INT-1945 Initial Commit

[garyrussell]

This is the initial version currently in use at our customer.

It is non-invasive in that the only modified files are the namespace handlers, schemas, and docs. There is a small amount of code duplication in the gateway from the synchronizing inbound adapter.

This could go in M1 with the TODOs below in M2.

TODO:

Factor out common schema elements
Refactor minor code duplication
Explore RemoteFileTemplate

[markfisher]

Gary, This looks great. Sorry it took me so long to get around to the review; it actually turned out to be less intense than I expected ;)

I made a few minor changes and pushed to my fork: https://github.com/markfisher/spring-integration/tree/INT-1945

Please check that out when you get a chance. I'll plan on merging this tomorrow before the M1 release.

A few other comments...

1. I'm definitely looking forward to a RemoteFileTemplate in M2 (maybe even a FileTemplate, as a base class for the remote impl if a distinction is necessary).
2. I'm wondering if we might want to expand FileHeaders.REMOTE_DIR to FileHeaders.REMOTE_DIRECTORY
   There are some inconsistencies already. For example, FileInfo has getRemoteDir(), and AbstractRemoteFileOutboundGateway has isDir(), but ARFOG also has setLocalDirectory(File localDirectory). I know the underlying SFTP code typically abbreviates "dir", but the commons FTP code seems to be explicit with "directory".
3. This one's very minor, but I wonder if OPTION_JUST_NAME in AbstractRemoteFileOutboundGateway might be better as OPTION _NAME_ONLY?

/cc @olegz

[garyrussell]

Thanks for the polishing - my bad c&p in the schema stuff really reiterates we need common schema for these modules.

#2 - I agree we should be consistent.
#3 - I concur - I pushed this change.

[markfisher]

I made one more commit to change several instances of "dir" to "directory":
754917b

Then, I merged.