Support Forums: Message List - Learning about soft and weak references in Java 5 http://www.theserverside.com Most recent forum messages en Jive Forums Silver 5.5.30 (www.jivesoftware.com) Sun, 26 May 2013 05:29:35 -0400 soft-reference key or value ? http://www.theserverside.com/discussions/thread.tss?thread_id=29865 I get your point, i don't get the first point.
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iow: what's the advantage (for cache implementation) of implementing the put(k,v) like this   return hash.put(key, new SoftValue(value, key, queue));over...]]> Mon, 29 Nov 2004 10:44:34 -0500 Mon, 29 Nov 2004 10:44:34 -0500 Mon, 29 Nov 2004 10:44:34 -0500 Nov 29, 2004 James Watson 0 soft-reference key or value ? http://www.theserverside.com/discussions/thread.tss?thread_id=29865
In newsletter 15, I described a SoftReference based HashMap, where the values were embedded in soft references. (The WeakHashMap has the keys embedded in weak references, so that would not be useful for building a...]]> Fri, 26 Nov 2004 07:25:50 -0500 Fri, 26 Nov 2004 07:25:50 -0500 Fri, 26 Nov 2004 07:25:50 -0500 Nov 26, 2004 Dieter Cailliau 1 WeakHashMap not usefull for cache? http://www.theserverside.com/discussions/thread.tss?thread_id=29865 I read in the article:"The WeakHashMap has the keys embedded in weak references, so that would not be useful for building a cache."In javadoc for WeakHashMap, i read:"When a key has been discarded its entry is effectively...]]> Tue, 23 Nov 2004 12:55:14 -0500 Tue, 23 Nov 2004 12:55:14 -0500 Tue, 23 Nov 2004 12:55:14 -0500 Nov 23, 2004 James Watson 2 WeakHashMap not usefull for cache? http://www.theserverside.com/discussions/thread.tss?thread_id=29865
"The WeakHashMap has the keys embedded in weak references, so that would not be useful for building a cache."

In javadoc for WeakHashMap, i read:

"When a key has been discarded its entry is...]]> Mon, 22 Nov 2004 08:33:05 -0500 Mon, 22 Nov 2004 08:33:05 -0500 Mon, 22 Nov 2004 08:33:05 -0500 Nov 22, 2004 Dieter Cailliau 3 Learning about soft and weak references in Java 5 http://www.theserverside.com/discussions/thread.tss?thread_id=29865 Fri, 12 Nov 2004 14:03:48 -0500 Fri, 12 Nov 2004 14:03:48 -0500 Fri, 12 Nov 2004 14:03:48 -0500 Nov 12, 2004 kschneid 0 Use for Phantom Reference http://www.theserverside.com/discussions/thread.tss?thread_id=29865 the object has already been finalized
Maybe that's the key. With WR, I may run into concurrency issues with the finalizer, with PR the finalizer is definetely through.]]> Fri, 12 Nov 2004 06:21:55 -0500 Fri, 12 Nov 2004 06:21:55 -0500 Fri, 12 Nov 2004 06:21:55 -0500 Nov 12, 2004 Matthias Ernst 0 Code quality remark http://www.theserverside.com/discussions/thread.tss?thread_id=29865
Just make sure you use "Collections.synchronizedSet (new HashSet())" instead of "new HashSet()" in the GhostReference class. ;)

Vitaliy Shevchuk]]> Fri, 12 Nov 2004 05:21:16 -0500 Fri, 12 Nov 2004 05:21:16 -0500 Fri, 12 Nov 2004 05:21:16 -0500 Nov 12, 2004 Vitaly Shevchuc 0 Use for Phantom Reference http://www.theserverside.com/discussions/thread.tss?thread_id=29865
The way you can make use of PhantomReferences is to build a Map associating the references to other Objects. When the PhantomReference shows up in the queue you use it to look up it's associated Object and do what ever needs to...]]> Thu, 11 Nov 2004 23:18:41 -0500 Thu, 11 Nov 2004 23:18:41 -0500 Thu, 11 Nov 2004 23:18:41 -0500 Nov 11, 2004 Clive Brettingham-Moore 1 Use for Phantom Reference http://www.theserverside.com/discussions/thread.tss?thread_id=29865 The way you can make use of PhantomReferences is to build a Map associating the references to other Objects. When the PhantomReference shows up in the queue you use it to look up it's associated Object and do what ever needs to be done...I...]]> Thu, 11 Nov 2004 16:16:34 -0500 Thu, 11 Nov 2004 16:16:34 -0500 Thu, 11 Nov 2004 16:16:34 -0500 Nov 11, 2004 Matthias Ernst 2 Phantom Refernence clearing http://www.theserverside.com/discussions/thread.tss?thread_id=29865 However a straight PhantomReference - hmmm. Dangerous as well - you must remember to let go of your PhantomReference, plus call "clear()" on it, otherwise you develop a memory leak.

Are you sure about that? The...]]> Thu, 11 Nov 2004 12:33:28 -0500 Thu, 11 Nov 2004 12:33:28 -0500 Thu, 11 Nov 2004 12:33:28 -0500 Nov 11, 2004 James Watson 0 GhostReference http://www.theserverside.com/discussions/thread.tss?thread_id=29865
"In order to ensure that a reclaimable object remains so, the referent of a phantom reference...]]> Thu, 11 Nov 2004 11:38:21 -0500 Thu, 11 Nov 2004 11:38:21 -0500 Thu, 11 Nov 2004 11:38:21 -0500 Nov 11, 2004 James Watson 0 Use for Phantom Reference http://www.theserverside.com/discussions/thread.tss?thread_id=29865 Thu, 11 Nov 2004 11:04:58 -0500 Thu, 11 Nov 2004 11:04:58 -0500 Thu, 11 Nov 2004 11:04:58 -0500 Nov 11, 2004 James Watson 3 Am I too stupid? http://www.theserverside.com/discussions/thread.tss?thread_id=29865
As the author notes, it's best to have some tests handy to see if your JVM behaves like you expect. - Don

Yes, and even then it is rather risky. It is a pity that the contract for how they are...]]> Thu, 11 Nov 2004 08:20:44 -0500 Thu, 11 Nov 2004 08:20:44 -0500 Thu, 11 Nov 2004 08:20:44 -0500 Nov 11, 2004 Cameron Purdy 0 Am I too stupid? http://www.theserverside.com/discussions/thread.tss?thread_id=29865 As the author notes, it's best to have some tests handy to see if your JVM behaves like you expect. - Don
Yes, and even then it is rather risky. It is a pity that the contract for how they are supposed to behave was...]]> Thu, 11 Nov 2004 04:09:44 -0500 Thu, 11 Nov 2004 04:09:44 -0500 Thu, 11 Nov 2004 04:09:44 -0500 Nov 11, 2004 Heinz Kabutz 1 Am I too stupid? http://www.theserverside.com/discussions/thread.tss?thread_id=29865 Thu, 11 Nov 2004 00:53:12 -0500 Thu, 11 Nov 2004 00:53:12 -0500 Thu, 11 Nov 2004 00:53:12 -0500 Nov 11, 2004 Donald Smith 2