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

• java.lang.Object

• • java.util.concurrent.atomic.AtomicStampedReference

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

public class AtomicStampedReference
extends Object
An AtomicStampedReference maintains an object reference along with an integer "stamp", that can be updated atomically.
Implementation note: This implementation maintains stamped references by creating internal objects representing "boxed" [reference, integer] pairs.
Since:
1.5

• • Constructor Summary

  Constructors

  Constructor	Description
  AtomicStampedReference​(V initialRef, int initialStamp)	Creates a new AtomicStampedReference with the given initial values.

  • Method Summary

  All Methods Instance Methods Concrete Methods

  Modifier and Type	Method	Description
  boolean	attemptStamp​(V expectedReference, int newStamp)	Atomically sets the value of the stamp to the given update value if the current reference is == to the expected reference.
  boolean	compareAndSet​(V expectedReference,V newReference, int expectedStamp, int newStamp)	Atomically sets the value of both the reference and stamp to the given update values if the current reference is == to the expected reference and the current stamp is equal to the expected stamp.
  V	get​(int[] stampHolder)	Returns the current values of both the reference and the stamp.
  V	getReference​()	Returns the current value of the reference.
  int	getStamp​()	Returns the current value of the stamp.
  void	set​(V newReference, int newStamp)	Unconditionally sets the value of both the reference and stamp.
  boolean	weakCompareAndSet​(V expectedReference,V newReference, int expectedStamp, int newStamp)	Atomically sets the value of both the reference and stamp to the given update values if the current reference is == to the expected reference and the current stamp is equal to the expected stamp.

     * ### 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

     * #### AtomicStampedReference  
     public AtomicStampedReference​([V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") initialRef,  
                                   int initialStamp)  
     Creates a new `AtomicStampedReference` with the given initial values.  
     Parameters:  
     `initialRef` \- the initial reference  
     `initialStamp` \- the initial stamp  

  • Method Detail

    * #### getReference  
    public [V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") getReference​()  
    Returns the current value of the reference.  
    Returns:  
    the current value of the reference  
    * #### getStamp  
    public int getStamp​()  
    Returns the current value of the stamp.  
    Returns:  
    the current value of the stamp  
    * #### get  
    public [V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") get​(int[] stampHolder)  
    Returns the current values of both the reference and the stamp. Typical usage is `int[1] holder; ref = v.get(holder); `.  
    Parameters:  
    `stampHolder` \- an array of size of at least one. On return,`stampHolder[0]` will hold the value of the stamp.  
    Returns:  
    the current value of the reference  
    * #### weakCompareAndSet  
    public boolean weakCompareAndSet​([V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") expectedReference,  
                                     [V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") newReference,  
                                     int expectedStamp,  
                                     int newStamp)  
    Atomically sets the value of both the reference and stamp to the given update values if the current reference is `==` to the expected reference and the current stamp is equal to the expected stamp.  
    [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  
    `expectedStamp` \- the expected value of the stamp  
    `newStamp` \- the new value for the stamp  
    Returns:  
    `true` if successful  
    * #### compareAndSet  
    public boolean compareAndSet​([V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") expectedReference,  
                                 [V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") newReference,  
                                 int expectedStamp,  
                                 int newStamp)  
    Atomically sets the value of both the reference and stamp to the given update values if the current reference is `==` to the expected reference and the current stamp is equal to the expected stamp.  
    Parameters:  
    `expectedReference` \- the expected value of the reference  
    `newReference` \- the new value for the reference  
    `expectedStamp` \- the expected value of the stamp  
    `newStamp` \- the new value for the stamp  
    Returns:  
    `true` if successful  
    * #### set  
    public void set​([V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") newReference,  
                    int newStamp)  
    Unconditionally sets the value of both the reference and stamp.  
    Parameters:  
    `newReference` \- the new value for the reference  
    `newStamp` \- the new value for the stamp  
    * #### attemptStamp  
    public boolean attemptStamp​([V](../../../../java/util/concurrent/atomic/AtomicStampedReference.html "type parameter in AtomicStampedReference") expectedReference,  
                                int newStamp)  
    Atomically sets the value of the stamp 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  
    `newStamp` \- the new value for the stamp  
    Returns:  
    `true` if successful

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