Add collection manipulation methods for union maps and union lists

[EricWittmann]

Summary

Union maps and union lists now generate the same collection manipulation methods as entity maps and entity lists. This provides a consistent API for working with all types of collections in the generated models.

Problem

Previously, union maps and union lists only generated:

• Factory create methods for each union type
• A getter method
• A setter method

Entity maps and entity lists generated:

• Factory create methods
• add, clear, insert, remove methods (named after property)
• A getter method
• No setter (users manipulate via collection methods)

This inconsistency made union collections harder to use and less intuitive.

Solution

Updated the code generator to treat union maps/lists like entity maps/lists:

Generated Methods (example for property "schemas" with types StandardSchema|MultiFormatSchema):

• addSchema(String name, MultiFormatSchemaStandardSchemaUnion value) - add to map
• removeSchema(String name) - remove from map
• clearSchemas() - clear all
• getSchemas() - get the map
• insertSchema(...) - insert at position (for lists)
• createStandardSchema() - factory for StandardSchema
• createMultiFormatSchema() - factory for MultiFormatSchema
• No setter - manipulate via add/clear/remove/insert methods

Methods are named after the property name (singularized), not the union or entity type names.

Changes

1. AbstractCreateMethodsStage.java

   • Added createAddMethod, createClearMethod, createRemoveMethod, createInsertMethod calls for union maps/lists
   • Removed setter generation for union collections
   • Extended method creation logic to handle union types

2. CreateImplMethodsStage.java

   • Extended collection method body generation to handle union types
   • Added parent property tracking for entities within union collections

3. AbstractJavaStage.java

   • Extended JavaType class to support union types in toJavaTypeString() and addImportsTo()

4. CreateReadersStage.java

   • Updated handleUnionListProperty and handleUnionMapProperty to use add methods instead of setters
   • Singularized property names when generating add method calls

5. UnionMapTest.java

   • Added comprehensive testCollectionMethods() test validating all new methods work correctly

Testing

All 10 integration tests pass:

• 9 tests in union-map-test (up from 8) ✅
• New test validates: add, insert, remove, clear methods for union maps, union lists, and union lists of primitives
• Verifies serialization/deserialization works correctly after using collection methods

Build Summary:
  Passed: 10, Failed: 0, Errors: 0, Skipped: 0