Class AtomicLong
- java.lang.Object
-
- java.lang.Number
-
- java.util.concurrent.atomic.AtomicLong
- All Implemented Interfaces:
Serializable
public class AtomicLong extends Number implements Serializable
A long
value that may be updated atomically. See the VarHandle
specification for descriptions of the properties of atomic accesses. An AtomicLong
is used in applications such as atomically incremented sequence numbers, and cannot be used as a replacement for a Long
. However, this class does extend Number
to allow uniform access by tools and utilities that deal with numerically-based classes.
- Since:
- 1.5
- See Also:
- Serialized Form
Constructor Summary
Constructor | Description |
---|---|
AtomicLong() | Creates a new AtomicLong with initial value |
AtomicLong(long initialValue) | Creates a new AtomicLong with the given initial value. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
long | accumulateAndGet(long x,
LongBinaryOperator accumulatorFunction) | Atomically updates (with memory effects as specified by |
long | addAndGet(long delta) | Atomically adds the given value to the current value, with memory effects as specified by |
long | compareAndExchange(long expectedValue,
long newValue) | Atomically sets the value to |
long | compareAndExchangeAcquire(long expectedValue,
long newValue) | Atomically sets the value to |
long | compareAndExchangeRelease(long expectedValue,
long newValue) | Atomically sets the value to |
boolean | compareAndSet(long expectedValue,
long newValue) | Atomically sets the value to |
long | decrementAndGet() | Atomically decrements the current value, with memory effects as specified by |
double | doubleValue() | Returns the current value of this |
float | floatValue() | Returns the current value of this |
long | get() | Returns the current value, with memory effects as specified by |
long | getAcquire() | Returns the current value, with memory effects as specified by |
long | getAndAccumulate(long x,
LongBinaryOperator accumulatorFunction) | Atomically updates (with memory effects as specified by |
long | getAndAdd(long delta) | Atomically adds the given value to the current value, with memory effects as specified by |
long | getAndDecrement() | Atomically decrements the current value, with memory effects as specified by |
long | getAndIncrement() | Atomically increments the current value, with memory effects as specified by |
long | getAndSet(long newValue) | Atomically sets the value to |
long | getAndUpdate(LongUnaryOperator updateFunction) | Atomically updates (with memory effects as specified by |
long | getOpaque() | Returns the current value, with memory effects as specified by |
long | getPlain() | Returns the current value, with memory semantics of reading as if the variable was declared non- |
long | incrementAndGet() | Atomically increments the current value, with memory effects as specified by |
int | intValue() | Returns the current value of this |
void | lazySet(long newValue) | Sets the value to |
long | longValue() | Returns the current value of this |
void | set(long newValue) | Sets the value to |
void | setOpaque(long newValue) | Sets the value to |
void | setPlain(long newValue) | Sets the value to |
void | setRelease(long newValue) | Sets the value to |
String | toString() | Returns the String representation of the current value. |
long | updateAndGet(LongUnaryOperator updateFunction) | Atomically updates (with memory effects as specified by |
boolean | weakCompareAndSet(long expectedValue,
long newValue) | Deprecated. This method has plain memory effects but the method name implies volatile memory effects (see methods such as compareAndExchange(long, long) and compareAndSet(long, long) ). |
boolean | weakCompareAndSetAcquire(long expectedValue,
long newValue) | Possibly atomically sets the value to |
boolean | weakCompareAndSetPlain(long expectedValue,
long newValue) | Possibly atomically sets the value to |
boolean | weakCompareAndSetRelease(long expectedValue,
long newValue) | Possibly atomically sets the value to |
boolean | weakCompareAndSetVolatile(long expectedValue,
long newValue) | Possibly atomically sets the value to |
Methods declared in class java.lang.Number
byteValue, shortValue
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Constructor Detail
AtomicLong
public AtomicLong(long initialValue)
Creates a new AtomicLong with the given initial value.
- Parameters:
-
initialValue
- the initial value
AtomicLong
public AtomicLong()
Creates a new AtomicLong with initial value 0
.
Method Detail
get
public final long get()
Returns the current value, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...)
.
- Returns:
- the current value
set
public final void set(long newValue)
Sets the value to newValue
, with memory effects as specified by VarHandle.setVolatile(java.lang.Object...)
.
- Parameters:
-
newValue
- the new value
lazySet
public final void lazySet(long newValue)
Sets the value to newValue
, with memory effects as specified by VarHandle.setRelease(java.lang.Object...)
.
- Parameters:
-
newValue
- the new value - Since:
- 1.6
getAndSet
public final long getAndSet(long newValue)
Atomically sets the value to newValue
and returns the old value, with memory effects as specified by VarHandle.getAndSet(java.lang.Object...)
.
- Parameters:
-
newValue
- the new value - Returns:
- the previous value
compareAndSet
public final boolean compareAndSet(long expectedValue, long newValue)
Atomically sets the value to newValue
if the current value == expectedValue
, with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
-
true
if successful. False return indicates that the actual value was not equal to the expected value.
weakCompareAndSet
@Deprecated(since="9") public final boolean weakCompareAndSet(long expectedValue, long newValue)
compareAndExchange(long, long)
and compareAndSet(long, long)
). To avoid confusion over plain or volatile memory effects it is recommended that the method weakCompareAndSetPlain(long, long)
be used instead.Possibly atomically sets the value to newValue
if the current value == expectedValue
, with memory effects as specified by VarHandle.weakCompareAndSetPlain(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
-
true
if successful - See Also:
weakCompareAndSetPlain(long, long)
weakCompareAndSetPlain
public final boolean weakCompareAndSetPlain(long expectedValue, long newValue)
Possibly atomically sets the value to newValue
if the current value == expectedValue
, with memory effects as specified by VarHandle.weakCompareAndSetPlain(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
-
true
if successful - Since:
- 9
getAndIncrement
public final long getAndIncrement()
Atomically increments the current value, with memory effects as specified by VarHandle.getAndAdd(java.lang.Object...)
.
Equivalent to getAndAdd(1)
.
- Returns:
- the previous value
getAndDecrement
public final long getAndDecrement()
Atomically decrements the current value, with memory effects as specified by VarHandle.getAndAdd(java.lang.Object...)
.
Equivalent to getAndAdd(-1)
.
- Returns:
- the previous value
getAndAdd
public final long getAndAdd(long delta)
Atomically adds the given value to the current value, with memory effects as specified by VarHandle.getAndAdd(java.lang.Object...)
.
- Parameters:
-
delta
- the value to add - Returns:
- the previous value
incrementAndGet
public final long incrementAndGet()
Atomically increments the current value, with memory effects as specified by VarHandle.getAndAdd(java.lang.Object...)
.
Equivalent to addAndGet(1)
.
- Returns:
- the updated value
decrementAndGet
public final long decrementAndGet()
Atomically decrements the current value, with memory effects as specified by VarHandle.getAndAdd(java.lang.Object...)
.
Equivalent to addAndGet(-1)
.
- Returns:
- the updated value
addAndGet
public final long addAndGet(long delta)
Atomically adds the given value to the current value, with memory effects as specified by VarHandle.getAndAdd(java.lang.Object...)
.
- Parameters:
-
delta
- the value to add - Returns:
- the updated value
getAndUpdate
public final long getAndUpdate(LongUnaryOperator updateFunction)
Atomically updates (with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)
) the current value with the results of applying the given function, returning the previous value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.
- Parameters:
-
updateFunction
- a side-effect-free function - Returns:
- the previous value
- Since:
- 1.8
updateAndGet
public final long updateAndGet(LongUnaryOperator updateFunction)
Atomically updates (with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)
) the current value with the results of applying the given function, returning the updated value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.
- Parameters:
-
updateFunction
- a side-effect-free function - Returns:
- the updated value
- Since:
- 1.8
getAndAccumulate
public final long getAndAccumulate(long x, LongBinaryOperator accumulatorFunction)
Atomically updates (with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)
) the current value with the results of applying the given function to the current and given values, returning the previous value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value as its first argument, and the given update as the second argument.
- Parameters:
-
x
- the update value -
accumulatorFunction
- a side-effect-free function of two arguments - Returns:
- the previous value
- Since:
- 1.8
accumulateAndGet
public final long accumulateAndGet(long x, LongBinaryOperator accumulatorFunction)
Atomically updates (with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...)
) the current value with the results of applying the given function to the current and given values, returning the updated value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value as its first argument, and the given update as the second argument.
- Parameters:
-
x
- the update value -
accumulatorFunction
- a side-effect-free function of two arguments - Returns:
- the updated value
- Since:
- 1.8
toString
public String toString()
Returns the String representation of the current value.
intValue
public int intValue()
Returns the current value of this AtomicLong
as an int
after a narrowing primitive conversion, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...)
.
- Specified by:
-
intValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
int
.
longValue
public long longValue()
Returns the current value of this AtomicLong
as a long
, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...)
. Equivalent to get()
.
- Specified by:
-
longValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
long
.
floatValue
public float floatValue()
Returns the current value of this AtomicLong
as a float
after a widening primitive conversion, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...)
.
- Specified by:
-
floatValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
float
.
doubleValue
public double doubleValue()
Returns the current value of this AtomicLong
as a double
after a widening primitive conversion, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...)
.
- Specified by:
-
doubleValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
double
.
getPlain
public final long getPlain()
Returns the current value, with memory semantics of reading as if the variable was declared non-volatile
.
- Returns:
- the value
- Since:
- 9
setPlain
public final void setPlain(long newValue)
Sets the value to newValue
, with memory semantics of setting as if the variable was declared non-volatile
and non-final
.
- Parameters:
-
newValue
- the new value - Since:
- 9
getOpaque
public final long getOpaque()
Returns the current value, with memory effects as specified by VarHandle.getOpaque(java.lang.Object...)
.
- Returns:
- the value
- Since:
- 9
setOpaque
public final void setOpaque(long newValue)
Sets the value to newValue
, with memory effects as specified by VarHandle.setOpaque(java.lang.Object...)
.
- Parameters:
-
newValue
- the new value - Since:
- 9
getAcquire
public final long getAcquire()
Returns the current value, with memory effects as specified by VarHandle.getAcquire(java.lang.Object...)
.
- Returns:
- the value
- Since:
- 9
setRelease
public final void setRelease(long newValue)
Sets the value to newValue
, with memory effects as specified by VarHandle.setRelease(java.lang.Object...)
.
- Parameters:
-
newValue
- the new value - Since:
- 9
compareAndExchange
public final long compareAndExchange(long expectedValue, long newValue)
Atomically sets the value to newValue
if the current value, referred to as the witness value, == expectedValue
, with memory effects as specified by VarHandle.compareAndExchange(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
- the witness value, which will be the same as the expected value if successful
- Since:
- 9
compareAndExchangeAcquire
public final long compareAndExchangeAcquire(long expectedValue, long newValue)
Atomically sets the value to newValue
if the current value, referred to as the witness value, == expectedValue
, with memory effects as specified by VarHandle.compareAndExchangeAcquire(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
- the witness value, which will be the same as the expected value if successful
- Since:
- 9
compareAndExchangeRelease
public final long compareAndExchangeRelease(long expectedValue, long newValue)
Atomically sets the value to newValue
if the current value, referred to as the witness value, == expectedValue
, with memory effects as specified by VarHandle.compareAndExchangeRelease(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
- the witness value, which will be the same as the expected value if successful
- Since:
- 9
weakCompareAndSetVolatile
public final boolean weakCompareAndSetVolatile(long expectedValue, long newValue)
Possibly atomically sets the value to newValue
if the current value == expectedValue
, with memory effects as specified by VarHandle.weakCompareAndSet(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
-
true
if successful - Since:
- 9
weakCompareAndSetAcquire
public final boolean weakCompareAndSetAcquire(long expectedValue, long newValue)
Possibly atomically sets the value to newValue
if the current value == expectedValue
, with memory effects as specified by VarHandle.weakCompareAndSetAcquire(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
-
true
if successful - Since:
- 9
weakCompareAndSetRelease
public final boolean weakCompareAndSetRelease(long expectedValue, long newValue)
Possibly atomically sets the value to newValue
if the current value == expectedValue
, with memory effects as specified by VarHandle.weakCompareAndSetRelease(java.lang.Object...)
.
- Parameters:
-
expectedValue
- the expected value -
newValue
- the new value - Returns:
-
true
if successful - Since:
- 9