Head First 设计模式之命令模式，各司其职提高效率

/**
 * 命令(Command)角色
 */
public interface Command {
 public void execute();
}

/**
 * 具体命令
 */
public class LightOffCommand implements Command{
 private Receiver receiver;
 public LightOffCommand(Receiver receiver) {
 this.receiver = receiver;
 }
 public void execute() {
 receiver.turnOFF();
 }
}

/**
 *
 * 具体命令
 */
public class LightOnCommand implements Command{
 private Receiver receiver;
 public LightOnCommand(Receiver receiver) {
 this.receiver = receiver;
 }
 public void execute() {
 receiver.turnON();
 }
}

/**
 *
 * 命令接收者：执行命令
 */
public class Receiver {
 public void turnON() {
 System.out.println("执行开灯操作...");
 }
 public void turnOFF() {
 System.out.println("执行关灯操作...");
 }
}

/**
 * Created by zengjianlu on 2018/2/24.
 *
 * 命令调用者：负责调用
 */
public class Invoker {
 public void execute(Command command){
 command.execute();
 }
}

/**
 * 测试类
 */
public class Test {
 public static void main(String[] args) {
 Receiver receiver = new Receiver();
 Invoker invoker = new Invoker();
 Command turnOnLight = new LightOnCommand(receiver);
 Command turnOffLight = new LightOffCommand(receiver);
 invoker.execute(turnOnLight);
 invoker.execute(turnOffLight);
 }
}

public interface Runnable {
 /**
 * When an object implementing interface <code>Runnable</code> is used
 * to create a thread, starting the thread causes the object's
 * <code>run</code> method to be called in that separately executing
 * thread.
 * <p>
 * The general contract of the method <code>run</code> is that it may
 * take any action whatsoever.
 *
 * @see java.lang.Thread#run()
 */
 public abstract void run();
}

public synchronized void start() {
 /**
 * This method is not invoked for the main method thread or "system"
 * group threads created/set up by the VM. Any new functionality added
 * to this method in the future may have to also be added to the VM.
 *
 * A zero status value corresponds to state "NEW".
 */
 if (threadStatus != 0)
 throw new IllegalThreadStateException();
 /* Notify the group that this thread is about to be started
 * so that it can be added to the group's list of threads
 * and the group's unstarted count can be decremented. */
 group.add(this);
 boolean started = false;
 try {
 start0();
 started = true;
 } finally {
 try {
 if (!started) {
 group.threadStartFailed(this);
 }
 } catch (Throwable ignore) {
 /* do nothing. If start0 threw a Throwable then
 it will be passed up the call stack */
 }
 }
}

/**
 * jdk Runnable 命令模式
 *
 */
public class TurnOffThread implements Runnable{
 private Receiver receiver;
 public TurnOffThread(Receiver receiver) {
 this.receiver = receiver;
 }
 public void run() {
 receiver.turnOFF();
 }
}

/**
 * 测试类
 */
public class TurnOffThreadTest {
 public static void main(String[] args) {
 Receiver receiver = new Receiver();
 TurnOffThread turnOffThread = new TurnOffThread(receiver);
 Thread thread = new Thread(turnOffThread);
 thread.start();
 }
}