@AssertTrue(message = "one of 'topic', 'topicExpression', 'queue', 'queueExpression', 'key', 'keyExpression' options must be set explicitly")
	public boolean isOptionRequired() {
		return ((queue != null) || (topic != null) || (key != null) || (queueExpression != null)
				|| (topicExpression != null) || (keyExpression != null));
	}
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