[Java Design Patten] Single Threaded Execution

Gate 클래스는 SharedResource 역할을 담당하고 있다. 그리고 자세히 보면 pass 에 Synchronized 키워드를 사용한 것을 주목하자 

사용한 이유는 동시에 복수의 Thread가 접근하면 문제가 발생하기 때문이다.

public class Gate {

private int counter = 0;

private String name = "Nobody";

private String address = "NoWhere";

public synchronized void pass (final String name, final String address) {

this.counter++;

this.name = name;

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");

}

}

}

public class UserThread extends Thread {

private final Gate gate;

private final String myname;

private final String myAddress;

public UserThread (final Gate gate, final String myname, final 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 (final String[] agrs) {

final Gate gate = new Gate();

new UserThread(gate,"aaa", "bbb").start();

new UserThread(gate,"ccc", "ddd").start();

new UserThread(gate,"eee", "fff").start();

}

}