/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.click.examples.page.tree;
import org.apache.click.examples.page.BorderPage;
import org.apache.click.extras.tree.Tree;
import org.apache.click.extras.tree.TreeNode;
/**
* Example usage of the {@link Tree} control.
*
* @author Bob Schellink
*/
public class TreePage extends BorderPage {
public static final String TREE_NODES_SESSION_KEY = "treeNodes";
protected Tree tree;
// --------------------------------------------------------- Event Handlers
/**
* @see org.apache.click.Page#onInit()
*/
@Override
public void onInit() {
super.onInit();
//Create the tree and tree model and add it to the page
tree = buildTree();
addControl(tree);
}
/**
* @see org.apache.click.Page#onGet()
*/
@Override
public void onGet() {
String selectId = getContext().getRequestParameter(Tree.SELECT_TREE_NODE_PARAM);
String expandId = getContext().getRequestParameter(Tree.EXPAND_TREE_NODE_PARAM);
if(selectId == null && expandId == null) {
return;
}
TreeNode node = null;
if(selectId != null) {
node = tree.find(selectId);
} else {
node = tree.find(expandId);
}
addModel("treeNode", node);
}
// --------------------------------------------------------- Protected Methods
/**
* Creates and return a new tree instance.
*/
protected Tree createTree() {
return new Tree("tree");
}
/**
* Build the tree and tree nodes and store the nodes in the session.
*/
protected Tree buildTree() {
tree = createTree();
//Try and load the already stored nodes from the session.
//If this is the first time we access the page, this method
//will return null, indicating no nodes is stored.
TreeNode existingRootNode = loadNodesFromSession();
if(existingRootNode != null) {
//OK we had already nodes stored in the session, so no need
//to rebuild them. We attach the root node and return.
tree.setRootNode(existingRootNode);
//By default root node is not displayed in browser. Here we expand it,
//so that the root's children are visible.
tree.expand(existingRootNode);
return tree;
}
TreeNode root = createNodes();
//Attach the root node containing all the other nodes to the tree
tree.setRootNode(root);
//By default root node is not displayed in browser. Here we expand it,
//so that the root's children are visible.
tree.expand(root);
//Store the tree nodes in the session so on the next request we do not
//have to rebuild it. Also because we keep the tree nodes in the session
//the nodes will keep their state between requests.
storeNodesInSession(root);
return tree;
}
/**
* Create the tree nodes. The nodes represents a directory consisting of
* files and folders as found on an Operating System.
*
* @return the root tree node
*/
protected TreeNode createNodes() {
//Create a node representing the root directory with the specified
//parameter as the value. Because an id is not specified, a random
//one will be generated by the node. By default the root node is
//not rendered by the tree. This can be changed by calling
//tree.setRootNodeDisplayed(true).
TreeNode root = new TreeNode("c:");
//Create a new directory, setting the root directory as its parent. Here
//we do specify a id as the 2nd argument, so no id is generated.
TreeNode dev = new TreeNode("dev","1", root);
//The follwing 3 nodes represent files in the directory, setting the
//dev node as their parent. Note the false argument to the constructor.
//This means that the specific node does not support child nodes, and
//it will be rendered as a leaf icon. If children are supported (the
//default value) then even if the node is a leaf, it will still be rendered
//as a collapsed icon. In the example a default leaf node will be
//rendered as a directory, and a node that does not support children is
//rendered as a file.
// Also note the node with the long text, will cause the tree to overflow
// and add scrollbars
new TreeNode("java.pdf", "1.1", dev, false);
new TreeNode("JEE 6 - the new fantastic approach to write better software (apparently)", "1.2", dev, false);
new TreeNode("ruby.pdf", "1.3", dev, false);
//We continue constructing the rest of the tree
TreeNode programFiles = new TreeNode("program files", "2", root);
new TreeNode("Adobe", "2.1", programFiles);
TreeNode download = new TreeNode("downloads","3", root);
TreeNode web = new TreeNode("web", "3.1", download);
new TreeNode("html.pdf", "3.1.1", web, false);
new TreeNode("css.html", "3.1.2", web, false);
TreeNode databases = new TreeNode("databases", "3.2", download);
TreeNode relationalDb = new TreeNode("relational", "3.2.1", databases);
new TreeNode("mysql.html", "3.2.1.1", relationalDb, false);
new TreeNode("oracle.pdf", "3.2.1.2", relationalDb, false);
new TreeNode("postgres", "3.2.1.3", relationalDb, false);
TreeNode objectDb = new TreeNode("object", "3.2.2", databases);
new TreeNode("db4o.html", "3.2.2.1", objectDb, false);
return root;
}
/**
* Return the string under which the nodes are stored in the session.
*
* @return the string under which the nodes are stored in the session
*/
protected String getSessionKey() {
return TREE_NODES_SESSION_KEY;
}
/**
* Store the tree nodes in the session
*/
protected void storeNodesInSession(TreeNode rootNode) {
if (tree.getRootNode() == null) {
return;
}
getContext().getSession().setAttribute(getSessionKey(), rootNode);
}
/**
* Retrieve the tree nodes from the session if available. Otherwise we return
* null.
*/
protected TreeNode loadNodesFromSession() {
return (TreeNode) getContext().getSession().getAttribute(getSessionKey());
}
}