中间件!
public class MakerThread extends Thread { private final Random random; private final Table table; private static int id = 0; // 蛋糕的流水号(所有厨师共通) public MakerThread(String name, Table table, long seed) { super(name); this.table = table; this.random = new Random(seed); } public void run() { try { while (true) { Thread.sleep(random.nextInt(1000)); String cake = "[ Cake No." + nextId() + " by " + getName() + " ]"; table.put(cake); } } catch (InterruptedException e) { } } private static synchronized int nextId() { return id++; } }
public class EaterThread extends Thread { private final Random random; private final Table table; public EaterThread(String name, Table table, long seed) { super(name); this.table = table; this.random = new Random(seed); } public void run() { try { while (true) { String cake = table.take(); Thread.sleep(random.nextInt(1000)); } } catch (InterruptedException e) { } } }
public class Table { private final String[] buffer; private int tail; //下一个放put的地方 private int head; //下一个放的take地方 よ private int count; // buffer内的蛋糕数 public Table(int count) { this.buffer = new String[count]; this.head = 0; this.tail = 0; this.count = 0; } // 放置蛋糕 public synchronized void put(String cake) throws InterruptedException { System.out.println(Thread.currentThread().getName() + " puts " + cake); while (count >= buffer.length) { wait(); } buffer[tail] = cake; tail = (tail + 1) % buffer.length; count++; notifyAll(); } // 取得蛋糕 public synchronized String take() throws InterruptedException { while (count <= 0) { wait(); } String cake = buffer[head]; head = (head + 1) % buffer.length; count--; notifyAll(); System.out.println(Thread.currentThread().getName() + " takes " + cake); return cake; } }
public class Main { public static void main(String[] args) { Table table = new Table(3); // 建立可以放置3個蛋糕的桌子 new MakerThread("MakerThread-1", table, 31415).start(); new MakerThread("MakerThread-2", table, 92653).start(); new MakerThread("MakerThread-3", table, 58979).start(); new EaterThread("EaterThread-1", table, 32384).start(); new EaterThread("EaterThread-2", table, 62643).start(); new EaterThread("EaterThread-3", table, 38327).start(); } }