[100%] Phase 1: Extract Mapper interface and add config option

[evanchooly]

Parent: #4179

Goal

Make Mapper an interface (@MorphiaInternal), rename current implementation to ReflectiveMapper, add mapper() config to MorphiaConfig.

Details

See Phase 1 in planning doc

Tasks

• Create MapperType enum (LEGACY, CRITTER)
• Add mapper() to MorphiaConfig interface with default LEGACY
• Add mapper field to ManualMorphiaConfig
• Convert Mapper class to interface
• Create AbstractMapper with shared logic (registration, discriminator, listeners, config)
• Create ReflectiveMapper extends AbstractMapper (current implementation)
• Update MorphiaDatastore to use factory method for mapper creation
• Add Sofia error message for invalid config
• Verify all existing tests pass unchanged

Constraint

Any changes to the Mapper interface contract require explicit review.

Progress Tracking

phase_percentage = (completed_tasks / 9) * 100, rounded to nearest integer
gh issue edit 4184 --repo MorphiaOrg/morphia --title "[XX%] Phase 1: Extract Mapper interface and add config option"

parent_percentage = (total_completed_tasks_across_all_phases / 53) * 100, rounded to nearest integer
gh issue edit 4179 --repo MorphiaOrg/morphia --title "[XX%] Integrate critter-core into morphia-core"

When all tasks are complete (100%), close this issue and check its box in #4179.

[evanchooly]

@claude implement the mapper type

[claude]

Claude finished @evanchooly's task in 2m 16s —— View job • claude/issue-4184-20260227-2336 • Create PR ➔

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Implementing MapperType

Tasks

• Gather context and understand the request
• Read planning doc and relevant files
• Create MapperType enum (LEGACY, CRITTER)
• Add mapper() to MorphiaConfig interface with default LEGACY
• Add mapper field to ManualMorphiaConfig
• Commit and push

Summary

Created the MapperType enum and wired it into the config system:

• core/src/main/java/dev/morphia/mapping/MapperType.java — new enum with LEGACY and CRITTER values
• MorphiaConfig.java — added mapper() returning MapperType with @WithDefault("legacy"), plus fluent setter mapper(MapperType value). MorphiaConfigHelper requires no changes — it already handles enums dynamically via reflection.
• ManualMorphiaConfig.java — added mapper field, updated copy constructor, added mapper() getter returning orDefault(mapper, MapperType.LEGACY), updated toString()

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[evanchooly]

Phase 1 complete. All 9 tasks done. PR: #4193