AtomicLongFieldUpdater (Java Platform SE 7 ) (original) (raw)

java.lang.Object
- java.util.concurrent.atomic.AtomicLongFieldUpdater
Type Parameters:
T - The type of the object holding the updatable field

public abstract class AtomicLongFieldUpdater
extends Object
A reflection-based utility that enables atomic updates to designated volatile long fields of designated classes. This class is designed for use in atomic data structures in which several fields of the same node are independently subject to atomic updates.
Note that the guarantees of the compareAndSet method in this class are weaker than in other atomic classes. Because this class cannot ensure that all uses of the field are appropriate for purposes of atomic access, it can guarantee atomicity only with respect to other invocations ofcompareAndSet and set on the same updater.
Since:
1.5

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AtomicLongFieldUpdater() Protected do-nothing constructor for use by subclasses.

Method Summary

Methods

Modifier and Type	Method and Description
long	addAndGet(T obj, long delta) Atomically adds the given value to the current value of the field of the given object managed by this updater.
abstract boolean	compareAndSet(T obj, long expect, long update) Atomically sets the field of the given object managed by this updater to the given updated value if the current value == the expected value.
long	decrementAndGet(T obj) Atomically decrements by one the current value of the field of the given object managed by this updater.
abstract long	get(T obj) Gets the current value held in the field of the given object managed by this updater.
long	getAndAdd(T obj, long delta) Atomically adds the given value to the current value of the field of the given object managed by this updater.
long	getAndDecrement(T obj) Atomically decrements by one the current value of the field of the given object managed by this updater.
long	getAndIncrement(T obj) Atomically increments by one the current value of the field of the given object managed by this updater.
long	getAndSet(T obj, long newValue) Atomically sets the field of the given object managed by this updater to the given value and returns the old value.
long	incrementAndGet(T obj) Atomically increments by one the current value of the field of the given object managed by this updater.
abstract void	lazySet(T obj, long newValue) Eventually sets the field of the given object managed by this updater to the given updated value.
static AtomicLongFieldUpdater	newUpdater(Class tclass,String fieldName) Creates and returns an updater for objects with the given field.
abstract void	set(T obj, long newValue) Sets the field of the given object managed by this updater to the given updated value.
abstract boolean	weakCompareAndSet(T obj, long expect, long update) Atomically sets the field of the given object managed by this updater to the given updated value if the current value == the expected value.

   * ### Methods inherited from class java.lang.[Object](../../../../java/lang/Object.html "class in java.lang")  
   `[clone](../../../../java/lang/Object.html#clone%28%29), [equals](../../../../java/lang/Object.html#equals%28java.lang.Object%29), [finalize](../../../../java/lang/Object.html#finalize%28%29), [getClass](../../../../java/lang/Object.html#getClass%28%29), [hashCode](../../../../java/lang/Object.html#hashCode%28%29), [notify](../../../../java/lang/Object.html#notify%28%29), [notifyAll](../../../../java/lang/Object.html#notifyAll%28%29), [toString](../../../../java/lang/Object.html#toString%28%29), [wait](../../../../java/lang/Object.html#wait%28%29), [wait](../../../../java/lang/Object.html#wait%28long%29), [wait](../../../../java/lang/Object.html#wait%28long,%20int%29)`

Constructor Detail

 * #### AtomicLongFieldUpdater  
 protected AtomicLongFieldUpdater()  
 Protected do-nothing constructor for use by subclasses.

Method Detail

* #### newUpdater  
public static <U> [AtomicLongFieldUpdater](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "class in java.util.concurrent.atomic")<U> newUpdater([Class](../../../../java/lang/Class.html "class in java.lang")<U> tclass,  
                                       [String](../../../../java/lang/String.html "class in java.lang") fieldName)  
Creates and returns an updater for objects with the given field. The Class argument is needed to check that reflective types and generic types match.  
Parameters:  
`tclass` \- the class of the objects holding the field  
`fieldName` \- the name of the field to be updated.  
Returns:  
the updater  
Throws:  
`[IllegalArgumentException](../../../../java/lang/IllegalArgumentException.html "class in java.lang")` \- if the field is not a volatile long type.  
`[RuntimeException](../../../../java/lang/RuntimeException.html "class in java.lang")` \- with a nested reflection-based exception if the class does not hold field or is the wrong type.  
* #### compareAndSet  
public abstract boolean compareAndSet([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj,  
                    long expect,  
                    long update)  
Atomically sets the field of the given object managed by this updater to the given updated value if the current value `==` the expected value. This method is guaranteed to be atomic with respect to other calls to `compareAndSet` and `set`, but not necessarily with respect to other changes in the field.  
Parameters:  
`obj` \- An object whose field to conditionally set  
`expect` \- the expected value  
`update` \- the new value  
Returns:  
true if successful.  
Throws:  
`[ClassCastException](../../../../java/lang/ClassCastException.html "class in java.lang")` \- if `obj` is not an instance of the class possessing the field established in the constructor.  
* #### weakCompareAndSet  
public abstract boolean weakCompareAndSet([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj,  
                        long expect,  
                        long update)  
Atomically sets the field of the given object managed by this updater to the given updated value if the current value `==` the expected value. This method is guaranteed to be atomic with respect to other calls to `compareAndSet` and `set`, but not necessarily with respect to other changes in the field.  
May [fail spuriously](package-summary.html#Spurious) and does not provide ordering guarantees, so is only rarely an appropriate alternative to `compareAndSet`.  
Parameters:  
`obj` \- An object whose field to conditionally set  
`expect` \- the expected value  
`update` \- the new value  
Returns:  
true if successful.  
Throws:  
`[ClassCastException](../../../../java/lang/ClassCastException.html "class in java.lang")` \- if `obj` is not an instance of the class possessing the field established in the constructor.  
* #### set  
public abstract void set([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj,  
       long newValue)  
Sets the field of the given object managed by this updater to the given updated value. This operation is guaranteed to act as a volatile store with respect to subsequent invocations of `compareAndSet`.  
Parameters:  
`obj` \- An object whose field to set  
`newValue` \- the new value  
* #### lazySet  
public abstract void lazySet([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj,  
           long newValue)  
Eventually sets the field of the given object managed by this updater to the given updated value.  
Parameters:  
`obj` \- An object whose field to set  
`newValue` \- the new value  
Since:  
1.6  
* #### get  
public abstract long get([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj)  
Gets the current value held in the field of the given object managed by this updater.  
Parameters:  
`obj` \- An object whose field to get  
Returns:  
the current value  
* #### getAndSet  
public long getAndSet([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj,  
             long newValue)  
Atomically sets the field of the given object managed by this updater to the given value and returns the old value.  
Parameters:  
`obj` \- An object whose field to get and set  
`newValue` \- the new value  
Returns:  
the previous value  
* #### getAndIncrement  
public long getAndIncrement([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj)  
Atomically increments by one the current value of the field of the given object managed by this updater.  
Parameters:  
`obj` \- An object whose field to get and set  
Returns:  
the previous value  
* #### getAndDecrement  
public long getAndDecrement([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj)  
Atomically decrements by one the current value of the field of the given object managed by this updater.  
Parameters:  
`obj` \- An object whose field to get and set  
Returns:  
the previous value  
* #### getAndAdd  
public long getAndAdd([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj,  
             long delta)  
Atomically adds the given value to the current value of the field of the given object managed by this updater.  
Parameters:  
`obj` \- An object whose field to get and set  
`delta` \- the value to add  
Returns:  
the previous value  
* #### incrementAndGet  
public long incrementAndGet([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj)  
Atomically increments by one the current value of the field of the given object managed by this updater.  
Parameters:  
`obj` \- An object whose field to get and set  
Returns:  
the updated value  
* #### decrementAndGet  
public long decrementAndGet([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj)  
Atomically decrements by one the current value of the field of the given object managed by this updater.  
Parameters:  
`obj` \- An object whose field to get and set  
Returns:  
the updated value  
* #### addAndGet  
public long addAndGet([T](../../../../java/util/concurrent/atomic/AtomicLongFieldUpdater.html "type parameter in AtomicLongFieldUpdater") obj,  
             long delta)  
Atomically adds the given value to the current value of the field of the given object managed by this updater.  
Parameters:  
`obj` \- An object whose field to get and set  
`delta` \- the value to add  
Returns:  
the updated value

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AtomicLongFieldUpdater (Java Platform SE 7 ) (original) (raw)

Constructor Summary

Method Summary

Constructor Detail

Method Detail