public synchronized boolean containsKey(CacheKey key) {
    Preconditions.checkNotNull(key);
    if (!mMap.containsKey(key)) {
      return false;
    }
    EncodedImage storedEncodedImage = mMap.get(key);
    synchronized (storedEncodedImage) {
      if (!EncodedImage.isValid(storedEncodedImage)) {
        // Reference is not valid, this means that someone cleared reference while it was still in
        // use. Log error
        // TODO: 3697790
        mMap.remove(key);
        FLog.w(
            TAG,
            "Found closed reference %d for key %s (%d)",
            System.identityHashCode(storedEncodedImage),
            key.getUriString(),
            System.identityHashCode(key));
        return false;
      }
      return true;
    }
  }
Determine if an valid entry for the key exists in the staging area.
imagepipeline/src/main/java/com/facebook/imagepipeline/cache/StagingArea.java