Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
import org.eclipse.ui.navigator.INavigatorFilterService;
import org.eclipse.ui.navigator.INavigatorPipelineService;
import org.eclipse.ui.navigator.INavigatorSorterService;
import org.eclipse.ui.navigator.INavigatorViewerDescriptor;
import org.eclipse.ui.navigator.NavigatorActivationService;
/**
 * <p>
 * Provides centralized access to the information provided by
 * NavigatorContentExtensions. Can be instantiated as needed, but should be
 * cached for active viewers. Information specific to a given viewer will be
 * cached by the NavigatorContentService, not including ContentProviders and
 * Label Providers created by {@link #createCommonContentProvider()}and
 * {@link #createCommonLabelProvider()}respectively.
 * </p>
 * 
 * <p>
 * The following class is experimental until fully documented.
 * </p>
 */
public class NavigatorContentService implements IExtensionActivationListener,
		IMementoAware, INavigatorContentService {
	private static final NavigatorContentDescriptorManager CONTENT_DESCRIPTOR_REGISTRY = NavigatorContentDescriptorManager
			.getInstance();
	private static final NavigatorViewerDescriptorManager VIEWER_DESCRIPTOR_REGISTRY = NavigatorViewerDescriptorManager
			.getInstance();
	private static final ITreeContentProvider[] NO_CONTENT_PROVIDERS = new ITreeContentProvider[0];
	private static final ILabelProvider[] NO_LABEL_PROVIDERS = new ILabelProvider[0];
	private static final INavigatorContentDescriptor[] NO_DESCRIPTORS = new INavigatorContentDescriptor[0];
	private static final String[] NO_EXTENSION_IDS = new String[0];
	private final NavigatorViewerDescriptor viewerDescriptor;