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

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

public abstract class AtomicIntegerFieldUpdater
extends Object
A reflection-based utility that enables atomic updates to designated volatile int 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	AtomicIntegerFieldUpdater() Protected do-nothing constructor for use by subclasses.

Method Summary

Methods

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

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

Method Detail

* #### newUpdater  
public static <U> [AtomicIntegerFieldUpdater](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.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 integer 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/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
                    int expect,  
                    int 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/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
                        int expect,  
                        int 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/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
       int 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/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
           int 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 int get([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") 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 int getAndSet([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
            int 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 int getAndIncrement([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") 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 int getAndDecrement([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") 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 int getAndAdd([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
            int 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 int incrementAndGet([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") 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 int decrementAndGet([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") 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 int addAndGet([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
            int 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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AtomicIntegerFieldUpdater (Java Platform SE 7 ) (original) (raw)

Constructor Summary

Method Summary

Constructor Detail

Method Detail