How to make this simple Groovy code concurrent/multi-threaded?

Question

I have a very simple groovy script that works through a JSON and performs some actions. Since there are no dependencies between the JSON records and actions I was hoping I could speed up the execution a bit. Given this code…

def recordJSON = new JsonSlurper().parseText(myFile.text)

recordJSON.each{ 
    do stuff here
}

Is there a way to thread the execution or perform them in parallel? I've done a bit of reading on the topic, but I'm a casual coder and they seem to be a bit over my head.

Answer 1

The easiest is to use GPars which is part of groovy:

import static groovyx.gpars.GParsPool.withPool

withPool {
    recordJSON.eachParallel {
        do stuff here
    }
}

Answer 2

If you are more comfortable with Java thread constructions, this might be of interest (Groovy offers all of the usual Java goodies, with less boilerplate):

import java.util.concurrent.*
import groovy.json.*

class MyTask implements Runnable {
    File file

    void run() {
        def recordJSON = new JsonSlurper().parseText(file.text)
        println "do stuff here ${file.name}"
    }
}

// ------ main
def pool = Executors.newCachedThreadPool()

(1..6).each {
    def f = new File("f${it}.json")
    pool.submit(new MyTask(file: f))  
}