GH-508: Support for Call Hierarchy

[kittaakos]

Issue: #508.

This PR contains

• the migration of the o.e.j.i.coreext.callhierarchy package to the the JDT LS.
  • Copied o.e.j.i.corext.callhierarchy source from JDT UI to LS. ccf7771
  • Switched from JavaPlugin to JavaLanguageServerPlugin. c7ea1da
  • Got rid of the Eclipse workbench dependencies. 33b0a71
• the handler for the language server.

[kittaakos]

This PR is ready for review. I start working on the client implementation in Theia, and I will update this PR with an example so reviewers can try the new call hierarchy LS feature in action.

[kittaakos]

The next LSP4J release is 21 February according to our plans. It will include the call- and type-hierarchy capabilities.

[fbricon]

Can you check if the changes in jdt core are sufficient to cover your needs? #508 (comment)

[kittaakos]

Can you check if the changes in jdt core are sufficient to cover your needs?

I have looked into the PR, and all seems reasonable. The DEFAULT_IGNORE_FILTERS is initialized with an empty String in the CallHierarchyCore, and I am not aware of any other required modifications. Thank you for the refactoring! 👍

Do I have to wait till the jdt.core changes get merged?

[fbricon]

So it seems the Call Hierarchy API has changed in the past couple weeks microsoft/vscode-languageserver-node#420 (comment). We'll need lsp4j to adjust to the new API and then propagate the impacts to this PR

[fbricon]

@rgrunber @jjohnstn when can we expect the changes in jdt core to be available?

[rgrunber]

I'll have a look at the change next week. and hopefully we can get it pushed in. After that it should be available within a day since you track 4.12-I-builds in your target platform.

[fbricon]

@kittaakos FYI, the JDT changes have been merged upstream

[kittaakos]

@kittaakos FYI, the JDT changes have been merged upstream

Thank you for the update, @fbricon!

I'll try to adjust the PR in the forthcoming days.

[yaohaizh]

@kittaakos Any update on this PR? Would like to try this feature if possible.

[testforstephen]

Looks like this PR is pending for a while, really look forward to have a play with this feature.

@kittaakos is there any update about this PR? If you feel it's ok, i would like to provide help to resolve the remaining issue.

[kittaakos]

If you feel it's ok, i would like to provide help to resolve the remaining issue.

Feel free grabbing and reusing whatever you want. I won't have time to work on this in the near future. Please keep in mind this: eclipse-lsp4j/lsp4j#330.

Without the LSP4J changes, you have to build and host your own target platform.

[testforstephen]

Have tried the feature locally, here is the status:

The VS Code client implementation is proposed api, and it lags behind the language server proposal, i have to change lsp4j back for local integration test, it works very well. Thank @kittaakos for your great work.

In the next step, I need wait for VS Code client being stable and fully ready in the official version, before finalizing the server side implementation.

[kittaakos]

change lsp4j back

Please note, I have created a PR in LSP4J, so it is in-sync with the proposed protocol: eclipse-lsp4j/lsp4j#336

[MaskRay]

I think it will be good not to call it hierarchy, because nothing prevents the result from being a flattened list. See microsoft/vscode-languageserver-node#420 (comment)

[testforstephen]

Merged as part of #1306

Thanks @kittaakos