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AtomicIntegerArrayTest.javaAPI DocAndroid 1.5 API10547Wed May 06 22:41:02 BST 2009tests.api.java.util.concurrent

AtomicIntegerArrayTest

public class AtomicIntegerArrayTest extends JSR166TestCase

Fields Summary
static final int
COUNTDOWN
Constructors Summary
Methods Summary
public static voidmain(java.lang.String[] args)

        junit.textui.TestRunner.run (suite());
public static junit.framework.Testsuite()

        return new TestSuite(AtomicIntegerArrayTest.class);
public voidtestAddAndGet()
addAndGet adds given value to current, and returns current value

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertEquals(3,ai.addAndGet(i,2));
            assertEquals(3,ai.get(i));
            assertEquals(-1,ai.addAndGet(i,-4));
            assertEquals(-1,ai.get(i));
        }
public voidtestCompareAndSet()
compareAndSet succeeds in changing value if equal to expected else fails

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertTrue(ai.compareAndSet(i, 1,2));
            assertTrue(ai.compareAndSet(i, 2,-4));
            assertEquals(-4,ai.get(i));
            assertFalse(ai.compareAndSet(i, -5,7));
            assertFalse((7 == ai.get(i)));
            assertTrue(ai.compareAndSet(i, -4,7));
            assertEquals(7,ai.get(i));
        }
public voidtestCompareAndSetInMultipleThreads()
compareAndSet in one thread enables another waiting for value to succeed

        final AtomicIntegerArray a = new AtomicIntegerArray(1);
        a.set(0, 1);
        Thread t = new Thread(new Runnable() {
                public void run() {
                    while(!a.compareAndSet(0, 2, 3)) Thread.yield();
                }});
        try {
            t.start();
            assertTrue(a.compareAndSet(0, 1, 2));
            t.join(LONG_DELAY_MS);
            assertFalse(t.isAlive());
            assertEquals(a.get(0), 3);
        }
        catch(Exception e) {
            unexpectedException();
        }
public voidtestConstructor()
constructor creates array of given size with all elements zero

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE);
        for (int i = 0; i < SIZE; ++i) 
            assertEquals(0,ai.get(i));
public voidtestConstructor2()
constructor with array is of same size and has all elements

        int[] a = { 17, 3, -42, 99, -7};
        AtomicIntegerArray ai = new AtomicIntegerArray(a);
        assertEquals(a.length, ai.length());
        for (int i = 0; i < a.length; ++i) 
            assertEquals(a[i], ai.get(i));
public voidtestConstructor2NPE()
constructor with null array throws NPE

        try {
            int[] a = null;
            AtomicIntegerArray ai = new AtomicIntegerArray(a);
        } catch (NullPointerException success) {
        } catch (Exception ex) {
            unexpectedException();
        }
public voidtestCountingInMultipleThreads()
Multiple threads using same array of counters successfully update a number of times equal to total count

        try {
            final AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
            for (int i = 0; i < SIZE; ++i) 
                ai.set(i, COUNTDOWN);
            Counter c1 = new Counter(ai);
            Counter c2 = new Counter(ai);
            Thread t1 = new Thread(c1);
            Thread t2 = new Thread(c2);
            t1.start();
            t2.start();
            t1.join();
            t2.join();
            assertEquals(c1.counts+c2.counts, SIZE * COUNTDOWN);
        }
        catch(InterruptedException ie) {
            unexpectedException();
        }
public voidtestDecrementAndGet()
decrementAndGet decrements and returns current value

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertEquals(0,ai.decrementAndGet(i));
            assertEquals(-1,ai.decrementAndGet(i));
            assertEquals(-2,ai.decrementAndGet(i));
            assertEquals(-2,ai.get(i));
        }
public voidtestGetAndAdd()
getAndAdd returns previous value and adds given value

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertEquals(1,ai.getAndAdd(i,2));
            assertEquals(3,ai.get(i));
            assertEquals(3,ai.getAndAdd(i,-4));
            assertEquals(-1,ai.get(i));
        }
public voidtestGetAndDecrement()
getAndDecrement returns previous value and decrements

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertEquals(1,ai.getAndDecrement(i));
            assertEquals(0,ai.getAndDecrement(i));
            assertEquals(-1,ai.getAndDecrement(i));
        }
public voidtestGetAndIncrement()
getAndIncrement returns previous value and increments

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertEquals(1,ai.getAndIncrement(i));
            assertEquals(2,ai.get(i));
            ai.set(i,-2);
            assertEquals(-2,ai.getAndIncrement(i));
            assertEquals(-1,ai.getAndIncrement(i));
            assertEquals(0,ai.getAndIncrement(i));
            assertEquals(1,ai.get(i));
        }
public voidtestGetAndSet()
getAndSet returns previous value and sets to given value at given index

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertEquals(1,ai.getAndSet(i,0));
            assertEquals(0,ai.getAndSet(i,-10));
            assertEquals(-10,ai.getAndSet(i,1));
        }
public voidtestGetSet()
get returns the last value set at index

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertEquals(1,ai.get(i));
            ai.set(i, 2);
            assertEquals(2,ai.get(i));
            ai.set(i, -3);
            assertEquals(-3,ai.get(i));
        }
public voidtestIncrementAndGet()
incrementAndGet increments and returns current value

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            assertEquals(2,ai.incrementAndGet(i));
            assertEquals(2,ai.get(i));
            ai.set(i, -2);
            assertEquals(-1,ai.incrementAndGet(i));
            assertEquals(0,ai.incrementAndGet(i));
            assertEquals(1,ai.incrementAndGet(i));
            assertEquals(1,ai.get(i));
        }
public voidtestIndexing()
get and set for out of bound indices throw IndexOutOfBoundsException

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE);
        try {
            ai.get(SIZE);
        } catch(IndexOutOfBoundsException success){
        }
        try {
            ai.get(-1);
        } catch(IndexOutOfBoundsException success){
        }
        try {
            ai.set(SIZE, 0);
        } catch(IndexOutOfBoundsException success){
        }
        try {
            ai.set(-1, 0);
        } catch(IndexOutOfBoundsException success){
        }
public voidtestSerialization()
a deserialized serialized array holds same values

        AtomicIntegerArray l = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) 
            l.set(i, -i);

        try {
            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
            out.writeObject(l);
            out.close();

            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
            AtomicIntegerArray r = (AtomicIntegerArray) in.readObject();
            for (int i = 0; i < SIZE; ++i) {
                assertEquals(l.get(i), r.get(i));
            }
        } catch(Exception e){
            e.printStackTrace();
            unexpectedException();
        }
public voidtestToString()
toString returns current value.

        int[] a = { 17, 3, -42, 99, -7};
        AtomicIntegerArray ai = new AtomicIntegerArray(a);
        assertEquals(Arrays.toString(a), ai.toString());
public voidtestWeakCompareAndSet()
repeated weakCompareAndSet succeeds in changing value when equal to expected

        AtomicIntegerArray ai = new AtomicIntegerArray(SIZE); 
        for (int i = 0; i < SIZE; ++i) {
            ai.set(i, 1);
            while(!ai.weakCompareAndSet(i, 1,2));
            while(!ai.weakCompareAndSet(i, 2,-4));
            assertEquals(-4,ai.get(i));
            while(!ai.weakCompareAndSet(i, -4,7));
            assertEquals(7,ai.get(i));
        }