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Search found 1358 results on 55 pages for 'concurrency violation'.

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• Using @NotNull in a project where both IntelliJ and Eclipse developers are working

  - by Gugussee

  A co-worker on IntelliJ IDEA (working on another project) showed me the amazing @NotNull annotation. I've read messages here on SO about how starting to add @NotNull everywhere saved lots of time and headaches (and IntelliJ 10 can even add automatically @NotNull to old code when it detects that null would break havoc). Since I read my first "Probable @NotNull violation" message (in real-time, in the IDE, even on a partial .java file that doesn't compile yet) my jaw dropped and I got hooked. So I was wondering: is there anything that needs to be known if we want to start using @NotNull in a project where developers are using both Eclipse and IntelliJ? I know IntelliJ ships with the annotations.jar. Is this compatible with Eclipse?

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• performance of parameterized queries for different db's

  - by tuinstoel

  A lot of people know that it is important to use parameterized queries to prevent sql injection attacks. Parameterized queries are also much faster in sqlite and oracle when doing online transaction processing because the query optimizer doesn't have to reparse every parameterized sql statement before executing. I've seen sqlite becoming 3 times faster when you use parameterized queries, oracle can become 10 times faster when you use parameterized queries in some extreme cases with a lot of concurrency. How about other db's like mysql, ms sql, db2 and postgresql? Is there an equal difference in performance between parameterized queries and literal queries?

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• Java: Set<E> collection, where items are identified by its class

  - by mschayna

  I need Set collection, where its items will be identified by items class. Something like ReferenceIdentityMap from Appache Collections, but on class scope i.e. two different instances of same class must be identified as same in this collection. You know, it is a violation of equals()/hashCode() identity principle but in occasional use it makes sense. I have done this in simple class backing with Map<Class<? extends E>, E>, but due to simplicity it doesn't implement Set<E>. There may be a more elegant solution, decorator of any Set<E> would be great. Is there any implementation of such collection there (Apache/Google/something/... Collections)?

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• How to assert/unit-test servers JSON response?

  - by shazax

  My current project uses JSON as data interchange format. Both Front-end and Back-end team agree upon a JSON structure before start integrating a service. At times due to un-notified changes in JSON structure by back-end team; it breaks the front-end code. Is there any external library that we could use to compare a mock JSON (fixture) with servers JSON response. Basically it should assert the whole JSON object and should throw an error if there is any violation in servers JSON format. Additional info: App is built on JQuery consuming REST JSON services.

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• How do I safely Debug.Assert in ASP.NET?

  - by MatthewMartin

  Asserts can't be caught. This is good because some errors I don't want to be wrapped in try/catch, at least not on the development server. But Asserts seem awefully dangerous. If they get onto production, it can hang the ASP.NET server with a msgbox. //Don't want this on prod even if debug=true is in the web.config #if DEBUG //A future client programmer can wrap this in a try{}catch{} if (!EverythingIsOkay) throw new InvalidOperationException("Dagnabbit, programming error"); //This stops the but has less information that an // Exception and hangs the server if this accidentally // runs on production System.Diagnostics.Debug.Assert(!EverythingIsOkay); #endif Is there better way to communicate an violation of a inviolable condition to a developer without risking hanging IIS? UPDATE: After reading the first replies, I guess the answer hinges on a foolproof way to detect when code is running in a development environment and when it is on a production server, or figuring out how to throw an exception that can't be caught and ignored.

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• how to initialize spring bean from database

  - by wavelet

  hi,i use spring security and my config is in database: <sec:http auto-config="true" entry-point-ref="casProcessingFilterEntryPoint"> <sec:remember-me /> <sec:session-management> <sec:concurrency-control max-sessions="1" error-if-maximum-exceeded="true" /> </sec:session-management> <sec:logout logout-success-url="${host.url}/logout/" /> <sec:custom-filter ref="casAuthenticationFilter" after="CAS_FILTER" /> <sec:custom-filter ref="filterInvocationInterceptor" before="FILTER_SECURITY_INTERCEPTOR" /> </sec:http> like ${host.url} is in database how can i initialize ?

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• cron job for updating user profile data imported via facebook connect

  - by Abidoon Nadeem

  I want to write a cron job for updating user profile data on my website that I pull for users that register via facebook connect on my website. The objective is to keep their profile data on my website in sync with their profile data on facebook. So if a user updates their profile picture on facebook. I want to update his profile picture on my website as well via a cron job which will run every 24 hours. I wanted to know if this is possible and secondly if this is in violation of facebook privacy policy. Based on my research it seems doable but I wanted to know if anyone has already done something like this before. It would really help.

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• What parallel programming model do you recommend today to take advantage of the manycore processors

  - by Doctor J

  If you were writing a new application from scratch today, and wanted it to scale to all the cores you could throw at it tomorrow, what parallel programming model/system/language/library would you choose? Why? I am particularly interested in answers along these axes: Programmer productivity / ease of use (can mortals successfully use it?) Target application domain (what problems is it (not) good at?) Concurrency style (does it support tasks, pipelines, data parallelism, messages...?) Maintainability / future-proofing (will anybody still be using it in 20 years?) Performance (how does it scale on what kinds of hardware?) I am being deliberately vauge on the nature of the application in anticipation of getting good general answers useful for a variety of applications.

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• Copying Data between table without identity column

  - by user668479

  I have two table and I need to copy the data across from SRCServiceUsers to Clients Everytime i run it I get the following: Violation of PRIMARY KEY constraint 'PK_Clients'. Cannot insert duplicate key in object 'dbo.Clients'. The statement has been terminated. The Primary key ClientId field is not an identity column and therefore requires filling To date I have the following insert into Clients( ClientID, Title, Forenames, FamilyName, [Address], Town, County, PostCode, PhoneNumber, StartDate) SELECT ( Select Max(Clients.ClientID)+ 1, SRCServiceUsers.Title, SRCServiceUsers.[First Names], SRCServiceUsers.Surname, --BUILD UP MUITIPLE COLUMNS SRCServiceUsers.[Property Name] + ', ' + SRCServiceUsers.Street + ', ' + SRCServiceUsers.Suburb as [Address], SRCServiceUsers.Town, SRCServiceUsers.County, SRCServiceUsers.Postcode, SRCServiceUsers.Telephone, SRCServiceUsers.[Start Date] From srcsERVICEuSERS How can i autoincrement the PK field - CLientID when inserting the data? Many thanks Andrew

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• Can we view objects in the JVM memory?

  - by Sebastien Lorber

  Hey, At work we found that on some instances (particulary the slow ones) we have a different behaviour, acquired at the reboot. We guess a cache is not initialized correctly, or maybe a concurrency problem... Anyway it's not reproductible in any other env than production. We actually don't have loggers to activate... it's an old component... Thus i'd like to know if there are tools that can help us to see the different objets present in the JVM memory in order to check the content of the cache... Thank you!

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• What is the preferred sql server column definition to use for a LINQ to SQL Version property?

  - by Mike Two

  We are using the IsVersion property on the ColumnAttribute on a property in a LINQ to SQL class for optimistic concurrency checks. What should the column definition be in the database? Currently we are using version_number int NOT NULL IDENTITY (1, 1) Do we need Identity? Can we get LINQ to SQL to update the version number for us? The only issue with Identity is that every row has a different number. We'd like to see the number increment by 1 when the row is updated.

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• Advice about a good Java book?

  - by camac1

  Hi people, I am new to Java but have experience programming in C/C++/C#. I wanted to learn Java SE 6 first before moving to Java EE 6. After making some research online for appropriate Java SE 6 books, I found that these are appropriate for me to get an excellent idea of Java SE 6: 1) Head First Java, 2nd Edition 2) An Intermediate Level Book <----------- 3) Effective Java (2nd Edition) 4) Java Concurrency in Practice 5) Java Generics and Collections 6) Java Concise Reference Series: Swing And AWT 7) Java Reflection in Action However, I am having trouble choosing an Intermediate Level Book which will provide me with breadth and depth in Java SE 6. I was thinking about the book "Thinking in Java (4th Edition)"....Unfortunately, its deals with Java SE 5 and not the latest version. Could anybody please advice me an intermediate level book which could provide me with breadth and depth in Java SE 6. Regards

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• problem with doctrine:build-schema

  - by Ying

  Hi, im using symfony with doctrine, and Im trying to generate the schema yml file from a db. I get an this error SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'group' at line 1. Failing Query: "DESCRIBE group"I have a table named group in my database, and I suspect that this is screwing it up. Its not access problems as ive checked my db previleges. Any suggestions on what I can do? I have tried the quote-identifier attribute but with no luck : ( Im also struggling to find some good doctrine documentation. i cant seem to find where a list of attributes are, say for a creating a column in the schema.yml file. I tried reaching out to symfony forums but they are not responsive! Any help would be greatly appreciated! Thanks..

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• Working with foreign keys - cannot insert

  - by Industrial

  Hi everyone! Doing my first tryouts with foreign keys in a mySQL database and are trying to do a insert, that fails for this reason: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails Does this mean that foreign keys restrict INSERTS as well as DELETES and/or UPDATES on each table that is enforced with foreign keys relations? Thanks! Updated description: Products ---------------------------- id | type ---------------------------- 0 | 0 1 | 3 ProductsToCategories ---------------------------- productid | categoryid ---------------------------- 0 | 0 1 | 1 Product table has following structure CREATE TABLE IF NOT EXISTS `alpha`.`products` ( `id` MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT , `type` TINYINT(2) UNSIGNED NOT NULL DEFAULT 0 , PRIMARY KEY (`id`) , CONSTRAINT `prodsku` FOREIGN KEY (`id` ) REFERENCES `alpha`.`productsToSku` (`product` ) ON DELETE CASCADE, ON UPDATE CASCADE) ENGINE = InnoDB;

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• Injecting EntityManager Vs. EntityManagerFactory

  - by SB

  A long question, please bear with me. We are using Spring+JPA for a web application. My team is debating over injecting EntityManagerFactory in the GenericDAO(a DAO based on Generics something on the lines provided by APPFUSE, we do not use JpaDaosupport for some reason) over injecting an EntityManager. We are using "application managed persistence". The arguments against injecting a EntityManagerFactory is that its too heavy and so is not required, the EntityManager does what we need. Also, as Spring would create a new instance of a DAO for every web request(I doubt this) there are not going to be any concurrency issues as in the same EntityManager instance is shared by two threads. The argument for injecting EFM is that its a good practice over all its always good to have a handle to a factory. I am not sure which is the best approach, can someone please enlighten me? SB

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• Problem passing a reference as a named parameter to a variadic function

  - by Michael Mrozek

  I'm having problems in Visual Studio 2003 with the following: void foo(const char*& str, ...) { va_list args; va_start(args, str); const char* foo; while((foo = va_arg(args, const char*)) != NULL) { printf("%s\n", foo); } } When I call it: const char* one = "one"; foo(one, "two", "three", NULL); I get: Access violation reading location 0xcccccccc on the printf() line -- va_arg() returned 0xcccccccc. I finally discovered it's the first parameter being a reference that breaks it -- if I make it a normal char* everything is fine. It doesn't seem to matter what the type is; being a reference causes it to fail at runtime. Is this a known problem with VS2003, or is there some way in which that's legal behavior? It doesn't happen in GCC; I haven't tested with newer Visual Studios to see if the behavior goes away

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• one primary key column foreign key to 2 other table columns.How to resolve data entry issue.

  - by Rohit

  I have a requirement according to which I have to create a central Login system.We have 2 things Corporate and Brand each represented by tables "Corporate" and "Brand". When a corporate gets registered,corporateID is given,When a user under that corporate gets registered there is a table corporateuser in which corporateID is a foreign key and CorporateUserID is a primary key.Similarly in the case of a brand. So we have CorporateUserId and BrandUserID. Now i have a table called RegisteredUsers in which i want to have corporate as well as brand users.UserID is a primary key in this table which is a foreign key to both corporateuser as well as Branduser. now when i enter a corporateuser,I do an entry to corporateuser as well as RegisteredUsers.When i enter CorporateUserID in userID for RegisteredUsers.It gives foreign key violation error. I fully understand this error.How can i achieve this.This requirement is very rigid.Please tell a workaround

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• What is the optimal number of threads for performing IO operations in java?

  - by marc

  In Goetz's "Java Concurrency in Practice", in a footnote on page 101, he writes "For computational problems like this that do not I/O and access no shared data, Ncpu or Ncpu+1 threads yield optimal throughput; more threads do not help, and may in fact degrade performance..." My question is, when performing I/O operations such as file writing, file reading, file deleting, etc, are there guidelines for the number of threads to use to achieve maximum performance? I understand this will be just a guide number, since disk speeds and a host of other factors play into this. Still, I'm wondering: can 20 threads write 1000 separate files to disk faster than 4 threads can on a 4-cpu machine?

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• unable to catch org.hibernate.StaleObjectStateException while deleting record that doesn't exists in database

  - by JAB

  My application has a delete user option. Now in order to check concurrency condition I tried the following use case opened application in chrome and firefox browser. deleted user in firefox now trying to delete the same user in chrome browser I get exception org.hibernate.StaleObjectStateException .. which is right .. since I am trying to delete an object which doesn't exists. But I am not able to catch this exception try{ getHibernateTemplate().delete(userObj); } catch (StaleObjectStateException e) { e.printStackTrace(); } How do i catch this exception ??

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• Another dynamic memory allocation bug.

  - by m4design

  I'm trying to allocate memory for a multidimensional array (8 rows, 3 columns). Here's the code for the allocation (I'm sure the error is clear for you) char **ptr = (char **) malloc( sizeof(char) * 8); for (i = 0; i < 3; i++) ptr[i] = (char *) malloc( sizeof(char) * 3); The crash happens when I reference this: ptr[3][0]; Unhandled exception at 0x0135144d in xxxx.exe: 0xC0000005: Access violation writing location 0xabababab. Are there any recommended references/readings for this kind of subject? Thanks.

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• STL member variable initalization issue with windows API

  - by Django

  I am creating a windows app that uses a vector of stings as a member variable. For some reason, I can compile but when it tries to get at any of the vectors members is crashes. the error is 0xC0000005: Access violation reading location 0xcdcdcdd9. in the member function of the vector class. this is the size() function where it breaks. size_type capacity() const { // return current length of allocated storage return (this->_Myend - this->_Myfirst); } I am using visual studios 2010. thank you Django

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• Correct association mapping in Entity Framework

  - by Matt Thrower

  Hi, Trying to change two relationships in our entity framework from many-to-one to many-to-many relationships. So I tried the obvious thing: clicked on each association on the diagram, changed the appropriate end of the association accordingly and then changed the name of the navigation property to a plural to reflect the change. This lead to the following build error, or one each for the two changes I've made: Error 3002: Problem in mapping fragments starting at line 1761:Potential runtime violation of table CustomerServices's keys (CustomerServices.Id): Columns (CustomerServices.Id) are mapped to EntitySet CompiledDatabaseCustomerService's properties (CompiledDatabaseCustomerService.CustomerService.Id) on the conceptual side but they do not form the EntitySet's key properties (CompiledDatabaseCustomerService.CompiledDatabase.Id, CompiledDatabaseCustomerService.CustomerService.Id) I'm not entirely sure why this is happening, so unsurprisngly I haven't had much luck fixing it. I've tried fiddling with the mapping details and adding referential constraints to no avail. Anyone point me in the right direction? cheers, Matt

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• Creating a Better Tabbed Interface in Django

  - by ygd

  I've been trying to create a tabbed interface using Django. The current effort (which works fine) is having each template have the header hard-coded in, with the selected tab given the "selected" CSS attribute. Of course, this is a massive violation of DRY and I'm looking to remedy it. My current idea is adding a jQuery script to the page that looks at all the tabs and sets one to "selected" if it's text matches the beginning of the title for the page. Is there a better way to do this without using JavaScript and just pure CSS?

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• hidden forms and thr handles

  - by shraddha

  i am hiding the form using SetVisibleCore to false, but now i cant get the handle of this form in other application which i am retrieving using EnumWindow its giving me exception "Attempted to read or write protected memory. This is often an indication that other memory is corrupt." an ACCESS VIOLATION EXCEPTION. so i am searching on 2 ways 1. find out the other way to get handle here we cant use FindWindow cause its not returning any handle 2. find a another way to hide the form but this should be done before loading of the form so,,,plz help me if anybody can

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• INSERT INTO statement that copies rows and auto-increments non-identity key ID column

  - by AmoebaMan17

  Given a table that has three columns ID (Primary Key, not-autoincrementing) GroupID SomeValue I am trying to write a single SQL INSERT INTO statement that will make a copy of every row that has one GroupID into a new GroupID. Example beginning table: ID | GroupID | SomeValue ------------------------ 1 | 1 | a 2 | 1 | b Goal after I run a simple INSERT INTO statement: ID | GroupID | SomeValue ------------------------ 1 | 1 | a 2 | 1 | b 3 | 2 | a 4 | 2 | b I thought I could do something like: INSERT INTO MyTable ( [ID] ,[GroupID] ,[SomeValue] ) ( SELECT (SELECT MAX(ID) + 1 FROM MyTable) ,@NewGroupID ,[SomeValue] FROM MyTable WHERE ID = @OriginalGroupID ) This causes a PrimaryKey violation since it will end up reusing the same Max(ID)+1 value multiple times as it seems. Is my only recourse to a bunch of INSERT statements in a T-SQL WHILE statement that has an incrementing Counter value? I also don't have the option of turning the ID into an auto-incrementing Identity column since that would breaking code I don't have source for.

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