cn.alotus.core.collection.RingIndexUtil Maven / Gradle / Ivy
The newest version!
package cn.alotus.core.collection;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import cn.alotus.core.lang.Assert;
/**
* 集合索引环形获取工具类
*
* @author ZhouChuGang
* @since 5.7.15
*/
public class RingIndexUtil {
/**
* 通过cas操作 实现对指定值内的回环累加
*
* @param object 集合
*
* - Collection - the collection size
*
- Map - the map size
*
- Array - the array size
*
- Iterator - the number of elements remaining in the iterator
*
- Enumeration - the number of elements remaining in the enumeration
*
* @param atomicInteger 原子操作类
* @return 索引位置
*/
public static int ringNextIntByObj(Object object, AtomicInteger atomicInteger) {
Assert.notNull(object);
int modulo = CollUtil.size(object);
return ringNextInt(modulo, atomicInteger);
}
/**
* 通过cas操作 实现对指定值内的回环累加
*
* @param modulo 回环周期值
* @param atomicInteger 原子操作类
* @return 索引位置
*/
public static int ringNextInt(int modulo, AtomicInteger atomicInteger) {
Assert.notNull(atomicInteger);
Assert.isTrue(modulo > 0);
if (modulo <= 1) {
return 0;
}
for (; ; ) {
int current = atomicInteger.get();
int next = (current + 1) % modulo;
if (atomicInteger.compareAndSet(current, next)) {
return next;
}
}
}
/**
* 通过cas操作 实现对指定值内的回环累加
* 此方法一般用于大量数据完成回环累加(如数据库中的值大于int最大值)
*
* @param modulo 回环周期值
* @param atomicLong 原子操作类
* @return 索引位置
*/
public static long ringNextLong(long modulo, AtomicLong atomicLong) {
Assert.notNull(atomicLong);
Assert.isTrue(modulo > 0);
if (modulo <= 1) {
return 0;
}
for (; ; ) {
long current = atomicLong.get();
long next = (current + 1) % modulo;
if (atomicLong.compareAndSet(current, next)) {
return next;
}
}
}
}