Java™ Platform
Standard Ed. 6

java.util.concurrent.atomic
Class AtomicLong

java.lang.Object
  extended by java.lang.Number
      extended by 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 java.util.concurrent.atomic package specification for description of the properties of atomic variables. 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
AtomicLong()
          Creates a new AtomicLong with initial value 0.
AtomicLong(long initialValue)
          Creates a new AtomicLong with the given initial value.
 
Method Summary
 long addAndGet(long delta)
          Atomically adds the given value to the current value.
 boolean compareAndSet(long expect, long update)
          Atomically sets the value to the given updated value if the current value == the expected value.
 long decrementAndGet()
          Atomically decrements by one the current value.
 double doubleValue()
          Returns the value of the specified number as a double.
 float floatValue()
          Returns the value of the specified number as a float.
 long get()
          Gets the current value.
 long getAndAdd(long delta)
          Atomically adds the given value to the current value.
 long getAndDecrement()
          Atomically decrements by one the current value.
 long getAndIncrement()
          Atomically increments by one the current value.
 long getAndSet(long newValue)
          Atomically sets to the given value and returns the old value.
 long incrementAndGet()
          Atomically increments by one the current value.
 int intValue()
          Returns the value of the specified number as an int.
 void lazySet(long newValue)
          Eventually sets to the given value.
 long longValue()
          Returns the value of the specified number as a long.
 void set(long newValue)
          Sets to the given value.
 String toString()
          Returns the String representation of the current value.
 boolean weakCompareAndSet(long expect, long update)
          Atomically sets the value to the given updated value if the current value == the expected value.
 
Methods inherited from class java.lang.Number
byteValue, shortValue
 
Methods inherited from 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()
Gets the current value.

Returns:
the current value

set

public final void set(long newValue)
Sets to the given value.

Parameters:
newValue - the new value

lazySet

public final void lazySet(long newValue)
Eventually sets to the given value.

Parameters:
newValue - the new value
Since:
1.6

getAndSet

public final long getAndSet(long newValue)
Atomically sets to the given value and returns the old value.

Parameters:
newValue - the new value
Returns:
the previous value

compareAndSet

public final boolean compareAndSet(long expect,
                                   long update)
Atomically sets the value to the given updated value if the current value == the expected value.

Parameters:
expect - the expected value
update - the new value
Returns:
true if successful. False return indicates that the actual value was not equal to the expected value.

weakCompareAndSet

public final boolean weakCompareAndSet(long expect,
                                       long update)
Atomically sets the value to the given updated value if the current value == the expected value.

May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to compareAndSet.

Parameters:
expect - the expected value
update - the new value
Returns:
true if successful.

getAndIncrement

public final long getAndIncrement()
Atomically increments by one the current value.

Returns:
the previous value

getAndDecrement

public final long getAndDecrement()
Atomically decrements by one the current value.

Returns:
the previous value

getAndAdd

public final long getAndAdd(long delta)
Atomically adds the given value to the current value.

Parameters:
delta - the value to add
Returns:
the previous value

incrementAndGet

public final long incrementAndGet()
Atomically increments by one the current value.

Returns:
the updated value

decrementAndGet

public final long decrementAndGet()
Atomically decrements by one the current value.

Returns:
the updated value

addAndGet

public final long addAndGet(long delta)
Atomically adds the given value to the current value.

Parameters:
delta - the value to add
Returns:
the updated value

toString

public String toString()
Returns the String representation of the current value.

Overrides:
toString in class Object
Returns:
the String representation of the current value.

intValue

public int intValue()
Description copied from class: Number
Returns the value of the specified number as an int. This may involve rounding or truncation.

Specified by:
intValue in class Number
Returns:
the numeric value represented by this object after conversion to type int.

longValue

public long longValue()
Description copied from class: Number
Returns the value of the specified number as a long. This may involve rounding or truncation.

Specified by:
longValue in class Number
Returns:
the numeric value represented by this object after conversion to type long.

floatValue

public float floatValue()
Description copied from class: Number
Returns the value of the specified number as a float. This may involve rounding.

Specified by:
floatValue in class Number
Returns:
the numeric value represented by this object after conversion to type float.

doubleValue

public double doubleValue()
Description copied from class: Number
Returns the value of the specified number as a double. This may involve rounding.

Specified by:
doubleValue in class Number
Returns:
the numeric value represented by this object after conversion to type double.

Java™ Platform
Standard Ed. 6

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