Java in a Nutshell, 5th Edition [Electronic resources] نسخه متنی

This threadsafe class holds a mutable reference
to an object of type V and also holds a
mutable boolean value or
"mark." It defines atomic
operations and volatile access semantics for the reference and the
mark. The set( ) method unconditionally sets the
reference and mark value. The get( ) method
queries both, returning the reference as its return value, and
storing the current value of the mark in element 0 of the specified
boolean array. The reference and mark can also be
queried individually (and nonatomically) with getreference(
) and isMarked( ).

The atomic compareAndSet( ) and
weakCompareAndSet( ) methods take expected and new
values for both the reference and the mark, and neither is set to its
new value unless both match their expected values.
attemptMark( ) atomically sets the value of the
mark but only if the reference is equal to the expected value. Like
weakCompareAndSet( ), this method may fail
spuriously, even if the reference does equal the expected value.
Repeated invocation eventually succeeds, however, as long as the
expected value is correct, and other threads are not continuously
changing the reference value.

public class

AtomicMarkableReference<V> {
// Public Constructors
public

AtomicMarkableReference (V

initialRef , boolean

initialMark );
// Public Instance Methods
public boolean

attemptMark (V

expectedReference , boolean

newMark );
public boolean

compareAndSet (V

expectedReference , V

newReference ,
boolean

expectedMark , boolean

newMark );
public V

get (boolean[ ]

markHolder );
public V

getReference ( );
public boolean

isMarked ( );
public void

set (V

newReference , boolean

newMark );
public boolean

weakCompareAndSet (V

expectedReference , V

newReference ,
boolean

expectedMark , boolean

newMark );
}