question: public PercentEscaper ( String safeChars , boolean plusForSpace ) { if ( safeChars . matches ( ".*[0-9A-Za-z].*" ) ) { throw new IllegalArgumentException ( "Alphanumeric characters are always 'safe' and should not be " + "explicitly specified" ) ; } if ( plusForSpace && safeChars . contains ( " " ) ) { throw new IllegalArgumentException ( "plusForSpace cannot be specified when space is a 'safe' character" ) ; } if ( safeChars . contains ( "%" ) ) { throw new IllegalArgumentException ( "The '%' character cannot be specified as 'safe'" ) ; } this . plusForSpace = plusForSpace ; this . safeOctets = createSafeOctets ( safeChars ) ; }
target:  Constructs a URI escaper with the specified safe characters and optional handling of the space character.