자바 11장,8장(스레드) 예제/연습문제

스레드 구현 두가지 방법

1. Thread 클래스를 확장하고 run()메소드 작성

2. Runnable 인터페이스 구현하고 run()메소드 작성. 그리고 Threaed클래스의 생성자를 통해 객체를 생성해야 한다.

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예제11.1 simpleThreadTest

class SimpleThread extends Thread {
	public SimpleThread(String name) {
		super(name);  // 슈퍼클래스 Thread에 저장
	}
	public void run() {
		System.out.println(getName() + " is now running.");
	}
}
public class SimpleThreadTest {
	public static void main(String[] args) {
		SimpleThread t = new SimpleThread("SimpleThread");
		System.out.println("Here : 1");
		t.start();
		System.out.println("Here : 2");
	}
}

11.2

public class YieldTest extends Thread {
	static boolean doYield; // 다른 스레드로 제어를 양보할 것인가?
	static int howOften; // 몇 번 출력할 것인가?
	String word;
	YieldTest(String whatToSay) {
		word = whatToSay;
	}
	public void run() {
		for (int i = 0; i < howOften; i++) {
			System.out.println(word);
			if (doYield) yield(); // 다른 스레드에게 양보한다.
		}
	}
	public static void main(String[] args) {
		howOften = Integer.parseInt(args[1]);
		doYield = new Boolean(args[0]).booleanValue();
		Thread cur = currentThread();
		cur.setPriority(Thread.MAX_PRIORITY);
		for (int i = 2; i < args.length; i++)
			new YieldTest(args[i]).start();
	}
}

11.4

class RunThread extends Thread {
	public RunThread(String name) {
		super(name);
	}
	public void run() {
		for(int i = 1; i <= 200000; i++) {
			if (i % 50000 == 0)
			System.out.println("Thread [" + getName() + "] is activated => " + i);
		}
	}
}
public class SchedulerTest {
	private final static int NUM = 2;
	public static void main(String[] args) {
		Thread[] p = new RunThread[NUM];
		p[0] = new RunThread("Pear ");
		p[1] = new RunThread("Apple");
		p[0].start();
		p[1].start();
	}
}

11.6

class CircularQueue {
	private int contents[], size; // 큐의 내용, 크기
	private int head, tail; // head와 tail
	private int count; // 큐 내에 있는 원소의 수
	public CircularQueue(int sz) {
		size = sz;
		head = tail = 0;
		count = 0;
		contents = new int[size];
	}
	public synchronized int get() {
		int res;
		while (count == 0)
			try { wait();
			} catch (InterruptedException e) { }
		res = contents[tail];
		tail = (tail + 1) % size; // 환형 큐
		count--;
		notifyAll();
		return res;
	}
	public synchronized void put(int value) {
		while ( count == size )
			try { wait();
			} catch (InterruptedException e) { }
		contents[head] = value;
	head = (head + 1) % size; // 환형 큐
	count++;
	notifyAll();
	}
}

11.7

class Producer extends Thread {
	private CircularQueue boundedBuffer;
	private int number;
	public Producer(CircularQueue c, int number) {
		super("Producer #" + number);
		boundedBuffer = c;
		this.number = number;
	}
	public void run() {
		for (int i = 0; i < 10; i++) {
			boundedBuffer.put(i);
			System.out.println(getName() + " put: " + i);
			try {
				sleep((int)(Math.random() * 100));
			} catch (InterruptedException e) { }
		}
	}
}

11.8

class Consumer extends Thread {
	private CircularQueue boundedBuffer;
	private int number;
	public Consumer(CircularQueue c, int number) {
		super("Consumer #" + number);
		boundedBuffer = c;
		this.number = number;
	}
	public void run() {
		int value = 0;
		for (int i = 0; i < 10; i++) {
			value = boundedBuffer.get();
			System.out.println(getName() + " got: " + value);
		}
	}
}

11.9

public class ProducerConsumerTest {
	public static void main(String[] args) {
		CircularQueue c = new CircularQueue(1); // 버퍼의 크기는 1로 한정
		Producer p1 = new Producer(c, 1);
		Consumer c1 = new Consumer(c, 1);
		p1.start();
		c1.start();
	}
}

11.10

public class ThreadGrpTree {
	public static void main(String[] args) {
		ThreadGroup g = Thread.currentThread().getThreadGroup();
		ThreadGroup root = g.getParent();
		ThreadGroup g1 = new ThreadGroup("g1");
		Thread t = new Thread(g1, "x");
		root.list();
	}
}

11.11

public class ThrGrpMethodTest extends Thread {
	ThrGrpMethodTest(ThreadGroup g, String name) {
		super(g, name);
	}
	public void run() {
		try {
			sleep(100);
			System.out.println("Active Thread is " + getName());
		} catch (InterruptedException e) {
		}
	}
	public static void main(String[] args) {
		ThreadGroup g1 = new ThreadGroup("g1"),
					g2 = new ThreadGroup(g1, "g2");
		g1.setMaxPriority(Thread.MAX_PRIORITY - 2);
		Thread t1 = new ThrGrpMethodTest(g1, "x"),
			   t2 = new ThrGrpMethodTest(g2, "y"),
			   t3 = new ThrGrpMethodTest(g2, "z");
		t1.setPriority(Thread.MAX_PRIORITY);
		t1.start();	t2.start(); t3.start();
		g1.list();
		
		Thread[] thrAll = new Thread[g1.activeCount()]; // 3개의 배열 생성
		g1.enumerate(thrAll);
		
		for(Thread t : thrAll)
			System.out.println(t.toString());
		
	}
}

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연습문제 11.6

package quiz_2;

class SimpleThread extends Thread{
	public SimpleThread(String name) {
		super(name);
	}
	public void run() {
		for(int i=0; i<3; i++) {
			System.out.println(i + " " + getName());
			try {
				sleep ((int)(Math.random ()*1000));
			}catch(InterruptedException e) {}
		}
		System.out.println("DONE! " + getName());
	}
}

public class Quiz_11_6 {
	public static void main(String[] args) {
		new SimpleThread("Seoul").start();
		new SimpleThread("Pusan").start();
	}
}

연습문제 11.7

package quiz_2;

class MyThread extends Thread{
	MyThread(String name){
		super(name);
	}
	
	public void run() {
		while(true) {
			System.out.println(getName() + " is now running");
			try {
				sleep (30);
			} catch(InterruptedException e) {
				System.out.println("Interrupted is received");
				break;
			}
		}  //end while
	}  //end run()
}  //end MyThread

public class Quiz_11_7 {
	public static void main(String[] args) {
		MyThread t1 = new MyThread("ThreadOne");
		MyThread t2 = new MyThread("ThreadTwo");
		t1.start();
		t2.start();
		try {
			Thread.sleep (100);
		}catch(Exception e) {}
		
		t1.interrupt();
		t2.interrupt();
	}
}