A case study of lock+condition relative to Wait+notify

Description of the problem

Starting 3 threads prints an incremented number, thread 1 prints 1,2,3,4,5 first, then thread 2 prints 6,7,8,9,10, and then thread 3 prints 11,12,13,14,15. Then the thread 1 prints 16,17,18,19,20 .... And so on, until you print to 45.

Wait+notify implementation:

Package Com.tonyluis;public class Numberprintdemo {static int n = 1;static int state = 0;public static void Main (string[] args) {new Thread (new MyThread (0)). Start (); New Thread (New MyThread (1)). Start (); New Thread (New MyThread (2)). Start ();} Class MyThread implements runnable{private int state; MyThread () {this (0);} MyThread (int state) {this.state=state;} public void Run () {String threadname=thread.currentthread (). GetName (), for (int i = 0; i < 3; i++) {synchronized (Mythre Ad.class) {while (state = numberprintdemo.state) try {MyThread.class.wait ();} catch (Interruptedexception e) { E.printstacktrace ();} for (int j = 0; J < 5; j + +) System.out.println (threadname+ ":" + numberprintdemo.n++); System.out.println (); numberprintdemo.state++; numberprintdemo.state%=3; MyThread.class.notifyAll ();}}}

Lock+condition implementation:

Package Com.tonyluis;import java.util.concurrent.locks.*;p ublic class Numberprint {static int state = 0;static int n = 1;s  Tatic Lock lock = new Reentrantlock (), Static Condition condition[]=new condition[3];p ublic static void Main (string[] args) {for (int i=0;i<condition.length;i++) condition[i]=lock.newcondition (); New Thread (New MyThread (0)). Start (); new Thread (new MyThread (1)). Start (); New Thread (New MyThread (2)). Start ();}} Class MyThread implements runnable{private int state; MyThread () {this (0);} MyThread (int state) {this.state=state;} public void Run () {String threadname=thread.currentthread (). GetName (), for (int i = 0; i < 5; i++) {try {Numberprint.loc K.lock (); while (state = numberprint.state) try {numberprint.condition[state].await ();} catch (Interruptedexception e) {E.printstacktrace ();} for (int j = 0; J < 5; j + +) System.out.println (threadname+ ":" + numberprint.n++); System.out.println (); numberprint.state++; Numberprint.state%=numberprint.condition.length; Numberprint.condition[numbErprint.state].signal ();} finally {NumberPrint.lock.unlock ();}}}}

With the implementation of Wait+notify, after thread 0 enters the Notifyall () method, threads 1 and 2 are awakened, thread 1 and thread 2, and thread 0 will compete, although eventually the thread 1 gets the locks, the process may be more tortuous.

Using the Lock+condition implementation method, thread 0 only wakes up thread 1, so that only thread 1 and thread 0 compete, more precisely, especially if the concurrency is relatively large.

A case study of lock+condition relative to Wait+notify