Add CheckReturnValue to queries

It allows to detect incorrect API usage through static checkers in IDEs or Findbugs.

Findbugs and the IDEs work in a nice way and one can define an annotation named @CheckReturnValue in their own package and the checkers will honer it. There won’t be any need for a dependency to a 3rd party.

Marking a class with @CheckReturnValue will apply that to all of it’s method. In order to ignore a particular method one can annotate it with an annotation named @CanIgnoreReturnValue.

All this would be beneficial for a better developer experience with the Flowable Java API

[filiphr]

@lamtrhieu you don’t need to write a custom detector for findbugs.

An example of what an incorrect usage is:

ProcessInstnaceQuery query = ...

query.processDefinitionKey("key");

The problem is not calling one of singleResult, list, listPage or count.

An example how this looks like in AssertJ can be found in this.

This is how the CheckReturnValue annotation works in Findbug.

There is also a possibility to use a custom CanIgnoreReturnValue. This is how it was done in AssertJ.

All things said, if you want to do something I would suggest you do one query and we see how it works, because I think that there might be some issues (at least discovery in IntelliJ)

[lamtrhieu]

Hi @filiphr Can you please help to answer all my questions when you have time ? Thanks