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## java.util.concurrent.atomic
Class AtomicMarkableReference<V>

    java.lang.Object
      java.util.concurrent.atomic.AtomicMarkableReference<V>

Type Parameters:
  `V` - The type of object referred to by this reference

    public class AtomicMarkableReference<V>

extends Object

An `AtomicMarkableReference` maintains an object reference along with a mark bit, that can be updated atomically.

Implementation note. This implementation maintains markable references by creating internal objects representing "boxed" [reference, boolean] pairs.

Since:
  1.5

Constructor Summary
`AtomicMarkableReference(V initialRef, boolean initialMark)` Creates a new `AtomicMarkableReference` with the given initial values.

Method Summary
`boolean` | `attemptMark(V expectedReference, boolean newMark)` Atomically sets the value of the mark to the given update value if the current reference is `==` to the expected reference.
`boolean` | `compareAndSet(V expectedReference, V newReference, boolean expectedMark, boolean newMark)` Atomically sets the value of both the reference and mark to the given update values if the current reference is `==` to the expected reference and the current mark is equal to the expected mark.
`V` | `get(boolean[] markHolder)` Returns the current values of both the reference and the mark.
`V` | `getReference()` Returns the current value of the reference.
`boolean` | `isMarked()` Returns the current value of the mark.
`void` | `set(V newReference, boolean newMark)` Unconditionally sets the value of both the reference and mark.
`boolean` | `weakCompareAndSet(V expectedReference, V newReference, boolean expectedMark, boolean newMark)` Atomically sets the value of both the reference and mark to the given update values if the current reference is `==` to the expected reference and the current mark is equal to the expected mark.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### AtomicMarkableReference

    public AtomicMarkableReference(V initialRef,
                                   boolean initialMark)

  Creates a new `AtomicMarkableReference` with the given initial values.

  Parameters:
    `initialRef` - the initial reference
    `initialMark` - the initial mark

Method Detail

### getReference

    public V getReference()

  Returns the current value of the reference.

  Returns:
    the current value of the reference

### isMarked

    public boolean isMarked()

  Returns the current value of the mark.

  Returns:
    the current value of the mark

### get

    public V get(boolean[] markHolder)

  Returns the current values of both the reference and the mark. Typical usage is `boolean[1] holder; ref = v.get(holder);` .

  Parameters:
    `markHolder` - an array of size of at least one. On return, `markholder[0]` will hold the value of the mark.
  Returns:
    the current value of the reference

### weakCompareAndSet

    public boolean weakCompareAndSet(V expectedReference,
                                     V newReference,
                                     boolean expectedMark,
                                     boolean newMark)

  Atomically sets the value of both the reference and mark to the given update values if the current reference is `==` to the expected reference and the current mark is equal to the expected mark.

  May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to `compareAndSet`.

  Parameters:
    `expectedReference` - the expected value of the reference
    `newReference` - the new value for the reference
    `expectedMark` - the expected value of the mark
    `newMark` - the new value for the mark
  Returns:
    true if successful

### compareAndSet

    public boolean compareAndSet(V expectedReference,
                                 V newReference,
                                 boolean expectedMark,
                                 boolean newMark)

  Atomically sets the value of both the reference and mark to the given update values if the current reference is `==` to the expected reference and the current mark is equal to the expected mark.

  Parameters:
    `expectedReference` - the expected value of the reference
    `newReference` - the new value for the reference
    `expectedMark` - the expected value of the mark
    `newMark` - the new value for the mark
  Returns:
    true if successful

### set

    public void set(V newReference,
                    boolean newMark)

  Unconditionally sets the value of both the reference and mark.

  Parameters:
    `newReference` - the new value for the reference
    `newMark` - the new value for the mark

### attemptMark

    public boolean attemptMark(V expectedReference,
                               boolean newMark)

  Atomically sets the value of the mark to the given update value if the current reference is `==` to the expected reference. 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.

  Parameters:
    `expectedReference` - the expected value of the reference
    `newMark` - the new value for the mark
  Returns:
    true if successful

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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