Extract Component - Generate Module Extract list

[rnveach]

Taken from discussions in #29 ,

We need to generate a list of modules, properties, and hierarchy from checkstyle PR for our analysis and to identify full regression model needed.

This the list of information we need right now:

-- Module Information

Package
Class Name
Class hierarchy: Can contain multiple classes. If AbstractSuperCheck is modified, we need to determine that SuperCloneCheck and SuperFinalizeCheck need regression. Must contain full class path.
Interfaces: Same reason as class heirarchy.
Parent Module: Checker or TreeWalker
List of properties

-- Property Information

Name
Type
Default Value
Acceptable Tokens (only for Java and Javadoc checks)

Based on discussions at #19 (comment) and in issue:

As of right now, this probably has to be loaded as a file from a separate maven process.

invoke some simple program in our PR copy of Checkstyle through maven and have it generate the results for us that we need. It will pass the information back to our regression-tool's JVM by a file. We don't need the actual class in memory, we just need it's meta-information.

So we don't have to inject gson dependency into Checkstyle too, I think we should just write out file by hand.
It is ok if we can't cover external maven command by coverage or UT for now.

This is blocked by #19 .

[rnveach]

See https://github.com/checkstyle/checkstyle/blob/0b6721b6b4ad77115cd443f9a7bddf973c2ab224/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsPagesTest.java and https://github.com/checkstyle/checkstyle/blob/0b6721b6b4ad77115cd443f9a7bddf973c2ab224/src/test/java/com/puppycrawl/tools/checkstyle/internal/CheckUtil.java on how to get this information we need.

Modules: https://github.com/checkstyle/checkstyle/blob/0b6721b6b4ad77115cd443f9a7bddf973c2ab224/src/test/java/com/puppycrawl/tools/checkstyle/internal/CheckUtil.java#L151
Properties: https://github.com/checkstyle/checkstyle/blob/0b6721b6b4ad77115cd443f9a7bddf973c2ab224/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsPagesTest.java#L881
Tokens: https://github.com/checkstyle/checkstyle/blob/0b6721b6b4ad77115cd443f9a7bddf973c2ab224/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsPagesTest.java#L450-L480 and https://github.com/checkstyle/checkstyle/blob/0b6721b6b4ad77115cd443f9a7bddf973c2ab224/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsPagesTest.java#L555 and https://github.com/checkstyle/checkstyle/blob/0b6721b6b4ad77115cd443f9a7bddf973c2ab224/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsPagesTest.java#L572

We should ignore properties for now until #5 and only focus on the other module information.

[rnveach]

Is this component only for json related code and named as json?

This component should be between the components git and module.

It should contain only code relating to everything needed to execute the external maven command and read the Checkstyle extract file produced into memory. If file failed to be created, we should throw a FileNotFoundException, with any additional information if possible.

I am currently preferring the name extract. Is this ok?

[Luolc]

In #40 we completed the work of getting the info for reader of json file and putting the info to memory.

We also need to implement the execution of checkstyle project maven process to generate the extract info file, and fetch the contents of it.