How to synchronize access to LinkedList??

[Tobi Krausl]

Hi!

I need a java-implementation of a queue and found out that
java.util.LinkedList is suitable. In my program there are several
threds accessing and maniplating that LinkedList. Consequently I've to
synchronize access to it.

I found the follwing which doesn't work:
http://javaalmanac.com/egs/java.util/coll_Queue.html?l=rel

e342. Implementing a Queue
LinkedList queue = new LinkedList();

queue.add(object);

Object o = queue.removeFirst();

//Here I get a class-cast-exception, why??????
queue = (LinkedList)Collections.synchronizedList(queue);



I always get a class-cast-exception!

What's wrong??

Tnx,
Tobi

 

[VisionSet]

--
Mike W

Hi!

I need a java-implementation of a queue and found out that
java.util.LinkedList is suitable. In my program there are several
threds accessing and maniplating that LinkedList. Consequently I've to
synchronize access to it.

I found the follwing which doesn't work:
http://javaalmanac.com/egs/java.util/coll_Queue.html?l=rel

e342. Implementing a Queue
LinkedList queue = new LinkedList();

queue.add(object);

Object o = queue.removeFirst();

//Here I get a class-cast-exception, why??????
queue = (LinkedList)Collections.synchronizedList(queue);



I always get a class-cast-exception!

What's wrong??

If it returned a LinkedList you wouldn't have achieved anything, it returns
an implementation of List that is synchronized. You are just limited to the
List interface.

try:

List queue = new LinkedList();

queue.add(object);

Object o = queue.removeFirst();

queue = (LinkedList)Collections.synchronizedList(queue);

 

[Michael Borgwardt]

Hi!

I need a java-implementation of a queue and found out that
java.util.LinkedList is suitable. In my program there are several
threds accessing and maniplating that LinkedList. Consequently I've to
synchronize access to it.

Note that this naive synchronizing of method calls will be insufficient
if you iterate over the list or have sequences of calls that depend on
each other.