protected static String getPartialEndedWord(String str, int pos){
		assert(pos < str.length() && pos >= 0);

		if(	posIsAtWord(str, pos) ){
			int prevSpace = findLastNonLetterOrDigit(str, pos);

			return str.substring(prevSpace+1, pos+1);
		}
		return null;
	}
protected static String getPartialEndedWord ( String str , int pos ) { assert ( pos < str . length ( ) && pos >= 0 ) ; if ( posIsAtWord ( str , pos ) ) { int prevSpace = findLastNonLetterOrDigit ( str , pos ) ; return str . substring ( prevSpace + 1 , pos + 1 ) ; } return null ; }
If pos is ending a word in str: returns this word.
Else: returns null;