package java8.streams;

import java.util.Arrays;
import java.util.concurrent.ForkJoinPool;
/*
 * This will demonstrate how parallelStream internally create pool for parallel stream execution. By defailt pool size is 3.
 * We can defined it by setting below JVM properties
 * -Djava.util.concurrent.ForkJoinPool.common.parallelism=5
 */
public class ParallelStreamOperation {

	public static void main(String[] args) {

		//parallelStream internally create below pool
		ForkJoinPool commonPool = ForkJoinPool.commonPool();
		System.out.println(commonPool.getParallelism());    // 3
		System.out.println(commonPool.getQueuedTaskCount());
		System.out.println(commonPool.getCommonPoolParallelism());
		System.out.println(commonPool.getActiveThreadCount());

		//Example 1
		Arrays.asList("xy", "xz", "ab", "ac", "cb")
	    .parallelStream()
	    .filter(s -> {
	        System.out.format("filter: %s [%s]\n",
	            s, Thread.currentThread().getName());
	        return true;
	    })
	    .map(s -> {
	        System.out.format("map: %s [%s]\n",
	            s, Thread.currentThread().getName());
	        return s.toUpperCase();
	    })
	    .forEach(s -> System.out.format("forEach: %s [%s]\n",
	        s, Thread.currentThread().getName()));

		//added shorting
		Arrays.asList("xy", "xz", "ab", "ac", "cb")
	    .parallelStream()
	    .filter(s -> {
	        System.out.format("filter: %s [%s]\n",
	            s, Thread.currentThread().getName());
	        return true;
	    })
	    .map(s -> {
	        System.out.format("map: %s [%s]\n",
	            s, Thread.currentThread().getName());
	        return s.toUpperCase();
	    })
	    .sorted((s1, s2) -> {
	    	System.out.format("sort: %s <> %s [%s]\n", s1, s2, Thread.currentThread().getName());
	    	 return s1.compareTo(s2);
	    })
	    .forEach(s -> System.out.format("forEach: %s [%s]\n",
	        s, Thread.currentThread().getName()));
	}

}