Java基于命令模式實(shí)現(xiàn)郵局發(fā)信功能詳解

package com.demo.receiver;
/**
 * 信件接收者接口
 *
 * @author
 *
 */
public interface IReceiver {
  /**
   * 收件人收到信件讀取
   *
   * @param message
   */
  public void readMail(String message);
}

package com.demo.receiver;
/**
 * 信件接收者
 *
 * @author
 *
 */
public class Receiver implements IReceiver {
  /**
   * 收件人收到信件讀取
   *
   * @param message
   */
  public void readMail(String message) {
    System.out.println("收件人讀取信件：" + message);
  }
}

package com.demo.command;
/**
 * 郵局接口
 *
 * @author
 *
 */
public interface IPost {
  /**
   * 郵局發(fā)送信件
   *
   * @param message
   */
  public void sendMail(String message);
}

package com.demo.command;
import com.demo.receiver.IReceiver;
/**
 * 郵局實(shí)現(xiàn)類
 *
 * @author
 *
 */
public class Post implements IPost {
  // 收信人對(duì)象實(shí)例
  private final IReceiver receiver;
  /**
   * 構(gòu)造方法傳入收信人對(duì)象實(shí)例
   *
   * @param receiver
   */
  public Post(IReceiver receiver) {
    this.receiver = receiver;
  }
  /**
   * 郵局發(fā)送信件
   *
   * @param message
   */
  @Override
  public void sendMail(String message) {
    System.out.println("郵局將信件發(fā)給收信人...");
    // 郵局發(fā)送信件給收信人
    this.receiver.readMail(message);
  }
}

package com.demo.invoker;
import com.demo.command.IPost;
/**
 * 發(fā)信人
 *
 * @author
 *
 */
public class Invoker {
  // 郵局私有屬性
  private IPost post;
  /**
   * 設(shè)置郵局對(duì)象實(shí)例
   *
   * @param post
   */
  public void setPost(IPost post) {
    this.post = post;
  }
  /**
   * 發(fā)信人發(fā)送信件
   *
   * @param message
   */
  public void postMail(String message) {
    System.out.println("發(fā)信人投遞信件給郵局...");
    this.post.sendMail(message);
  }
}

package com.demo;
import com.demo.command.IPost;
import com.demo.command.Post;
import com.demo.invoker.Invoker;
import com.demo.receiver.Receiver;
/**
 * 客戶端應(yīng)用程序
 *
 * @author
 *
 */
public class Client {
  /**
   * @param args
   */
  public static void main(String[] args) {
    // 創(chuàng)建一個(gè)收信人對(duì)象實(shí)例
    Receiver receiver = new Receiver();
    // 創(chuàng)建一個(gè)郵局對(duì)象實(shí)例 傳入收信人對(duì)象實(shí)例
    IPost post = new Post(receiver);
    // 創(chuàng)建一個(gè)發(fā)信人對(duì)象實(shí)例 傳入郵局對(duì)象實(shí)例
    Invoker invoker = new Invoker();
    // 設(shè)置郵局
    invoker.setPost(post);
    // 發(fā)信人開始發(fā)送信息！?。?    invoker.postMail("你好！好久不見，最近工作忙嗎？");
  }
}