Java The Complete Reference, Seventh Edition

806 Part II: The Java Library

return sum;

}

}

class Hypot implements Callable<Double> {

double side1, side2;

Hypot(double s1, double s2) {

side1 = s1;

side2 = s2;

}

public Double call() {

return Math.sqrt((side1*side1) + (side2*side2));

}

}

class Factorial implements Callable<Integer> {

int stop;

Factorial(int v) { stop = v; }

public Integer call() {

int fact = 1;

for(int i = 2; i <= stop; i++) {

fact *= i;

}

return fact;

}

}

The output is shown here:

Starting

55

5.0

120

Done

The TimeUnit Enumeration

The concurrent API defines several methods that take an argument of typeTimeUnit,

whichindicates a time-out period.TimeUnitis an enumeration that is used to specify the

granularity(or resolution) of the timing.TimeUnitis defined withinjava.util.concurrent.

It can be one of the following values:

DAYS

HOURS

MINUTES

SECONDS

MICROSECONDS

MILLISECONDS

NANOSECONDS