artembilan/spring-integration — comment on commit 53248ad74c671efb774c6700492a70b1b27351d3
File:  line 0
By olegz:

I would rephrase it as such:

As many other Spring Integration components <inbound-channel-adapter> and <outbound-channel-adapter>
also provide support for SpEL expression via 'expression' attribute in contrast to method-invocation via 'ref/method' attributes, while following the same contract where:
expression for <inbound-channel-adapter> must always return non-null value,
while the one for <outbound-channel-adapter> must be equivalent of void return type.