AtomicLong (Java Platform SE 7 ) (original) (raw)

• 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 thejava.util.concurrent.atomic package specification for description of the properties of atomic variables. AnAtomicLong is used in applications such as atomically incremented sequence numbers, and cannot be used as a replacement for a Long. However, this class does extendNumber to allow uniform access by tools and utilities that deal with numerically-based classes.
Since:
1.5
See Also:
Serialized Form

• • Constructor Summary

  Constructors

  Constructor and Description
  AtomicLong() Creates a new AtomicLong with initial value 0.
  AtomicLong(long initialValue) Creates a new AtomicLong with the given initial value.

  • Method Summary

  Methods

  Modifier and Type	Method and Description
  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](../../../../java/lang/Number.html "class in java.lang")  
     `[byteValue](../../../../java/lang/Number.html#byteValue%28%29), [shortValue](../../../../java/lang/Number.html#shortValue%28%29)`  
     * ### Methods inherited from class java.lang.[Object](../../../../java/lang/Object.html "class in java.lang")  
     `[clone](../../../../java/lang/Object.html#clone%28%29), [equals](../../../../java/lang/Object.html#equals%28java.lang.Object%29), [finalize](../../../../java/lang/Object.html#finalize%28%29), [getClass](../../../../java/lang/Object.html#getClass%28%29), [hashCode](../../../../java/lang/Object.html#hashCode%28%29), [notify](../../../../java/lang/Object.html#notify%28%29), [notifyAll](../../../../java/lang/Object.html#notifyAll%28%29), [wait](../../../../java/lang/Object.html#wait%28%29), [wait](../../../../java/lang/Object.html#wait%28long%29), [wait](../../../../java/lang/Object.html#wait%28long,%20int%29)`

• • 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](package-summary.html#Spurious) 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](../../../../java/lang/String.html "class in java.lang") toString()  
    Returns the String representation of the current value.  
    **Overrides:**  
    `[toString](../../../../java/lang/Object.html#toString%28%29)` in class `[Object](../../../../java/lang/Object.html "class in java.lang")`  
    Returns:  
    the String representation of the current value.  
    * #### intValue  
    public int intValue()  
    **Description copied from class: `[Number](../../../../java/lang/Number.html#intValue%28%29)`**  
    Returns the value of the specified number as an `int`. This may involve rounding or truncation.  
    **Specified by:**  
    `[intValue](../../../../java/lang/Number.html#intValue%28%29)` in class `[Number](../../../../java/lang/Number.html "class in java.lang")`  
    Returns:  
    the numeric value represented by this object after conversion to type `int`.  
    * #### longValue  
    public long longValue()  
    **Description copied from class: `[Number](../../../../java/lang/Number.html#longValue%28%29)`**  
    Returns the value of the specified number as a `long`. This may involve rounding or truncation.  
    **Specified by:**  
    `[longValue](../../../../java/lang/Number.html#longValue%28%29)` in class `[Number](../../../../java/lang/Number.html "class in java.lang")`  
    Returns:  
    the numeric value represented by this object after conversion to type `long`.  
    * #### floatValue  
    public float floatValue()  
    **Description copied from class: `[Number](../../../../java/lang/Number.html#floatValue%28%29)`**  
    Returns the value of the specified number as a `float`. This may involve rounding.  
    **Specified by:**  
    `[floatValue](../../../../java/lang/Number.html#floatValue%28%29)` in class `[Number](../../../../java/lang/Number.html "class in java.lang")`  
    Returns:  
    the numeric value represented by this object after conversion to type `float`.  
    * #### doubleValue  
    public double doubleValue()  
    **Description copied from class: `[Number](../../../../java/lang/Number.html#doubleValue%28%29)`**  
    Returns the value of the specified number as a `double`. This may involve rounding.  
    **Specified by:**  
    `[doubleValue](../../../../java/lang/Number.html#doubleValue%28%29)` in class `[Number](../../../../java/lang/Number.html "class in java.lang")`  
    Returns:  
    the numeric value represented by this object after conversion to type `double`.

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