Make ScheduledTransitLeg, FlexibleTransitLeg fully immutable

[leonardehrenfried]

Summary

Right now the ScheduledTransitLeg is mostly immutable apart from a few fields

• distanceMeters due to testing
• alerts because they are added later
• fareProducts they are also added later

Because Aracadis has a few sandbox features that manipulate the legs over the years I had to fix many bugs because of the leg is half immutable and half mutable. I would like to fix all of them at once and therefore I'm making the ScheduledTransitLeg and FlexibleTransitLeg immutable and all fields must now be set via a builder.

There is also the special sandbox leg ConsolidatedStopLeg which also required some special handling but it is now also fully immutable and has a builder.

Unit tests

Lots of tests added and some re-written.

Documentation

Javadoc.

[codecov]

Codecov Report

Attention: Patch coverage is 93.24324% with 10 lines in your changes missing coverage. Please review.

Project coverage is 69.86%. Comparing base (448ad8f) to head (b2ac81f).
Report is 235 commits behind head on dev-2.x.

Files with missing lines	Patch %	Lines
...r/ext/fares/impl/CombinedInterlinedTransitLeg.java	0.00%	3 Missing ⚠️
...ntripplanner/ext/fares/FaresToItineraryMapper.java	50.00%	1 Missing and 1 partial ⚠️
...ntripplanner/model/plan/UnknownTransitPathLeg.java	0.00%	2 Missing ⚠️
...tripplanner/model/plan/LegConstructionSupport.java	87.50%	1 Missing ⚠️
...terchain/filters/transit/DecorateTransitAlert.java	83.33%	1 Missing ⚠️
...er/routing/algorithm/mapping/AlertToLegMapper.java	92.85%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             dev-2.x    #6386      +/-   ##
=============================================
+ Coverage      69.72%   69.86%   +0.14%     
- Complexity     18016    18156     +140     
=============================================
  Files           2057     2072      +15     
  Lines          76967    77324     +357     
  Branches        7844     7851       +7     
=============================================
+ Hits           53666    54026     +360     
+ Misses         20550    20543       -7     
- Partials        2751     2755       +4     

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[habrahamsson-skanetrafiken]

This is great work. Making these model classes fully immutable makes stuff so much simpler to reason about.

[leonardehrenfried]

I've moved the computation of distanceMeters entirely outside of ScheduledTransitLeg and its builder. This is ready for review again.

[t2gran]

Thank you for fixing the "small things" it makes the code easier to read.