lock類似於synchronized，拓展讀寫鎖，讀鎖之間不互斥，寫鎖之間互斥

Condition類似於執行緒技術中的wait和notify

使用lock和Condition能實現更多的特性

設計三個執行緒，第一個執行緒迴圈1次，第二個執行緒迴圈2次，第三個執行緒迴圈5次

                  接著第一個執行緒迴圈1次，第二個執行緒迴圈2次，第三個執行緒迴圈5次

                 如此迴圈50次

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class ConditionCommunication {

	public static void main(String[] args) {
		final Business business = new Business();

		new Thread(new Runnable() {
			public void run() {
				for (int i = 1; i <= 50; i++) {
					business.sub2(i);
				}
			}
		}).start();
		
		new Thread(new Runnable() {
			public void run() {
				for (int i = 1; i <= 50; i++) {
					business.sub3(i);
				}
			}
		}).start();

		for (int i = 1; i <= 50; i++) {
			business.main(i);
		}

	}

	static class Business {
		Lock lock = new ReentrantLock();
		Condition condition1 = lock.newCondition();
		Condition condition2 = lock.newCondition();
		Condition condition3 = lock.newCondition();
		private int flag = 1;

		public void sub2(int i) {
			lock.lock();
			try {
				while (flag!=2) {
					try {
						condition2.await();
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
				for (int j = 1; j <= 2; j++) {
					System.out.println("sub2第" + j + "次迴圈,總迴圈：" + i);
				}
				flag = 3;
				condition3.signal();
			} finally {
				lock.unlock();
			}
		}

		public void sub3(int i) {
			lock.lock();
			try {
				while (flag!=3) {
					try {
						condition3.await();
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
				for (int j = 1; j <= 5; j++) {
					System.out.println("sub3第" + j + "次迴圈,總迴圈：" + i);
				}
				flag = 1;
				condition1.signal();
			} finally {
				lock.unlock();
			}
		}
		
		public void main(int i) {
			lock.lock();
			try {
				while (flag!=1) {
					try {
						condition1.await();
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
				for (int j = 1; j <= 1; j++) {
					System.out.println("sub1第" + j + "次迴圈,總迴圈：" + i);
				}
				flag = 2;
				condition2.signal();
			} finally {
				lock.unlock();
			}
		}
		
	}
}