Description Chuck Imperato 2006-05-02 12:22:49 EDT

The use case is as follows:

Create a perspective using the addContribution method of the IExtensionRegistry interface.  Save the perspective state when the platform is shutdown.  Restart the platform, load the perspective and try to reset it.  The reset does not change the UI back to the original definition.  The problem is because the reset code needs to re-create the IPerspectiveFactory object and it never does because the configElement for the PerspectiveDescriptor is always null.  This is because the original perspective was created using a dynamic extension and is not persisted across restarts.  One possible solution would be to include the following in the PerspectiveDescriptor code:

    public IPerspectiveFactory createFactory() throws CoreException {
        // if there is an originalId, then use that descriptor instead
        if (originalId != null) {
            // Get the original descriptor to create the factory. If the
            // original is gone then nothing can be done.
            IPerspectiveDescriptor target = ((PerspectiveRegistry) WorkbenchPlugin
                    .getDefault().getPerspectiveRegistry())
                    .findPerspectiveWithId(originalId);

            return target == null ? null : ((PerspectiveDescriptor) target)
                    .createFactory();
        }

        /*****************************************************************
         * Code that could be added to attempt to find a matching config 
         * element for the perspective id.
         ****************************************************************/
        if (configElement == null) {
        	IExtensionRegistry registry = RegistryFactory.getRegistry( );
        	IConfigurationElement[] elements = registry.getConfigurationElementsFor("org.eclipse.ui.perspectives");
        	for (int idx = 0; idx < elements.length; idx++) {
        		String perspId = elements[idx].getAttribute("id");
        		if (perspId != null && perspId.equals(this.id)) {
        			configElement = elements[idx];
        			break;
        		}
        	}
        }
        
        // otherwise try to create the executable extension
        if (configElement != null)
            try {
                return (IPerspectiveFactory) configElement
                            .createExecutableExtension(IWorkbenchRegistryConstants.ATT_CLASS);
            } catch (CoreException e) {
                // do nothing
            }

        return null;
    }

The other issue is the inability to determine if a perspective has a custom definition without using the internal API.  It would be beneficial to make public the hasCustomDefinition method in order to know whether or not this is a saved perspective descriptor and whether or not the consumer needs to delete it.  Since dynamic extensions are not persisted, every time the platform loads, a new perspective descriptor needs to be created for that perspective if we are not using the saved state.