/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * 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 org.argeo.cms.ui.jcr.model;
  
  import javax.jcr.Node;
  import javax.jcr.NodeIterator;
  import javax.jcr.RepositoryException;
  import javax.jcr.Workspace;
  
  import org.argeo.eclipse.ui.EclipseUiException;
  import org.argeo.eclipse.ui.TreeParent;
  
  /**
   * UI Tree component. Wraps a node of a JCR {@link Workspace}. It also keeps a
   * reference to its parent node that can either be a {@link WorkspaceElem}, a
   * {@link SingleJcrNodeElem} or null if the node is "mounted" as the root of the
   * UI tree.
   */
  public class SingleJcrNodeElem extends TreeParent {
  
  	private final Node node;
  	private String alias = null;
  
  	/** Creates a new UiNode in the UI Tree */
  	public SingleJcrNodeElem(TreeParent parent, Node node, String name) {
  		super(name);
  		setParent(parent);
  		this.node = node;
  	}
  
  	/**
  	 * Creates a new UiNode in the UI Tree, keeping a reference to the alias of
  	 * the corresponding repository in the current UI environment. It is useful
  	 * to be able to mount nodes as roots of the UI tree.
  	 */
  	public SingleJcrNodeElem(TreeParent parent, Node node, String name, String alias) {
  		super(name);
  		setParent(parent);
  		this.node = node;
  		this.alias = alias;
  	}
  
  	/** Returns the node wrapped by the current UI object */
  	public Node getNode() {
  		return node;
  	}
  
  	protected String getRepositoryAlias() {
  		return alias;
  	}
  
  	/**
  	 * Overrides normal behaviour to initialise children only when first
  	 * requested
  	 */
  	@Override
  	public synchronized Object[] getChildren() {
  		if (isLoaded()) {
  			return super.getChildren();
  		} else {
  			// initialize current object
  			try {
  				NodeIterator ni = node.getNodes();
  				while (ni.hasNext()) {
  					Node curNode = ni.nextNode();
  					addChild(new SingleJcrNodeElem(this, curNode, curNode.getName()));
  				}
  				return super.getChildren();
  			} catch (RepositoryException re) {
  				throw new EclipseUiException("Cannot initialize SingleJcrNode children", re);
  			}
  		}
  	}
  
  	@Override
  	public boolean hasChildren() {
  		try {
  			if (node.getSession().isLive())
  				return node.hasNodes();
  			else
  				return false;
  		} catch (RepositoryException re) {
  			throw new EclipseUiException("Cannot check children node existence", re);
  		}
  	}
  }