AtomicIntegerFieldUpdater (Java SE 9 & JDK 9 ) (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.
Object arguments for parameters of type T that are not instances of the class passed to newUpdater(java.lang.Class, java.lang.String) will result in a ClassCastException being thrown.
Since:
1.5

Constructor Summary

Constructors

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

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods

Modifier and Type	Method	Description
int	accumulateAndGet(T obj, int x,IntBinaryOperator accumulatorFunction)	Atomically updates (with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)) the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the updated value.
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)	Returns the current value held in the field of the given object managed by this updater.
int	getAndAccumulate(T obj, int x,IntBinaryOperator accumulatorFunction)	Atomically updates (with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)) the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the previous value.
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	getAndUpdate(T obj,IntUnaryOperator updateFunction)	Atomically updates (with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)) the field of the given object managed by this updater with the results of applying the given function, returning the previous 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.
int	updateAndGet(T obj,IntUnaryOperator updateFunction)	Atomically updates (with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)) the field of the given object managed by this updater with the results of applying the given function, returning the 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--), [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

 * #### 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.  
Type Parameters:  
`U` \- the type of instances of tclass  
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, or the field is inaccessible to the caller according to Java language access control  
* #### 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  
* #### 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 and does not provide ordering guarantees](package-summary.html#weakCompareAndSet), 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  
* #### 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)  
Returns 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  
* #### getAndUpdate  
public final int getAndUpdate([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
                              [IntUnaryOperator](../../../../java/util/function/IntUnaryOperator.html "interface in java.util.function") updateFunction)  
Atomically updates (with memory effects as specified by [VarHandle.compareAndSet(java.lang.Object...)](../../../../java/lang/invoke/VarHandle.html#compareAndSet-java.lang.Object...-)) the field of the given object managed by this updater with the results of applying the given function, returning the previous value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.  
Parameters:  
`obj` \- An object whose field to get and set  
`updateFunction` \- a side-effect-free function  
Returns:  
the previous value  
Since:  
1.8  
* #### updateAndGet  
public final int updateAndGet([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
                              [IntUnaryOperator](../../../../java/util/function/IntUnaryOperator.html "interface in java.util.function") updateFunction)  
Atomically updates (with memory effects as specified by [VarHandle.compareAndSet(java.lang.Object...)](../../../../java/lang/invoke/VarHandle.html#compareAndSet-java.lang.Object...-)) the field of the given object managed by this updater with the results of applying the given function, returning the updated value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.  
Parameters:  
`obj` \- An object whose field to get and set  
`updateFunction` \- a side-effect-free function  
Returns:  
the updated value  
Since:  
1.8  
* #### getAndAccumulate  
public final int getAndAccumulate([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
                                  int x,  
                                  [IntBinaryOperator](../../../../java/util/function/IntBinaryOperator.html "interface in java.util.function") accumulatorFunction)  
Atomically updates (with memory effects as specified by [VarHandle.compareAndSet(java.lang.Object...)](../../../../java/lang/invoke/VarHandle.html#compareAndSet-java.lang.Object...-)) the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the previous value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value as its first argument, and the given update as the second argument.  
Parameters:  
`obj` \- An object whose field to get and set  
`x` \- the update value  
`accumulatorFunction` \- a side-effect-free function of two arguments  
Returns:  
the previous value  
Since:  
1.8  
* #### accumulateAndGet  
public final int accumulateAndGet([T](../../../../java/util/concurrent/atomic/AtomicIntegerFieldUpdater.html "type parameter in AtomicIntegerFieldUpdater") obj,  
                                  int x,  
                                  [IntBinaryOperator](../../../../java/util/function/IntBinaryOperator.html "interface in java.util.function") accumulatorFunction)  
Atomically updates (with memory effects as specified by [VarHandle.compareAndSet(java.lang.Object...)](../../../../java/lang/invoke/VarHandle.html#compareAndSet-java.lang.Object...-)) the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the updated value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value as its first argument, and the given update as the second argument.  
Parameters:  
`obj` \- An object whose field to get and set  
`x` \- the update value  
`accumulatorFunction` \- a side-effect-free function of two arguments  
Returns:  
the updated value  
Since:  
1.8

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

Constructor Summary

Method Summary

Constructor Detail

Method Detail