CopyOnWriteArrayList原理

首先每次写操作,都将数组copy一份,并赋值给arrays

读操作读不加锁

写操作加锁

ReentrantLock

因为每次写都要copy数组,这是一项繁重的操作,因此

CopyOnWriteArrayList适合读多写少的情况。

add方法的源码如下:

public boolean add(E e) {
final ReentrantLock lock = this.lock;
lock.lock();
try {
Object[] elements = getArray();
int len = elements.length;
Object[] newElements = Arrays.copyOf(elements, len + 1);
newElements[len] = e;
setArray(newElements);
return true;
} finally {
lock.unlock();
}
}

参考文章:

http://blog.csdn.net/wjwj1203/article/details/8109000

http://www.cnblogs.com/sunwei2012/archive/2010/10/08/1845656.html

05-11 19:58
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