Module java.base
Package 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

    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 java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • 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