Bug 132868

Description Scott Barkley 2006-03-22 12:14:50 EST

The issue described affects the classes:
org.eclipse.gef.ui.palette.PaletteViewer
org.eclipse.gef.ui.palette.DefaultPaletteViewerPreferences
in (at least) GEF 3.1.0, 3.1.1, and the currently commited files in 3.2.

PaletteViewer fails to initialize (with a java.lang.ExceptionInInitializerError) when it is accessed in an RCP application in which the GEF plug-in is not installed, but rather the GEF code is accessed via a jar in a common plug-in, as follows:

Plugin 'Common' shows 'org.eclipse.gef_3.1.1.jar' (with a plain jar icon) in the Libraries tab of the Java Build Path dialog, and also shows that jar as exported on the Order and Export tab.

Plugin 'x' shows 'Common' as a Required Plug-in on the Dependencies tab of its plug-in manifest, and can access all of the GEF code via 'Common'.


The cause of the problem is on line 88 of PaletteViewer:

private static final PaletteViewerPreferences PREFERENCE_STORE = new DefaultPaletteViewerPreferences();

In the default constructor to DefaultPaletteViewerPreferences, the call to GEFPlugin.getDefault().getPreferenceStore() fails because
1) GEFPlugin() has not been called to initialize the singleton, and if that
is remedied, then 
2) the call to AbstractUIPlugin.getPreferenceStore() fails because Plugin.getBundle() returns null.
(InternalGEFPlugin in the 3.2 builds will have the same problem)


Potential ways to resolve include:

1) Handling exception in DefaultPaletteViewerPreferences() to quietly initialize to useless if it can't get the preference store it wants.

2) Removing the definition of PREFERENCE_STORE as a constant in PaletteViewer.  That constant is only used once, to initialize a private field, which could be done elsewhere in such a way as to quietly initialize the field to null if needed.  This would be a nice, localized fix and easy for developers to work with due to the availability of the public PaletteViewer.setPaletteViewerPreferences(PaletteViewerPreferences) method.  Then, if a preference store has not been set and the default is unavailable, the developer can cleanly fix the problem with a preference store from elsewhere.