Solved

ManualResetEvent alternative in Java

Posted on 2006-11-29
1
1,853 Views
Last Modified: 2012-06-22
I have a Java application that communicates with a scales through TCP.
It uses two threads:

class ScalesCommunication {
   // called by thread 1
   void readLoop() {
      // connects to the scales
      // reads data sent by it
   }

   // called by thread 2
   String sendCommand(String command) {
       // sends a command and waits for its answer
   }
}

I would like to solve some synchronization problems
- sendCommand should wait until connection is built up
- after a command has been sent, the answer should be waited for

One thread is not enough, because I should deal with asynchronous messages such as keypresses. The interface is given, I can't separate building up the connection from reading incoming data.
In .NET this kind of synchronization can easily be solved by means of ManualResetEvent synchronization objects. Is there any alternative in Java?
0
Comment
Question by:pallosp
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 18

Accepted Solution

by:
Ravi Singh earned 250 total points
ID: 18041985
Hi, you can achieve synchronization using the java.util.concurrent.Semaphore class (use 0 permit).

http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/Semaphore.html

Example below shows you how to solve the first sync problem, the other will be similar:

import java.util.concurrent.Semaphore;

class ScalesCommunication {

   private static Semaphore sem = new Semaphore(0);

   // called by thread 1
   void readLoop() {
      //...

      //after connection established, release semaphore (value incremented by 1)
      sem.release();
   }

   // called by thread 2
   String sendCommand(String command) {

       sem.acquire(); // thread waits here if sem value == 0

       // at this point connection is established
       //...
   }
}
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction Java can be integrated with native programs using an interface called JNI(Java Native Interface). Native programs are programs which can directly run on the processor. JNI is simply a naming and calling convention so that the JVM (Java…
In this post we will learn how to make Android Gesture Tutorial and give different functionality whenever a user Touch or Scroll android screen.
Viewers learn about the “for” loop and how it works in Java. By comparing it to the while loop learned before, viewers can make the transition easily. You will learn about the formatting of the for loop as we write a program that prints even numbers…
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …

615 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question