Refactor/new object diagram design level

[ahmedkha79]

MVP refactor: scaffold Presenter & Model, decouple view/canvas; add PlantUML docs

Summary

Introduce an incremental MVP scaffold for the object diagram to decouple UI rendering (view/canvas) from orchestration and persistence. This PR adds Presenter and Model contracts and light scaffolding so the subsequent, low-risk migration steps can proceed in small, testable commits.

Motivation

The original NewObjectDiagram (and its view) mixed rendering, user input handling, business logic and persistence. This created a large God class, high cyclomatic complexity and bidirectional couplings that reduce testability and maintainability. The scaffold in this PR prepares a Passive-View MVP: view = UI only; presenter = orchestrator; model = state; repository = persistence.

What changed

• Added/updated Presenter and Model scaffolding for the object diagram.
• Decoupled view/canvas from orchestration; view forwards events to Presenter.
• Introduced PlacementRepository contract (persistence hook) and Null adapters to preserve current runtime behavior while migrating.
• Added PlantUML documentation for current and target MVP in docs/.
• Left fallbacks in place intentionally to avoid regressions during incremental migration.

Files included in this PR

(Committed files relevant to this PR)

• use-gui/src/main/java/org/tzi/use/gui/views/diagrams/objectdiagram/NewObjectDiagramPresenter.java
• use-gui/src/main/java/org/tzi/use/gui/views/diagrams/objectdiagram/NewObjectDiagramView.java
• use-gui/src/main/java/org/tzi/use/gui/views/diagrams/objectdiagram/ObjectDiagramModel.java
• use-gui/src/main/java/org/tzi/use/gui/views/diagrams/objectdiagram/PlacementRepository.java
• use-gui/src/main/java/org/tzi/use/gui/views/diagrams/objectdiagram/NullPlacementRepository.java
• use-gui/src/main/java/org/tzi/use/gui/views/diagrams/objectdiagram/NullContextMenuProvider.java
• use-gui/src/main/java/org/tzi/use/gui/views/diagrams/objectdiagram/NullApplicationController.java
• docs/objectdiagram_mvp_current.puml
• docs/objectdiagram_mvp_target.puml

Behavior & backward compatibility

• The commit is scaffolding only. Runtime behavior should remain unchanged because Null adapters act as no-ops that mirror the old code path for now.
• Follow-up commits will incrementally move logic from NewObjectDiagram into Presenter and Model. Each chunk should be small and accompanied by a compile/run check.

Testing / QA instructions (PowerShell)

1. Build GUI module:
   cd C:\Users\ahmed\IdeaProjects\use
   mvn -pl use-gui -DskipTests compile

2. Smoke test (manual):

   • Start the application and open the Object Diagram.
   • Verify that the diagram opens without exceptions and that basic actions (select, context menu, basic create/delete) behave as before.

3. Unit tests (next phase):

   • Write Presenter unit tests that mock the View and the PlacementRepository. Verify orchestration rules.

Acceptance checklist for merge

• mvn -pl use-gui -DskipTests compile -> Build passes
• Smoke test: Object Diagram opens and basic interactions work
• Reviewers have checked the PlantUML architecture diagrams in docs/
• Plan for next refactor chunks is acknowledged in the PR comments

Next steps (recommended incremental chunks)

1. Move placement persistence (restore/storePlacementInfos) entirely to PlacementRepository; call from Presenter. (Chunk 1)
2. Move visibility/highlight/selection state from NewObjectDiagram into ObjectDiagramModel; make NewObjectDiagram render model snapshots only. (Chunk 2)
3. Route all menu actions, toolbar and shortcuts through the Presenter (remove direct application/system calls from view/diagram). (Chunk 3)
4. Remove Null adapters, finalize API naming (drop I- prefixes if desired), add JavaDoc and unit tests. (Chunk 4)

Risks & mitigation

• Risk: intermediate commits may create compile errors. Mitigation: perform small, reversible chunks, run build after each.
• Risk: Null adapters could remain in code permanently by accident. Mitigation: mark them TODO/FIXME and schedule purge in the final chunk.
• Risk: UI thread (Swing EDT) violations. Mitigation: Presenter must ensure View updates happen on EDT; tests should cover UI behavior where possible.

Suggested reviewers & labels

• Reviewers: GUI/diagram maintainers, architecture reviewers
• Labels: enhancement, refactor, needs-review, MVP

Short PR summary (for PR subject line)

MVP refactor: scaffold Presenter+Model to decouple view/canvas; add PlacementRepository and PlantUML docs

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