Android开源框架Universal-Image-Loader学习无——WeakMemoryCache 和 FuzzyKeyMemoryCache

WeakMemoryCache 源码：

BaseMemoryCache参见：http://blog.csdn.net/woliuyunyicai/article/details/45330867

/**
 * Memory cache with {@linkplain WeakReference weak references} to {@linkplain android.graphics.Bitmap bitmaps}<br />
 * <br />
 * <b>NOTE:</b> This cache uses only weak references for stored Bitmaps.
 *
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 * @since 1.5.3
 */
public class WeakMemoryCache extends BaseMemoryCache {
    @Override
    protected Reference<Bitmap> createReference(Bitmap value) {
        return new WeakReference<Bitmap>(value);
    }
}

FuzzyKeyMemoryCache源码：

/**
 * MemoryCache的装饰者模式。为cache提供一个特殊功能：（使用Comparator）使得一些不同的keys被当做是等价的。当使用key put一些值到cache中
 * 具有“相同”意义的keys将会先被移除（一般不会用到该class）
 * NOTE: Used for internal needs. Normally you don't need to use this class.
 */
public class FuzzyKeyMemoryCache implements MemoryCache {

    private final MemoryCache cache;
    private final Comparator<String> keyComparator;

    public FuzzyKeyMemoryCache(MemoryCache cache, Comparator<String> keyComparator) {
        this.cache = cache;
        this.keyComparator = keyComparator;
    }

    @Override
    public boolean put(String key, Bitmap value) {
        // Search equal key and remove this entry
        synchronized (cache) {
            String keyToRemove = null;
            for (String cacheKey : cache.keys()) {
                if (keyComparator.compare(key, cacheKey) == 0) {
                    keyToRemove = cacheKey;
                    break;
                }
            }
            if (keyToRemove != null) {
                cache.remove(keyToRemove);
            }
        }
        return cache.put(key, value);
    }

    @Override
    public Bitmap get(String key) {
        return cache.get(key);
    }

    @Override
    public Bitmap remove(String key) {
        return cache.remove(key);
    }

    @Override
    public void clear() {
        cache.clear();
    }

    @Override
    public Collection<String> keys() {
        return cache.keys();
    }
}