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| java.lang.Object
 java.util.concurrent.atomic.AtomicLongFieldUpdater
| AtomicLongFieldUpdater | | abstract public class AtomicLongFieldUpdater (Code) | | A reflection-based utility that enables atomic updates to
designated
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
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.
since:
1.5
author:
Doug Lea<
Parameters:
T - > The type of the object holding the updatable field |
| Constructor Summary | |
| protected | AtomicLongFieldUpdater()
Protected do-nothing constructor for use by subclasses. |
| Method Summary | |
| public long | addAndGet(T obj, long delta)
Atomically adds the given value to the current value of the field of
the given object managed by this updater. | | abstract public boolean | compareAndSet(T 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. | | public long | decrementAndGet(T obj)
Atomically decrements by one the current value of the field of the
given object managed by this updater. | | abstract public long | get(T obj)
Gets the current value held in the field of the given object managed
by this updater. | | public long | getAndAdd(T obj, long delta)
Atomically adds the given value to the current value of the field of
the given object managed by this updater. | | public long | getAndDecrement(T obj)
Atomically decrements by one the current value of the field of the
given object managed by this updater. | | public long | getAndIncrement(T obj)
Atomically increments by one the current value of the field of the
given object managed by this updater. | | public long | getAndSet(T obj, long newValue)
Atomically sets the field of the given object managed by this updater
to the given value and returns the old value. | | public long | incrementAndGet(T obj)
Atomically increments by one the current value of the field of the
given object managed by this updater. | | abstract public void | lazySet(T obj, long newValue)
Eventually sets the field of the given object managed by this
updater to the given updated value. | | public static AtomicLongFieldUpdater<U> | newUpdater(Class<U> 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
Parameters:
fieldName - the name of the field to be updated. | | abstract public void | set(T obj, long newValue)
Sets the field of the given object managed by this updater to the
given updated value. | | abstract public boolean | weakCompareAndSet(T 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. |
| AtomicLongFieldUpdater | | protected AtomicLongFieldUpdater()(Code) | | Protected do-nothing constructor for use by subclasses.
|
| addAndGet | | public long addAndGet(T obj, long delta)(Code) | | 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
Parameters:
delta - the value to add the updated value |
| compareAndSet | | abstract public boolean compareAndSet(T obj, long expect, long update)(Code) | | 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
Parameters:
expect - the expected value
Parameters:
update - the new value true if successful.
throws:
ClassCastException - if obj is not an instanceof the class possessing the field established in the constructor. |
| decrementAndGet | | public long decrementAndGet(T obj)(Code) | | 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 the updated value |
| get | | abstract public long get(T obj)(Code) | | Gets the current value held in the field of the given object managed
by this updater.
Parameters:
obj - An object whose field to get the current value |
| getAndAdd | | public long getAndAdd(T obj, long delta)(Code) | | 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
Parameters:
delta - the value to add the previous value |
| getAndDecrement | | public long getAndDecrement(T obj)(Code) | | 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 the previous value |
| getAndIncrement | | public long getAndIncrement(T obj)(Code) | | 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 the previous value |
| getAndSet | | public long getAndSet(T obj, long newValue)(Code) | | 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
Parameters:
newValue - the new value the previous value |
| incrementAndGet | | public long incrementAndGet(T obj)(Code) | | 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 the updated value |
| lazySet | | abstract public void lazySet(T obj, long newValue)(Code) | | 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
Parameters:
newValue - the new value
since:
1.6 |
| newUpdater | | public static AtomicLongFieldUpdater<U> newUpdater(Class<U> tclass, String fieldName)(Code) | | 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
Parameters:
fieldName - the name of the field to be updated. the updater
throws:
IllegalArgumentException - if the field is not avolatile long type.
throws:
RuntimeException - with a nested reflection-basedexception if the class does not hold field or is the wrong type. |
| set | | abstract public void set(T obj, long newValue)(Code) | | 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
Parameters:
newValue - the new value |
| weakCompareAndSet | | abstract public boolean weakCompareAndSet(T obj, long expect, long update)(Code) | | 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 .
Parameters:
obj - An object whose field to conditionally set
Parameters:
expect - the expected value
Parameters:
update - the new value true if successful.
throws:
ClassCastException - if obj is not an instanceof the class possessing the field established in the constructor. |
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