java.util.concurrent源码学习二

public class AtomicInteger extends Number implements java.io.Serializable
一：作用

An int value that may be updated atomically

二：成员变量

 与上一篇文章基本相同

三：主要成员方法，这里只展示AtomicInteger特有的方法

 将原来的值+1，并且返回修改前的值

public final int getAndIncrement() {
for (;;) {
int current = get();
int next = current + 1;
if (compareAndSet(current, next))
return current;
}
}

将原来的值-1，并且返回修改前的值

public final int getAndDecrement() {
for (;;) {
int current = get();
int next = current - 1;
if (compareAndSet(current, next))
return current;
}
}

将原来的值增加指定值，并返回修改后的值

/**
* Atomically adds the given value to the current value.
*
* @param delta the value to add
* @return the updated value
*/
public final int addAndGet(int delta) {
for (;;) {
int current = get();
int next = current + delta;
if (compareAndSet(current, next))
return next;
}
}

将原来的值-1，并返回修改后的值

/**
* Atomically decrements by one the current value.
*
* @return the updated value
*/
public final int decrementAndGet() {
for (;;) {
int current = get();
int next = current - 1;
if (compareAndSet(current, next))
return next;
}
}

将原来的值+1，并返回修改后的值

/**
* Atomically increments by one the current value.
*
* @return the updated value
*/
public final int incrementAndGet() {
for (;;) {
int current = get();
int next = current + 1;
if (compareAndSet(current, next))
return next;
}
}