Is there a better way to do implement a simple lock like below? I only want to to the "DOSOMETHING" if it's not already being run. Should I be using reall locks here? if I use lock will that cause everything to queue up and wait for the lock to release? (that's not what I want!) Thanks bool running = false; void DataDisplayVi...
I need to read a Windows file that may be locked, but I don't want to create any kind lock that will prevent other processes from writing to the file. In addition, even if the file is locked for exclusive use, I'd like to see what's inside. Although this isn't my exact use case, consider how to read a SQL/Exchange log or database file ...
Consider the following function that implements non-blocking access to only the one thread. public bool TryCancelGroup() { if (Monitor.TryEnter(_locked)) { if (_locked == false) { _locked = true; try { // do something } catch (Exception ...
Do I need locking for _userByNameQuery static field Yes/No and way? public class SomeClass { static Func<Entities, string, IQueryable<User>> _userByNameQuery = CompiledQuery.Compile<Entities, string, IQueryable<User>> ((context, userName) => context.Users.Where(u => u.UserName.ToUpper() == userN...
I have a SQL Server query (using the LLBL ORM, if that is important to the question) that is doing a large fetch on a set of related tables. This query is being performed in a transaction with the Isolation Level of Repeatable Read, and is being filtered by two 'state' columns in the main table of the query. Will the records being 'wri...
Hi all. Imagine a winform app, who copy updated assemblies from a source folder A to a destination folder B. I use simple DirectoryInfo.GetFiles methods to fill a listview, comparing version of assembly in folder A and B; if some assemblies are newer, I start my update method. In this method, before copying, I try if all file in B folde...
I have a desktop Java/Swing application which is deployed via Java Webstart (clients are using Java 6u20 on XP). I have received intermittent reports from users of the application hanging. I managed to log on to such a system during a hang found that the UI was not being drawn (as though EDT was blocked). I used jstack to list the thre...
I am running into situations in my application where I need to use table lock hints or set the transaction isolation level to something other than the default Read Committed, in order to resolve deadlock issues. I am using a service oriented architecture, with each service call operating as an atomic operation, and Linq To Sql is servin...
I want to implement lazy initialization for multithreading in Java. I have some code of the sort: class Foo { private Helper helper = null; public Helper getHelper() { if (helper == null) { Helper h; synchronized(this) { h = helper; if (h == null) ...
I have an activity, on which when I press the Keyguard lock button, the onDestroy() function is called. At then when I disable the keyguard lock, that activity is shown no more as I get a RuntimeException in Illegal View State. How can I prevent from onDestroy() to be called? Please help. ...
Lets say we have an object that can be accessed by multiple threads and a global singleton handing out the object's reference, also accessible by multiple threads. class Book { private string title; public Book(string title) { this.title = title; } public string Title { get { return title; } } } class Bookstore...
I'm trying to use double-checked locking to maintain an array of binomial coefficients, but I read recently that double-checked locking doesn't work. Efficiency is extremely important so using volatile isn't an option unless it's only inside the conditional statements. I can't see a way to use a static class with a singleton object (th...
Hello =) I have implemented a singleton that works well... (implemented like this example: public sealed class Singleton { static Singleton instance=null; static readonly object padlock = new object(); Singleton() { //breakpoint } public static Singleton Instance { get { ...
I have a bunch of different methods that are not supposed to run concurrently, so I use a single lock to synchronize them. Looks something like this: selected_method = choose_method() with lock: selected_method() In some of these methods, I sometimes call a helper function that does some slow network IO. (Let's call that one netw...
What is the best approach to achieve thread-safety for rather simple operations? Consider a pair of functions: void setVal(int val) { this->_val = val; } int getVal() { return this->_val; } Since even assignments of primitive types aren't guaranteed to be atomic, should I modify every getter and setter in the program in th...
I am building an update system in which I need to be able to replace a referenced jar of a running application jar at runtime. I am finding I am running into file locking issues on Windows when trying to perform file utility functions on the jar such as 'setLastModified'. After some googling I found this snippet... What I found in m...
Do We really need Locking for Static methods(Static Class) when the methods are heavily used by threads? Is it required when Static methods are using resources like SQL Queries/StoredProcedures ? Thanks Pankaj ...
Hi. I have an windows application in VB.NET (2.0) and Oracle Database, the connections are handled by System.Data.OracleClient. My oracle client is 10g. In the server side, the AutoCommit is off. The application uses transtactions (isolationLevel: ReadCommitted) for certain operations. The problem is that in some machines (and only in...
I need to have a MsSql database table and another 8 (identical) processes accessing the same table in parallel - making a select top n, processing those n rows, and updating a column of those rows. The problem is that I need to select and process each row just once. This means that if one process got to the database and selected the top ...
So here is the problem. I have a local snapshot in my local windows system and i run my ant script and it builds. I have build system which is also winxp but its a vmware built inside ubuntu. i have also a snapshot there too in winxp , and my script runs against this. But clearcase doesnt allow to write anything on this folder and buil...