CacheValuesIterator.java

package com.xiaoleilu.hutool.cache.impl;

import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * {@link com.xiaoleilu.hutool.cache.impl.AbstractCache} 的值迭代器.
 */
public class CacheValuesIterator<V> implements Iterator<V> {

	private Iterator<? extends CacheObj<?, V>> iterator;

	private CacheObj<?,V> nextValue;

	CacheValuesIterator(AbstractCache<?,V> abstractCacheMap) {
		iterator = abstractCacheMap.cacheMap.values().iterator();
		nextValue();
	}

	/**
	 * 下一个值，当不存在则下一个值为null
	 */
	private void nextValue() {
		while (iterator.hasNext()) {
			nextValue = iterator.next();
			if (nextValue.isExpired() == false) {
				return;
			}
		}
		nextValue = null;
	}

	/**
	 * @return 是否有下一个值
	 */
	@Override
	public boolean hasNext() {
		return nextValue != null;
	}

	/**
	 * @return 下一个值
	 */
	@Override
	public V next() {
		if (false == hasNext()) {
			throw new NoSuchElementException();
		}
		final V cachedObject = nextValue.obj;
		nextValue();
		return cachedObject;
	}

	/**
	 * 从缓存中移除没有过期的当前值
	 */
	@Override
	public void remove() {
		iterator.remove();
	}
}