branch.java

一个实用工具类

/*
 * Copyright (C) butor.com. All rights reserved.
 *
 * This software is published under the terms of the GNU Library General
 * Public License (GNU LGPL), a copy of which has been included with this
 * distribution in the LICENSE.txt file. 
 */


package org.butor.web.menu;

import java.util.ArrayList;
import java.util.Collection;

import org.butor.log.Log;

/**
 * This class represents an item in the item hierarchy. A branch can be
 * a leaf or it can contain other children branches. This clas provides 
 * methods to manage the children item of this branch.
 *
 * @author Nguyen The Hung
 */
public class Branch implements IBranch {

	/**
	 * Name of this node
	 */
	protected String f_name;
	/**
	 * Name of the parent node
	 */
	protected String f_parentName;
	/**
	 * Array of children nodes
	 */
	protected ArrayList f_children;
	
	
	/**
	 * Constructor for Branch.
	 * @param name java.lang.String
	 * @param parentName java.lang.String
	 */
	public Branch(String name, String parentName) {
				 	
		super();

		f_name = name;
		f_parentName = parentName;
		f_children = new ArrayList();
	}
	
	/**
	 * Add a child node to the current node.
	 * @param child org.butor.wak.menu.IBranch
	 */
	protected void addBranch(IBranch child) {

		if (child == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "addBranch()", "Cannot add branch [null].");
			return;
		}

		Log.logStr(Log.LOG_LEVEL_LOW, this, Log.LOG_TYPE_INFO, "addBranch()", "Name : " + child.getName());
		
		f_children.add(child);
	}

	/**
	 * Add a node.
	 * @param parentName java.lang.String Name of the parent node to which the child node will be attached.
	 * @param child org.butor.wak.menu.IBranch
	 * @return org.butor.wak.menu.Branch The node to which the child is attached or null if there is no parent node.
	 */
	protected Branch addBranch(String parentName, IBranch child) {

		if (parentName == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "addBranch()", "Cannot add branch. Parent name = [null].");
			return null;
		}
		if (child == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "addBranch()", "Cannot add branch. Child = [null].");
			return null;
		}


		// Find the parent node
		Branch parentNode = (Branch) getBranch(parentName);
		
		if (parentNode == null) {
			StringBuffer buff = new StringBuffer();
			buff.append("Cannot add branch. [Parent Id: ");
			buff.append(parentName);
			buff.append("; Id : ");
			buff.append(child.getName());
			buff.append("]");

			Log.logStr(this, 
					   Log.LOG_TYPE_WARN, 
					   "addBranch()", 
					   buff.toString());
		} else {
			parentNode.addBranch(child);
		}
		
		return parentNode;
	}
	
	/**
	 * Remove a child node from the current node.
	 * @param child org.butor.wak.menu.IBranch
	 * @return boolean
	 */
	protected boolean removeBranch(IBranch child) {

		if (child == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "removeBranch()", "Cannot remove branch [null].");
			return false;
		}
		
		String name = child.getName();
		if (name == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "removeBranch()", "Cannot remove branch. Name = [null].");
			return false;
		}
		

		Log.logStr(Log.LOG_LEVEL_LOW, this, Log.LOG_TYPE_INFO, "removeBranch()", "Name : " + name);
		
		for (int i = 0; i < f_children.size(); i++) {
			IBranch node = (IBranch) f_children.get(i);
			
			if (node.getName().equals(name)) {
				if (node.hasChild()) {
					Log.logStr(Log.LOG_LEVEL_LOW, 
							   this, 
							   Log.LOG_TYPE_INFO, 
							   "removeBranch()", 
							   "Cannot remove branch (got child(s)).");
					return false;
				} else {
					f_children.remove(i);
					return true;
				}
			}
		}

		Log.logStr(Log.LOG_LEVEL_LOW, 
				   this, 
				   Log.LOG_TYPE_INFO, 
				   "removeBranch()", 
				   "Branch not found.");
		return false;
	}

	/**
	 * Remove a child node.
	 * @param parentName java.lang.String Name of the parent node from which the child node will be removed.
	 * @param child org.butor.wak.menu.IBranch
	 * @return boolean
	 */
	protected boolean removeBranch(String parentName, IBranch child) {

		if (parentName == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "removeBranch()", "Cannot remove branch. Parent name = [null].");
			return false;
		}
		if (child == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "removeBranch()", "Cannot remove branch. Child = [null].");
			return false;
		}

		// Find the parent node
		Branch parentNode = (Branch) getBranch(parentName);
		
		if (parentNode == null) {
			StringBuffer buff = new StringBuffer();
			buff.append("Cannot remove branch. [Parent Id: ");
			buff.append(parentName);
			buff.append("; Id : ");
			buff.append(child.getName());
			buff.append("]");

			Log.logStr(this, 
					   Log.LOG_TYPE_WARN, 
					   "removeBranch()", 
					   buff.toString());
			return false;
		} else {
			parentNode.removeBranch(child);
			return true;
		}
	}
	
	/**
	 * Remove all the children nodes
	 */
	protected void removeAllChildren() {

		Log.logStr(Log.LOG_LEVEL_LOW, this, Log.LOG_TYPE_INFO, "removeAllChildren()", "");
		
		f_children.clear();
	}

	/**
	 * Get the node of the specified id (down the hierarchy).
	 * @param name java.lang.String 
	 * @return org.butor.wak.menu.IBranch
	 */
	public IBranch getBranch(String name) {
		
		if (name == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "getBranch()", "Cannot get branch. Name = [null].");
			return null;
		}

		// If the current node has the same name, then return self
		if (name.equals(f_name)) {
			return this;
		}
			
		// Loop thru the children nodes to find the node with the specified id.
		for (int i = 0; i < f_children.size(); i++) {
			IBranch child = (IBranch) f_children.get(i);
			IBranch node = child.getBranch(name);
			
			if (node != null) {
				return node;
			}
		}
		return null;
	}
	
	/**
	 * Get the children nodes.
	 * @return java.util.Collection
	 */
	public Collection getChildren() {
		return f_children;
	}
	
	/**
	 * Return the whether the current node has any child node.
	 * @return boolean
	 */
	public boolean hasChild() {
		return !f_children.isEmpty();
	}
	

	/************************ Gettter/Setter Methods ************************/

	/**
	 * Return the id of the current node.
	 * @return java.lang.String
	 */
	public String getName() {
		return f_name;
	}
	
	/**
	 * Return the name of the parent node.
	 * @return java.lang.String
	 */
	public String getParentName() {
		return f_parentName;
	}
}