java.util.concurrent.atomic
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.
static | AtomicIntegerFieldUpdater newUpdater(Class tclass, String fieldName) - Creates and returns an updater for objects with the given field.
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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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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.
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clone , equals , extends Object> getClass , finalize , hashCode , notify , notifyAll , toString , wait , wait , wait |
AtomicIntegerFieldUpdater newUpdater
public static AtomicIntegerFieldUpdater 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.
tclass
- the class of the objects holding the fieldfieldName
- the name of the field to be updated
addAndGet
public 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.
obj
- An object whose field to get and setdelta
- the value to add
compareAndSet
public 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. 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 constructor
decrementAndGet
public int decrementAndGet(T obj)
Atomically decrements by one the current value of the field of the
given object managed by this updater.
obj
- An object whose field to get and set
get
public abstract int get(T obj)
Gets the current value held in the field of the given object managed
by this updater.
obj
- An object whose field to get
getAndAdd
public 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.
obj
- An object whose field to get and setdelta
- the value to add
getAndDecrement
public int getAndDecrement(T obj)
Atomically decrements by one the current value of the field of the
given object managed by this updater.
obj
- An object whose field to get and set
getAndIncrement
public int getAndIncrement(T obj)
Atomically increments by one the current value of the field of the
given object managed by this updater.
obj
- An object whose field to get and set
getAndSet
public 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.
obj
- An object whose field to get and setnewValue
- the new value
incrementAndGet
public int incrementAndGet(T obj)
Atomically increments by one the current value of the field of the
given object managed by this updater.
obj
- An object whose field to get and set
lazySet
public abstract void lazySet(T obj,
int newValue)
Eventually sets the field of the given object managed by this
updater to the given updated value.
obj
- An object whose field to setnewValue
- the new value
set
public abstract void set(T 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.
obj
- An object whose field to setnewValue
- the new value
weakCompareAndSet
public 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. 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 constructor