SwingWorker process(List V chunks) but List isn't thread safe is it.

Question

Folks,
Am I missing something or does
protected void process(List<V> chunks)in the new 1.6 javax.swing.SwingWorker represent a potential threading issue?
List isn't thread safe... so why not use a Vector, which is? Except that Vector is currently considered persona-non-grata by bigger brains than me.
Hmmm... Of course, I don't know which implementation of List is being used under the hood, so I suppose I just have to trust the Java Gods who built the new SwingWorker to have used a thread safe implementation... which is pretty good bet, I suppose...
Can anyone state categorically that it isn't a problem?
Thanx. Keith.
Message was edited by: corlettk PS: I'm knee deep in thread gruel and going down fast.

Answer 1

publish definitely does not block until process is finished.
In fact calling publish does not necessarily mean that process will be called right away.
From the API:
Because the process method is invoked asynchronously on the Event Dispatch Thread multiple invocations to the publish method might occur before the process method is executed. For performance purposes all these invocations are coalesced into one invocation with concatenated arguments.
For example:
publish("1");
publish("2", "3");
publish("4", "5", "6");
might result in:
process("1", "2", "3", "4", "5", "6")
Edit:
The only source I could find for AccumulativeRunnable (the class used to accumulate the arguments passed to publish) was here:
http://fisheye5.cenqua.com/browse/swingworker/src/java/org/jdesktop/swingworker/AccumulativeRunnable.java?r=1.2
which isn't necessarily the implementation in the JDK but it's probably close.
That shows that before process is called the accumulating list reference is nulled, meaning that there is no way that publish can append to the list during a call to process.
In fact calling publish as the same time as process is executing on the EDT appends the published arguments to a fresh list, leading to another call to process at some later time (in SwingWorker the delay between a call to publish and a call to process is at most 1000/30 milliseconds).
Message was edited by:
dwg