Threadsafe access to ArrayList

[Phil]

I have two threads that access an ArrayList.

One thread will store new entries. The other thread will retrieve the
entries and then remove them from the list. Is this a thread-safe operation
or do I need to use the Synchronization system?

Thanks,

Phil

 

[Ignacio Machin ( .NET/ C# MVP )]

I have two threads that access an ArrayList.

One thread will store new entries.  The other thread will retrieve the
entries and then remove them from the list.  Is this a thread-safe operation
or do I need to use the Synchronization system?

Thanks,

Phil

Hi,

No, it's not.
You should use a Queue (or Stack) instead of an ArrayList. Queue has
a Synchronizedn method that you can use to make it thread safe.

 

[Ashutosh Bhawasinka]

There is an alternative,
you can create a global(which is accessible to both threads)
synchronization object which can simply be an variable of type Object

Then in each thread use this

//global or class level
Object ArraySyncObject;

thread1:

while(...)
{
lock(ArraySyncObject)
{
//add entryies here
}
}
-----------

thread2:
while(...)
{
lock(ArraySyncObject)
{
//retreive entries
//remove entries
}
}

This is just an alternative. So, make sure that you don't do much
processing in the lock block, as this will block the other thread from
execution.

Regards,
Ashutosh Bhawasinka