AbstractFileWrapperChildrenProvider.java

/* license-start
 * 
 * Copyright (C) 2008 - 2013 Crispico, <http://www.crispico.com/>.
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation version 3.
 * 
 * This program 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 General Public License for more details, at <http://www.gnu.org/licenses/>.
 * 
 * Contributors:
 *   Crispico - Initial API and implementation
 *
 * license-end
 */
package org.flowerplatform.web.explorer;

import java.io.File;
import java.util.ArrayList;
import java.util.Collection;

import org.flowerplatform.common.util.Pair;
import org.flowerplatform.communication.tree.GenericTreeContext;
import org.flowerplatform.communication.tree.IChildrenProvider;
import org.flowerplatform.communication.tree.remote.TreeNode;

/**
 * Provides File wrappers, i.e. a <code>Pair</code> containg a File + a String = the node type
 * that must by provided by implementing the {@link #getNodeType()} abstract method.
 * 
 * <p>
 * {@link #getFile(Object)} may be overridden to provide the file corresponding to the parent
 * node, if it is not also a <code>Pair</code>.
 * 
 * @author Cristian Spiescu
 */
public abstract class AbstractFileWrapperChildrenProvider implements IChildrenProvider {
	
	protected abstract String getNodeType();

	protected File getFile(Object node) {
		if (node instanceof Pair) {
			@SuppressWarnings("unchecked")
			Pair<File, String> realNode = (Pair<File, String>) node;
			return realNode.a;
		} else {
			throw new IllegalArgumentException(String.format("Don't know how to get the File from class = %s, instance = %s. SUPER should have overridden and handled this type", node.getClass(), node));
		}
	}
	
	protected Object getChildToProvide(File realChild) {
		return new Pair<File, String>(realChild, getNodeType());
	}
	
	@Override
	public Collection<Pair<Object, String>> getChildrenForNode(Object node, TreeNode treeNode, GenericTreeContext context) {
		File[] children = getFile(node).listFiles();
		if (children != null) {
			Collection<Pair<Object, String>> result = new ArrayList<Pair<Object, String>>(children.length);
			
			for (File child : children) {
				Pair<Object, String> pair = new Pair<Object, String>(getChildToProvide(child), getNodeType());
				result.add(pair);
			}
			
			return result;
		}
		return new ArrayList<Pair<Object, String>>();
	}

	@Override
	public Boolean nodeHasChildren(Object node, TreeNode treeNode, GenericTreeContext context) {
		File file = getFile(node);
		return file.isDirectory() && file.list().length > 0;
	}

}