rakevisitor.java

来自「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」· Java 代码 · 共 55 行

package com.oozinoz.dublin;

import com.oozinoz.machine.*;
import java.util.*;

/*
 * Copyright (c) 2001 Steven J. Metsker.
 * 
 * Steve Metsker makes no representations or warranties about
 * the fitness of this software for any particular purpose, 
 * including the implied warranty of merchantability.
 *
 * Please use this software as you wish with the sole
 * restriction that you may not claim that you wrote it.
 */
/**
 * This class uses the visitor mechanics of the machine
 * hierarchy to add a behavior that finds all the leaf-node
 * machines in a composite.
 * 
 * @author Steven J. Metsker
 * @see com.oozinoz.applications.ShowRake
 */
public class RakeVisitor implements MachineVisitor 
{
	private Set leaves;
/**
 * Find all the leaf-node machines in a composite.
 */
public Set getLeaves(MachineComponent mc)
{
	leaves = new HashSet();
	mc.accept(this);
	return leaves;
}
/**
 * Add this machine to the set of leaf nodes.
 */
public void visit(Machine m)
{
	leaves.add(m);
}
/**
 * Visit all the children of the provided composite
 * to see if they are leaf nodes.
 */
public void visit(MachineComposite mc)
{
	Iterator i = mc.getComponents().iterator();
	while (i.hasNext())
	{
		((MachineComponent) i.next()).accept(this);
	}
}
}