JAVA多线程设计模式一 Single Threaded Execution

public class Gate {
	
	private int counter = 0;
	private String name = "Nobody";
	private String address = "Nowhere";

	public synchronized void  pass(String name, String address) {
		this.counter++;
		this.name = name;
		try {
			Thread.sleep(1000);
		} catch (InterruptedException e) {
		}
		this.address = address;
		check();
	}

	public  String toString() {
		return "No." + counter + ": " + name + ", " + address;
	}

	private void check() {
		if (name.charAt(0) != address.charAt(0)) {
			System.out.println("***** BROKEN ***** " + toString());
		}
	}
}

public class UserThread extends Thread {
	private final Gate gate;
	private final String myname;
	private final String myaddress;

	public UserThread(Gate gate, String myname, String myaddress) {
		this.gate = gate;
		this.myname = myname;
		this.myaddress = myaddress;
	}

	public void run() {
		System.out.println(myname + " BEGIN");
		while (true) {
			gate.pass(myname, myaddress);
		}
	}
}

public class Main {
    public static void main(String[] args) {
        System.out.println("Testing Gate, hit CTRL+C to exit.");
        Gate gate = new Gate();
        new UserThread(gate, "Alice", "Alaska").start();
        new UserThread(gate, "Bobby", "Brazil").start();
        new UserThread(gate, "Chris", "Canada").start();
    }
}

Gate 类中的方法，同步关键字的有无。 执行程序看看。