org.eclipse.gmf.runtime.common.ui/src/org/eclipse/gmf/runtime/common/ui/internal/dialogs/SelectableElementsContentProvider.java

/******************************************************************************
 * Copyright (c) 2002, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    IBM Corporation - initial API and implementation 
 ****************************************************************************/

package org.eclipse.gmf.runtime.common.ui.internal.dialogs;

import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.Viewer;

import org.eclipse.gmf.runtime.common.ui.dialogs.SelectableElement;

/**
 * Content provider for SelectableElement viewer
 * 
 * @author Wayne Diu, wdiu
 */
public class SelectableElementsContentProvider
	implements ITreeContentProvider {

	/**
	 * An empty object array
	 */
	private static Object[] EMPTY_ARRAY = new Object[0];

	/**
	 * Tree viewer for content provider
	 */
	protected TreeViewer viewer;

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.IContentProvider#dispose()
	 */
	public void dispose() {
		/* method not implemented */
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer,
	 *      java.lang.Object, java.lang.Object)
	 */
	public void inputChanged(Viewer aViewer, Object oldInput, Object newInput) {
		this.viewer = (TreeViewer) aViewer;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.ITreeContentProvider#getChildren(java.lang.Object)
	 */
	public Object[] getChildren(Object parentElement) {
		if (parentElement instanceof SelectableElement) {
			return ((SelectableElement) parentElement).getChildren();
		}
		return EMPTY_ARRAY;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.ITreeContentProvider#getParent(java.lang.Object)
	 */
	public Object getParent(Object element) {
		if (element instanceof SelectableElement) {
			return ((SelectableElement) element).getParent();
		}
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(java.lang.Object)
	 */
	public boolean hasChildren(Object element) {
		return getChildren(element).length > 0;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
	 */
	public Object[] getElements(Object inputElement) {
		return getChildren(inputElement);
	}

}