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AtomicInteger (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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java.util.concurrent.atomic
Class AtomicInteger

java.lang.Object
  java.lang.Number
      java.util.concurrent.atomic.AtomicInteger

All Implemented Interfaces:

Serializable

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public class AtomicInteger
extends Number
implements Serializable

An int value that may be updated atomically. See the java.util.concurrent.atomic package specification for description of the properties of atomic variables. An AtomicInteger is used in applications such as atomically incremented counters, and cannot be used as a replacement for an Integer. 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

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Constructor Summary
AtomicInteger()           Create a new AtomicInteger with initial value 0.
AtomicInteger(int initialValue)           Create a new AtomicInteger with the given initial value.

 

Method Summary
int	addAndGet(int delta)           Atomically add the given value to current value.
boolean	compareAndSet(int expect, int update)           Atomically set the value to the given updated value if the current value == the expected value.
int	decrementAndGet()           Atomically decrement 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.
int	get()           Get the current value.
int	getAndAdd(int delta)           Atomically add the given value to current value.
int	getAndDecrement()           Atomically decrement by one the current value.
int	getAndIncrement()           Atomically increment by one the current value.
int	getAndSet(int newValue)           Set to the give value and return the old value.
int	incrementAndGet()           Atomically increment by one the current value.
int	intValue()           Returns the value of the specified number as an int.
long	longValue()           Returns the value of the specified number as a long.
void	set(int newValue)           Set to the given value.
String	toString()           Returns the String representation of the current value.
boolean	weakCompareAndSet(int expect, int update)           Atomically set 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

AtomicInteger

public AtomicInteger(int initialValue)

Create a new AtomicInteger with the given initial value.

Parameters:

initialValue - the initial value

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AtomicInteger

public AtomicInteger()

Create a new AtomicInteger with initial value 0.

Method Detail

get

public final int get()

Get the current value.

Returns:

the current value

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set

public final void set(int newValue)

Set to the given value.

Parameters:

newValue - the new value

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getAndSet

public final int getAndSet(int newValue)

Set to the give value and return the old value.

Parameters:

newValue - the new value

Returns:

the previous value

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compareAndSet

public final boolean compareAndSet(int expect,
                                   int update)

Atomically set 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.

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weakCompareAndSet

public final boolean weakCompareAndSet(int expect,
                                       int update)

Atomically set the value to the given updated value if the current value == the expected value. May fail spuriously.

Parameters:

expect - the expected value

update - the new value

Returns:

true if successful.

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getAndIncrement

public final int getAndIncrement()

Atomically increment by one the current value.

Returns:

the previous value

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getAndDecrement

public final int getAndDecrement()

Atomically decrement by one the current value.

Returns:

the previous value

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getAndAdd

public final int getAndAdd(int delta)

Atomically add the given value to current value.

Parameters:

delta - the value to add

Returns:

the previous value

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incrementAndGet

public final int incrementAndGet()

Atomically increment by one the current value.

Returns:

the updated value

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decrementAndGet

public final int decrementAndGet()

Atomically decrement by one the current value.

Returns:

the updated value

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addAndGet

public final int addAndGet(int delta)

Atomically add the given value to current value.

Parameters:

delta - the value to add

Returns:

the updated value

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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.

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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.

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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.

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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.

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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.

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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