machinetreemodel.java

本书透彻讲解了经典的《设计模式：可复用面向对象软件的基础》一书涵盖的23种基本设计模式。本书将这些设计模式分成五类：接口型模式、责任型模式、构造型模式、操作型模式

package com.oozinoz.dublin;

import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;

import com.oozinoz.machine.Machine;
import com.oozinoz.machine.MachineComponent;
import com.oozinoz.machine.MachineComposite;

/**
 * This class adapts a machine composite to behave as 
 * a tree model.
 *
 * (You might think that this class should subclass
 * DefaultTreeModel, but that class requires its 
 * nodes to be TreeNode objects.)
 * 
 * @author Steven J. Metsker
 */
public class MachineTreeModel implements TreeModel 
{
	protected MachineComponent root;

/**
 * Ignored.
 */
public void addTreeModelListener(
	javax.swing.event.TreeModelListener l)
{
}
/**
 * Returns the child of the provided parent at the 
 * provided index. 
 *
 * @param   parent  a node in the tree
 * @return  the child of the parent at the given index
 */
public Object getChild(Object parent, int index)
{
	if (parent instanceof MachineComposite)
	{
		MachineComposite c = (MachineComposite) parent;
		return c.getComponents().get(index);
	}
	return null;
}
/**
 * Returns the number of children in the provided node 
 *
 * @param   parent  a node in the tree
 * @return  the number of children at the give node
 */
public int getChildCount(Object parent)
{
	if (parent instanceof MachineComposite)
	{
		MachineComposite c = (MachineComposite) parent;
		return c.getComponents().size();
	}
	return 0;
}
/**
 * Returns the index of the child at a parent node 
 *
 * @param   parent  a node in the tree
 * @param   child  a node in the tree
 * @return  the index of the child at the parent node
 */
public int getIndexOfChild(Object parent, Object child)
{
	if (parent instanceof MachineComposite)
	{
		MachineComposite c = (MachineComposite) parent;
		return c.getComponents().indexOf(child);
	}
	return 0;
}
/**
 * Returns the root of the tree. 
 *
 * @return  the root of the tree
 */
public Object getRoot()
{
	return root;
}
/**
 * Returns true if the provided node is a leaf.
 *
 * @param   node    a node in the tree
 * @return  true if the given node is a leaf
 */
public boolean isLeaf(Object node)
{
	return node instanceof Machine;
}
/**
 * Ignored.
 */
public void removeTreeModelListener(
	javax.swing.event.TreeModelListener l)
{
}
/**
 * Ignored.
 */
public void valueForPathChanged(
	TreePath path,
	Object newValue)
{
}

/**
 * Construct a tree model of the supplied 
 * MachineComponent object.
 */
public MachineTreeModel(MachineComponent root)
{
	this.root = root;
}
}