() where this subtraction is being carried out is cout << "The difference is: " << ArrayOfNumbers[0] - ArrayOfNumbers[1] << endl; ArrayOfNumbers contains two Number objects. The class declaration is #include <iostream> using namespace std; class Number { private: int Value[50]; int NumberSize; public: Number(); // Default constructor Number(const Number&); // Copy constructor Number(int, int); // Non-default constructor void SetMemberValues(int, int); // Manually set member values int GetNumberSize() const; // Return NumberSize member int GetValue() const; // Return Value[] member Number& operator-=(const Number&); }; inline Number operator-(Number Lhs, const Number& Rhs); ostream& operator<<(ostream&, const Number&); The full class definition is as follows: #include <iostream> #include "../headers/number.h" using namespace std; // Default constructor Number :: Number() {} // Copy constructor Number :: Number(const Number& NumberObject) { int Temp[NumberSize]; NumberSize = NumberObject.GetNumberSize(); for (int count = 0; count < NumberObject.GetNumberSize(); count ++) { Temp[count] = Value[count] - NumberObject.GetValue(); } } // Manually set member values void Number :: SetMemberValues(int NewNumberValue, int NewNumberSize) { NumberSize = NewNumberSize; for (int count = NewNumberSize - 1; count >= 0; count --) { Value[count] = NewNumberValue % 10; NewNumberValue = NewNumberValue / 10; } } // Non-default constructor Number :: Number(int NumberValue, int NewNumberSize) { NumberSize = NewNumberSize; for (int count = NewNumberSize - 1; count >= 0; count --) { Value[count] = NumberValue % 10; NumberValue = NumberValue / 10; } } // Return the NumberSize member int Number :: GetNumberSize() const { return NumberSize; } // Return the Value[] member int Number :: GetValue() const { int ResultSoFar; for (int count2 = 0; count2 < NumberSize; count2 ++) { ResultSoFar = ResultSoFar * 10 + Value[count2]; } return ResultSoFar; } Number& operator-=(const Number& Rhs) { for (int count = 0; count < NumberSize; count ++) { Value[count] -= Rhs.Value[count]; } return *this; } inline Number operator-(Number Lhs, const Number& Rhs) { Lhs -= Rhs; return Lhs; } // Overloaded output operator ostream& operator<<(ostream& OutputStream, const Number& NumberObject) { OutputStream << NumberObject.GetValue(); return OutputStream; }

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  • Help in building an 16 bit os

    - by Barshan Das
    I am trying to build an old 16 bit dos like os. My bootloader code: ; This is not my code. May be of Fritzos. I forgot the source. ORG 7c00h jmp Start drive db 0 msg db " Loader Initialization",0 msg2 db "ACos Loaded",0 print: lodsb cmp al, 0 je end mov ah, 0Eh int 10h jmp print end: ret Start: mov [ drive ], dl ; Get the floppy OS booted from ; Update the segment registers xor ax, ax ; XOR ax mov ds, ax ; Mov AX into DS mov si,msg call print ; Load Kernel. ResetFloppy: mov ax, 0x00 ; Select Floppy Reset BIOS Function mov dl, [ drive ] ; Select the floppy ADos booted from int 13h ; Reset the floppy drive jc ResetFloppy ; If there was a error, try again. ReadFloppy: mov bx, 0x9000 ; Load kernel at 9000h. mov ah, 0x02 ; Load disk data to ES:BX mov al, 17 ; Load two floppy head full's worth of data. mov ch, 0 ; First Cylinder mov cl, 2 ; Start at the 2nd Sector to load the Kernel mov dh, 0 ; Use first floppy head mov dl, [ drive ] ; Load from the drive kernel booted from. int 13h ; Read the floppy disk. jc ReadFloppy ; Error, try again. ; Clear text mode screen mov ax, 3 int 10h ;print starting message mov si,msg2 call print mov ax, 0x0 mov ss, ax mov sp, 0xFFFF jmp 9000h ; This part makes sure the bootsector is 512 bytes. times 510-($-$$) db 0 ;bootable sector signature dw 0xAA55 My example kernel code: asm(".code16\n"); void putchar(char); int main() { putchar('A'); return 0; } void putchar(char val) { asm("movb %0, %%al\n" "movb $0x0E, %%ah\n" "int $0x10\n" : :"r"(val) ) ; } This is how I compile it : nasm -f bin -o ./bin/boot.bin ./source/boot.asm gcc -nostdinc -fno-builtin -I./include -c -o ./bin/kernel.o ./source/kernel.c ld -Ttext=0x9000 -o ./bin/kernel.bin ./bin/kernel.o -e 0x0 dd if=/dev/zero of=./bin/empty.bin bs=1440K count=1 cat ./bin/boot.bin ./bin/kernel.bin ./bin/empty.bin|head -c 1440K > ./bin/os rm ./bin/empty.bin and I run it in virtual machine. When I make the putchar function ( in kernel code ) for constant value ....i.e like this: void putchar() { char val = 'A'; asm("movb %0, %%al\n" "movb $0x0E, %%ah\n" "int $0x10\n" : :"r"(val) ) ; } then it works fine. But when I pass argument to it ( That is in the previous code ) , then it prints a space for any character. What should I do?

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  • Resumable upload from Java client to Grails web application?

    - by dersteps
    After almost 2 workdays of Googling and trying several different possibilities I found throughout the web, I'm asking this question here, hoping that I might finally get an answer. First of all, here's what I want to do: I'm developing a client and a server application with the purpose of exchanging a lot of large files between multiple clients on a single server. The client is developed in pure Java (JDK 1.6), while the web application is done in Grails (2.0.0). As the purpose of the client is to allow users to exchange a lot of large files (usually about 2GB each), I have to implement it in a way, so that the uploads are resumable, i.e. the users are able to stop and resume uploads at any time. Here's what I did so far: I actually managed to do what I wanted to do and stream large files to the server while still being able to pause and resume uploads using raw sockets. I would send a regular request to the server (using Apache's HttpClient library) to get the server to send me a port that was free for me to use, then open a ServerSocket on the server and connect to that particular socket from the client. Here's the problem with that: Actually, there are at least two problems with that: I open those ports myself, so I have to manage open and used ports myself. This is quite error-prone. I actually circumvent Grails' ability to manage a huge amount of (concurrent) connections. Finally, here's what I'm supposed to do now and the problem: As the problems I mentioned above are unacceptable, I am now supposed to use Java's URLConnection/HttpURLConnection classes, while still sticking to Grails. Connecting to the server and sending simple requests is no problem at all, everything worked fine. The problems started when I tried to use the streams (the connection's OutputStream in the client and the request's InputStream in the server). Opening the client's OutputStream and writing data to it is as easy as it gets. But reading from the request's InputStream seems impossible to me, as that stream is always empty, as it seems. Example Code Here's an example of the server side (Groovy controller): def test() { InputStream inStream = request.inputStream if(inStream != null) { int read = 0; byte[] buffer = new byte[4096]; long total = 0; println "Start reading" while((read = inStream.read(buffer)) != -1) { println "Read " + read + " bytes from input stream buffer" //<-- this is NEVER called } println "Reading finished" println "Read a total of " + total + " bytes" // <-- 'total' will always be 0 (zero) } else { println "Input Stream is null" // <-- This is NEVER called } } This is what I did on the client side (Java class): public void connect() { final URL url = new URL("myserveraddress"); final byte[] message = "someMessage".getBytes(); // Any byte[] - will be a file one day HttpURLConnection connection = url.openConnection(); connection.setRequestMethod("GET"); // other methods - same result // Write message DataOutputStream out = new DataOutputStream(connection.getOutputStream()); out.writeBytes(message); out.flush(); out.close(); // Actually connect connection.connect(); // is this placed correctly? // Get response BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream())); String line = null; while((line = in.readLine()) != null) { System.out.println(line); // Prints the whole server response as expected } in.close(); } As I mentioned, the problem is that request.inputStream always yields an empty InputStream, so I am never able to read anything from it (of course). But as that is exactly what I'm trying to do (so I can stream the file to be uploaded to the server, read from the InputStream and save it to a file), this is rather disappointing. I tried different HTTP methods, different data payloads, and also rearranged the code over and over again, but did not seem to be able to solve the problem. What I hope to find I hope to find a solution to my problem, of course. Anything is highly appreciated: hints, code snippets, library suggestions and so on. Maybe I'm even having it all wrong and need to go in a totally different direction. So, how can I implement resumable file uploads for rather large (binary) files from a Java client to a Grails web application without manually opening ports on the server side?

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  • Termite colony simulator using java

    - by ashii
    hi everyone, i hve to design a simulator that will maintain an environment, which consists of a collection of patches arranged in a rectangular grid of arbitrary size. Each patch contains zero or more wood chips. A patch may be occupied by one or more termites or predators, which are mobile entities that live within the world and behave according to simple rules. A TERMITE can pick up a wood chip from the patch that it is currently on, or drop a wood chip that it is carrying. Termites travel around the grid by moving randomly from their current patch to a neighbouring patch, in one of four possible directions. New termites may hatch from eggs, and this is simulated by the appearance of a new termite at a random patch within the environment. A PREDATOR moves in a similar way to termites, and if a predator moves onto a patch that is occupied by a termite, then the predator eats the termite. At initialization, the termites, predators, and wood chips are distributed randomly in the environment. Simulation then proceeds in a loop, and the new state of the environment is obtained at each iteration. i have designed the arena using jpanel but im not able to randomnly place wood,termite and predator in that arena. can any one help me out?? my code for the arena is as following: 01 import java.awt.*; 02 import javax.swing.*; 03 04 public class Arena extends JPanel 05 { 06 private static final int Rows = 8; 07 private static final int Cols = 8; 08 public void paint(Graphics g) 09 { 10 Dimension d = this.getSize(); 11 // don't draw both sets of squares, when you can draw one 12 // fill in the entire thing with one color 13 g.setColor(Color.WHITE); 14 // make the background 15 g.fillRect(0,0,d.width,d.height); 16 // draw only black 17 g.setColor(Color.BLACK); 18 // pick a square size based on the smallest dimension 19 int sqsize = ((d.width<d.height) ? d.width/Cols : d.height/Rows); 20 // loop for rows 21 for (int row=0; row<Rows; row++) 22 { 23 int y = row*sqsize; // y stays same for entire row, set here 24 int x = (row%2)*sqsize; // x starts at 0 or one square in 25 for (int i=0; i<Cols/2; i++) 26 { 27 // you will only be drawing half the squares per row 28 // draw square 29 g.fillRect(x,y,sqsize,sqsize); 30 // move two square sizes over 31 x += sqsize*2; 32 } 33 } 34 35 } 36 37 38 39 public void update(Graphics g) { paint(g); } 40 41 42 43 public static void main (String[] args) 44 { 45 46 JFrame frame = new JFrame("Arena"); 47 frame.setSize(600,400); 48 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 49 frame.setContentPane(new Arena()); 50 frame.setVisible(true); 51 } 52 53 }

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  • Decomposing a rotation matrix

    - by DeadMG
    I have a rotation matrix. How can I get the rotation around a specified axis contained within this matrix? Edit: It's a 3D matrix (4x4), and I want to know how far around a predetermined (not contained) axis the matrix rotates. I can already decompose the matrix but D3DX will only give the entire matrix as one rotation around one axis, whereas I need to split the matrix up into angle of rotation around an already-known axis, and the rest. Sample code and brief problem description: D3DXMATRIX CameraRotationMatrix; D3DXVECTOR3 CameraPosition; //D3DXVECTOR3 CameraRotation; inline D3DXMATRIX GetRotationMatrix() { return CameraRotationMatrix; } inline void TranslateCamera(float x, float y, float z) { D3DXVECTOR3 rvec, vec(x, y, z); #pragma warning(disable : 4238) D3DXVec3TransformNormal(&rvec, &vec, &GetRotationMatrix()); #pragma warning(default : 4238) CameraPosition += rvec; RecomputeVPMatrix(); } inline void RotateCamera(float x, float y, float z) { D3DXVECTOR3 RotationRequested(x, y, z); D3DXVECTOR3 XAxis, YAxis, ZAxis; D3DXMATRIX rotationx, rotationy, rotationz; XAxis = D3DXVECTOR3(1, 0, 0); YAxis = D3DXVECTOR3(0, 1, 0); ZAxis = D3DXVECTOR3(0, 0, 1); #pragma warning(disable : 4238) D3DXVec3TransformNormal(&XAxis, &XAxis, &GetRotationMatrix()); D3DXVec3TransformNormal(&YAxis, &YAxis, &GetRotationMatrix()); D3DXVec3TransformNormal(&ZAxis, &ZAxis, &GetRotationMatrix()); #pragma warning(default : 4238) D3DXMatrixIdentity(&rotationx); D3DXMatrixIdentity(&rotationy); D3DXMatrixIdentity(&rotationz); D3DXMatrixRotationAxis(&rotationx, &XAxis, RotationRequested.x); D3DXMatrixRotationAxis(&rotationy, &YAxis, RotationRequested.y); D3DXMatrixRotationAxis(&rotationz, &ZAxis, RotationRequested.z); CameraRotationMatrix *= rotationz; CameraRotationMatrix *= rotationy; CameraRotationMatrix *= rotationx; RecomputeVPMatrix(); } inline void RecomputeVPMatrix() { D3DXMATRIX ProjectionMatrix; D3DXMatrixPerspectiveFovLH( &ProjectionMatrix, FoV, (float)D3DDeviceParameters.BackBufferWidth / (float)D3DDeviceParameters.BackBufferHeight, FarPlane, NearPlane ); D3DXVECTOR3 CamLookAt; D3DXVECTOR3 CamUpVec; #pragma warning(disable : 4238) D3DXVec3TransformNormal(&CamLookAt, &D3DXVECTOR3(1, 0, 0), &GetRotationMatrix()); D3DXVec3TransformNormal(&CamUpVec, &D3DXVECTOR3(0, 1, 0), &GetRotationMatrix()); #pragma warning(default : 4238) D3DXMATRIX ViewMatrix; #pragma warning(disable : 4238) D3DXMatrixLookAtLH(&ViewMatrix, &CameraPosition, &(CamLookAt + CameraPosition), &CamUpVec); #pragma warning(default : 4238) ViewProjectionMatrix = ViewMatrix * ProjectionMatrix; D3DVIEWPORT9 vp = { 0, 0, D3DDeviceParameters.BackBufferWidth, D3DDeviceParameters.BackBufferHeight, 0, 1 }; D3DDev->SetViewport(&vp); } Effectively, after a certain time, when RotateCamera is called, it begins to rotate in the relative X axis- even though constant zero is passed in for that request when responding to mouse input, so I know that when moving the mouse, the camera should not roll at all. I tried spamming 0,0,0 requests and saw no change (one per frame at 1500 frames per second), so I'm fairly sure that I'm not seeing FP error or matrix accumulation error. I tried writing a RotateCameraYZ function and stripping all X-axis from the function. I've spent several days trying to discover why this is the case, and eventually decided on just hacking around it. Just for reference, I've seen some diagrams on Wikipedia, and I actually have a relatively strange axis layout, which is Y axis up, but X axis forwards and Z axis right, so Y axis yaw, Z axis pitch, X axis roll.

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  • Agile: User Stories for Machine Learning Project?

    - by benjismith
    I've just finished up with a prototype implementation of a supervised learning algorithm, automatically assigning categorical tags to all the items in our company database (roughly 5 million items). The results look good, and I've been given the go-ahead to plan the production implementation project. I've done this kind of work before, so I know how the functional components of the software. I need a collection of web crawlers to fetch data. I need to extract features from the crawled documents. Those documents need to be segregated into a "training set" and a "classification set", and feature-vectors need to be extracted from each document. Those feature vectors are self-organized into clusters, and the clusters are passed through a series of rebalancing operations. Etc etc etc etc. So I put together a plan, with about 30 unique development/deployment tasks, each with time estimates. The first stage of development -- ignoring some advanced features that we'd like to have in the long-term, but aren't high enough priority to make it into the development schedule yet -- is slated for about two months worth of work. (Keep in mind that I already have a working prototype, so the final implementation is significantly simpler than if the project was starting from scratch.) My manager said the plan looked good to him, but he asked if I could reorganize the tasks into user stories, for a few reasons: (1) our project management software is totally organized around user stories; (2) all of our scheduling is based on fitting entire user stories into sprints, rather than individually scheduling tasks; (3) other teams -- like the web developers -- have made great use of agile methodologies, and they've benefited from modelling all the software features as user stories. So I created a user story at the top level of the project: As a user of the system, I want to search for items by category, so that I can easily find the most relevant items within a huge, complex database. Or maybe a better top-level story for this feature would be: As a content editor, I want to automatically create categorical designations for the items in our database, so that customers can easily find high-value data within our huge, complex database. But that's not the real problem. The tricky part, for me, is figuring out how to create subordinate user stories for the rest of the machine learning architecture. Case in point... I know that the algorithm requires two major architectural subdivisions: (A) training, and (B) classification. And I know that the training portion of the architecture requires construction of a cluster-space. All the Agile Development literature I've read seems to indicate that a user story should be the "smallest possible implementation that provides any business value". And that makes a lot of sense when designing a piece of end-user software. Start small, and then incrementally add value when users demand additional functionality. But a cluster-space, in and of itself, provides zero business value. Nor does a crawler, or a feature-extractor. There's no business value (not for the end-user, or for any of the roles internal to the company) in a partial system. A trained cluster-space is only possible with the crawler and feature extractor, and only relevant if we also develop an accompanying classifier. I suppose it would be possible to create user stories where the subordinate components of the system act as the users in the stories: As a supervised-learning cluster-space construction routine, I want to consume data from a feature extractor, so that I can exist. But that seems really weird. What benefit does it provide me as the developer (or our users, or any other stakeholders, for that matter) to model my user stories like that? Although the main story can be easily divided along architectural-component boundaries (crawler, trainer, classifier, etc), I can't think of any useful decomposition from a user's perspective. What do you guys think? How do you plan Agile user stories for sophisticated, indivisible, non-user-facing components?

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  • Create and Share a File (Also a mysterious error)

    - by Kirk
    My goal is to create a XML file and then send it through the share Intent. I'm able to create a XML file using this code FileOutputStream outputStream = context.openFileOutput(fileName, Context.MODE_WORLD_READABLE); PrintStream printStream = new PrintStream(outputStream); String xml = this.writeXml(); // get XML here printStream.println(xml); printStream.close(); I'm stuck trying to retrieve a Uri to the output file in order to share it. I first tried to access the file by converting the file to a Uri File outFile = context.getFileStreamPath(fileName); return Uri.fromFile(outFile); This returns file:///data/data/com.my.package/files/myfile.xml but I cannot appear to attach this to an email, upload, etc. If I manually check the file length, it's proper and shows there is a reasonable file size. Next I created a content provider and tried to reference the file and it isn't a valid handle to the file. The ContentProvider doesn't ever seem to be called a any point. Uri uri = Uri.parse("content://" + CachedFileProvider.AUTHORITY + "/" + fileName); return uri; This returns content://com.my.package.provider/myfile.xml but I check the file and it's zero length. How do I access files properly? Do I need to create the file with the content provider? If so, how? Update Here is the code I'm using to share. If I select Gmail, it does show as an attachment but when I send it gives an error Couldn't show attachment and the email that arrives has no attachment. public void onClick(View view) { Log.d(TAG, "onClick " + view.getId()); switch (view.getId()) { case R.id.share_cancel: setResult(RESULT_CANCELED, getIntent()); finish(); break; case R.id.share_share: MyXml xml = new MyXml(); Uri uri; try { uri = xml.writeXmlToFile(getApplicationContext(), "myfile.xml"); //uri is "file:///data/data/com.my.package/files/myfile.xml" Log.d(TAG, "Share URI: " + uri.toString() + " path: " + uri.getPath()); File f = new File(uri.getPath()); Log.d(TAG, "File length: " + f.length()); // shows a valid file size Intent shareIntent = new Intent(); shareIntent.setAction(Intent.ACTION_SEND); shareIntent.putExtra(Intent.EXTRA_STREAM, uri); shareIntent.setType("text/plain"); startActivity(Intent.createChooser(shareIntent, "Share")); } catch (FileNotFoundException e) { e.printStackTrace(); } break; } } I noticed that there is an Exception thrown here from inside createChooser(...), but I can't figure out why it's thrown. E/ActivityThread(572): Activity com.android.internal.app.ChooserActivity has leaked IntentReceiver com.android.internal.app.ResolverActivity$1@4148d658 that was originally registered here. Are you missing a call to unregisterReceiver()? I've researched this error and can't find anything obvious. Both of these links suggest that I need to unregister a receiver. Chooser Activity Leak - Android Why does Intent.createChooser() need a BroadcastReceiver and how to implement? I have a receiver setup, but it's for an AlarmManager that is set elsewhere and doesn't require the app to register / unregister. Code for openFile(...) In case it's needed, here is the content provider I've created. public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException { String fileLocation = getContext().getCacheDir() + "/" + uri.getLastPathSegment(); ParcelFileDescriptor pfd = ParcelFileDescriptor.open(new File(fileLocation), ParcelFileDescriptor.MODE_READ_ONLY); return pfd; }

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  • What is the MVC version of this code?

    - by Ian Boyd
    i'm trying to wrap my head around how to enterprise up my code: taking a simple routine and splitting it up into 5 or 6 methods in 3 or 4 classes. i quickly came up three simple examples of code how i currently write it. Could someone please convert these into an MVC/MVP obfuscated version? Example 1: The last name is mandatory. Color the text box red if nothing is entered. Color it green if stuff is entered: private void txtLastname_TextChanged(object sender, EventArgs e) { //Lastname mandatory. //Color pinkish if nothing entered. Greenish if entered. if (txtLastname.Text.Trim() == "") { //Lastname is required, color pinkish txtLastname.BackColor = ControlBad; } else { //Lastname entered, remove the coloring txtLastname.BackColor = ControlGood; } } Example 2: The first name is optional, but try to get it. We'll add a bluish tint to this "try to get" field: private void txtFirstname_TextChanged(object sender, EventArgs e) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (txtFirstname.Text == "") { //Nothing there, hint it blue txtFirstname.BackColor = ControlRequired; } else if (txtFirstname.Text.Trim() == "") { //They entered spaces - bad user! txtFirstname.BackColor = ControlBad; } else { //Entered stuff, remove coloring txtFirstname.BackColor = SystemColors.Window; } } Example 3 The age is totally optional. If an age is entered, it better be valid: private void txtAge_TextChanged(object sender, EventArgs e) { //Age is optional, but if entered it better be valid int nAge = 0; if (Int32.TryParse(txtAge.Text, out nAge)) { //Valid integer entered if (nAge < 0) { //Negative age? i don't think so txtAge.BackColor = ControlBad; } else { //Valid age entered, remove coloring txtAge.BackColor = SystemColors.Window; } } else { //Whatever is in there: it's *not* a valid integer, if (txtAge.Text == "") { //Blank is okay txtAge.BackColor = SystemColors.Window; } else { //Not a valid age, bad user txtAge.BackColor = ControlBad; } } } Every time i see MVC code, it looks almost like random splitting of code into different methods, classes, and files. i've not been able to determine a reason or pattern to their madness. Without any understanding of they why it's being one some way, it makes no sense. And using the words model, view, controller and presenter, like i'm supposed to know what that means, doesn't help. The model is your data. The view shows data on screen. The controller is used to carry out the users actions And oranges taste orangy. Here's my attempt at splitting things up in order to make the code more difficult to follow. Is this anywhere close to MVC? private void txtFirstname_TextChanged(object sender, EventArgs e) { FirstnameTextChangedHandler(sender, e); } private void FirstnameTextChangedHandler(sender, e) { string firstname = GetFirstname(); Color firstnameTextBoxColor = GetFirstnameTextBoxColor(firstname); SetFirstNameTextBoxColor(firstnameTextBoxColor); } private string GetFirstname() { return txtFirstname.Text; } private Color GetFirstnameTextBoxColor(string firstname) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (firstname == "") { //Nothing there, hint it blue return GetControlRequiredColor(); } else if (firstname.Trim() == "") { //They entered spaces - bad user! return GetControlBadColor(); } else { //Entered stuff, remove coloring return GetControlDefaultColor(); } } private Color GetControlRequiredColor() { return ControlRequired; } private Color GetControlBadColor() { return ControlBad; } private Color GetControlGoodColor() { return ControlGood; } //am i doin it rite i've obfuscated the code, but it's still altogether. The next step in the MVC obfuscation, i gather, is to hide the code in 3 or 4 different files. It's that next step that i don't understand. What is the logical separation of which functions are moved into what other classes? Can someone translate my 3 simple examples above into full fledged MVC obfuscation? Edit: Not ASP/ASP.NET/Online. Pretend it's on a desktop, handheld, surface, kiosk. And pretend it's language agnostic.

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  • Javascript style objects in Objective-C

    - by awolf
    Background: I use a ton of NSDictionary objects in my iPhone and iPad code. I'm sick of the verbose way of getting/setting keys to these state dictionaries. So a little bit of an experiment: I just created a class I call Remap. Remap will take any arbitrary set[VariableName]:(NSObject *) obj selector and forward that message to a function that will insert obj into an internal NSMutableDictionary under the key [vairableName]. Remap will also take any (zero argument) arbitrary [variableName] selector and return the NSObject mapped in the NSMutableDictionary under the key [variableName]. e.g. Remap * remap = [[Remap alloc] init]; NSNumber * testNumber = [NSNumber numberWithInt:46]; [remap setTestNumber:testNumber]; testNumber = [remap testNumber]; [remap setTestString:@"test string"]; NSString * testString = [remap testString]; NSMutableDictionary * testDict = [NSMutableDictionary dictionaryWithObject:testNumber forKey:@"testNumber"]; [remap setTestDict:testDict]; testDict = [remap testDict]; where none of the properties testNumber, testString, or testDict are actually defined in Remap. The crazy thing? It works... My only question is how can I disable the "may not respond to " warnings for JUST accesses to Remap? P.S. : I'll probably end up scrapping this and going with macros since message forwarding is quite inefficient... but aside from that does anyone see other problems with Remap? Here's Remap's .m for those who are curious: #import "Remap.h" @interface Remap () @property (nonatomic, retain) NSMutableDictionary * _data; @end @implementation Remap @synthesize _data; - (void) dealloc { relnil(_data); [super dealloc]; } - (id) init { self = [super init]; if (self != nil) { NSMutableDictionary * dict = [[NSMutableDictionary alloc] init]; [self set_data:dict]; relnil(dict); } return self; } - (void)forwardInvocation:(NSInvocation *)anInvocation { NSString * selectorName = [NSString stringWithUTF8String: sel_getName([anInvocation selector])]; NSRange range = [selectorName rangeOfString:@"set"]; NSInteger numArguments = [[anInvocation methodSignature] numberOfArguments]; if (range.location == 0 && numArguments == 4) { //setter [anInvocation setSelector:@selector(setData:withKey:)]; [anInvocation setArgument:&selectorName atIndex:3]; [anInvocation invokeWithTarget:self]; } else if (numArguments == 3) { [anInvocation setSelector:@selector(getDataWithKey:)]; [anInvocation setArgument:&selectorName atIndex:2]; [anInvocation invokeWithTarget:self]; } } - (NSMethodSignature *) methodSignatureForSelector:(SEL) aSelector { NSString * selectorName = [NSString stringWithUTF8String: sel_getName(aSelector)]; NSMethodSignature * sig = [super methodSignatureForSelector:aSelector]; if (sig == nil) { NSRange range = [selectorName rangeOfString:@"set"]; if (range.location == 0) { sig = [self methodSignatureForSelector:@selector(setData:withKey:)]; } else { sig = [self methodSignatureForSelector:@selector(getDataWithKey:)]; } } return sig; } - (NSObject *) getDataWithKey: (NSString *) key { NSObject * returnValue = [[self _data] objectForKey:key]; return returnValue; } - (void) setData: (NSObject *) data withKey:(NSString *)key { if (key && [key length] >= 5 && data) { NSRange range; range.length = 1; range.location = 3; NSString * firstChar = [key substringWithRange:range]; firstChar = [firstChar lowercaseString]; range.length = [key length] - 5; // the 4 we have processed plus the training : range.location = 4; NSString * adjustedKey = [NSString stringWithFormat:@"%@%@", firstChar, [key substringWithRange:range]]; [[self _data] setObject:data forKey:adjustedKey]; } else { //assert? } } @end

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  • Which workaround to use for the following SQL deadlock?

    - by Marko
    I found a SQL deadlock scenario in my application during concurrency. I belive that the two statements that cause the deadlock are (note - I'm using LINQ2SQL and DataContext.ExecuteCommand(), that's where this.studioId.ToString() comes into play): exec sp_executesql N'INSERT INTO HQ.dbo.SynchronizingRows ([StudioId], [UpdatedRowId]) SELECT @p0, [t0].[Id] FROM [dbo].[UpdatedRows] AS [t0] WHERE NOT (EXISTS( SELECT NULL AS [EMPTY] FROM [dbo].[ReceivedUpdatedRows] AS [t1] WHERE ([t1].[StudioId] = @p0) AND ([t1].[UpdatedRowId] = [t0].[Id]) ))',N'@p0 uniqueidentifier',@p0='" + this.studioId.ToString() + "'; and exec sp_executesql N'INSERT INTO HQ.dbo.ReceivedUpdatedRows ([UpdatedRowId], [StudioId], [ReceiveDateTime]) SELECT [t0].[UpdatedRowId], @p0, GETDATE() FROM [dbo].[SynchronizingRows] AS [t0] WHERE ([t0].[StudioId] = @p0)',N'@p0 uniqueidentifier',@p0='" + this.studioId.ToString() + "'; The basic logic of my (client-server) application is this: Every time someone inserts or updates a row on the server side, I also insert a row into the table UpdatedRows, specifying the RowId of the modified row. When a client tries to synchronize data, it first copies all of the rows in the UpdatedRows table, that don't contain a reference row for the specific client in the table ReceivedUpdatedRows, to the table SynchronizingRows (the first statement taking part in the deadlock). Afterwards, during the synchronization I look for modified rows via lookup of the SynchronizingRows table. This step is required, otherwise if someone inserts new rows or modifies rows on the server side during synchronization I will miss them and won't get them during the next synchronization (explanation scenario to long to write here...). Once synchronization is complete, I insert rows to the ReceivedUpdatedRows table specifying that this client has received the UpdatedRows contained in the SynchronizingRows table (the second statement taking part in the deadlock). Finally I delete all rows from the SynchronizingRows table that belong to the current client. The way I see it, the deadlock is occuring on tables SynchronizingRows (abbreviation SR) and ReceivedUpdatedRows (abbreviation RUR) during steps 2 and 3 (one client is in step 2 and is inserting into SR and selecting from RUR; while another client is in step 3 inserting into RUR and selecting from SR). I googled a bit about SQL deadlocks and came to a conclusion that I have three options. Inorder to make a decision I need more input about each option/workaround: Workaround 1: The first advice given on the web about SQL deadlocks - restructure tables/queries so that deadlocks don't happen in the first place. Only problem with this is that with my IQ I don't see a way to do the synchronization logic any differently. If someone wishes to dwelve deeper into my current synchronization logic, how and why it is set up the way it is, I'll post a link for the explanation. Perhaps, with the help of someone smarter than me, it's possible to create a logic that is deadlock free. Workaround 2: The second most common advice seems to be the use of WITH(NOLOCK) hint. The problem with this is that NOLOCK might miss or duplicate some rows. Duplication is not a problem, but missing rows is catastrophic! Another option is the WITH(READPAST) hint. On the face of it, this seems to be a perfect solution. I really don't care about rows that other clients are inserting/modifying, because each row belongs only to a specific client, so I may very well skip locked rows. But the MSDN documentaion makes me a bit worried - "When READPAST is specified, both row-level and page-level locks are skipped". As I said, row-level locks would not be a problem, but page-level locks may very well be, since a page might contain rows that belong to multiple clients (including the current one). While there are lots of blog posts specifically mentioning that NOLOCK might miss rows, there seems to be none about READPAST (never) missing rows. This makes me skeptical and nervous to implement it, since there is no easy way to test it (implementing would be a piece of cake, just pop WITH(READPAST) into both statements SELECT clause and job done). Can someone confirm whether the READPAST hint can miss rows? Workaround 3: The final option is to use ALLOW_SNAPSHOT_ISOLATION and READ_COMMITED_SNAPSHOT. This would seem to be the only option to work 100% - at least I can't find any information that would contradict with it. But it is a little bit trickier to setup (I don't care much about the performance hit), because I'm using LINQ. Off the top of my head I probably need to manually open a SQL connection and pass it to the LINQ2SQL DataContext, etc... I haven't looked into the specifics very deeply. Mostly I would prefer option 2 if somone could only reassure me that READPAST will never miss rows concerning the current client (as I said before, each client has and only ever deals with it's own set of rows). Otherwise I'll likely have to implement option 3, since option 1 is probably impossible... I'll post the table definitions for the three tables as well, just in case: CREATE TABLE [dbo].[UpdatedRows]( [Id] [uniqueidentifier] NOT NULL ROWGUIDCOL DEFAULT NEWSEQUENTIALID() PRIMARY KEY CLUSTERED, [RowId] [uniqueidentifier] NOT NULL, [UpdateDateTime] [datetime] NOT NULL, ) ON [PRIMARY] GO CREATE NONCLUSTERED INDEX IX_RowId ON dbo.UpdatedRows ([RowId] ASC) WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE TABLE [dbo].[ReceivedUpdatedRows]( [Id] [uniqueidentifier] NOT NULL ROWGUIDCOL DEFAULT NEWSEQUENTIALID() PRIMARY KEY NONCLUSTERED, [UpdatedRowId] [uniqueidentifier] NOT NULL REFERENCES [dbo].[UpdatedRows] ([Id]), [StudioId] [uniqueidentifier] NOT NULL REFERENCES, [ReceiveDateTime] [datetime] NOT NULL, ) ON [PRIMARY] GO CREATE CLUSTERED INDEX IX_Studios ON dbo.ReceivedUpdatedRows ([StudioId] ASC) WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO CREATE TABLE [dbo].[SynchronizingRows]( [StudioId] [uniqueidentifier] NOT NULL [UpdatedRowId] [uniqueidentifier] NOT NULL REFERENCES [dbo].[UpdatedRows] ([Id]) PRIMARY KEY CLUSTERED ([StudioId], [UpdatedRowId]) ) ON [PRIMARY] GO PS! Studio = Client. PS2! I just noticed that the index definitions have ALLOW_PAGE_LOCK=ON. If I would turn it off, would that make any difference to READPAST? Are there any negative downsides for turning it off?

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  • How do I recursively define a Hash in Ruby from supplied arguments?

    - by Sarah Beckham
    This snippet of code populates an @options hash. values is an Array which contains zero or more heterogeneous items. If you invoke populate with arguments that are Hash entries, it uses the value you specify for each entry to assume a default value. def populate(*args) args.each do |a| values = nil if (a.kind_of? Hash) # Converts {:k => "v"} to `a = :k, values = "v"` a, values = a.to_a.first end @options[:"#{a}"] ||= values ||= {} end end What I'd like to do is change populate such that it recursively populates @options. There is a special case: if the values it's about to populate a key with are an Array consisting entirely of (1) Symbols or (2) Hashes whose keys are Symbols (or some combination of the two), then they should be treated as subkeys rather than the values associated with that key, and the same logic used to evaluate the original populate arguments should be recursively re-applied. That was a little hard to put into words, so I've written some test cases. Here are some test cases and the expected value of @options afterwards: populate :a => @options is {:a => {}} populate :a => 42 => @options is {:a => 42} populate :a, :b, :c => @options is {:a => {}, :b => {}, :c => {}} populate :a, :b => "apples", :c => @options is {:a => {}, :b => "apples", :c => {}} populate :a => :b => @options is {:a => :b} # Because [:b] is an Array consisting entirely of Symbols or # Hashes whose keys are Symbols, we assume that :b is a subkey # of @options[:a], rather than the value for @options[:a]. populate :a => [:b] => @options is {:a => {:b => {}}} populate :a => [:b, :c => :d] => @options is {:a => {:b => {}, :c => :d}} populate :a => [:a, :b, :c] => @options is {:a => {:a => {}, :b => {}, :c => {}}} populate :a => [:a, :b, "c"] => @options is {:a => [:a, :b, "c"]} populate :a => [:one], :b => [:two, :three => "four"] => @options is {:a => :one, :b => {:two => {}, :three => "four"}} populate :a => [:one], :b => [:two => {:four => :five}, :three => "four"] => @options is {:a => :one, :b => { :two => { :four => :five } }, :three => "four" } } It is acceptable if the signature of populate needs to change to accommodate some kind of recursive version. There is no limit to the amount of nesting that could theoretically happen. Any thoughts on how I might pull this off?

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  • Can i use a switch to hold a function?

    - by TIMOTHY
    I have a 3 file program, basically teaching myself c++. I have an issue. I made a switch to use the math function. I need and put it in a variable, but for some reason I get a zero as a result. Also another issue, when I select 4 (divide) it crashes... Is there a reason? Main file: #include <iostream> #include "math.h" #include <string> using namespace std; int opersel; int c; int a; int b; string test; int main(){ cout << "Welcome to Math-matrix v.34"<< endl; cout << "Shall we begin?" <<endl; //ASK USER IF THEY ARE READY TO BEGIN string answer; cin >> answer; if(answer == "yes" || answer == "YES" || answer == "Yes") { cout << "excellent lets begin..." << endl; cout << "please select a operator..." << endl << endl; cout << "(1) + " << endl; cout << "(2) - " << endl; cout << "(3) * " << endl; cout << "(4) / " << endl; cin >> opersel; switch(opersel){ case 1: c = add(a,b); break; case 2: c = sub(a,b); break; case 3: c = multi(a,b); break; case 4: c = divide(a,b); break; default: cout << "error... retry" << endl; }// end retry cout << "alright, how please select first digit?" << endl; cin >> a; cout << "excellent... and your second?" << endl; cin >> b; cout << c; cin >> test; }else if (answer == "no" || answer == "NO" || answer == "No"){ }//GAME ENDS }// end of int main Here is my math.h file #ifndef MATH_H #define MATH_H int add(int a, int b); int sub(int a, int b); int multi(int a, int b); int divide(int a, int b); #endif Here is my math.cpp: int add(int a, int b) { return a + b; } int sub(int a, int b) { return a - b; } int multi(int a, int b) { return a * b; } int divide(int a, int b) { return a / b; } }// end of int main

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  • Can't append to second container

    - by George Katsanos
    I have the following script: (function($) { $.fn.easyPaginate = function(options){ var defaults = { step: 4, delay: 100, numeric: true, nextprev: true, controls: 'pagination', current: 'current' }; var options = $.extend(defaults, options); var step = options.step; var lower, upper; var children = $(this).children(); var count = children.length; var obj, next, prev; var page = 1; var timeout; var clicked = false; function show(){ clearTimeout(timeout); lower = ((page-1) * step); upper = lower+step; $(children).each(function(i){ var child = $(this); child.hide(); if(i>=lower && i<upper){ setTimeout(function(){ child.fadeIn('fast') }, ( i-( Math.floor(i/step) * step) )*options.delay ); } if(options.nextprev){ if(upper >= count) { next.addClass('stop'); } else { next.removeClass('stop'); }; if(lower >= 1) { prev.removeClass('stop'); } else { prev.addClass('stop'); }; }; }); $('li','#'+ options.controls).removeClass(options.current); $('li[data-index="'+page+'"]','#'+ options.controls).addClass(options.current); if(options.auto){ if(options.clickstop && clicked){}else{ timeout = setTimeout(auto,options.pause); }; }; }; function auto(){ if(upper <= count){ page++; show(); } else { page--; show(); } }; this.each(function(){ obj = this; if(count>step){ var pages = Math.floor(count/step); if((count/step) > pages) pages++; var ol = $('<ol id="'+ options.controls +'" class="pagin"></ol>').insertAfter(obj); if(options.nextprev){ prev = $('<li class="prev">prev</li>') .appendTo(ol) .bind('click', function() { //check to see if there are any more pages in the negative direction if (page > 1) { clicked = true; page--; show(); } }); } if(options.numeric){ for(var i=1;i<=pages;i++){ $('<li data-index="'+ i +'">'+ i +'</li>') .appendTo(ol) .click(function(){ clicked = true; page = $(this).attr('data-index'); show(); }); }; }; if(options.nextprev){ next = $('<li class="next">next</li>') .appendTo(ol) .bind('click', function() { //check to see if there are any pages in the positive direction if (page < (count / 4)) { clicked = true; page++; show(); } }); } show(); }; }); }; })(jQuery); jQuery(function($){ $('ul.news').easyPaginate({step:4}); }); which is a carousel-like plugin that produces this html structure for the navigation: <ol id="pagination" class="pagin"><li class="prev">prev</li><li data-index="1" class="">1</li><li data-index="2" class="">2</li><li data-index="3" class="current">3</li><li class="next stop">next</li></ol> And all I want is to enclose this list in a div. Seems simple, but appendTo doesn't want to cooperate with me, or I'm doing something wrong (I'd appreciate if you would help me understand what that is..) So I'm modifying as such: var ol = $('<ol id="'+ options.controls +'" class="pagin"></ol>'); var tiv = $('<div id="lala"></div>'); ol.appendTo('#lala'); tiv.insertAfter(obj); I know how to chain, but I'm in "debugging" mode trying to understand why I don't get the result I imagine I would get: <div id="lala> <ol id="pagination><li>...... </li></ol> </div> I tried putting some console.log's to see the status of my variables but couldn't find something useful.. I guess there's something with DOM insertion I don't get.

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  • Double Linked List header node keeps returning first value as 0

    - by Craig
    I will preface to say that this is my first question. I am currently getting my Masters degree in Information Security and I had to take C++ programming this semester. So this is homework related. I am not looking for you to answer my homework but I am running into a peculiar situation. I have created the program to work with a doubly linked list and everything works fine. However when I have the user create a list of values the first node keeps returning 0. I have tried finding some reading on this and I cannot locate any reference to it. My question is then is the header node(first node) always going to be zero? Or am I doing something wrong. case: 'C': cout<<"Please enter a list:"<<endl; while(n!=-999){ myList.insert(n); cin>> n;} break; I now enter: 12321, 1234,64564,346346. The results in 0, 12321, 1234, 64564,346346. Is this what should happen or am I doing something wrong? Also as this is my first post please feel free to criticize or teach me how to color code the keywords. Anyway this is a homework assignment so I am only looking for guidance and constructive criticism. Thank you all in advance So I cannot figure out the comment sections on this forum so I will edit the original post The first section is the constructor code: template <class Type> doublyLinkedList<Type>::doublyLinkedList() { first= NULL; last = NULL; count = 0; } Then there is my insert function : template <class Type> void doublyLinkedList<Type>::insert(const Type& insertItem) { nodeType<Type> *current; //pointer to traverse the list nodeType<Type> *trailCurrent; //pointer just before current nodeType<Type> *newNode; //pointer to create a node bool found; newNode = new nodeType<Type>; //create the node newNode->info = insertItem; //store the new item in the node newNode->next = NULL; newNode->back = NULL; if(first == NULL) //if the list is empty, newNode is //the only node { first = newNode; last = newNode; count++; } else { found = false; current = first; while (current != NULL && !found) //search the list if (current->info >= insertItem) found = true; else { trailCurrent = current; current = current->next; } if (current == first) //insert newNode before first { first->back = newNode; newNode->next = first; first = newNode; count++; } else { //insert newNode between trailCurrent and current if (current != NULL) { trailCurrent->next = newNode; newNode->back = trailCurrent; newNode->next = current; current->back = newNode; } else { trailCurrent->next = newNode; newNode->back = trailCurrent; last = newNode; } count++; }//end else }//end else }//end Then I have an initialization function too: template <class Type> void doublyLinkedList<Type>::initializeList() { destroy(); } Did I miss anything?

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  • Rotating images makes ui slow

    - by 5w4rley
    i'm trying to implement kind of speedometer. i'm getting informations about rounds per minute, boost and load of an engine over bluetooth and i try to display them on the screen witch 3 arrows witch should point in the right direktion. i tried to use a rotate animation evry time i get data(10-100ms) to setup the arrows. but that makes my ui extremly slow. 500ms to react on a buttonclick. Doese someone know how to make it work better? source code: public void setTacho() { //rotate Tachonadel Rpmcurrentdegree=Rpmcurrentdegree+Rpmdegree; Rpmdegree=((rpms-lastrpm)*RPMtoDegree); RpmAnim=new RotateAnimation((float)Rpmcurrentdegree, (float)Rpmdegree, ivNadel.getWidth()/2, ivNadel.getHeight()/2); RpmAnim.setFillEnabled(true); RpmAnim.setFillAfter(true); ivNadel.setAnimation(RpmAnim); RpmAnim.start(); //rotate Boostbalken currentBoostDegree=currentBoostDegree+BoostDegree; BoostDegree=(boost-lastBoost)*BOOSTtoDegree; //rotate Loadbalken currentLoadDegree=currentLoadDegree+LoadDegree; LoadDegree=(load-lastLoad)*LOADtoDegree; BoostAnim=new RotateAnimation((float)-currentBoostDegree, (float)-BoostDegree, ivBoost.getWidth()/2, ivBoost.getHeight()/2); BoostAnim.setFillEnabled(true); BoostAnim.setFillAfter(true); ivBoost.setAnimation(BoostAnim); BoostAnim.start(); LoadAnim=new RotateAnimation((float)currentLoadDegree, (float)LoadDegree, ivLoad.getWidth()/2, ivLoad.getHeight()/2); LoadAnim.setFillEnabled(true); LoadAnim.setFillAfter(true); ivLoad.setAnimation(LoadAnim); LoadAnim.start(); } when i try to make the rotation only if the values have changed then it works only while they are changing but if they aren't the arrows jump back to the zero position. isnt setfillafter to tell the image that it should hold the new position? code: public void setTacho() { //rotate Tachonadel Rpmcurrentdegree=Rpmcurrentdegree+Rpmdegree; Rpmdegree=((rpms-lastrpm)*RPMtoDegree); if(Rpmdegree!=0) { RpmAnim=new RotateAnimation((float)Rpmcurrentdegree, (float)Rpmdegree, ivNadel.getWidth()/2, ivNadel.getHeight()/2); RpmAnim.setFillEnabled(true); RpmAnim.setFillAfter(true); ivNadel.setAnimation(RpmAnim); RpmAnim.start(); } //rotate Boostbalken currentBoostDegree=currentBoostDegree+BoostDegree; BoostDegree=(boost-lastBoost)*BOOSTtoDegree; //rotate Loadbalken currentLoadDegree=currentLoadDegree+LoadDegree; LoadDegree=(load-lastLoad)*LOADtoDegree; if(BoostDegree!=0) { BoostAnim=new RotateAnimation((float)-currentBoostDegree, (float)-BoostDegree, ivBoost.getWidth()/2, ivBoost.getHeight()/2); BoostAnim.setFillEnabled(true); BoostAnim.setFillAfter(true); ivBoost.setAnimation(BoostAnim); BoostAnim.start(); } if(LoadDegree!=0) { LoadAnim=new RotateAnimation((float)currentLoadDegree, (float)LoadDegree, ivLoad.getWidth()/2, ivLoad.getHeight()/2); LoadAnim.setFillEnabled(true); LoadAnim.setFillAfter(true); ivLoad.setAnimation(LoadAnim); LoadAnim.start(); } } i don't get it =( thx 4 help EDIT: part of the bluetooth Thread that calls the callback while (run) { try { bytes = mmInStream.read(buffer); if (connection.btCallback != null) { connection.btCallback.getData(buffer,bytes); } } catch (IOException e) { break; } the callback methode of the bluetooth thread: public void getData(byte[] bytes, int len) { setTacho(); }

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  • C Program not running as intended, hangs after input

    - by user41419
    The program I am writing to take a number and display that number as a calculator would display it (shown below) is compiling with no issues, but when I try to run it, I am able to input my number, but nothing happens. It seems like it is "hanging", since no further output is shown as I would have expected. Might anyone know what the problem is? #include <stdio.h> #define MAX_DIGITS 20 char segments[10][7] = /* seven segment array */ {{'1','1','1','1','1','1','0'}, /* zero */ {'0','1','1','0','0','0','0'}, /* one */ {'1','1','0','1','1','0','1'}, /* two */ {'1','1','1','1','0','0','1'}, /* three */ {'0','1','1','0','0','1','1'}, /* four */ {'1','0','1','1','0','1','1'}, /* five */ {'1','0','1','1','1','1','1'}, /* six */ {'1','1','1','0','0','0','0'}, /* seven */ {'1','1','1','1','1','1','1'}, /* eight */ {'1','1','1','0','0','1','1'}};/* nine */ char digits[3][MAX_DIGITS * 4]; /* digits array */ int i, j; /* count variables */ int adjust; /* output formatting */ int main(void) { clear_digits_array(); int digit[20]; for (i = 0; i < 20; i++) { digit[i] = 0; } int count = 20; int position = 0; printf("Enter a number: "); int number = scanf("%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d%d", &digit[0], &digit[1], &digit[2], &digit[3], &digit[4], &digit[5], &digit[6], &digit[7], &digit[8], &digit[9], &digit[10], &digit[11], &digit[12], &digit[13], &digit[14], &digit[15], &digit[16], &digit[17], &digit[18], &digit[19]); //NOTHING HAPPENS AFTER HERE printf("Got input, number is %d", number); while (count > 0) { printf("Reading digits, count is %d", count); process_digit(digit[20 - count], position); position++; count--; } print_digits_array(); printf("\n"); return 0; } void clear_digits_array(void) { /* fill all positions in digits array with blank spaces */ for (i = 0; i < 3; i++) { for (j = 0; j < (MAX_DIGITS * 4); j++) { digits[i][j] = ' '; } } } void process_digit(int digit, int position) { /* check each segment to see if segment should be filled in for given digit */ for (i = 0; i < 7; i++) { printf("Processing digit %d at position %d, i is %d", digit, position, i); if (segments[digit][i] == 1) { switch (i) { case 0: digits[0][(position * 4) + 1] = '_'; break; case 1: digits[1][(position * 4) + 2] = '|'; break; case 2: digits[2][(position * 4) + 2] = '|'; break; case 3: digits[2][(position * 4) + 1] = '_'; break; case 4: digits[2][(position * 4) + 0] = '|'; break; case 5: digits[1][(position * 4) + 0] = '|'; break; case 6: digits[1][(position * 4) + 1] = '_'; break; } } } } void print_digits_array(void) { /* print each character in digits array */ for (i = 0; i < 3; i++) { for (j = 0; j < (MAX_DIGITS * 4); j++) { printf("%c", digits[i][j]); } printf("/n"); } }

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  • database design help for game / user levels / progress

    - by sprugman
    Sorry this got long and all prose-y. I'm creating my first truly gamified web app and could use some help thinking about how to structure the data. The Set-up Users need to accomplish tasks in each of several categories before they can move up a level. I've got my Users, Tasks, and Categories tables, and a UserTasks table which joins the three. ("User 3 has added Task 42 in Category 8. Now they've completed it.") That's all fine and working wonderfully. The Challenge I'm not sure of the best way to track the progress in the individual categories toward each level. The "business" rules are: You have to achieve a certain number of points in each category to move up. If you get the number of points needed in Cat 8, but still have other work to do to complete the level, any new Cat 8 points count toward your overall score, but don't "roll over" into the next level. The number of Categories is small (five currently) and unlikely to change often, but by no means absolutely fixed. The number of points needed to level-up will vary per level, probably by a formula, or perhaps a lookup table. So the challenge is to track each user's progress toward the next level in each category. I've thought of a few potential approaches: Possible Solutions Add a column to the users table for each category and reset them all to zero each time a user levels-up. Have a separate UserProgress table with a row for each category for each user and the number of points they have. (Basically a Many-to-Many version of #1.) Add a userLevel column to the UserTasks table and use that to derive their progress with some kind of SUM statement. Their current level will be a simple int in the User table. Pros & Cons (1) seems like by far the most straightforward, but it's also the least flexible. Perhaps I could use a naming convention based on the category ids to help overcome some of that. (With code like "select cats; for each cat, get the value from Users.progress_{cat.id}.") It's also the one where I lose the most data -- I won't know which points counted toward leveling up. I don't have a need in mind for that, so maybe I don't care about that. (2) seems complicated: every time I add or subtract a user or a category, I have to maintain the other table. I foresee synchronization challenges. (3) Is somewhere in between -- cleaner than #2, but less intuitive than #1. In order to find out where a user is, I'd have mildly complex SQL like: SELECT categoryId, SUM(points) from UserTasks WHERE userId={user.id} & countsTowardLevel={user.level} groupBy categoryId Hmm... that doesn't seem so bad. I think I'm talking myself into #3 here, but would love any input, advice or other ideas.

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  • jQuery Templates and Data Linking (and Microsoft contributing to jQuery)

    - by ScottGu
    The jQuery library has a passionate community of developers, and it is now the most widely used JavaScript library on the web today. Two years ago I announced that Microsoft would begin offering product support for jQuery, and that we’d be including it in new versions of Visual Studio going forward. By default, when you create new ASP.NET Web Forms and ASP.NET MVC projects with VS 2010 you’ll find jQuery automatically added to your project. A few weeks ago during my second keynote at the MIX 2010 conference I announced that Microsoft would also begin contributing to the jQuery project.  During the talk, John Resig -- the creator of the jQuery library and leader of the jQuery developer team – talked a little about our participation and discussed an early prototype of a new client templating API for jQuery. In this blog post, I’m going to talk a little about how my team is starting to contribute to the jQuery project, and discuss some of the specific features that we are working on such as client-side templating and data linking (data-binding). Contributing to jQuery jQuery has a fantastic developer community, and a very open way to propose suggestions and make contributions.  Microsoft is following the same process to contribute to jQuery as any other member of the community. As an example, when working with the jQuery community to improve support for templating to jQuery my team followed the following steps: We created a proposal for templating and posted the proposal to the jQuery developer forum (http://forum.jquery.com/topic/jquery-templates-proposal and http://forum.jquery.com/topic/templating-syntax ). After receiving feedback on the forums, the jQuery team created a prototype for templating and posted the prototype at the Github code repository (http://github.com/jquery/jquery-tmpl ). We iterated on the prototype, creating a new fork on Github of the templating prototype, to suggest design improvements. Several other members of the community also provided design feedback by forking the templating code. There has been an amazing amount of participation by the jQuery community in response to the original templating proposal (over 100 posts in the jQuery forum), and the design of the templating proposal has evolved significantly based on community feedback. The jQuery team is the ultimate determiner on what happens with the templating proposal – they might include it in jQuery core, or make it an official plugin, or reject it entirely.  My team is excited to be able to participate in the open source process, and make suggestions and contributions the same way as any other member of the community. jQuery Template Support Client-side templates enable jQuery developers to easily generate and render HTML UI on the client.  Templates support a simple syntax that enables either developers or designers to declaratively specify the HTML they want to generate.  Developers can then programmatically invoke the templates on the client, and pass JavaScript objects to them to make the content rendered completely data driven.  These JavaScript objects can optionally be based on data retrieved from a server. Because the jQuery templating proposal is still evolving in response to community feedback, the final version might look very different than the version below. This blog post gives you a sense of how you can try out and use templating as it exists today (you can download the prototype by the jQuery core team at http://github.com/jquery/jquery-tmpl or the latest submission from my team at http://github.com/nje/jquery-tmpl).  jQuery Client Templates You create client-side jQuery templates by embedding content within a <script type="text/html"> tag.  For example, the HTML below contains a <div> template container, as well as a client-side jQuery “contactTemplate” template (within the <script type="text/html"> element) that can be used to dynamically display a list of contacts: The {{= name }} and {{= phone }} expressions are used within the contact template above to display the names and phone numbers of “contact” objects passed to the template. We can use the template to display either an array of JavaScript objects or a single object. The JavaScript code below demonstrates how you can render a JavaScript array of “contact” object using the above template. The render() method renders the data into a string and appends the string to the “contactContainer” DIV element: When the page is loaded, the list of contacts is rendered by the template.  All of this template rendering is happening on the client-side within the browser:   Templating Commands and Conditional Display Logic The current templating proposal supports a small set of template commands - including if, else, and each statements. The number of template commands was deliberately kept small to encourage people to place more complicated logic outside of their templates. Even this small set of template commands is very useful though. Imagine, for example, that each contact can have zero or more phone numbers. The contacts could be represented by the JavaScript array below: The template below demonstrates how you can use the if and each template commands to conditionally display and loop the phone numbers for each contact: If a contact has one or more phone numbers then each of the phone numbers is displayed by iterating through the phone numbers with the each template command: The jQuery team designed the template commands so that they are extensible. If you have a need for a new template command then you can easily add new template commands to the default set of commands. Support for Client Data-Linking The ASP.NET team recently submitted another proposal and prototype to the jQuery forums (http://forum.jquery.com/topic/proposal-for-adding-data-linking-to-jquery). This proposal describes a new feature named data linking. Data Linking enables you to link a property of one object to a property of another object - so that when one property changes the other property changes.  Data linking enables you to easily keep your UI and data objects synchronized within a page. If you are familiar with the concept of data-binding then you will be familiar with data linking (in the proposal, we call the feature data linking because jQuery already includes a bind() method that has nothing to do with data-binding). Imagine, for example, that you have a page with the following HTML <input> elements: The following JavaScript code links the two INPUT elements above to the properties of a JavaScript “contact” object that has a “name” and “phone” property: When you execute this code, the value of the first INPUT element (#name) is set to the value of the contact name property, and the value of the second INPUT element (#phone) is set to the value of the contact phone property. The properties of the contact object and the properties of the INPUT elements are also linked – so that changes to one are also reflected in the other. Because the contact object is linked to the INPUT element, when you request the page, the values of the contact properties are displayed: More interesting, the values of the linked INPUT elements will change automatically whenever you update the properties of the contact object they are linked to. For example, we could programmatically modify the properties of the “contact” object using the jQuery attr() method like below: Because our two INPUT elements are linked to the “contact” object, the INPUT element values will be updated automatically (without us having to write any code to modify the UI elements): Note that we updated the contact object above using the jQuery attr() method. In order for data linking to work, you must use jQuery methods to modify the property values. Two Way Linking The linkBoth() method enables two-way data linking. The contact object and INPUT elements are linked in both directions. When you modify the value of the INPUT element, the contact object is also updated automatically. For example, the following code adds a client-side JavaScript click handler to an HTML button element. When you click the button, the property values of the contact object are displayed using an alert() dialog: The following demonstrates what happens when you change the value of the Name INPUT element and click the Save button. Notice that the name property of the “contact” object that the INPUT element was linked to was updated automatically: The above example is obviously trivially simple.  Instead of displaying the new values of the contact object with a JavaScript alert, you can imagine instead calling a web-service to save the object to a database. The benefit of data linking is that it enables you to focus on your data and frees you from the mechanics of keeping your UI and data in sync. Converters The current data linking proposal also supports a feature called converters. A converter enables you to easily convert the value of a property during data linking. For example, imagine that you want to represent phone numbers in a standard way with the “contact” object phone property. In particular, you don’t want to include special characters such as ()- in the phone number - instead you only want digits and nothing else. In that case, you can wire-up a converter to convert the value of an INPUT element into this format using the code below: Notice above how a converter function is being passed to the linkFrom() method used to link the phone property of the “contact” object with the value of the phone INPUT element. This convertor function strips any non-numeric characters from the INPUT element before updating the phone property.  Now, if you enter the phone number (206) 555-9999 into the phone input field then the value 2065559999 is assigned to the phone property of the contact object: You can also use a converter in the opposite direction also. For example, you can apply a standard phone format string when displaying a phone number from a phone property. Combining Templating and Data Linking Our goal in submitting these two proposals for templating and data linking is to make it easier to work with data when building websites and applications with jQuery. Templating makes it easier to display a list of database records retrieved from a database through an Ajax call. Data linking makes it easier to keep the data and user interface in sync for update scenarios. Currently, we are working on an extension of the data linking proposal to support declarative data linking. We want to make it easy to take advantage of data linking when using a template to display data. For example, imagine that you are using the following template to display an array of product objects: Notice the {{link name}} and {{link price}} expressions. These expressions enable declarative data linking between the SPAN elements and properties of the product objects. The current jQuery templating prototype supports extending its syntax with custom template commands. In this case, we are extending the default templating syntax with a custom template command named “link”. The benefit of using data linking with the above template is that the SPAN elements will be automatically updated whenever the underlying “product” data is updated.  Declarative data linking also makes it easier to create edit and insert forms. For example, you could create a form for editing a product by using declarative data linking like this: Whenever you change the value of the INPUT elements in a template that uses declarative data linking, the underlying JavaScript data object is automatically updated. Instead of needing to write code to scrape the HTML form to get updated values, you can instead work with the underlying data directly – making your client-side code much cleaner and simpler. Downloading Working Code Examples of the Above Scenarios You can download this .zip file to get with working code examples of the above scenarios.  The .zip file includes 4 static HTML page: Listing1_Templating.htm – Illustrates basic templating. Listing2_TemplatingConditionals.htm – Illustrates templating with the use of the if and each template commands. Listing3_DataLinking.htm – Illustrates data linking. Listing4_Converters.htm – Illustrates using a converter with data linking. You can un-zip the file to the file-system and then run each page to see the concepts in action. Summary We are excited to be able to begin participating within the open-source jQuery project.  We’ve received lots of encouraging feedback in response to our first two proposals, and we will continue to actively contribute going forward.  These features will hopefully make it easier for all developers (including ASP.NET developers) to build great Ajax applications. Hope this helps, Scott P.S. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu]

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  • Parallelism in .NET – Part 9, Configuration in PLINQ and TPL

    - by Reed
    Parallel LINQ and the Task Parallel Library contain many options for configuration.  Although the default configuration options are often ideal, there are times when customizing the behavior is desirable.  Both frameworks provide full configuration support. When working with Data Parallelism, there is one primary configuration option we often need to control – the number of threads we want the system to use when parallelizing our routine.  By default, PLINQ and the TPL both use the ThreadPool to schedule tasks.  Given the major improvements in the ThreadPool in CLR 4, this default behavior is often ideal.  However, there are times that the default behavior is not appropriate.  For example, if you are working on multiple threads simultaneously, and want to schedule parallel operations from within both threads, you might want to consider restricting each parallel operation to using a subset of the processing cores of the system.  Not doing this might over-parallelize your routine, which leads to inefficiencies from having too many context switches. In the Task Parallel Library, configuration is handled via the ParallelOptions class.  All of the methods of the Parallel class have an overload which accepts a ParallelOptions argument. We configure the Parallel class by setting the ParallelOptions.MaxDegreeOfParallelism property.  For example, let’s revisit one of the simple data parallel examples from Part 2: Parallel.For(0, pixelData.GetUpperBound(0), row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re looping through an image, and calling a method on each pixel in the image.  If this was being done on a separate thread, and we knew another thread within our system was going to be doing a similar operation, we likely would want to restrict this to using half of the cores on the system.  This could be accomplished easily by doing: var options = new ParallelOptions(); options.MaxDegreeOfParallelism = Math.Max(Environment.ProcessorCount / 2, 1); Parallel.For(0, pixelData.GetUpperBound(0), options, row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); Now, we’re restricting this routine to using no more than half the cores in our system.  Note that I included a check to prevent a single core system from supplying zero; without this check, we’d potentially cause an exception.  I also did not hard code a specific value for the MaxDegreeOfParallelism property.  One of our goals when parallelizing a routine is allowing it to scale on better hardware.  Specifying a hard-coded value would contradict that goal. Parallel LINQ also supports configuration, and in fact, has quite a few more options for configuring the system.  The main configuration option we most often need is the same as our TPL option: we need to supply the maximum number of processing threads.  In PLINQ, this is done via a new extension method on ParallelQuery<T>: ParallelEnumerable.WithDegreeOfParallelism. Let’s revisit our declarative data parallelism sample from Part 6: double min = collection.AsParallel().Min(item => item.PerformComputation()); Here, we’re performing a computation on each element in the collection, and saving the minimum value of this operation.  If we wanted to restrict this to a limited number of threads, we would add our new extension method: int maxThreads = Math.Max(Environment.ProcessorCount / 2, 1); double min = collection .AsParallel() .WithDegreeOfParallelism(maxThreads) .Min(item => item.PerformComputation()); This automatically restricts the PLINQ query to half of the threads on the system. PLINQ provides some additional configuration options.  By default, PLINQ will occasionally revert to processing a query in parallel.  This occurs because many queries, if parallelized, typically actually cause an overall slowdown compared to a serial processing equivalent.  By analyzing the “shape” of the query, PLINQ often decides to run a query serially instead of in parallel.  This can occur for (taken from MSDN): Queries that contain a Select, indexed Where, indexed SelectMany, or ElementAt clause after an ordering or filtering operator that has removed or rearranged original indices. Queries that contain a Take, TakeWhile, Skip, SkipWhile operator and where indices in the source sequence are not in the original order. Queries that contain Zip or SequenceEquals, unless one of the data sources has an originally ordered index and the other data source is indexable (i.e. an array or IList(T)). Queries that contain Concat, unless it is applied to indexable data sources. Queries that contain Reverse, unless applied to an indexable data source. If the specific query follows these rules, PLINQ will run the query on a single thread.  However, none of these rules look at the specific work being done in the delegates, only at the “shape” of the query.  There are cases where running in parallel may still be beneficial, even if the shape is one where it typically parallelizes poorly.  In these cases, you can override the default behavior by using the WithExecutionMode extension method.  This would be done like so: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .Select(i => i.PerformComputation()) .Reverse(); Here, the default behavior would be to not parallelize the query unless collection implemented IList<T>.  We can force this to run in parallel by adding the WithExecutionMode extension method in the method chain. Finally, PLINQ has the ability to configure how results are returned.  When a query is filtering or selecting an input collection, the results will need to be streamed back into a single IEnumerable<T> result.  For example, the method above returns a new, reversed collection.  In this case, the processing of the collection will be done in parallel, but the results need to be streamed back to the caller serially, so they can be enumerated on a single thread. This streaming introduces overhead.  IEnumerable<T> isn’t designed with thread safety in mind, so the system needs to handle merging the parallel processes back into a single stream, which introduces synchronization issues.  There are two extremes of how this could be accomplished, but both extremes have disadvantages. The system could watch each thread, and whenever a thread produces a result, take that result and send it back to the caller.  This would mean that the calling thread would have access to the data as soon as data is available, which is the benefit of this approach.  However, it also means that every item is introducing synchronization overhead, since each item needs to be merged individually. On the other extreme, the system could wait until all of the results from all of the threads were ready, then push all of the results back to the calling thread in one shot.  The advantage here is that the least amount of synchronization is added to the system, which means the query will, on a whole, run the fastest.  However, the calling thread will have to wait for all elements to be processed, so this could introduce a long delay between when a parallel query begins and when results are returned. The default behavior in PLINQ is actually between these two extremes.  By default, PLINQ maintains an internal buffer, and chooses an optimal buffer size to maintain.  Query results are accumulated into the buffer, then returned in the IEnumerable<T> result in chunks.  This provides reasonably fast access to the results, as well as good overall throughput, in most scenarios. However, if we know the nature of our algorithm, we may decide we would prefer one of the other extremes.  This can be done by using the WithMergeOptions extension method.  For example, if we know that our PerformComputation() routine is very slow, but also variable in runtime, we may want to retrieve results as they are available, with no bufferring.  This can be done by changing our above routine to: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .WithMergeOptions(ParallelMergeOptions.NotBuffered) .Select(i => i.PerformComputation()) .Reverse(); On the other hand, if are already on a background thread, and we want to allow the system to maximize its speed, we might want to allow the system to fully buffer the results: var reversed = collection .AsParallel() .WithExecutionMode(ParallelExecutionMode.ForceParallelism) .WithMergeOptions(ParallelMergeOptions.FullyBuffered) .Select(i => i.PerformComputation()) .Reverse(); Notice, also, that you can specify multiple configuration options in a parallel query.  By chaining these extension methods together, we generate a query that will always run in parallel, and will always complete before making the results available in our IEnumerable<T>.

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  • Bug Triage

    In this blog post brain dump, I'll attempt to describe the process my team tries to follow when dealing with new bug reports (specifically, code defect reports). This is not official Microsoft policy, just the way we do things… if you do things differently and want to share, you can do so at the bottom in the comments (or on your blog).Feature Triage TeamA subset of the feature crew, the triage team (which has representations from the PM, Dev and QA disciplines), looks at all unassigned bugs at regular intervals. This can be weekly or daily (or other frequency) dependent on which part of the product cycle we are in and what the untriaged bug load looks like. They discuss each bug considering the evidence and make a decision of whether the bug goes from Not Yet Assigned to Assigned (plus the name of the DEV to fix this) or whether it goes from Active to Resolved (which means it gets assigned back to the requestor for closure or further debate if they were not present at the triage meeting). Close to critical milestones, the feature triage team needs to further justify bugs they take to additional higher-level triage teams.Bug Opened = Not Yet AssignedSomeone (typically an SDET from the QA team) creates the bug item (e.g. in TFS), ensuring they populate all the relevant fields including: Title, Description, Repro Steps (including the Actual Result at the end of the steps), attachments of code and/or screenshots, Build number that they observed the issue in, regression details if applicable, how it was found, if a test case exists or needs to be created etc. They also indicate their opinion on the Priority and Severity. The bug status is left as Not Yet Assigned."Issue" versus "Fix for issue"The solution to some bugs is easy to determine, e.g. "bug: the column name is misspelled". Obviously the fix is to correct the spelling – still, the triage team should be explicit and enter the correct spelling in the bug's Description. Note that a bad bug name here would be "bug: fix the spelling of the column" (it describes the solution, rather than the problem).Other solutions are trickier to establish, e.g. "bug: the column header is not accessible (can only be clicked on with the mouse, not reached via keyboard)". What is the correct solution here? The last thing to do is leave this undetermined and just assign it to a developer. The solution has to be entered in the description. Behind this type of a bug usually hides a spec defect or a new feature request.The person opening the bug should focus on describing the issue, rather than the solution. The person indicates what the fix is in their opinion by stating the Expected Result (immediately after stating the Actual Result). If they have a complex suggested solution, that should be split out in a separate part, but the triage team has the final say before assigning it. If the solution is lengthy/complicated to describe, the bug can be assigned to the PM. Note: the strict interpretation suggests that any bug with no clear, obvious solution is always a hole in the spec and should always go to the PM. This also ensures the spec gets updated.Not Yet Assigned - Not Yet Assigned (on someone else's plate)If the bug is observed in our feature, but the cause is actually another team, we change the Area Path (which is the way we identify teams in TFS) and leave it as Not Yet Assigned. The triage team may add more comments as appropriate including potentially changing the repro steps. In some cases, we may even resolve the bug in our area path and open a new bug in the area path of the other team.Even though there is no action on a dev on the team, the bug still needs to be tracked. One way of doing this is to implement some notification system that informs the team when the tracked bug changed status; another way is to occasionally run a global query (against all area paths) for bugs that have been opened by a member of the team and follow up with the current owners for stale bugs.Not Yet Assigned - ResolvedThis state transition can only be made by the Feature Triage Team.0. Sometimes the bug description is not clear and in that case it gets Resolved as More Information Needed, so the original requestor can provide it.After understanding what the bug item is about, the first decision is to determine whether it needs to go to a dev.1. If it is a known bug, it gets resolved as "Duplicate" and linked to the existing bug.2. If it is "By Design" it gets resolved as such, indicating that the triage team does not think this is a bug.3. If the bug does not repro on latest bits, it is resolved as "No Repro"4. The most painful: If it is decided that we cannot fix it for this release it gets resolved as "Postponed" or "Won't Fix". The former is typically due to resources and time constraints, while the latter is due to deciding that it is not important enough to consume our resources in any release (yes, not all bugs must be fixed!). For both cases, there are other factors that contribute to the decision such as: existence of a reasonable workaround, frequency we expect users to encounter the issue, dependencies on other team to offer a solution, whether it breaks a core scenario, whether it prohibits customer feedback on a major feature, is it a regression from a previous release, impact of the fix on other partner teams (e.g. User Education, User Experience, Localization/Globalization), whether this is the right fix, does the fix impact performance goals, and last but not least, severity of bug (e.g. loss of customer data, security threat, crash, hang). The bar for fixing a bug goes up as the release date approaches. The triage team becomes hardnosed about which bugs to take, while the developers are busy resolving assigned bugs thus everyone drives for Zero Bug Bounce (ZBB). ZBB is when you have 0 active bugs older than 48 hours.Not Yet Assigned - AssignedIf the bug is something we decide to fix in this release and the solution is known, then it is assigned to a DEV. This is either the developer that will do the work, or a Lead that can further assign it to one of his developer team based on a load balancing algorithm of their choosing.Sometimes, the triage team needs the dev to do some investigation work before deciding whether to take the fix; similarly, the checkin for the fix may be gated on code review by the triage team. In these cases, these instructions are provided in the comments section of the bug and when the developer is done they notify the triage team for final decision.Additionally, a Priority and Severity (from 0 to 4) has to be entered, e.g. a P0 means "drop anything you are doing and fix this now" whereas a P4 is something you get to after all P0,1,2,3 bugs are fixed.From a testing perspective, if the bug was found through ad-hoc testing or an external team, the decision is made whether test cases should be added to avoid future regressions. This is communicated to the QA team.Assigned - ResolvedWhen the developer receives the bug (they should be checking daily for new bugs on their plate looking at bugs in order of priority and from older to newer) they can send it back to triage if the information is not clear. Otherwise, they investigate the bug, setting the Sub Status to "Investigating"; if they cannot make progress, they set the Sub Status to "Blocked" and discuss this with triage or whoever else can help them get unblocked. Once they are unblocked, they set the Sub Status to "Working on Solution"; once they are code complete they send a code review request, setting the Sub Status to "Fix Available". After the iterative code review process is over and everyone is happy with the fix, the developer checks it in and changes the state of the bug from Active (and Assigned to them) to Resolved (and Assigned to someone else).The developer needs to ensure that when the status is changed to Resolved that it is assigned to a QA person. For example, maybe the PM opened the bug, but it should be a QA person that will verify the fix - the developer needs to manually change the assignee in that case. Typically the QA person will send an email to the original requestor notifying them that the fix is verified.Resolved - ??In all cases above, note that the final state was Resolved. What happens after that? The final step should be Closed. The bug is closed once the QA person verifying the fix is happy with it. If the person is not happy, then they change the state from Resolved to Active, thus sending it back to the developer. If the developer and QA person cannot reach agreement, then triage can be brought into it. An easy way to do that is change the status back to Not Yet Assigned with appropriate comments so the triage team can re-review.It is important to note that only QA can close a bug. That means that if the opener of the bug was a PM, when the bug gets resolved by the dev it may land on the PM's plate and after a quick review, the PM would re-assign to an SDET, which is the only role that can close bugs. One exception to this is if the person that filed the bug is external: in that case, we leave it Resolved and assigned to them and also send them a notification that they need to verify the fix. Another exception is if specialized developer knowledge is needed for verifying the bug fix (e.g. it was a refactoring suggestion bug typically not observable by the user) in which case it is fine to have a developer verify the fix, and ideally a different developer to the one that opened the bug.Other links on bug triageA quick search reveals that others have talked about this subject, e.g. here, here, here, here and here.Your take?If you have other best practices your team uses to deal with incoming bug reports, feel free to share in the comments below or on your blog. Comments about this post welcome at the original blog.

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