question: public void addAll ( Collection < ? extends T > collection ) { if ( mEventDelegate != null ) mEventDelegate . addData ( collection == null ? 0 : collection . size ( ) ) ; if ( collection != null && collection . size ( ) != 0 ) { synchronized ( mLock ) { mObjects . addAll ( collection ) ; } } int dataCount = collection == null ? 0 : collection . size ( ) ; if ( mObserver != null ) mObserver . onItemRangeInserted ( getCount ( ) - dataCount + 1 , dataCount ) ; if ( mNotifyOnChange ) notifyItemRangeInserted ( headers . size ( ) + getCount ( ) - dataCount + 1 , dataCount ) ; log ( "addAll notifyItemRangeInserted " + ( headers . size ( ) + getCount ( ) - dataCount + 1 ) + "," + ( dataCount ) ) ; }
target:  Adds the specified Collection at the end of the array.