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11 : tod 1.7 <title>Eclipse 3.1 Plug-in Migration FAQ</title>
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15 :    
16 :     <h1>Eclipse 3.1 Plug-in Migration FAQ</h1>
17 : tod 1.5 <ol>
18 :     <li><a href="#IPreferenceStore">IPreferenceStore has more explicit API</a></li>
19 : tod 1.7 <li><a href="#IWorkbenchWindow">IWorkbenchWindow#getShell() has more explicit API</a></li>
20 : tod 1.5 </ol>
21 : dmegert 1.11 <h2> <a name="IPreferenceStore"></a>IPreferenceStore has more explicit API</h2>
22 :     <p>Although the behavior of the IPreferenceStore provided by <code>AbstractUIPlugin#getPreferenceStore()
23 : tod 1.4 </code>hasn't changed we have updated the specification of IPreferenceStore
24 :     to explicitly define the behavior that we have provided.</p>
25 :     <p><strong>Typing of PropertyChangeEvents</strong></p>
26 :     <p>Any property change event from an IPreferenceStore must have an old and new
27 :     value of the same type that is consistent with the setValue call that generated
28 : tod 1.6 it. </p>
29 : tod 1.4 <p>For instance if you call<code> IPreferenceStore#setValue(String name, long
30 :     value) </code>the values in the PropertyChangeEvent generated from this method
31 : tod 1.6 will both be of type <code>java.lang.Long</code>.</p>
32 : tod 1.4 <p><strong>putValue</strong></p>
33 : johna 1.13 <p>Calls to <code>#putValue</code> will not generate a <code>PropertyChangedEvent</code>;
34 :     Calls to the various <code>#setValue</code> methods will generate an event.</p>
35 : tod 1.4 <p><strong>Relationship between the OSGI Preference and an IPreferenceStore</strong></p>
36 :     <p>The IPreferenceStore provided by <code>AbstractUIPlugin#getPreferenceStore()</code>is
37 :     an instance of <code>ScopedPreferenceStore</code> which uses <code>org.osgi.service.prefs.Preferences</code>
38 :     as a back end. <code>org.osgi.service.prefs.Preferences</code> propagates change
39 :     events as Strings only. </p>
40 :     <p>The <code>ScopedPreferenceStore</code> wrappers those OSGI events generated
41 :     by <code>IPreferenceStore#setValue(String name, String value)</code> and one
42 :     of it's own <code>PropertyChangeEvents</code> and forwards that event to it's
43 :     listeners. For the other implementations of <code>IPreferenceStore#setValue</code>
44 :     the <code>ScopedPreferenceStore</code> will create it's own events of the correct
45 :     type and not propagate the events from the OSGI preferences.</p>
46 : tod 1.7 <p>Listeners to a <code>ScopedPreferenceStore</code> should be prepared for both
47 :     typed and String values in thier change events as it is still possible to get
48 :     an event via the OSGI preferences (during a preference import for instance).
49 :     OSGI events are always of type <code>java.lang.String.</code></p>
50 :     <h2><a name="IWorkbenchWindow"></a>IWorkbenchWindow#getShell() has more explict API</h2>
51 :     <p>It has always been possible to get a null org.eclipse.swt.widgets.Shell from
52 :     the existing IWorkbenchWindows in the Eclipse SDK. We now explictly define the
53 :     conditions where this occurs, namely when the shell has not been created or
54 :     when the IWorkbenchWindow has been closed.</p>
55 : tod 1.8
56 : johna 1.1
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