src/plugins/db.core/src/com/motorolamobility/studio/android/db/core/ui/tree/DatabaseExplorerTreeContentProvider.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.motorolamobility.studio.android.db.core.ui.tree;

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

import com.motorolamobility.studio.android.db.core.ui.AbstractTreeNode;
import com.motorolamobility.studio.android.db.core.ui.ITreeNode;
import com.motorolamobility.studio.android.db.core.ui.LoadingNode;

/**
 * Content provider that uses {@link AbstractTreeNode} as the model 
 */
public class DatabaseExplorerTreeContentProvider implements ILazyTreeContentProvider
{

    private final TreeViewer treeViewer;

    public DatabaseExplorerTreeContentProvider(TreeViewer viewer)
    {
        this.treeViewer = viewer;
    }

    public void dispose()
    {
        //Nothing
    }

    public void inputChanged(Viewer viewer, Object oldInput, Object newInput)
    {
        //Nothing
    }

    public Object getParent(Object element)
    {
        if (element instanceof AbstractTreeNode)
        {
            ITreeNode treeNode = (ITreeNode) element;
            return treeNode.getParent();
        }
        return null;
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.viewers.ILazyTreeContentProvider#updateElement(java.lang.Object, int)
     */
    public void updateElement(Object parent, int index)
    {
        if (parent instanceof ITreeNode)
        {
            ITreeNode parentTreeNode = (ITreeNode) parent;
            ITreeNode child = null;
            if ((index == 0) && parentTreeNode.isLoading())
            {
                child = new LoadingNode(parentTreeNode);
            }
            else
            {
                child = parentTreeNode.getChild(index);
            }
            if (child != null)
            {
                treeViewer.replace(parent, index, child);
                if (!child.isLeaf())
                {
                    treeViewer.setHasChildren(child, true);
                }
            }
        }
    }

    /* (non-Javadoc)
     * @see org.eclipse.jface.viewers.ILazyTreeContentProvider#updateChildCount(java.lang.Object, int)
     */
    public void updateChildCount(Object element, int currentChildCount)
    {
        if (element instanceof AbstractTreeNode)
        {
            ITreeNode treeNode = (ITreeNode) element;
            treeNode.refreshAsync();
            int childCount = 0;
            if (treeNode.isLoading())
            {
                childCount = 1;
            }
            else
            {
                childCount = treeNode.getChildren().size();
            }
            if (childCount != currentChildCount)
            {
                treeViewer.setChildCount(element, childCount);
            }
        }
    }
}