code: 	protected void addEmptyValueMapping(DefaultMapper mapper, String field, Object model) {
  		ParserContext parserContext = new FluentParserContext().evaluate(model.getClass());
  		Expression target = expressionParser.parseExpression(field, parserContext);
  		try {
  			Class<?> propertyType = target.getValueType(model);
  			Expression source = new StaticExpression(getEmptyValue(propertyType));
  			DefaultMapping mapping = new DefaultMapping(source, target);
  			if (logger.isDebugEnabled()) {
  				logger.debug("Adding empty value mapping for parameter '" + field + "'");
  			}
  			mapper.addMapping(mapping);
  		} catch (EvaluationException e) {
  		}
  	}
  
  	/**
  	 * Adds a {@link DefaultMapping} between the given request parameter name and a matching model field.
  	 *
  	 * @param mapper the mapper to add the mapping to
  	 * @param parameter the request parameter name
  	 * @param model the model
  	 */
  