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Java™ Platform Standard Ed. 6 |
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java.lang.Object java.util.concurrent.atomic.AtomicIntegerFieldUpdater<T>
T
- The type of the object holding the updatable fieldpublic abstract class AtomicIntegerFieldUpdater<T>
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 of
compareAndSet
and set
on the same updater.
Constructor Summary | |
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protected |
AtomicIntegerFieldUpdater()
Protected do-nothing constructor for use by subclasses. |
Method Summary | ||
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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. |
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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. |
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int |
decrementAndGet(T obj)
Atomically decrements by one the current value of the field of the given object managed by this updater. |
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abstract int |
get(T obj)
Gets the current value held in the field of the given object managed by this updater. |
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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. |
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int |
getAndDecrement(T obj)
Atomically decrements by one the current value of the field of the given object managed by this updater. |
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int |
getAndIncrement(T obj)
Atomically increments by one the current value of the field of the given object managed by this updater. |
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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. |
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int |
incrementAndGet(T obj)
Atomically increments by one the current value of the field of the given object managed by this updater. |
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abstract void |
lazySet(T obj,
int newValue)
Eventually sets the field of the given object managed by this updater to the given updated value. |
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static
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newUpdater(Class<U> tclass,
String fieldName)
Creates and returns an updater for objects with the given field. |
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abstract void |
set(T obj,
int newValue)
Sets the field of the given object managed by this updater to the given updated value. |
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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 |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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protected AtomicIntegerFieldUpdater()
Method Detail |
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public static <U> AtomicIntegerFieldUpdater<U> newUpdater(Class<U> tclass, String fieldName)
tclass
- the class of the objects holding the fieldfieldName
- the name of the field to be updated
IllegalArgumentException
- if the field is not a
volatile integer type
RuntimeException
- with a nested reflection-based
exception if the class does not hold field or is the wrong typepublic abstract boolean compareAndSet(T obj, int expect, int update)
==
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.
obj
- An object whose field to conditionally setexpect
- the expected valueupdate
- the new value
ClassCastException
- if obj
is not an instance
of the class possessing the field established in the constructorpublic abstract boolean weakCompareAndSet(T obj, int expect, int update)
==
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, so is only rarely an
appropriate alternative to compareAndSet
.
obj
- An object whose field to conditionally setexpect
- the expected valueupdate
- the new value
ClassCastException
- if obj
is not an instance
of the class possessing the field established in the constructorpublic abstract void set(T obj, int newValue)
compareAndSet
.
obj
- An object whose field to setnewValue
- the new valuepublic abstract void lazySet(T obj, int newValue)
obj
- An object whose field to setnewValue
- the new valuepublic abstract int get(T obj)
obj
- An object whose field to get
public int getAndSet(T obj, int newValue)
obj
- An object whose field to get and setnewValue
- the new value
public int getAndIncrement(T obj)
obj
- An object whose field to get and set
public int getAndDecrement(T obj)
obj
- An object whose field to get and set
public int getAndAdd(T obj, int delta)
obj
- An object whose field to get and setdelta
- the value to add
public int incrementAndGet(T obj)
obj
- An object whose field to get and set
public int decrementAndGet(T obj)
obj
- An object whose field to get and set
public int addAndGet(T obj, int delta)
obj
- An object whose field to get and setdelta
- the value to add
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Java™ Platform Standard Ed. 6 |
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