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  • MessageListener didnt receive full message ASMACK Android

    - by Frank Junior
    i got problem when want to receive message, right now i am able to receive message, but some attribut is missing class MyMessageListener implements MessageListener { @Override public void processMessage(Chat chat, Message message) { Util.DebugLog("message->"+message.toXmlns()); } } what i got is <message to="[email protected]" type="chat" from="[email protected]/ff3b2485"><body asdf="asdf">aaa</body></message> talk_id and chat type inside message is missing. This is want i want when receive message <message to="[email protected]" type="chat" talk_id="304" chat_type="0" from="[email protected]/ff3b2485"><body asdf="asdf">aaa</body></message>

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  • postfix takes 60-90ms to queue email -- normal?

    - by Jeff Atwood
    We're seeing some (maybe?) strange delays when submitting individual emails to our local Postfix server. To help diagnose the issue, I wrote a little test program which sends 5 emails: get smtp 1ms ( 1 ms) email 0 677ms (676 ms) email 1 802ms (125 ms) email 2 890ms ( 88 ms) email 3 973ms ( 83 ms) email 4 1088ms (115 ms) Discounting the handshaking in the first email, that's about 90ms per email. These timings have also been corroborated with another test app written by someone else using a different codepath, so it appears to be server related. I turned on detailed logging and I can see that the delay is between the end of message \r\n\r\n and the receive: [16:31:29.95] [SEND] \r\n.\r\n [16:31:30.05] [RECV] 250 2.0.0 Ok: queued as B128E1E063\r\n [16:31:30.08] [SEND] \r\n.\r\n [16:31:30.17] [RECV] 250 2.0.0 Ok: queued as 4A7DE1E06E\r\n [16:31:30.19] [SEND] \r\n.\r\n [16:31:30.27] [RECV] 250 2.0.0 Ok: queued as 68ACC1E072\r\n [16:31:30.28] [SEND] \r\n.\r\n [16:31:30.34] [RECV] 250 2.0.0 Ok: queued as 7EFFE1E079\r\n [16:31:30.39] [SEND] \r\n.\r\n [16:31:30.45] [RECV] 250 2.0.0 Ok: queued as 9793C1E07A\r\n The time intervals tell the story (discounting the handshaking required for the initial email) -- each email is waiting about 60-90 milliseconds for postfix to queue! This seems .. excessive .. to me. Is it "normal" for postfix to take 60-90 ms for every email you send it? Or do I just have unreasonable expectations? I would expect the local postfix server to queue the email in about 20ms, tops!

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  • making a queue program

    - by seventhief
    Hi can someone help me making a queue program. i want to set the array[0] to be array[1] just in display but in real i am adding value at array[0]. i got how to run the add function to it. but i can't do the view and delete command that will view from ex. array[0] to array[4], when displayed array[1] to array[5] with the value inserted. #include <stdio.h> #include <stdlib.h> #define p printf #define s scanf int rear = 0; int front = 0; int *q_array = NULL; int size = 0; main() { int num, opt; char cont[] = { 'y' }; clrscr(); p("Queue Program\n\n"); p("Queue size: "); s("%d", &size); p("\n"); if(size > 0) { q_array = malloc(size * sizeof(int)); if(q_array == NULL) { p("ERROR: malloc() failed\n"); exit(2); } } else { p("ERROR: size should be positive integer\n"); exit(1); } while((cont[0] == 'y') || (cont[0] == 'Y')) { clrscr(); p("Queue Program"); p("\n\nQueue size: %d\n\n", size); p("MAIN MENU\n1. Add\n2. Delete\n3. View"); p("\n\nYour choice: "); s("%d", &opt); p("\n"); switch(opt) { case 1: if(rear==size) { p("You can't add more data"); } else { p("Enter data for Queue[%d]: ", rear+1); s("%d", &num); add(num); } break; case 2: delt(); break; case 3: view(); break; } p("\n\nDo you want to continue? (Y\/N)"); s("%s", &cont[0]); } } add(int a) { q_array[rear]=a; rear++; } delt() { if(front==rear) { p("Queue Empty"); } else { p("Queue[%d] = %d removed.", front, q_array[front]); front++; } } view() { int i; for(i=front;i<=rear;i++) p("\nQueue[%d] = %d", i, q_array[i]); }

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  • SQL SERVER – Parsing SSIS Catalog Messages – Notes from the Field #030

    - by Pinal Dave
    [Note from Pinal]: This is a new episode of Notes from the Field series. SQL Server Integration Service (SSIS) is one of the most key essential part of the entire Business Intelligence (BI) story. It is a platform for data integration and workflow applications. The tool may also be used to automate maintenance of SQL Server databases and updates to multidimensional cube data. In this episode of the Notes from the Field series I requested SSIS Expert Andy Leonard to discuss one of the most interesting concepts of SSIS Catalog Messages. There are plenty of interesting and useful information captured in the SSIS catalog and we will learn together how to explore the same. The SSIS Catalog captures a lot of cool information by default. Here’s a query I use to parse messages from the catalog.operation_messages table in the SSISDB database, where the logged messages are stored. This query is set up to parse a default message transmitted by the Lookup Transformation. It’s one of my favorite messages in the SSIS log because it gives me excellent information when I’m tuning SSIS data flows. The message reads similar to: Data Flow Task:Information: The Lookup processed 4485 rows in the cache. The processing time was 0.015 seconds. The cache used 1376895 bytes of memory. The query: USE SSISDB GO DECLARE @MessageSourceType INT = 60 DECLARE @StartOfIDString VARCHAR(100) = 'The Lookup processed ' DECLARE @ProcessingTimeString VARCHAR(100) = 'The processing time was ' DECLARE @CacheUsedString VARCHAR(100) = 'The cache used ' DECLARE @StartOfIDSearchString VARCHAR(100) = '%' + @StartOfIDString + '%' DECLARE @ProcessingTimeSearchString VARCHAR(100) = '%' + @ProcessingTimeString + '%' DECLARE @CacheUsedSearchString VARCHAR(100) = '%' + @CacheUsedString + '%' SELECT operation_id , SUBSTRING(MESSAGE, (PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1)) - (PATINDEX(@StartOfIDSearchString, MESSAGE) + LEN(@StartOfIDString) + 1))) AS LookupRowsCount , SUBSTRING(MESSAGE, (PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1)) - (PATINDEX(@ProcessingTimeSearchString, MESSAGE) + LEN(@ProcessingTimeString) + 1))) AS LookupProcessingTime , CASE WHEN (CONVERT(numeric(3,3),SUBSTRING(MESSAGE, (PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1)) - (PATINDEX(@ProcessingTimeSearchString, MESSAGE) + LEN(@ProcessingTimeString) + 1))))) = 0 THEN 0 ELSE CONVERT(bigint,SUBSTRING(MESSAGE, (PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1)) - (PATINDEX(@StartOfIDSearchString, MESSAGE) + LEN(@StartOfIDString) + 1)))) / CONVERT(numeric(3,3),SUBSTRING(MESSAGE, (PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@ProcessingTimeSearchString,MESSAGE) + LEN(@ProcessingTimeString) + 1)) - (PATINDEX(@ProcessingTimeSearchString, MESSAGE) + LEN(@ProcessingTimeString) + 1)))) END AS LookupRowsPerSecond , SUBSTRING(MESSAGE, (PATINDEX(@CacheUsedSearchString,MESSAGE) + LEN(@CacheUsedString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@CacheUsedSearchString,MESSAGE) + LEN(@CacheUsedString) + 1)) - (PATINDEX(@CacheUsedSearchString, MESSAGE) + LEN(@CacheUsedString) + 1))) AS LookupBytesUsed ,CASE WHEN (CONVERT(bigint,SUBSTRING(MESSAGE, (PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1)) - (PATINDEX(@StartOfIDSearchString, MESSAGE) + LEN(@StartOfIDString) + 1)))))= 0 THEN 0 ELSE CONVERT(bigint,SUBSTRING(MESSAGE, (PATINDEX(@CacheUsedSearchString,MESSAGE) + LEN(@CacheUsedString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@CacheUsedSearchString,MESSAGE) + LEN(@CacheUsedString) + 1)) - (PATINDEX(@CacheUsedSearchString, MESSAGE) + LEN(@CacheUsedString) + 1)))) / CONVERT(bigint,SUBSTRING(MESSAGE, (PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1), ((CHARINDEX(' ', MESSAGE, PATINDEX(@StartOfIDSearchString,MESSAGE) + LEN(@StartOfIDString) + 1)) - (PATINDEX(@StartOfIDSearchString, MESSAGE) + LEN(@StartOfIDString) + 1)))) END AS LookupBytesPerRow FROM [catalog].[operation_messages] WHERE message_source_type = @MessageSourceType AND MESSAGE LIKE @StartOfIDSearchString GO Note that you have to set some parameter values: @MessageSourceType [int] – represents the message source type value from the following results: Value     Description 10           Entry APIs, such as T-SQL and CLR Stored procedures 20           External process used to run package (ISServerExec.exe) 30           Package-level objects 40           Control Flow tasks 50           Control Flow containers 60           Data Flow task 70           Custom execution message Note: Taken from Reza Rad’s (excellent!) helper.MessageSourceType table found here. @StartOfIDString [VarChar(100)] – use this to uniquely identify the message field value you wish to parse. In this case, the string ‘The Lookup processed ‘ identifies all the Lookup Transformation messages I desire to parse. @ProcessingTimeString [VarChar(100)] – this parameter is message-specific. I use this parameter to specifically search the message field value for the beginning of the Lookup Processing Time value. For this execution, I use the string ‘The processing time was ‘. @CacheUsedString [VarChar(100)] – this parameter is also message-specific. I use this parameter to specifically search the message field value for the beginning of the Lookup Cache  Used value. It returns the memory used, in bytes. For this execution, I use the string ‘The cache used ‘. The other parameters are built from variations of the parameters listed above. The query parses the values into text. The string values are converted to numeric values for ratio calculations; LookupRowsPerSecond and LookupBytesPerRow. Since ratios involve division, CASE statements check for denominators that equal 0. Here are the results in an SSMS grid: This is not the only way to retrieve this information. And much of the code lends itself to conversion to functions. If there is interest, I will share the functions in an upcoming post. If you want to get started with SSIS with the help of experts, read more over at Fix Your SQL Server. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Notes from the Field, PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: SSIS

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  • win2008 r2 enterprise "Message Queuing" "Access is denied" "The list of messages cannot be retrieved"

    - by gerryLowry
    on my win7, I run compmgmt.msc and drill to a private queue folder ... when I click "Queue messages" or "Journal messages", I either see the messages, or "There are no items to show in this view". BUT, on win2008 R2 Enterprise, I run compmgmt.msc and drill to a private queue folder ... when I click "Queue messages" or "Journal messages", I see "There are no items to show in this view" which AFAIK is correct BUT I get this unwanted dialog: Message Queuing x ------------------------ (X) The list of messages cannot be retrieved. Error: Access is denied. [[ OK ]] On both computers, I'm a member of local Administrators. I'm concerned as a developer because I'm very soon going to be testing WCF/MSMQ software that works on my Win7 laptop. How to I get past this denied access problem? thnx / g.

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  • Wordpress Queue like Tumblr?

    - by Michael Hopkins
    Hi. Is there a way to give Wordpress the queue functionality that Tumblr has? Tumblr's queue, for those who don't know, is a way to space posts out without assigning specific post dates. For example, a Tumblr queue might be set to post every four hours between 9am and 5pm. Tumblr would drop the front post in the queue at 9am, 1pm and 5pm every day. Posts are added to the queue by clicking "add to queue" instead of "publish." It's quite simple. How can this feature be added to Wordpress?

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  • Is there a tool to do round trip software engineering between a sequence diagram and a group of objects that message back and forth?

    - by DeveloperDon
    Is there a tool to do round trip software engineering between a sequence diagram and a group of objects that message back and forth? Perhaps this seems a little exotic, but it seems like a function that includes message calls or even method invocations on other objects could be automatically converted to a sequence diagram given that it is not hard to do manually. Similarly, when a sequence diagram is modified, based on the message name and type of message, should it not be possible to add a message or method to the calling object?

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  • Why does std queue not define a swap method specialisation

    - by Jamie Cook
    I've read that all stl containers provide a specialisation of the swap algorithm so as to avoid calling the copy constructor and two assignment operations that the default method uses. However, when I thought it would be nice to use a queue in some code I was working on I noticed that (unlike vector and deque) queue doesn't provide this method? I just decided to use a deque instead of a queue, but still I'm interested to know why this is?

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  • Which Queue implementation to use in Java?

    - by devoured elysium
    I need to use a FIFO structure in my application. It needs to have at most 5 elements. I'd like to have something easy to use (I don't care for concurrency) that implements the Collection interface. I've tried the LinkedList, that seems to come from Queue, but it doesn't seem to allow me to set it's maximum capacity. It feels as if I just want at max 5 elements but try to add 20, it will just keep increasing in size to fit it. I'd like something that'd work the following way: XQueue<Integer> queue = new XQueue<Integer>(5); //where 5 is the maximum number of elements I want in my queue. for (int i = 0; i < 10; ++i) { queue.offer(i); } for (int i = 0; i < 5; ++i) { System.out.println(queue.poll()); } That'd print: 5 6 7 8 9 Thanks

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  • Windows Command queue?

    - by Stefano
    i'm thinking if does exist some kind of software that can put in a queue a bunch of windows commands... for example i can say to first copy some file somewhere, then rename those, then delete the old files, then edit one of them etc.... without waiting the effective execution of any of those passages.... this could be useful when copying big files that take a lot and i don't want to sit in front of the computer keeping the eyes on the progress bar... does exist anything like this?

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  • Another thread safe queue implementation

    - by jensph
    I have a class, Queue, that I tried to make thread safe. It has these three member variables: std::queue<T> m_queue; pthread_mutex_t m_mutex; pthread_cond_t m_condition; and a push and pop implemented as: template<class T> void Queue<T>::push(T value) { pthread_mutex_lock( &m_mutex ); m_queue.push(value); if( !m_queue.empty() ) { pthread_cond_signal( &m_condition ); } pthread_mutex_unlock( &m_mutex ); } template<class T> bool Queue<T>::pop(T& value, bool block) { bool rtn = false; pthread_mutex_lock( &m_mutex ); if( block ) { while( m_queue.empty() ) { pthread_cond_wait( &m_condition, &m_mutex ); } } if( !m_queue.empty() ) { value = m_queue.front(); m_queue.pop(); rtn = true; } pthread_mutex_unlock( &m_mutex ); return rtn; } Unfortunately there are occasional issues that may be the fault of this code. That is, there are two threads and sometimes thread 1 never comes out of push() and at other times thread 2 never comes out of pop() (the block parameter is true) though the queue isn't empty. I understand there are other implementations available, but I'd like to try to fix this code, if needed. Anyone see any issues? The constructor has the appropriate initializations: Queue() { pthread_mutex_init( &mMutex, NULL ); pthread_cond_init( &mCondition, NULL ); } and the destructor, the corresponding 'destroy' calls.

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  • 1600+ 'postfix-queue' processes - OK to have this many?

    - by atomicguava
    I have a Plesk 9.5.4 CentOS server running Postfix. I had been having massive problems with the mailq being full of 'double-bounce' email messages containing errors relating to 'Queue File Write Error', but I believe these are now fixed thanks to this thread. My new problem is that when I run top, I can see lots of processes called 'postfix-queue' and have fairly high load: top - 13:59:44 up 6 days, 21:14, 1 user, load average: 2.33, 2.19, 1.96 Tasks: 1743 total, 1 running, 1742 sleeping, 0 stopped, 0 zombie Cpu(s): 5.1%us, 8.8%sy, 0.0%ni, 85.3%id, 0.8%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 3145728k total, 1950640k used, 1195088k free, 0k buffers Swap: 0k total, 0k used, 0k free, 0k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1324 apache 16 0 344m 33m 5664 S 21.7 1.1 0:03.17 httpd 32443 apache 15 0 350m 36m 6864 S 14.4 1.2 0:13.83 httpd 1678 root 15 0 13948 2568 952 R 2.0 0.1 0:00.37 top 1890 mysql 15 0 689m 318m 7600 S 1.0 10.4 219:45.23 mysqld 1394 apache 15 0 352m 41m 5972 S 0.7 1.3 0:03.91 httpd 1369 apache 15 0 344m 33m 5444 S 0.3 1.1 0:02.03 httpd 1592 apache 15 0 349m 37m 5912 S 0.3 1.2 0:02.52 httpd 1633 apache 15 0 336m 20m 1828 S 0.3 0.7 0:00.01 httpd 1952 root 19 0 335m 28m 10m S 0.3 0.9 1:35.41 httpd 1 root 15 0 10304 732 612 S 0.0 0.0 0:04.41 init 1034 mhandler 15 0 11520 1160 884 S 0.0 0.0 0:00.00 postfix-queue 1036 mhandler 15 0 11516 1120 860 S 0.0 0.0 0:00.00 postfix-queue 1041 mhandler 17 0 11516 1156 884 S 0.0 0.0 0:00.00 postfix-queue 1043 mhandler 15 0 11512 1116 860 S 0.0 0.0 0:00.00 postfix-queue 1063 mhandler 16 0 11516 1160 884 S 0.0 0.0 0:00.00 postfix-queue 1068 mhandler 15 0 11516 1128 860 S 0.0 0.0 0:00.00 postfix-queue 1071 mhandler 17 0 11512 1152 884 S 0.0 0.0 0:00.00 postfix-queue 1072 mhandler 15 0 11512 1116 860 S 0.0 0.0 0:00.00 postfix-queue 1081 mhandler 16 0 11516 1156 884 S 0.0 0.0 0:00.00 postfix-queue 1082 mhandler 15 0 11512 1120 860 S 0.0 0.0 0:00.00 postfix-queue 1089 popuser 15 0 33892 1972 1200 S 0.0 0.1 0:00.02 pop3d 1116 mhandler 16 0 11516 1164 884 S 0.0 0.0 0:00.00 postfix-queue 1117 mhandler 15 0 11516 1124 860 S 0.0 0.0 0:00.00 postfix-queue 1120 mhandler 16 0 11516 1160 884 S 0.0 0.0 0:00.00 postfix-queue 1121 mhandler 15 0 11512 1120 860 S 0.0 0.0 0:00.00 postfix-queue 1130 mhandler 17 0 11516 1160 884 S 0.0 0.0 0:00.00 postfix-queue 1131 mhandler 15 0 11516 1120 860 S 0.0 0.0 0:00.00 postfix-queue 1149 root 17 -4 12572 680 356 S 0.0 0.0 0:00.00 udevd 1181 mhandler 16 0 11516 1160 884 S 0.0 0.0 0:00.00 postfix-queue 1183 mhandler 15 0 11512 1116 860 S 0.0 0.0 0:00.00 postfix-queue 1224 mhandler 16 0 11516 1160 884 S 0.0 0.0 0:00.00 postfix-queue 1225 mhandler 15 0 11516 1120 860 S 0.0 0.0 0:00.00 postfix-queue 1228 apache 15 0 345m 34m 5472 S 0.0 1.1 0:04.64 httpd 1241 mhandler 16 0 11516 1156 884 S 0.0 0.0 0:00.00 postfix-queue 1242 mhandler 15 0 11512 1120 860 S 0.0 0.0 0:00.00 postfix-queue 1251 mhandler 17 0 11516 1156 884 S 0.0 0.0 0:00.00 postfix-queue 1252 mhandler 15 0 11516 1120 860 S 0.0 0.0 0:00.00 postfix-queue 1258 apache 15 0 349m 37m 5444 S 0.0 1.2 0:01.28 httpd When I run ps -Al | grep -c postfix-queue it returns 1618! My question is this: is this normal or is there something else going wrong with Postfix? Right now, if I run mailq it is empty, and qshape deferred / qshape active are empty too. Thanks in advance for your help.

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  • Strange ASP.NET Queue Performance Counters Behavior?

    - by LemurTech
    We have an ASP.NET 2.0 site running in classic mode. I am seeing very strange behavior in the performance counter values. Perhaps these are bugs (I've been all over Google trying to verify this, without much luck), or perhaps it is just my inexperience with monitoring these things. This PerfMon graph (http://imgur.com/Jv5io5J) represents a load test where I add up to 350 virtual users to the site, at a rate of about 1/sec, performing relatively simple page browsing. At the end of the test, I gradually taper off the number of users. This is a 4 CPU server. Machine.config settings for are at the defaults. The solid blue line is ASP.NET Apps v2.x\Requests Executing for the application in question. The profile makes perfect sense, with a quick ramp-up to 32 executing requests (minWorkerThreads x 4CPUs), followed by a slower ramp-up to 48 ((maxWorkerThreads - minWorkerThreads) x 4CPUs). The solid yellow line is ASP.NET v2.x\Requests Queued. Again, this makes sense: after the initial 32 request threads are activated, the queue begins to build as new thread initialization can't keep pace with incoming requests. But as executing requests reaches its highest possible value of 48, the counter for ASP.NET Apps v2.x\Requests Queued (green solid line) suddenly springs to life and maintains step with the yellow counter. As far as I can tell, and with no other apps running on the server, these two counters should have had the same values from the start. One other odd thing: The counter for ASP.NET v2.x\Request Wait Time (dotted yellow line) also does not spring to life until executing requests reaches 48. Shouldn't I be seeing values here from the moment ASP.NET v2.x\Requests Queued begins to build? And likewise, why would ASP.NET Apps v2.x\Request Execution Time (dotted blue) increase significantly only after that peak of 48 is reached? Shouldn't it ramp-up gradually along with queued requests?

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  • 4.0/WCF: Best approach for bi-idirectional message bus?

    - by TomTom
    Just a technology update, now that .NET 4.0 is out. I write an application that communicates to the server through what is basically a message bus (instead of method calls). This is based on the internal architecture of the application (which is multi threaded, passing the messages around). There are a limited number of messages to go from the client to the server, quite a lot more from the server to the client. Most of those can be handled via a separate specialized mechanism, but at the end we talk of possibly 10-100 small messages per second going from the server to the client. The client is supposed to operate under "internet conditions". THis means possibly home end users behind standard NAT devices (i.e. typical DSL routers) - a firewalled secure and thus "open" network can not be assumed. I want to have as little latency and as little overhad for the communication as possible. What is the technologally best way to handle the message bus callback? I Have no problem regularly calling to the server for message delivery if something needs to be sent... ...but what are my options to handle the messagtes from the server to the client? WsDualHttp does work how? Especially under a NAT scenario? Just as a note: polling is most likely out - the main problem here is that I would have a significant overhead OR a significant delay, both aren ot really wanted. Technically I would love some sort of streaming appraoch, where the server can write messags to a stream while he generates them and they get sent to the client as they come. Not esure this is doable with WCF, though (if not, I may acutally decide to handle the whole message part outside of WCF and just do control / login / setup / destruction via WCF).

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  • How to implement Priority Queues in Python?

    - by dragosrsupercool
    Sorry for such a silly question but Python docs are confusing.. . Link 1: Queue Implementation http://docs.python.org/library/queue.html It says thats Queue has a contruct for priority queue. But I could not find how to implement it. class Queue.PriorityQueue(maxsize=0) Link 2: Heap Implementation http://docs.python.org/library/heapq.html Here they says that we can implement priority queues indirectly using heapq pq = [] # list of entries arranged in a heap entry_finder = {} # mapping of tasks to entries REMOVED = '<removed-task>' # placeholder for a removed task counter = itertools.count() # unique sequence count def add_task(task, priority=0): 'Add a new task or update the priority of an existing task' if task in entry_finder: remove_task(task) count = next(counter) entry = [priority, count, task] entry_finder[task] = entry heappush(pq, entry) def remove_task(task): 'Mark an existing task as REMOVED. Raise KeyError if not found.' entry = entry_finder.pop(task) entry[-1] = REMOVED def pop_task(): 'Remove and return the lowest priority task. Raise KeyError if empty.' while pq: priority, count, task = heappop(pq) if task is not REMOVED: del entry_finder[task] return task raise KeyError('pop from an empty priority queue' Which is the most efficient priority queue implementation in python? And how to implement it?

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  • Different Linux message queues have the same id?

    - by Halo
    I open a mesage queue in a .c file, and upon success it says the message queue id is 3. While that program is still running, in another terminal I start another program (of another .c file), that creates a new message queue with a different mqd_t. But its id also appears as 3. Is this a problem? server file goes like this: void server(char* req_mq) { struct mq_attr attr; mqd_t mqdes; struct request* msgptr; int n; char *bufptr; int buflen; pid_t apid; //attr.mq_maxmsg = 300; //attr.mq_msgsize = 1024; mqdes = mq_open(req_mq, O_RDWR | O_CREAT, 0666, NULL); if (mqdes == -1) { perror("can not create msg queue\n"); exit(1); } printf("server mq created, mq id = %d\n", (int) mqdes); and the client goes like: void client(char* req_mq, int min, int max, char* dir_path_name, char* outfile) { pid_t pid; /* get the process id */ if ((pid = getpid()) < 0) { perror("unable to get client pid"); } mqd_t mqd, dq; char pfx[50] = DQ_PRFX; char suffix[50]; // sprintf(suffix, "%d", pid); strcat(pfx, suffix); dq = mq_open(pfx, O_RDWR | O_CREAT, 0666, NULL); if (dq == -1) { perror("can not open data queue\n"); exit(1); } printf("data queue created, mq id = %d\n", (int) dq); mqd = mq_open(req_mq, O_RDWR); if (mqd == -1) { perror("can not open msg queue\n"); exit(1); } mqdes and dq seem to share the same id 3.

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  • Problem in creation MDB Queue connection at Jboss StartUp

    - by Amit Ruwali
    I am not able to create a Queue connection in JBOSS4.2.3GA Version & Java1.5, as I am using MDB as per the below details. I am putting this MDB in a jar file(named utsJar.jar) and copied it in deploy folder of JBOSS, In the test env. this MDB works well but in another env. [ env settings and jboss/java ver is same ] it is throwing error at jboss start up [attached below ]. I have searched for this error but couldn't find any solution till now; was there any issue of port confict or something related with configurations ? UTSMessageListner.java @MessageDriven(activationConfig = { @ActivationConfigProperty(propertyName="destinationType", propertyValue="javax.jms.Queue"), @ActivationConfigProperty(propertyName="destination", propertyValue="queue/UTSQueue") }) @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED) public class UTSMessageListner implements MessageListener { public void onMessage(Message msg) { ObjectMessage objmsg = (ObjectMessage) msg; try { UTSListVO utsMessageListVO = (UTSListVO) objmsg.getObject(); if(utsMessageListVO.getUtsMessageList()!=null) { UtsWebServiceLogger.logMessage("UTSMessageListner:onMessage: SIZE Of UTSMessage List =[" +utsMessageListVO.getUtsMessageList().size() + "]"); UTSDataLayerImpl.getInstance().insertUTSMessage(utsMessageListVO); } else { UtsWebServiceLogger.logMessage("UTSMessageListner:onMessage: Message List is NULL"); } } catch (Exception ex) { UtsWebServiceLogger.logMessage("UTSMessageListner:onMessage: Error Receiving Message"+ExceptionUtility.getStackTrace(ex)); } } } [ I have also attached whole server.log as an attach] /// ///////////////////////////////// Error Trace is Below while starting the server /////////////////////////// 2010-03-12 07:05:40,061 WARN [org.jboss.ejb3.mdb.MessagingContainer] Could not find the queue destination-jndi-name=queue/UTSQueue 2010-03-12 07:05:40,061 WARN [org.jboss.ejb3.mdb.MessagingContainer] destination not found: queue/UTSQueue reason: javax.naming.NameNotFoundException: queue not bound 2010-03-12 07:05:40,061 WARN [org.jboss.ejb3.mdb.MessagingContainer] creating a new temporary destination: queue/UTSQueue 2010-03-12 07:05:40,071 WARN [org.jboss.system.ServiceController] Problem starting service jboss.j2ee:ear=uts.ear,jar=utsJar.jar,name=UTSMessageListner,service=EJB3 java.lang.NullPointerException at org.jboss.mq.server.jmx.DestinationManager.createDestination(DestinationManager.java:336) at org.jboss.mq.server.jmx.DestinationManager.createQueue(DestinationManager.java:293) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.ejb3.JmxClientKernelAbstraction.invoke(JmxClientKernelAbstraction.java:44) at org.jboss.ejb3.jms.DestinationManagerJMSDestinationFactory.createDestination(DestinationManagerJMSDestinationFactory.java:75) at org.jboss.ejb3.mdb.MessagingContainer.createTemporaryDestination(MessagingContainer.java:573) at org.jboss.ejb3.mdb.MessagingContainer.createDestination(MessagingContainer.java:512) at org.jboss.ejb3.mdb.MessagingContainer.innerCreateQueue(MessagingContainer.java:438) at org.jboss.ejb3.mdb.MessagingContainer.jmsCreate(MessagingContainer.java:400) at org.jboss.ejb3.mdb.MessagingContainer.innerStart(MessagingContainer.java:166) at org.jboss.ejb3.mdb.MessagingContainer.start(MessagingContainer.java:152) at org.jboss.ejb3.mdb.MDB.start(MDB.java:126) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.ejb3.ServiceDelegateWrapper.startService(ServiceDelegateWrapper.java:103) at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289) at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMBeanSupport.java:245) at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:978) at $Proxy0.start(Unknown Source) at org.jboss.system.ServiceController.start(ServiceController.java:417) at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy53.start(Unknown Source) at org.jboss.ejb3.JmxKernelAbstraction.install(JmxKernelAbstraction.java:120) at org.jboss.ejb3.Ejb3Deployment.registerEJBContainer(Ejb3Deployment.java:301) at org.jboss.ejb3.Ejb3Deployment.start(Ejb3Deployment.java:362) at org.jboss.ejb3.Ejb3Module.startService(Ejb3Module.java:91) at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289) at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMBeanSupport.java:245) at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:978) at $Proxy0.start(Unknown Source) at org.jboss.system.ServiceController.start(ServiceController.java:417) at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy33.start(Unknown Source) at org.jboss.ejb3.EJB3Deployer.start(EJB3Deployer.java:512) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142) at org.jboss.mx.interceptor.DynamicInterceptor.invoke(DynamicInterceptor.java:97) at org.jboss.system.InterceptorServiceMBeanSupport.invokeNext(InterceptorServiceMBeanSupport.java:238) at org.jboss.wsf.container.jboss42.DeployerInterceptor.start(DeployerInterceptor.java:87) at org.jboss.deployment.SubDeployerInterceptorSupport$XMBeanInterceptor.start(SubDeployerInterceptorSupport.java:188) at org.jboss.deployment.SubDeployerInterceptor.invoke(SubDeployerInterceptor.java:95) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy34.start(Unknown Source) at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025) at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1015) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782) at sun.reflect.GeneratedMethodAccessor20.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy9.deploy(Unknown Source) at org.jboss.deployment.scanner.URLDeploymentScanner.deploy(URLDeploymentScanner.java:421) at org.jboss.deployment.scanner.URLDeploymentScanner.scan(URLDeploymentScanner.java:634) at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.doScan(AbstractDeploymentScanner.java:263) at org.jboss.deployment.scanner.AbstractDeploymentScanner.startService(AbstractDeploymentScanner.java:336) at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289) at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMBeanSupport.java:245) at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:978) at $Proxy0.start(Unknown Source) at org.jboss.system.ServiceController.start(ServiceController.java:417) at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy4.start(Unknown Source) at org.jboss.deployment.SARDeployer.start(SARDeployer.java:304) at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:766) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy5.deploy(Unknown Source) at org.jboss.system.server.ServerImpl.doStart(ServerImpl.java:482) at org.jboss.system.server.ServerImpl.start(ServerImpl.java:362) at org.jboss.Main.boot(Main.java:200) at org.jboss.Main$1.run(Main.java:508) at java.lang.Thread.run(Thread.java:595)

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  • Simulating Google Appengine's Task Queue with Gearman

    - by sotangochips
    One of the characteristics I love most about Google's Task Queue is its simplicity. More specifically, I love that it takes a URL and some parameters and then posts to that URL when the task queue is ready to execute the task. This structure means that the tasks are always executing the most current version of the code. Conversely, my gearman workers all run code within my django project -- so when I push a new version live, I have to kill off the old worker and run a new one so that it uses the current version of the code. My goal is to have the task queue be independent from the code base so that I can push a new live version without restarting any workers. So, I got to thinking: why not make tasks executable by url just like the google app engine task queue? The process would work like this: User request comes in and triggers a few tasks that shouldn't be blocking. Each task has a unique URL, so I enqueue a gearman task to POST to the specified URL. The gearman server finds a worker, passes the url and post data to a worker The worker simply posts to the url with the data, thus executing the task. Assume the following: Each request from a gearman worker is signed somehow so that we know it's coming from a gearman server and not a malicious request. Tasks are limited to run in less than 10 seconds (There would be no long tasks that could timeout) What are the potential pitfalls of such an approach? Here's one that worries me: The server can potentially get hammered with many requests all at once that are triggered by a previous request. So one user request might entail 10 concurrent http requests. I suppose I could have a single worker with a sleep before every request to rate-limit. Any thoughts?

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  • Segmentation fault with queue in C

    - by Trevor
    I am getting a segmentation fault with the following code after adding structs to my queue. The segmentation fault occurs when the MAX_QUEUE is set high but when I set it low (100 or 200), the error doesn't occur. It has been a while since I last programmed in C, so any help is appreciated. #include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX_QUEUE 1000 struct myInfo { char data[20]; }; struct myInfo* queue; void push(struct myInfo); int queue_head = 0; int queue_size = 0; int main(int argc, char *argv[]) { queue = (struct myInfo*) malloc(sizeof(struct myInfo) * MAX_QUEUE); struct myInfo info; char buf[10]; strcpy(buf, "hello"); while (1) { strcpy(info.data, buf); push(info); } } void push(struct myInfo info) { int next_index = sizeof(struct myInfo) * ((queue_size + queue_head) % MAX_QUEUE); printf("Pushing %s to %d\n", info.data, next_index); *(queue + (next_index)) = info; queue_size++; } Output: Pushing hello to 0 Pushing hello to 20 ... Pushing hello to 7540 Pushing hello to 7560 Pushing hello to 7580 Segmentation fault

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  • Message queue proxy in Python + Twisted

    - by gasper_k
    Hi, I want to implement a lightweight Message Queue proxy. It's job is to receive messages from a web application (PHP) and send them to the Message Queue server asynchronously. The reason for this proxy is that the MQ isn't always avaliable and is sometimes lagging, or even down, but I want to make sure the messages are delivered, and the web application returns immediately. So, PHP would send the message to the MQ proxy running on the same host. That proxy would save the messages to SQLite for persistence, in case of crashes. At the same time it would send the messages from SQLite to the MQ in batches when the connection is available, and delete them from SQLite. Now, the way I understand, there are these components in this service: message listener (listens to the messages from PHP and writes them to a Incoming Queue) DB flusher (reads messages from the Incoming Queue and saves them to a database; due to SQLite single-threadedness) MQ connection handler (keeps the connection to the MQ server online by reconnecting) message sender (collects messages from SQlite db and sends them to the MQ server, then removes them from db) I was thinking of using Twisted for #1 (TCPServer), but I'm having problem with integrating it with other points, which aren't event-driven. Intuition tells me that each of these points should be running in a separate thread, because all are IO-bound and independent of each other, but I could easily put them in a single thread. Even though, I couldn't find any good and clear (to me) examples on how to implement this worker thread aside of Twisted's main loop. The example I've started with is the chatserver.py, which uses service.Application and internet.TCPServer objects. If I start my own thread prior to creating TCPServer service, it runs a few times, but the it stops and never runs again. I'm not sure, why this is happening, but it's probably because I don't use threads with Twisted correctly. Any suggestions on how to implement a separate worker thread and keep Twisted? Do you have any alternative architectures in mind?

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  • Queue Data structure app crash with front() method

    - by Programer
    I am implementing queue data strcutre but my app gets crashed, I know I am doing something wrong with Node pointer front or front() method of queue class #include <iostream> using namespace std; class Node { public: int get() { return object; }; void set(int object) { this->object = object; }; Node * getNext() { return nextNode; }; void setNext(Node * nextNode) { this->nextNode = nextNode; }; private: int object; Node * nextNode; }; class queue{ private: Node *rear; Node *front; public: int dequeue() { int x = front->get(); Node* p = front; front = front->getNext(); delete p; return x; } void enqueue(int x) { Node* newNode = new Node(); newNode->set(x); newNode->setNext(NULL); rear->setNext(newNode); rear = newNode; } int Front() { return front->get(); } int isEmpty() { return ( front == NULL ); } }; main() { queue q; q.enqueue(2); cout<<q.Front(); system("pause"); }

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  • Java queue and multi-dimension array

    - by javaLearner.java
    First of all, this is my code (just started learning java): Queue<String> qe = new LinkedList<String>(); qe.add("b"); qe.add("a"); qe.add("c"); qe.add("d"); qe.add("e"); My question: Is it possible to add element to the queue with two values, like: qe.add("a","1"); // where 1 is integer So, that I know element "a" have value 1. If I want to add a number let say "2" to element a, I will have like a = 3. If this cant be done, what else in java classes that can handle this? I tried to use multi-dimention array, but its kinda hard to do the queue, like pop, push etc. (Maybe I am wrong) How to call specific element in the queue? Like, call element a, to check its value. [Note] Please don't give me links that ask me to read java docs. I was reading, and I still dont get it. The reason why I ask here is because, I know I can find the answer faster and easier.

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  • JMS Topic vs Queue - Intent

    - by Sandeep Jindal
    I am trying to understand on the design requirements for using Queue, and could not find this question (with answer). My understanding: Queue means one-to-one. Thus it would be used in a special case (if not rare, very few cases) when a designer is sure that the message would be intended for only one consumer. But even in those cases, I may want to use Topic (just to be future safe). The only extra case I would have to do is to make (each) subscription durable. Or, I special situations, I would use bridging / dispatcher mechanism. Give above, I would always (or in most cases) want to publish to a topic. Subscriber can be either durable topic(s) or dispatched queue(s). Please let me know what I am missing here or I am missing the original intent?

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  • change message body in blackberry of HTML message

    - by PankajV
    By using BlackBerry Api - mesasge.setContent( Object o );, we can change the message body of blackberry messaging application. But This work when message is plain text, How can we change / update the message body for HTML message programmaticay. message.setContent(object o); does not work for HTML message. Please advice

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