Export (0) Print
Expand All
0 out of 4 rated this helpful - Rate this topic

Queue.Synchronized Method

Returns a Queue wrapper that is synchronized (thread safe).

Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)

public:
static Queue^ Synchronized (
	Queue^ queue
)
public static Queue Synchronized (
	Queue queue
)
public static function Synchronized (
	queue : Queue
) : Queue
Not applicable.

Parameters

queue

The Queue to synchronize.

Return Value

A Queue wrapper that is synchronized (thread safe).
Exception typeCondition

ArgumentNullException

queue is a null reference (Nothing in Visual Basic).

NoteNote:

The HostProtectionAttribute attribute applied to this method has the following Resources property value: Synchronization. The HostProtectionAttribute does not affect desktop applications, which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser. For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

To guarantee the thread safety of the Queue, all operations must be done through this wrapper only.

Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.

The following code example shows how to lock the collection using the SyncRoot during the entire enumeration. This method is an O(1) operation.

No code example is currently available or this language may not be supported.

The following example shows how to synchronize a Queue, determine if a Queue is synchronized and use a synchronized Queue.

#using <system.dll>

using namespace System;
using namespace System::Collections;
int main()
{
   
   // Creates and initializes a new Queue.
   Queue^ myQ = gcnew Queue;
   myQ->Enqueue( "The" );
   myQ->Enqueue( "quick" );
   myQ->Enqueue( "brown" );
   myQ->Enqueue( "fox" );
   
   // Creates a synchronized wrapper around the Queue.
   Queue^ mySyncdQ = Queue::Synchronized( myQ );
   
   // Displays the sychronization status of both Queues.
   Console::WriteLine( "myQ is {0}.", myQ->IsSynchronized ? (String^)"synchronized" : "not synchronized" );
   Console::WriteLine( "mySyncdQ is {0}.", mySyncdQ->IsSynchronized ? (String^)"synchronized" : "not synchronized" );
}

/*
This code produces the following output.

myQ is not synchronized.
mySyncdQ is synchronized.
*/

import System.*;
import System.Collections.*;

public class SamplesQueue
{
    public static void main(String[] args)
    {
        // Creates and initializes a new Queue.
        Queue myQ =  new Queue();
        myQ.Enqueue("The");
        myQ.Enqueue("quick");
        myQ.Enqueue("brown");
        myQ.Enqueue("fox");

        // Creates a synchronized wrapper around the Queue.
        Queue mySyncdQ = Queue.Synchronized(myQ);

        // Displays the sychronization status of both Queues.
        Console.WriteLine("myQ is {0}.",
            (myQ.get_IsSynchronized()) ? "synchronized" : "not synchronized");
        
        Console.WriteLine("mySyncdQ is {0}.",(mySyncdQ.get_IsSynchronized()) ?
            "synchronized" : "not synchronized");
    } //main
} //SamplesQueue

/* 
 This code produces the following output.
 
 myQ is not synchronized.
 mySyncdQ is synchronized.
 */

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0
Did you find this helpful?
(1500 characters remaining)
Thank you for your feedback

Community Additions

ADD
Show:
© 2014 Microsoft. All rights reserved.