More details can be found on: http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/ExecutorService.html
An example of using these construction is here:
import java.util.Date;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class ExecutorServiceExample {
final int size = 20000000;
private long[] arr = new long[size];
class Task implements Callable {
private int index, range;
public Task(int index, int range) {
this.index = index;
this.range = range;
}
public Boolean call() throws Exception {
boolean ret = false;
for (int i = index; i < index + range; i++) {
}
return ret;
}
}
public ExecutorServiceExample() {
Random random = new Random(new Date().getTime());
for (int i = 0; i < size; i++) {
arr[i] = random.nextLong();
}
}
public static void main(String[] args) {
ExecutorServiceExample ese = new ExecutorServiceExample();
ese.findSeq(123456789012345678l);
ese.findConcur(123456789012345678l);
}
private boolean check(int i, long val) {
if (arr[i] * val * val == val * val * val) {
System.out.println("Found:" + i);
return true;
}
return false;
}
private void findConcur(long val) {
int range = 100;
long start = new Date().getTime();
ExecutorService service = Executors.newFixedThreadPool(100);
for (int i = 0; i < size / range; i++) {
service.submit(new Task(i * range, range));
}
service.shutdown();
System.out.println("Seq in " + (new Date().getTime() - start));
}
private void findSeq(long val) {
long start = new Date().getTime();
for (int i = 0; i < size; i++) {
check(i, val);
}
System.out.println("Seq in " + (new Date().getTime() - start));
}
}
To run this example you will probably need to add parameter to increase heap size (f.e. -Xmx1300m)
