DeferredContentProvider.java

/*
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.hibernate.eclipse.console.workbench;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.AbstractTreeViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.ui.model.BaseWorkbenchContentProvider;
import org.eclipse.ui.model.IWorkbenchAdapter;
import org.eclipse.ui.progress.DeferredTreeContentManager;
import org.eclipse.ui.progress.IDeferredWorkbenchAdapter;
import org.eclipse.ui.progress.PendingUpdateAdapter;
import org.hibernate.console.ImageConstants;
import org.hibernate.eclipse.console.utils.EclipseImages;

public class DeferredContentProvider extends BaseWorkbenchContentProvider {

	private DeferredTreeContentManager manager;
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
	 */
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
		if (viewer instanceof AbstractTreeViewer) {
			manager = new DeferredTreeContentManagerImpl((AbstractTreeViewer) viewer);
		}
		super.inputChanged(viewer, oldInput, newInput);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(java.lang.Object)
	 */
	public boolean hasChildren(Object element) {
		// the + box will always appear, but then disappear
		// if not needed after you first click on it.
		if (manager != null) {
			if (manager.isDeferredAdapter(element))
				return manager.mayHaveChildren(element);
		}

		return super.hasChildren(element);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.ui.model.WorkbenchContentProvider#getChildren(java.lang.Object)
	 */
	public Object[] getChildren(Object element) {
		if (manager != null) {
			Object[] children = manager.getChildren(element);
			if(children != null) {
				return children;
			}
		}
		return super.getChildren(element);
	}
	
	protected IWorkbenchAdapter getAdapter(Object o) {
	    if (o instanceof IAdaptable) {
        	return (IWorkbenchAdapter) ((IAdaptable) o).getAdapter(IWorkbenchAdapter.class);
        } else {
        	return (IWorkbenchAdapter) Platform.getAdapterManager().getAdapter(o, IWorkbenchAdapter.class);
        }
	}
	
	private class DeferredTreeContentManagerImpl extends DeferredTreeContentManager {
		public DeferredTreeContentManagerImpl(AbstractTreeViewer viewer) {
			super(viewer);
		}

		protected IDeferredWorkbenchAdapter getAdapter(Object element) {
			if (element instanceof IDeferredWorkbenchAdapter) {
				return (IDeferredWorkbenchAdapter) element;
			}
			Object adapter = Platform.getAdapterManager().getAdapter(element, IDeferredWorkbenchAdapter.class);
			return (IDeferredWorkbenchAdapter) adapter;
		}

		protected PendingUpdateAdapter createPendingUpdateAdapter() {
			return new PendingUpdateAdapter() {
				public ImageDescriptor getImageDescriptor(Object object) {
					return EclipseImages.getImageDescriptor(ImageConstants.RELOAD);
				}
			};
		}
	}
}