外观模式

public interface MemoryCache {
    Bitmap findFromMemory(String url);
}
public interface DiskCache {
    Bitmap findFromDisk(String url);
}
public interface NetworkCache {
    InputStream findFromNetwork(String url);
}

public class MemoryCacheImpl implements MemoryCache {
    @Override
    public Bitmap findFromMemory(String url) {
        System.out.println("从内存中查找");
        return null;
    }
}
public class DiskCacheImpl implements DiskCache {
    @Override
    public Bitmap findFromDisk(String url) {
        System.out.println("从硬盘查找");
        return null;
    }
}
public class NetworkCacheImpl implements NetworkCache {
    @Override
    public InputStream findFromNetwork(String url) {
        System.out.println("从网络获取");
        return null;
    }
}

MemoryCache memoryCache = new MemoryCacheImpl();
memoryCache.findFromMemory("http...");

DiskCache diskCache = new DiskCacheImpl();
diskCache.findFromDisk("http...");

NetworkCache networkCache = new NetworkCacheImpl();
networkCache.findFromNetwork("http...");

public class Facade {

    private String url;
    private MemoryCache mMemoryCache;
    private DiskCache mDiskCache;
    private NetworkCache mNetworkCache;

    public Facade(String url) {
        this.url = url;
        mMemoryCache = new MemoryCacheImpl();
        mDiskCache = new DiskCacheImpl();
        mNetworkCache = new NetworkCacheImpl();
    }

    public void load(){
       mNetworkCache.findFromNetwork(url);
       mDiskCache.findFromDisk(url);
       mNetworkCache.findFromNetwork(url);
    }
}

Facade facade = new Facade("http...");
facade.load();