gistfile1.java

  class SymbolReplacer {
    protected String stringToReplace;

    SymbolReplacer(String s) {
      this.stringToReplace = s;
    }

    String replace() {
      Pattern symbolPattern = Pattern.compile("\\$([a-zA-Z]\\w*)");
      int startingPosition = 0;
      while (true) {
        Matcher symbolMatcher =
symbolPattern.matcher(stringToReplace.substring(startingPosition));
        if (symbolMatcher.find()) {
          startingPosition += replaceSymbol(symbolMatcher);
        } else
          break;
      }
      return stringToReplace;
    }

    private int replaceSymbol(Matcher symbolMatcher) {
      String symbolName = symbolMatcher.group(1);
      if (getSymbol(symbolName) != null)
        stringToReplace = stringToReplace.replace("$" + symbolName,
translate(symbolName));
      return symbolMatcher.start(1);
    }

    protected String translate(String symbolName) {
      return getSymbol(symbolName);
    }

  }