AtomicLongFieldUpdater (Java Platform SE 6)

This documentation differs from the official API. Jadeite adds extra features to the API including: variable font sizes, constructions examples, placeholders for classes and methods, and auto-generated “See Also” links. Additionally it is missing some items found in standard Javadoc documentation, including: generics type information, “Deprecated” tags and comments, “See Also” links, along with other minor differences. Please send any questions or feedback to bam@cs.cmu.edu.

Overview

Package

Class

PREV CLASS NEXT CLASS

FRAMES NO FRAMES

SUMMARY: NESTED | FIELD | CONSTR | METHOD

DETAIL: FIELD | CONSTR | METHOD

java.util.concurrent.atomic
class AtomicLongFieldUpdater

java.lang.Object
  java.util.concurrent.atomic.AtomicLongFieldUpdater

public abstract class AtomicLongFieldUpdater
extends Object

A reflection-based utility that enables atomic updates to designated {@code 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 {@code 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 of {@code compareAndSet} and {@code set} on the same updater.

Constructor Summary
`protected`	`AtomicLongFieldUpdater()` Protected do-nothing constructor for use by subclasses.

Method Summary
`long`	`addAndGet(Object 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(Object 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(Object obj)` Atomically decrements by one the current value of the field of the given object managed by this updater.
`abstract long`	`get(Object obj)` Gets the current value held in the field of the given object managed by this updater.
`long`	`getAndAdd(Object 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(Object obj)` Atomically decrements by one the current value of the field of the given object managed by this updater.
`long`	`getAndIncrement(Object obj)` Atomically increments by one the current value of the field of the given object managed by this updater.
`long`	`getAndSet(Object 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(Object obj)` Atomically increments by one the current value of the field of the given object managed by this updater.
`abstract void`	`lazySet(Object 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(Object obj, long newValue)` Sets the field of the given object managed by this updater to the given updated value.
`abstract boolean`	`weakCompareAndSet(Object 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
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

AtomicLongFieldUpdater

protected AtomicLongFieldUpdater()

Protected do-nothing constructor for use by subclasses.

Method Detail

addAndGet

public long addAndGet(Object 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

compareAndSet

public abstract boolean compareAndSet(Object 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 {@code ==} the expected value. This method is guaranteed to be atomic with respect to other calls to {@code compareAndSet} and {@code 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.

decrementAndGet

public long decrementAndGet(Object 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

get

public abstract long get(Object 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

getAndAdd

public long getAndAdd(Object 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

getAndDecrement

public long getAndDecrement(Object 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

getAndIncrement

public long getAndIncrement(Object 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

getAndSet

public long getAndSet(Object 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

incrementAndGet

public long incrementAndGet(Object 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

lazySet

public abstract void lazySet(Object 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

newUpdater

public static AtomicLongFieldUpdater newUpdater(Class tclass,
                                                String 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

set

public abstract void set(Object 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 {@code compareAndSet}.

Parameters:: obj - An object whose field to set; newValue - the new value

weakCompareAndSet

public abstract boolean weakCompareAndSet(Object obj,
                                          long expect,
                                          long update)

May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to {@code compareAndSet}.

Parameters:: obj - An object whose field to conditionally set; expect - the expected value; update - the new value
Returns:: true if successful.