Add how to update and publish flux-commands.md

README.md

@@ -15,3 +15,51 @@ Here are some links to existing documentation:
 - [Introduction to Metafacture (workshop slides)](http://slides.lobid.org/metafacture-2020)
 - [Metamorph Book (work in progress, very early version)](http://b3e.net/metamorph-book/latest/)
 - [Metamorph-Dokumentation (entstanden im Projekt linked-swissbib)](https://swissbib.gitlab.io/metamorph-doku)
+
+## how to change flux-commands.md
+
+The entries in flux-commands.md describe the usage of commands used by flux.
+flux-commands.md is fully automatically generated. To make this happen one has to
+fill in the proper annotations in the correponding java classes. E.g.
+
+```
+reset-object-batch
+------------------
+- description:  Resets the downstream modules every batch-size objects
+- options:      batchsize (int)
+- signature:    Object -> Object
+- java class:   org.metafacture.flowcontrol.ObjectBatchResetter
+```
+
+is generated by reading following annotations in [ObjectBatchResetter.java](https://github.com/metafacture/metafacture-core/blob/511b4af8b993c85a33d6a18322258a195684d133/metafacture-flowcontrol/src/main/java/org/metafacture/flowcontrol/ObjectBatchResetter.java):
+
+```
+@Description("Resets the downstream modules every batch-size objects")
+@FluxCommand("reset-object-batch")
+@In(Object.class)
+@Out(Object.class)
+```
+The description of "options" is produced from all "public setter-methods", in this case:
+```
+ public void setBatchSize(final int batchSize) { ...
+```
+The option's name is produced by cutting away the "set" from the methods name, leaving
+"BatchSize" which is then lowercased. The parameter of this option is generated from the
+parameter type of the method - here an "int"eger.
+
+## how to publish flux-commands.md
+
+If you have updated some of these annotations, say "description", and these changes are
+merged into the master branch, generate a new flux-commands.md like this:
+
+Go to metafacture-core, checkout master and build a distribution and start flux.sh:
+```bash
+$ ./gradlew installDist`
+$ cd ./metafacture-runner/build/install/metafacture-core/
+$ flux.sh > flux-commands.md
+```
+
+Open the generated flux-commands.md and remove some boilerplate at the beginning of the
+file manually. Save it, copy it here, commit and push.
+
+The [publishing process will be automated with an github action](https://github.com/metafacture/metafacture-core/issues/368).