org.eclipse.mylyn.internal.reviews.ui.providers.GenericTreeContentProvider.java Source code

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Here is the source code for org.eclipse.mylyn.internal.reviews.ui.providers.GenericTreeContentProvider.java

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/*******************************************************************************
 * Copyright (c) 2012 Tasktop Technologies 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:
 *     Tasktop Technologies - initial API and implementation
 *******************************************************************************/

package org.eclipse.mylyn.internal.reviews.ui.providers;

import java.util.Collection;

import org.apache.commons.lang.ArrayUtils;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.Viewer;

/**
 * Provides common features for tree content providers including support for gathering children of collections
 * efficiently.
 * 
 * @author Miles Parker
 */
public abstract class GenericTreeContentProvider implements ITreeContentProvider {

    public Object[] getChildren(Object parentElement) {
        return getElements(parentElement);
    }

    public Object getParent(Object element) {
        return null;
    }

    public boolean hasChildren(Object element) {
        return getChildren(element).length > 0;
    }

    protected Object[] getCollectionChildren(Object element) {
        if (element instanceof Collection) {
            Collection<?> collection = (Collection<?>) element;
            Object[] elements = new Object[] {};
            for (Object member : collection) {
                elements = ArrayUtils.addAll(elements, getElements(member));
            }
            return elements;
        }
        return new Object[0];
    }

    /**
     * Optimization over getCollectionChildren() as we don't have to tour each member.
     */
    protected boolean hasCollectionChildren(Object element) {
        if (element instanceof Collection) {
            Collection<?> collection = (Collection<?>) element;
            for (Object member : collection) {
                if (hasChildren(member)) {
                    return true;
                }
            }
        }
        return false;
    }

    public void dispose() {
    }

    public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
    }
}