/**
* 无参构造函数 默认值为0
*/
public AtomicInteger() {
}
/**
* 指定初始值的构造函数,将内部维护的value变量值修改为参数值
*/
public AtomicInteger(int initialValue) {
value = initialValue;
}
2.5.2 get()
/**
* 返回当前的value值
*/
public final int get() {
return value;
}
2.5.3 set(int newValue)
/**
* 设置value的值
*/
public final void set(int newValue) {
value = newValue;
}
2.5.4 lazySet(int newValue)
/**
* 使用cas操作设置value的值
*/
public final void lazySet(int newValue) {
unsafe.putOrderedInt(this, valueOffset, newValue);
}
2.5.5 getAndSet(int newValue)
/**
* 使用Unsafe的原子性操作更新value的值并返回旧值
*/
public final int getAndSet(int newValue) {
return unsafe.getAndSetInt(this, valueOffset, newValue);
}
2.5.6 compareAndSet(int expect, int update)
/**
* 使用Unsafe的原子性操作:如果value的值和expect的值相等,则更新为update,并返回true,否则,返回false
*/
public final boolean compareAndSet(int expect, int update) {
return unsafe.compareAndSwapInt(this, valueOffset, expect, update);
}
2.5.7 weakCompareAndSet(int expect, int update)
/**
* compareAndSet(int expect, int update)方法的替代品,可能会出错,并且不提供顺序保证,很少用
*/
public final boolean weakCompareAndSet(int expect, int update) {
return unsafe.compareAndSwapInt(this, valueOffset, expect, update);
}
2.5.8 getAndIncrement()
/**
* 原子操作,使value值增加1然后返回旧值
*/
public final int getAndIncrement() {
return unsafe.getAndAddInt(this, valueOffset, 1);
}
2.5.9 getAndDecrement()
/**
* 原子操作,使得value值减一并返回旧值
*/
public final int getAndDecrement() {
return unsafe.getAndAddInt(this, valueOffset, -1);
}
2.5.10 getAndAdd(int delta)
/**
* 原子操作,使得value值增加delta,然后返回旧值
*/
public final int getAndAdd(int delta) {
return unsafe.getAndAddInt(this, valueOffset, delta);
}
2.5.11 incrementAndGet()
/**
* 原子操作,使得value值增加1后并返回增加后的值
*/
public final int incrementAndGet() {
return unsafe.getAndAddInt(this, valueOffset, 1) + 1;
}
2.5.12 decrementAndGet()
/**
* 原子操作,使得value值减一并返回新值
*/
public final int decrementAndGet() {
return unsafe.getAndAddInt(this, valueOffset, -1) - 1;
}
2.5.13 addAndGet(int delta)
/**
* 原子操作,使得value值增加delta然后返回新值
*/
public final int addAndGet(int delta) {
return unsafe.getAndAddInt(this, valueOffset, delta) + delta;
}
2.5.14 getAndUpdate(IntUnaryOperator updateFunction) TODO
public final int getAndUpdate(IntUnaryOperator updateFunction) {
int prev, next;
do {
prev = get();
next = updateFunction.applyAsInt(prev);
} while (!compareAndSet(prev, next));
return prev;
}
2.5.15 updateAndGet(IntUnaryOperator updateFunction) TODO
public final int updateAndGet(IntUnaryOperator updateFunction) {
int prev, next;
do {
prev = get();
next = updateFunction.applyAsInt(prev);
} while (!compareAndSet(prev, next));
return next;
}
2.5.16 getAndAccumulate(int x, IntBinaryOperator accumulatorFunction) TODO
public final int getAndAccumulate(long x, IntBinaryOperator accumulatorFunction) {
int prev, next;
do {
prev = get();
next = accumulatorFunction.applyAsInt(prev, x);
} while (!compareAndSet(prev, next));
return prev;
}
2.5.17 accumulateAndGet(Int x, LongBinaryOperator accumulatorFunction) TODO
public final int accumulateAndGet(int x, IntBinaryOperator accumulatorFunction) {
int prev, next;
do {
prev = get();
next = accumulatorFunction.applyAsInt(prev, x);
} while (!compareAndSet(prev, next));
return next;
}