Merge "Return the previous value when adding a new one."

  public class SparseArrayMap<K, V> {

    ctor public SparseArrayMap();

    method public void add(int, @NonNull K, @Nullable V);

    method public V add(int, @NonNull K, @Nullable V);

    method public void clear();

    method public boolean contains(int, @NonNull K);

    method public void delete(int);

public class SparseArrayMap<K, V> {

    private final SparseArray<ArrayMap<K, V>> mData = new SparseArray<>();

    /** Add an entry associating obj with the int-K pair. */

    public void add(int key, @NonNull K mapKey, @Nullable V obj) {

    /**

     * Add an entry associating obj with the int-K pair.

     *

     * @return the previous value associated with key, or null if there was no mapping for key.

     * (A null return can also indicate that the map previously associated null with key, if the

     * implementation supports null values.)

     */

    public V add(int key, @NonNull K mapKey, @Nullable V obj) {

        ArrayMap<K, V> data = mData.get(key);

        if (data == null) {

            data = new ArrayMap<>();

            mData.put(key, data);

        }

        data.put(mapKey, obj);

        return data.put(mapKey, obj);

    }

    /** Remove all entries from the map. */