gistfile1.java

/**
    * System property substitution
    * @param input The input string
    * @return The output
    */
   protected String getSubstitutionValue(String input)
   {
      if (input == null || input.trim().equals(""))
         return input;

      while (input.indexOf("${") != -1)
      {
         int from = input.indexOf("${");
         int to = input.indexOf("}");
         int dv = input.indexOf(":", from + 2);

         if (dv != -1)
         {
            if (dv > to)
               dv = -1;
         }

         String systemProperty = "";
         String defaultValue = "";
         if (dv == -1)
         {
            String s = input.substring(from + 2, to);
            if ("/".equals(s))
            {
               systemProperty = File.separator;
            }
            else if (":".equals(s))
            {
               systemProperty = File.pathSeparator;
            }
            else
            {
               systemProperty = SecurityActions.getSystemProperty(s);
            }
         }
         else
         {
            systemProperty = SecurityActions.getSystemProperty(input.substring(from + 2, dv));
            defaultValue = input.substring(dv + 1, to);
         }
         String prefix = "";
         String postfix = "";

         if (from != 0)
         {
            prefix = input.substring(0, from);
         }

         if (to + 1 < input.length() - 1)
         {
            postfix = input.substring(to + 1);
         }

         if (systemProperty != null && !systemProperty.trim().equals(""))
         {
            input = prefix + systemProperty + postfix;
         }
         else if (defaultValue != null && !defaultValue.trim().equals(""))
         {
            input = prefix + defaultValue + postfix;
         }
      }
      return input;
   }