Cursor support for not-cursor adapters

CursorAdapterBase.java

public class CursorAdapter extends AnyAdapter {
  private int mCount;

  private Cursor mCursor;
  private boolean mDataValid;
  private DataSetObserver mDataSetObserver;
  
  public CursorAdapter(Cursor cursor){
      super();
      mCursor = cursor;
      mDataValid = cursor != null;
      mDataSetObserver = new NotifyingDataSetObserver();
      if (mCursor != null) {
          mCursor.registerDataSetObserver(mDataSetObserver);
          findIndices();
      }
  }
  
  @Override
    public int getCount() {
        if (mCursor != null && !mCursor.isClosed()) {
            mCount = mCursor.getCount();
        }
        return mCount;
    }

    /**
     * Change the underlying cursor to a new cursor. If there is an existing cursor it will be
     * closed.
     */
    public void changeCursor(Cursor cursor) {
        Cursor old = swapCursor(cursor);
        if (old != null) {
            old.close();
        }
    }

    /**
     * Swap in a new Cursor, returning the old Cursor.  Unlike
     * {@link #changeCursor(Cursor)}, the returned old Cursor is <em>not</em>
     * closed.
     */
    public Cursor swapCursor(Cursor newCursor) {
        if (newCursor == mCursor) {
            return null;
        }
        final Cursor oldCursor = mCursor;
        if (oldCursor != null && mDataSetObserver != null) {
            oldCursor.unregisterDataSetObserver(mDataSetObserver);
        }
        mCursor = newCursor;
        if (mCursor != null) {
            if (mDataSetObserver != null) {
                mCursor.registerDataSetObserver(mDataSetObserver);
            }
            mDataValid = true;
            findIndices();
            notifyDataSetChanged();
        } else {
            mDataValid = false;
            notifyDataSetChanged();
            //There is no notifyDataSetInvalidated() method in RecyclerView.Adapter
        }
        return oldCursor;
    }

    protected void findIndices(){
      //TODO: store column indices in fields.
    }

    private class NotifyingDataSetObserver extends DataSetObserver {
        @Override
        public void onChanged() {
            super.onChanged();
            mDataValid = true;
            notifyDataSetChanged();
        }

        @Override
        public void onInvalidated() {
            super.onInvalidated();
            mDataValid = false;
            notifyDataSetChanged();
            //There is no notifyDataSetInvalidated() method in RecyclerView.Adapter
        }
    }
}