Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/extensions/NavigatorContentExtension.java
}
	}
	private void applyMemento(IMementoAware target) {
		if (target != null)
			target.restoreState(appliedMemento);
	}
	protected final void complainDisposedIfNecessary() {
		if (isDisposed)
			throw new IllegalStateException("INavigatorContentExtension " 
					+ descriptor.getId() + " is disposed!"); 
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.internal.navigator.extensions.INavigatorContentExtension#getStateModel()
	 */
	public IExtensionStateModel getStateModel() {
		if (stateModel == null)
			stateModel = new ExtensionStateModel(descriptor.getId(), viewerId);
		return stateModel;
	}
	/**
	 * @param anElement
	 *            The element for the query.
	 * @return Returns the overridingExtensions.
	 */
	public NavigatorContentExtension[] getOverridingExtensionsForTriggerPoint(
			Object anElement) {
		if (!descriptor.hasOverridingExtensions())
			return NO_EXTENSIONS;