AtomicMarkableReference (Java SE 9 & JDK 9 ) (original) (raw)

• java.lang.Object

• • java.util.concurrent.atomic.AtomicMarkableReference

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

public class AtomicMarkableReference
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

  All Methods Instance Methods Concrete Methods

  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 inherited from class java.lang.[Object](../../../../java/lang/Object.html "class in java.lang")  
     `[clone](../../../../java/lang/Object.html#clone--), [equals](../../../../java/lang/Object.html#equals-java.lang.Object-), [finalize](../../../../java/lang/Object.html#finalize--), [getClass](../../../../java/lang/Object.html#getClass--), [hashCode](../../../../java/lang/Object.html#hashCode--), [notify](../../../../java/lang/Object.html#notify--), [notifyAll](../../../../java/lang/Object.html#notifyAll--), [toString](../../../../java/lang/Object.html#toString--), [wait](../../../../java/lang/Object.html#wait--), [wait](../../../../java/lang/Object.html#wait-long-), [wait](../../../../java/lang/Object.html#wait-long-int-)`

• • Constructor Detail

     * #### AtomicMarkableReference  
     public AtomicMarkableReference​([V](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") 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](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") 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](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") 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](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") expectedReference,  
                                     [V](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") 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](package-summary.html#weakCompareAndSet), 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](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") expectedReference,  
                                 [V](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") 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](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") 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](../../../../java/util/concurrent/atomic/AtomicMarkableReference.html "type parameter in AtomicMarkableReference") 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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