Rework ChainInterceptor + configuration logic (Breaking Change)

[christiangoerdes]

Summary by CodeRabbit

• Refactor
  • Simplified chain definition syntax in configuration files.
  • Updated API routing mechanism to use direct path-based references instead of chain indirection.
  • Enhanced documentation for flow configuration.

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[coderabbitai]

📝 Walkthrough

Walkthrough

This refactoring removes the ChainDef class and the reference-based chain resolution mechanism from ChainInterceptor, replacing chain references with direct, flatter reference compositions in configuration files. Chain definitions are now expressed using simpler $ref syntax rather than nested chain reference structures.

Changes

Cohort / File(s)	Summary
Core Chain Mechanism Removal core/src/main/java/com/predic8/membrane/core/interceptor/chain/ChainDef.java	Deleted the ChainDef class entirely, which previously provided reusable chain definitions with interceptor lists and reference attributes.
Chain Interceptor Refactoring core/src/main/java/com/predic8/membrane/core/interceptor/chain/ChainInterceptor.java	Removed the ref field and all reference resolution logic, including the init() override, getInterceptorChainForRef(), getBean() helper, and public setRef()/getRef() accessors.
Documentation Enhancement core/src/main/java/com/predic8/membrane/core/interceptor/.../AbstractFlowWithChildrenInterceptor.java	Added JavaDoc documentation to the setFlow() method describing its purpose for configuring interceptor flow.
Configuration Examples Update distribution/examples/extending-membrane/reusable-plugin-chains/apis.yaml, distribution/examples/extending-membrane/reusable-plugin-chains/proxies.xml	Replaced chainDef with chain declarations and converted nested chain references to direct $ref pointers. Updated API routing from chain-based to path-based composition with explicit interceptor references.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• Chain: Migrate Example to YAML - Fix for component names #2529 — Adds bean lookup functionality to ChainInterceptor while this PR removes the reference-based chain resolution, representing complementary modifications to the same chain resolution mechanism.

Suggested reviewers

• rrayst

Poem

🐰 Chains no longer dance through refs so deep,
Now simpler paths the configs keep,
With $ref pointers, flat and clean,
The cleanest flow we've ever seen! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: removing the ChainDef class and reworking ChainInterceptor configuration logic, and appropriately flags it as a breaking change.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch chain-rework

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[membrane-ci-server]

This pull request needs "/ok-to-test" from an authorized committer.

[christiangoerdes]

/ok-to-test