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https://issues.apache.org/jira/browse/FLEX-27837?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13774440#comment-13774440
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nigel magnay commented on FLEX-27837:
-------------------------------------
Please find attached demo project;
If you click Test1, which registers for events in a model '1 layer deep', you
can see that change events fire when you click 'Change B' but not 'Change C'.
This is as you would expect.
When you click 'release', then click either change button - no events are
received, so the count does not go up. This is as you would expect, because we
asked for a weakly referenced changewatcher.
If you click Test2, which registers for events in a model '2 layer deep', you
can see that change events fire when you click 'Change B' and 'Change C'. This
is as you would expect.
When you click 'release', then click either change button - events are still
received. This is because the secondary change watcher in the chain incorrectly
has a strong reference to the change handler.
Test 3 and 4 are the same as 1 or 2, but with a 'fixed' ChangeWatcher.watch
implementation, as described. In this instance releasing the objects allows the
weak change watchers to also release, and events fired after 'release' is
clicked correctly do not get sunk.
> ChangeWatcher bug
> -----------------
>
> Key: FLEX-27837
> URL: https://issues.apache.org/jira/browse/FLEX-27837
> Project: Apache Flex
> Issue Type: Bug
> Components: .Unspecified - Framework
> Affects Versions: Adobe Flex SDK Previous
> Environment: Affected OS(s): Windows
> Affected OS(s): Windows XP
> Language Found: English
> Reporter: Adobe JIRA
> Labels: easyfix
> Attachments: BrokenFlex.zip
>
>
> When I used this class BindingUtils to binding work, I called this method:
> public static function bindSetter(setter:Function, host:Object,
> chain:Object,
> commitOnly:Boolean = false,
> useWeakReference:Boolean =
> false):ChangeWatcher
> I found there is a wrong description about the "useWeakReference", below is
> the signature of useWeakReference in the API Document:
> useWeakReference : Boolean
> (default = false) Determines whether the reference to the host is strong or
> weak.
> but I don't think it determines the host, but the ChangeWatcher instance
> itself, it determines whether the reference to the ChangeWatcher instance is
> strong or weak.
> So,I test the ChangeWatcher instance is real be gced. If the chain's length
> is only 1,the useWeakReference works, the ChangeWatcher instance will be
> gced,but if the chain's length is more than 1,the useWeakReference doesn't
> work.
> the source code:
> BindingUtils :
> public static function bindSetter(setter:Function, host:Object,
> chain:Object,
> commitOnly:Boolean = false,
> useWeakReference:Boolean =
> false):ChangeWatcher
> {
> var w:ChangeWatcher =
> ChangeWatcher.watch(host, chain, null, commitOnly,
> useWeakReference);
>
> if (w != null)
> {
> var invoke:Function = function(event:*):void
> {
> setter(w.getValue());
> };
> w.setHandler(invoke);
> invoke(null);
> }
>
> return w;
> }
> ChangeWatcher :
> public static function watch(host:Object, chain:Object,
> handler:Function,
> commitOnly:Boolean = false,
> useWeakReference:Boolean =
> false):ChangeWatcher
> {
> if (!(chain is Array))
> chain = [ chain ];
> if (chain.length > 0)
> {
> var w:ChangeWatcher =
> new ChangeWatcher(chain[0], handler, commitOnly,
> watch(null, chain.slice(1), handler, commitOnly));
> //there is the reason!the default arg is false,so the 1st ChangeWatcher is
> "useWeakReference = true",but others are "ChangeWatcher = false"
> w.useWeakReference = useWeakReference;
> w.reset(host);
> return w;
> }
> else
> {
> return null;
> }
> }
> I think the right code must be "watch(null, chain.slice(1), handler,
> commitOnly, useWeakReference)); "
> the chain of ChangeWatchers will not be gced.
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