@SuppressWarnings("unchecked")
	@Override
	public Tuple select(String expression) {
		EvaluationContext context = new StandardEvaluationContext(toMap());
		ExpressionParser parser = new SpelExpressionParser();
		Expression exp = parser.parseExpression(expression);

		Object result = exp.getValue(context);
		Map<String, Object> resultMap = null;
		if (ClassUtils.isAssignableValue(Map.class, result)) {
			resultMap = (Map<String, Object>) result;
		}
		if (resultMap != null) {
			return toTuple(resultMap);
		}
		else {
			return new DefaultTuple(new ArrayList<String>(0), new ArrayList<>(0),
					this.configurableConversionService);
		}
	}
@param index the index of the value
@return the converted raw value, trimmed
spring-xd-tuple/src/main/java/org/springframework/xd/tuple/DefaultTuple.java