code: static String expandUriComponent(String source, UriTemplateVariables uriVariables) {
  		if (source == null) {
  			return null;
  		}
  		if (source.indexOf('{') == -1) {
  			return source;
  		}
  		Matcher matcher = NAMES_PATTERN.matcher(source);
  		StringBuffer sb = new StringBuffer();
  		while (matcher.find()) {
  			String match = matcher.group(1);
  			String variableName = getVariableName(match);
  			Object variableValue = uriVariables.getValue(variableName);
  			if (UriTemplateVariables.SKIP_VALUE.equals(variableValue)) {
  				continue;
  			}
  			String variableValueString = getVariableValueAsString(variableValue);
  			String replacement = Matcher.quoteReplacement(variableValueString);
  			matcher.appendReplacement(sb, replacement);
  		}
  		matcher.appendTail(sb);
  		return sb.toString();
  	}
docs: static expansion helpers