A Glide memory cache backed by a delegate Picasso LruCache

GlideMemoryCache.java

import android.graphics.Bitmap;
import android.support.annotation.NonNull;

import com.bumptech.glide.load.Key;
import com.bumptech.glide.load.engine.Resource;
import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
import com.bumptech.glide.load.engine.cache.MemoryCacheAdapter;
import com.bumptech.glide.load.resource.bitmap.BitmapResource;
import com.squareup.picasso.LruCache;

public class GlideMemoryCache extends MemoryCacheAdapter {

    private static final String GLIDE_PREFIX = "glide ";

    @NonNull private LruCache picassoMemoryCache;
    @NonNull private BitmapPool bitmapPool;

    public GlideMemoryCache(@NonNull LruCache picassoMemoryCache, @NonNull BitmapPool bitmapPool) {
        this.picassoMemoryCache = picassoMemoryCache;
        this.bitmapPool = bitmapPool;
    }

    @Override
    public Resource<?> put(Key key, Resource<?> resource) {
        if (resource instanceof BitmapResource) {
            Bitmap bitmap = ((BitmapResource) resource).get();
            picassoMemoryCache.set(keyToString(key), bitmap);
        }
        return resource;
    }

    @Override
    public Resource<?> remove(Key key) {
        Bitmap bitmap = picassoMemoryCache.get(keyToString(key));
        if (bitmap != null) {
            return BitmapResource.obtain(bitmap, bitmapPool);
        }
        return null;
    }

    @Override
    public int getCurrentSize() {
        return picassoMemoryCache.size();
    }

    @Override
    public int getMaxSize() {
        return picassoMemoryCache.maxSize();
    }

    @Override
    public void clearMemory() {
        picassoMemoryCache.clear();
    }

    private String keyToString(Key key) {
        return GLIDE_PREFIX + key.toString();
    }
}