// Example 115 from page 87

//

class Example115 {

public static void main(String[] args) {

final int size = 100_000, tests = 10_000;

IntArray ia = new IntArray(size);

IntArrayVolatile iav = new IntArrayVolatile(size);

{

System.out.println("Field array not volatile:");

Timer t = new Timer();

for (int i=0; i<tests; i++)

if (!ia.isSorted())

System.out.println("Unexpected!");

System.out.printf("%10.1f us/call%n", t.check()*1E6/tests);

}

{

System.out.println("Field array volatile:");

Timer t = new Timer();

for (int i=0; i<tests; i++)

if (!iav.isSorted())

System.out.println("Unexpected!");

System.out.printf("%10.1f us/call%n", t.check()*1E6/tests);

}

}

// Simple timer, measuring wall-clock (elapsed) time in seconds

private final static class Timer {

private long start;

public Timer() {

start = System.nanoTime();

}

public double check() {

return (System.nanoTime() - start) / 1e9;

}

}

}

class IntArray {

private int[] array;

public IntArray(int length) {

array = new int[length];

for (int i=0; i<length; i++)

array[i] = 2 * i + 1;

}

public boolean isSorted() {

for (int i=1; i<array.length; i++)

if (array[i-1] > array[i])

return false;

return true;

}

}

class IntArrayVolatile {

private volatile int[] array;

public IntArrayVolatile(int length) {

array = new int[length];

for (int i=0; i<length; i++)

array[i] = 2 * i + 1;

}

public boolean isSorted() {

for (int i=1; i<array.length; i++)

if (array[i-1] > array[i])

return false;

return true;

}

}