Unaligned memory concurrent access atomicity test

gistfile1.java

public class DirectByteBufferUnalignedInLineAtomicityTests {

    public abstract static class ByteBufferTest implements
            Actor1_Effector1_Test<ByteBuffer, long[]> {
        @Override
        public ByteBuffer newState() {
            return allocateNaughtyBuffer(getSize());
        }

        abstract int getSize();

        @Override
        public long[] newResult() {
            return new long[1];
        }
    }

    public static class LongTest extends ByteBufferTest {
        int getSize() {
            return 8;
        }

        @Override
        public void effector1(ByteBuffer b) {
            b.putLong(0, -1L);
        }

        @Override
        public void actor1(ByteBuffer b, long[] r) {
            r[0] = b.getLong(0);
        }
    }

    private static final Random RANDOM = new Random();

    public static ByteBuffer allocateNaughtyBuffer(int size) {
        ByteBuffer buffy = allocateAlignedByteBuffer(CACHE_LINE_SIZE, CACHE_LINE_SIZE);
        // new position is always unaligned for a type of size
        int newPosition = (RANDOM.nextInt(CACHE_LINE_SIZE / size - 2)) * size
                + 1 + ((size > 2) ? RANDOM.nextInt(size - 2) : 0);
        buffy.position(newPosition);
        return buffy.slice().order(ByteOrder.nativeOrder());
    }
}