| 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 and volatile
semantics only with respect to other invocations of
compareAndSet and set.
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 add the given value to current value. | | abstract public boolean | compareAndSet(T obj, long expect, long update)
Atomically set the value of 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 decrement by one the current value. | | abstract public long | get(T obj)
Get the current value held in the field by the given object. | | public long | getAndAdd(T obj, long delta)
Atomically add the given value to current value. | | public long | getAndDecrement(T obj)
Atomically decrement by one the current value. | | public long | getAndIncrement(T obj)
Atomically increment by one the current value. | | public long | getAndSet(T obj, long newValue)
Set to the given value and return the old value. | | public long | incrementAndGet(T obj)
Atomically increment by one the current value. | | public static AtomicLongFieldUpdater<U> | newUpdater(Class<U> tclass, String fieldName)
Creates an updater for objects with the given field. | | abstract public void | set(T obj, long newValue)
Set the field of the given object managed by this updater. | | abstract public boolean | weakCompareAndSet(T obj, long expect, long update)
Atomically set the value of 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 add the given value to current value.
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 set the value of 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 decrement by one the current value.
Parameters:
obj - An object whose field to get and set the updated value; |
| get | | abstract public long get(T obj)(Code) | | Get the current value held in the field by the given object.
Parameters:
obj - An object whose field to get the current value |
| getAndAdd | | public long getAndAdd(T obj, long delta)(Code) | | Atomically add the given value to current value.
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 decrement by one the current value.
Parameters:
obj - An object whose field to get and set the previous value; |
| getAndIncrement | | public long getAndIncrement(T obj)(Code) | | Atomically increment by one the current value.
Parameters:
obj - An object whose field to get and set the previous value; |
| getAndSet | | public long getAndSet(T obj, long newValue)(Code) | | Set to the given value and return 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 increment by one the current value.
Parameters:
obj - An object whose field to get and set the updated value; |
| newUpdater | | public static AtomicLongFieldUpdater<U> newUpdater(Class<U> tclass, String fieldName)(Code) | | Creates 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) | | Set the field of the given object managed by this updater. 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 set the value of 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, and may fail spuriously.
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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