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

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

  • Method Summary

    Modifier and Type
    Method
    Description
    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 declared in class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
    boolean
    equals(Object o)
    Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    May cause performance issues, deadlocks and hangs.
    final Class<? extends Object>
    getClass()
    Answers the unique instance of java.lang.Class which represents the class of the receiver.
    int
    hashCode()
    Answers an integer hash code for the receiver.
    final void
    notify()
    Causes one thread which is waiting on the receiver to be made ready to run.
    final void
    notifyAll()
    Causes all threads which are waiting on the receiver to be made ready to run.
    String
    toString()
    Answers a string containing a concise, human-readable description of the receiver.
    final void
    wait()
    Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
    final void
    wait(long time)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
    final void
    wait(long time, int frac)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

  • Constructor Details

    • 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 Details

    • 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. This operation 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