public void WeakCompareAndSet()
{
AtomicReference <T> ai = new AtomicReference <T>(one);
while (!ai.WeakCompareAndSet(one, two))
{
}
while (!ai.WeakCompareAndSet(two, m4))
{
}
Assert.AreEqual(m4, ai.Value);
while (!ai.WeakCompareAndSet(m4, seven))
{
}
Assert.AreEqual(seven, ai.Value);
Assert.IsFalse(ai.WeakCompareAndSet(m4, seven));
}
/// <summary>
/// Atomically sets the value of both the reference and stamp
/// to the given update values if the
/// current reference is equals to the expected reference
/// and the current stamp is equal to the expected stamp. Any given
/// invocation of this operation may fail (return
/// false) spuriously, but repeated invocation when
/// the current value holds the expected value and no other thread
/// is also attempting to set the value will eventually succeed.
/// </summary>
/// <param name="expectedReference">
/// The expected value of the reference
/// </param>
/// <param name="newReference">
/// The new value for the reference
/// </param>
/// <param name="expectedStamp">
/// The expected value of the stamp
/// </param>
/// <param name="newStamp">
/// The new value for the stamp
/// </param>
/// <returns>
/// True if successful
/// </returns>
public virtual bool WeakCompareAndSet(T expectedReference, T newReference, int expectedStamp, int newStamp)
{
ReferenceIntegerPair <T> current = Pair;
return(expectedReference.Equals(current.Reference) && expectedStamp == current.Integer &&
((newReference.Equals(current.Reference) && newStamp == current.Integer) || _atomicReference.WeakCompareAndSet(current, new ReferenceIntegerPair <T>(newReference, newStamp))));
}
/// <summary>
/// Atomically sets both the value and stamp to the given update values
/// if the current value and the expected value <see cref="AreEqual"/>
/// and the current stamp is equal to the expected stamp. Any given
/// invocation of this operation may fail (return
/// false) spuriously, but repeated invocation when
/// the current value holds the expected value and no other thread
/// is also attempting to set the value will eventually succeed.
/// </summary>
/// <param name="expectedValue">
/// The expected value
/// </param>
/// <param name="newValue">
/// The new value
/// </param>
/// <param name="expectedStamp">
/// The expected value of the stamp
/// </param>
/// <param name="newStamp">
/// The new value for the stamp
/// </param>
/// <returns>
/// True if successful
/// </returns>
public virtual bool WeakCompareAndSet(T expectedValue, T newValue, int expectedStamp, int newStamp)
{
ValueIntegerPair current = Pair;
return(AreEqual(expectedValue, current.Value) && expectedStamp == current.Integer &&
((AreEqual(newValue, current.Value) && newStamp == current.Integer) || _atomicReference.WeakCompareAndSet(current, new ValueIntegerPair(newValue, newStamp))));
}