com.nostra13.universalimageloader.cache.memory.impl.LRULimitedMemoryCache Maven / Gradle / Ivy

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package com.nostra13.universalimageloader.cache.memory.impl;

import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;

import android.graphics.Bitmap;

import com.nostra13.universalimageloader.cache.memory.LimitedMemoryCache;

/**
 * Limited {@link Bitmap bitmap} cache. Provides {@link Bitmap bitmaps} storing. Size of all stored bitmaps will not to
 * exceed size limit. When cache reaches limit size then the least recently used bitmap is deleted from cache.
 * 
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 */
public class LRULimitedMemoryCache extends LimitedMemoryCache {

	private static final int INITIAL_CAPACITY = 10;
	private static final float LOAD_FACTOR = 1.1f;

	/** Cache providing Least-Recently-Used logic */
	private final Map lruCache = Collections.synchronizedMap(new LinkedHashMap(INITIAL_CAPACITY, LOAD_FACTOR, true));

	public LRULimitedMemoryCache(int sizeLimit) {
		super(sizeLimit);
	}

	@Override
	public boolean put(String key, Bitmap value) {
		if (super.put(key, value)) {
			lruCache.put(key, value);
			return true;
		} else {
			return false;
		}
	}

	@Override
	public Bitmap get(String key) {
		lruCache.get(key); // call "get" for LRU logic
		return super.get(key);
	}

	@Override
	public void remove(String key) {
		lruCache.remove(key);
		super.remove(key);
	}

	@Override
	public void clear() {
		lruCache.clear();
		super.clear();
	}

	@Override
	protected int getSize(Bitmap value) {
		return value.getRowBytes() * value.getHeight();
	}

	@Override
	protected Bitmap removeNext() {
		Bitmap mostLongUsedValue = null;
		synchronized (lruCache) {
			Iterator> it = lruCache.entrySet().iterator();
			if (it.hasNext()) {
				Entry entry = it.next();
				mostLongUsedValue = entry.getValue();
				it.remove();
			}
		}
		return mostLongUsedValue;
	}

	@Override
	protected Reference createReference(Bitmap value) {
		return new WeakReference(value);
	}
}