Threaded Java - Java - page 894

* Use RecursiveTask<T> where, as in this example, each call returns
* a value that represents the computation for its subset of the overall task.
* @author Ian Darwin
*/
public public class class RecursiveTaskDemo RecursiveTaskDemo extends extends RecursiveTask < Long > {

private private static static final final long long serialVersionUID = 3742774374013520116L ;

static static final final int int N = 10000000 ;

final final static static int int THRESHOLD = 500 ;

int int [] data ;

int

int start , length ;

public public static static void void main ( String [] args ) {

int int [] source = new new int int [ N ];

loadData ( source );
RecursiveTaskDemo fb = new

new RecursiveTaskDemo ( source , 0 , source . length );

ForkJoinPool pool = new new ForkJoinPool ();

long long before = System . currentTimeMillis ();

pool . invoke ( fb );
long

long after = System . currentTimeMillis ();
long long total = fb . getRawResult ();

long long avg = total / N ;

System . out . println ( "Average: " + avg );
System . out . println ( "Time :" + ( after - before ) + " mSec" );

}

static static void void loadData ( int int [] data ) {

Random r = new new Random ();

for for ( int int i = 0 ; i < data . length ; i ++) {

data [ i ] = r . nextInt ();

}

}

public public RecursiveTaskDemo ( int int [] data , int int start , int int length ) {

this this . data = data ;

this this . start = start ;

this

this . length = length ;

}

@Override
protected

protected Long compute () {
iif ( length <= THRESHOLD ) { // Compute Directly
long long total = 0 ;

for

for ( int int i = start ; i < start + length ; i ++) {