Bug 315281 update copyrights for 3.6
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorActivationService.java
* 
	 * Checks the known activation state for the given viewer id to determine if
	 * the given navigator extension is 'active'.
	 *  
	 * @param aNavigatorExtensionId
	 *            The unique identifier associated with a given extension.
	 * 
	 * @return True if the extension is active in the context of the viewer id.
	 */
	public boolean isNavigatorExtensionActive(String aNavigatorExtensionId) {
		Boolean b = (Boolean) activatedExtensionsMap.get(aNavigatorExtensionId);
		if(b != null)
			return b.booleanValue();
		synchronized (activatedExtensionsMap) {
			NavigatorContentDescriptor descriptor = CONTENT_DESCRIPTOR_REGISTRY.getContentDescriptor(aNavigatorExtensionId);
			if (descriptor == null)
				return false;
			if(descriptor.isActiveByDefault())
				activatedExtensionsMap.put(aNavigatorExtensionId, Boolean.TRUE);
			else
				activatedExtensionsMap.put(aNavigatorExtensionId, Boolean.FALSE);
			return descriptor.isActiveByDefault();
		}
	}
	/**
	 * Set the activation state for the given extension in the context of the
	 * given viewer id. Each instance of an INavigatorContentService listens for
	 * the activation service to update; and if those instances were created
	 * with viewers, they will issue a refresh. Otherwise, clients are
	 * responsible for refreshing the viewers.