スレッド反発

ここでは、教材を参照して書いたリードスレッドとライトスレッドを学習します.2つのスレッドには反発関係があります.

import java.util.LinkedList;

public class WriteRead {
	public static void main(String args[]) {
		WriteThread writeThread = new WriteThread();
		for (int i = 0; i < 20; i++) {
			writeThread.addElement("data " + i);
		}
		ReadThread readThread = new ReadThread(writeThread);
		writeThread.start();
		readThread.start();
	}
}

class WriteThread extends Thread {
	boolean empty = true;
	int i = 0;
	int count = 0;
	LinkedList<String> list = new LinkedList<String>();

	public void addElement(String str) {
		list.add(str);
		count++;
	}

	public void run() {
		while (true) {
			write();
		}
	}

	synchronized void write() {
		while (!empty || i >= count) {
			try {
				wait();
			} catch (Exception e) {
			}
		}
		toSleep();
		++i;
		System.out.println("write:" + list.get(i - 1) + ", i = " + i
				+ ", count = " + count);
		empty = false;
		notifyAll();
	}

	void toSleep() {
		try {
			Thread.sleep(200);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}

	synchronized void consume() {
		while (empty) {
			try {
				wait();
			} catch (Exception e) {
			}
		}
		toSleep();
		System.out.println("read:" + list.get(i - 1) + ", i = " + i
				+ ", count = " + count);
		empty = true;
		notifyAll();
	}
}

class ReadThread extends Thread {
	WriteThread writeThread;

	ReadThread(WriteThread writeThread) {
		this.writeThread = writeThread;
	}

	public void run() {
		while (true) {
			writeThread.consume();
		}
	}
}

 
実行結果は次のとおりです.
 
write:data 0, i = 1, count = 20read:data 0, i = 1, count = 20write:data 1, i = 2, count = 20read:data 1, i = 2, count = 20write:data 2, i = 3, count = 20read:data 2, i = 3, count = 20write:data 3, i = 4, count = 20read:data 3, i = 4, count = 20write:data 4, i = 5, count = 20read:data 4, i = 5, count = 20write:data 5, i = 6, count = 20read:data 5, i = 6, count = 20write:data 6, i = 7, count = 20read:data 6, i = 7, count = 20write:data 7, i = 8, count = 20read:data 7, i = 8, count = 20write:data 8, i = 9, count = 20read:data 8, i = 9, count = 20write:data 9, i = 10, count = 20read:data 9, i = 10, count = 20write:data 10, i = 11, count = 20read:data 10, i = 11, count = 20write:data 11, i = 12, count = 20read:data 11, i = 12, count = 20write:data 12, i = 13, count = 20read:data 12, i = 13, count = 20write:data 13, i = 14, count = 20read:data 13, i = 14, count = 20write:data 14, i = 15, count = 20read:data 14, i = 15, count = 20write:data 15, i = 16, count = 20read:data 15, i = 16, count = 20write:data 16, i = 17, count = 20read:data 16, i = 17, count = 20write:data 17, i = 18, count = 20read:data 17, i = 18, count = 20write:data 18, i = 19, count = 20read:data 18, i = 19, count = 20write:data 19, i = 20, count = 20read:data 19, i = 20, count = 20