Class AtomicInteger

最新推荐文章于 2025-09-12 18:08:49 发布

转载最新推荐文章于 2025-09-12 18:08:49 发布 · 50 阅读

·

0

·

0 ·

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/diggingdeeply/p/Class_AtomicInteger.html

文章标签：

#java #数据库

本文详细介绍了Java并发包中AtomicInteger类的使用方法及特性。包括构造方法、原子操作、比较并交换等关键方法，并解释了其作为数值类的扩展用途。

Java™ Platform
Standard Ed. 7

All Classes

Summary:
Nested |
Field |
Constr |
Method

Detail:
Field |
Constr |
Method

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

All Implemented Interfaces:
Serializable
```
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

Constructor Summary

Constructors
Constructor and Description
`AtomicInteger()` Creates a new AtomicInteger with initial value `0`.
`AtomicInteger(int initialValue)` Creates a new AtomicInteger with the given initial value.

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`addAndGet(int delta)` Atomically adds the given value to the current value.
`boolean`	`compareAndSet(int expect, int update)` Atomically sets the value to the given updated value if the current value `==` the expected value.
`int`	`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`.
`int`	`get()` Gets the current value.
`int`	`getAndAdd(int delta)` Atomically adds the given value to the current value.
`int`	`getAndDecrement()` Atomically decrements by one the current value.
`int`	`getAndIncrement()` Atomically increments by one the current value.
`int`	`getAndSet(int newValue)` Atomically sets to the given value and returns the old value.
`int`	`incrementAndGet()` Atomically increments by one the current value.
`int`	`intValue()` Returns the value of the specified number as an `int`.
`void`	`lazySet(int newValue)` Eventually sets to the given value.
`long`	`longValue()` Returns the value of the specified number as a `long`.
`void`	`set(int newValue)` Sets to the given value.
`String`	`toString()` Returns the String representation of the current value.
`boolean`	`weakCompareAndSet(int expect, int 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
  - AtomicInteger
```
public AtomicInteger(int initialValue)
```
    Creates a new AtomicInteger with the given initial value.
    
    Parameters:
    initialValue - the initial value
  - AtomicInteger
```
public AtomicInteger()
```
    Creates a new AtomicInteger with initial value 0.
- Method Detail
  - get
```
public final int get()
```
    Gets the current value.
    
    Returns:
    the current value
  - set
```
public final void set(int newValue)
```
    Sets to the given value.
    
    Parameters:
    newValue - the new value
  - lazySet
```
public final void lazySet(int newValue)
```
    Eventually sets to the given value.
    
    Parameters:
    newValue - the new value
    Since:
    1.6
  - getAndSet
```
public final int getAndSet(int 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(int expect,
                    int 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(int expect,
                        int 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 int getAndIncrement()
```
    Atomically increments by one the current value.
    
    Returns:
    the previous value
  - getAndDecrement
```
public final int getAndDecrement()
```
    Atomically decrements by one the current value.
    
    Returns:
    the previous value
  - getAndAdd
```
public final int getAndAdd(int delta)
```
    Atomically adds the given value to the current value.
    
    Parameters:
    delta - the value to add
    Returns:
    the previous value
  - incrementAndGet
```
public final int incrementAndGet()
```
    Atomically increments by one the current value.
    
    Returns:
    the updated value
  - decrementAndGet
```
public final int decrementAndGet()
```
    Atomically decrements by one the current value.
    
    Returns:
    the updated value
  - addAndGet
```
public final int addAndGet(int 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. 7

All Classes

Summary:
Nested |
Field |
Constr |
Method

Detail:
Field |
Constr |
Method

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2018, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

转载于:https://www.cnblogs.com/diggingdeeply/p/Class_AtomicInteger.html

Class AtomicInteger