code: public static Map<Pattern,String> compile(Map<String,String> placeholders) {
          Map<Pattern,String> compiled = new HashMap<Pattern, String>();
          for (Map.Entry<String, String> entry : placeholders.entrySet()) {
              String placeholder = entry.getKey();
              String value = entry.getValue();
              compiled.put(Pattern.compile("\\{" + Pattern.quote(placeholder) + "\\}"), value);
          }
          return unmodifiableMap(compiled);
      }
docs: <p>Compiles the given placeholder map.</p>
  <p>Placeholder keys reflects the placeholder name, and the value the value to use as replacement when placeholder are merged.</p>
  <p>Returns a map where keys are Patterns of the following form: {placeholdername}</p>
  @param placeholders placeholder map to compile
  @return compiled placeholder map