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Posted to issues@commons.apache.org by "Mark Thomas (JIRA)" <ji...@apache.org> on 2011/03/23 20:24:05 UTC

[jira] [Updated] (POOL-103) Tracing borrowed objects

     [ https://issues.apache.org/jira/browse/POOL-103?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Mark Thomas updated POOL-103:
-----------------------------

    Fix Version/s:     (was: 3.0)
                   2.0

Move to 2.0.x

> Tracing borrowed objects
> ------------------------
>
>                 Key: POOL-103
>                 URL: https://issues.apache.org/jira/browse/POOL-103
>             Project: Commons Pool
>          Issue Type: Improvement
>    Affects Versions: 1.3
>            Reporter: immars
>             Fix For: 2.0
>
>
> Once an object is borrowed from a GenericObjectPool, it could be returnObject()-ed once or invalidateObject()-ed once, but not both.
> However, in my working environment, people often tend to write code like this:
> MyObject mo = null;
> try{
> 	mo = myPool.borrowObject();
> }catch(Exception e){
> 	myPool.destoryObject(mo);
> }finally{
> 	if(mo != null){
> 		myPool.returnObject(mo);
> 	}
> }
> In this case, _numActive in GenericObjectPool would be decreased twice once an Exception is thrown.
> So eachtime I use GenericObjectPool, I always wrap the pool like this:
> class MyPool extends GenericObjectPool{
>     HashSet borrowed = new HashSet();
> 	public synchronized Object borrowObject() throws Exception {
> 		Object ret = null;
> 		ret = super.borrowObject();
> 		if (ret != null) {
> 			borrowed.add(ret);
> 		}
> 		return ret;
> 	}
> 	public synchronized void invalidateObject(MyObject mo) {
> 		if(borrowed.contains(mo)){
> 			borrowed.remove(mo);
> 			super.invalidateObject(mo);
> 		}
> 	}
> 	public synchronized void returnObject(Object obj) throws Exception {
> 		if (borrowed.contains(obj)) {
> 			borrowed.remove(obj);
> 			super.returnObject(obj);
> 		}
> 	}
> }
> So the inner counter _numActive would not get corrupted due to incorrect call to returnObject() or invalidateObject().
> I wonder if this feature could be included into the mighty commons-pool library to make this class completely FOOL proof  :)

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