Alterメソッドでsubmit処理を変更してみる

executor_alter.groovy

import java.util.concurrent.ExecutorService
import java.util.concurrent.BlockingQueue
import java.util.concurrent.LinkedBlockingQueue
import java.util.concurrent.Executors
import java.util.concurrent.Callable

ExecutorService.metaClass.define {
    alter = {
      this.submit = {Closure closure ->
        return delegate.submit (new Callable(){
            @Override
            Object call() {
                return closure()
            }
        })
      }
      this
    }
}

def executor = Executors.newSingleThreadExecutor().alter()
def future = executor.submit {
    def list = []
    (1..10).each {
        println "in Callable ${it}"
        list << it
    }
    return list
}
println "result get -> ${future.get()}"