private boolean checkMutuallyExclusive(String literal, String expression) {
		return (expression == null || literal == null) ? true
				: (expression.contains(literal) && (literal.length() + 2 == expression.length()));
	}
Check if the literal and expression values mutually exclusive (have different content).

@param literal
@param expression
@return boolean value
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/modules/metadata/RedisSinkOptionsMetadata.java