Versions Compared


  • This line was added.
  • This line was removed.
  • Formatting was changed.
Comment: Migrated to Confluence 5.3


Note: GPars comes bundled with Groovy 1.8.x distributions so this step is only requited if you are using an older version of Groovyshould normally be not required.

We'll use Groovy's Grape functionaity to grab all the requited dependencies for us. You may check ot the GPars Integration page for alternative ways to integrate GPars with your project.


Code Block
@Grab(group='org.codehaus.gpars', module='gpars', version='')

Step 3 - Experiment with parallel collection processing


Code Block
@Grab(group='org.codehaus.gpars', module='gpars', version='')
import groovyx.gpars.GParsPool

GParsPool.withPool {
    def animals = ['dog', 'ant', 'cat', 'whale']
    println(animals.anyParallel {it ==~ /ant/} ? 'Found an ant' : 'No ants found')
    println(animals.everyParallel {it.contains('a')} ? 'All animals contain a' : 'Some animals can live without an a')


To find out more about parallel collection processing, visit the Parallel Colections Collections section of the User Guide.

Step 4 - Actors

Now we could try to build an actor and send it a couple of messages to see it acting.

Code Block
@Grab(group='org.codehaus.gpars', module='gpars', version='')
import org.codehaus.groovy.runtime.NullObject

final class MyActor extends DynamicDispatchActor {
    private int counter = 0

    void onMessage(String message) {
        counter += message.size()
        println 'Received string'

    void onMessage(Integer message) {
        counter += message
        println 'Received integer'

    void onMessage(Object message) {
        counter += 1
        println 'Received object'

    void onMessage(NullObject message) {
        println 'Received a null object. Sending back the current counter value.'
        reply counter

final def actor = new MyActor()
actor.send 1
actor << 2
actor 20
actor 'Hello'
println actor.sendAndWait(null)

Our actor maintains a private counter and accepts different types of messages, which result in updating the counter. Sending a null value will make the actor reply the current counter value back to us. Notice the send() method name is optional and can be replaced by the << operator or ommited altogether.

The Actor section of the User Guide will help you dive deeper into GPars actors.


Now when you have GPars runing on your system, the time is up you opened up the User Guide, browsed the GPars code examples and continued experimenting. You may also consider checking out the Java Fast Track, in case you need to use GPars high-level concurency abstractions from Java code. Good luck!