[SIS-410] More stable MathTransform.Inverse serialization

• Type: New Feature
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.5, 0.6, 0.7, 0.8
• Fix Version/s: 1.0
• Component/s: Referencing
• Assignee: Martin Desruisseaux
• Reporter: Martin Desruisseaux
• Created: 05/Mar/18 13:57
• Updated: 20/Oct/19 19:20
• Resolved: 05/Mar/18 14:15

Description

The AbstractMathTransform.Inverse class is non-static. This cause the compiler to generate a this$0 private field. But this synthetic fields may not be the same across implementations of different Java compilers. Consequently reading a class serialized with an Apache SIS library compiled with a different compiler may not recognize the fields that are named differently (see http://developer.java.sun.com/developer/bugParade/bugs/4211550.html). We should use static inner class with a named field (e.g. "forward")instead. This is an incompatible change, but AbstractMathTransform.Inverse is protected rather than public.

In the particular case of AbstractMathTransform.Inverse, it also avoid a minor strangeness. Since we extends Inverse in different classes, we saw the synthetic this$0 field duplicated in each subclass. Using a named field instead will avoid that.