commandsequence.java

java设计模式源码

package com.oozinoz.robotInterpreter2;

/*
 * Copyright (c) 2001, 2005. 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.
 */

import java.util.ArrayList;
import java.util.List;

/**
 * This class contains a sequence of other commands.
 */
public class CommandSequence extends Command {
    protected List commands = new ArrayList();

    /**
     * Add a command to the sequence of commands to which this object will
     * cascade an Execute() command.
     * @param c a command to add
     */
    public void addCommand(Command c) {
        commands.add(c);
    }

    /**
     * @return a string description of this command sequence.
     */
    public String toString() {
        StringBuffer sb = new StringBuffer();
        boolean needLine = false;

        for (int i = 0; i < commands.size(); i++) {
            Command c = (Command) commands.get(i);
            if (needLine) sb.append("\n");
            sb.append(c);
            needLine = true;
        }

        return sb.toString();
    }

    /**
     * Ask each command in the sequence to execute.
     */
    public void execute() {
        for (int i = 0; i < commands.size(); i++) {
            Command c = (Command) commands.get(i);
            c.execute();
        }
    }
}