String grammar = "[%{BEGIN} - %{END}]";
String input = "[-3.4 - 8.43]";
ParserGenerator gen = new ParserGenerator( grammar );
Parser<Map<String,String>> parser = gen.newParser();
Map<String,String> data = parser.parse( input );
for( String key : data.keySet() ){
System.out.println( key + " = " + data.get( key ) );
}