Re: Collections and Decorators
On Mar 14, 3:25 pm, ankur <ankur.a.agar...@gmail.com> wrote:
On Mar 14, 2:57 pm, Mark Space <marksp...@sbc.global.net> wrote:
ankur wrote:
for thread safety, rather than having to do instead
Collection sync_c = Collections.synchronizedCollection(c);
synchronized(sync_c) {
//do something on the collection sync_c
}
You don't. Once you do
Collection sync_c = Collections.synchronizedCollection(c);
// do something on the collection sync_c
You don't need to used "synchronized()" explicitly any more. The
collection itself does it for you.
Note if you have an operation that takes more than one call -- like
read-modify-write -- you still have to synchronize on the collection fo=
r
the entire operation.
Ok, so why doesn't this
Collection sync_c = Collections.synchronizedCollection(c);
take care of everything ? I mean even after I have sync_c why am I
still required to synchronize on the collection "for an operation that
takes more than one call -- like read-modify - execute". Using an
iterator is one example.
Is this due to some incomplete implementation ? I know I can look at
the source code but before I did that I wanted to ask this so as to
make sure I am not missing any subtle point.
-Ankur- Hide quoted text -
- Show quoted text -
In Collections.java this code snippet is present :
public Iterator<E> iterator() {
return c.iterator(); // Must be manually synched by user!
}
So, thats why Iterator operations need to manually synched. But my
question is why was this left unsynched in Java ? All other public
methods are synched on Object mutex in the static class
static class SynchronizedCollection<E>
--Ankur
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