144-java-data-oriented-programming
This Claude Code skill applies data-oriented programming principles to Java projects, emphasizing separation of data structures from behavior using records, immutable transformations, and pure functions. Use it when refactoring code to improve design through flatter data models, generic-to-specific type conversions, validation functions, and flexible data access layers while maintaining compilation integrity throughout the process.
git clone --depth 1 https://github.com/jabrena/cursor-rules-java /tmp/144-java-data-oriented-programming && cp -r /tmp/144-java-data-oriented-programming/skills/144-java-data-oriented-programming ~/.claude/skills/144-java-data-oriented-programmingSKILL.md
# Java Data-Oriented Programming Best Practices Apply data-oriented programming in Java: separate data from behavior with records, use immutable data structures, pure functions for transformations, flat denormalized structures with ID references, generic-to-specific type conversion when needed, pure validation functions, and flexible generic data access layers. All transformations should be explicit, traceable, and composed of clear pure functional steps. **What is covered in this Skill?** - Separation of concerns: data structures (records, POJOs) vs behavior (utility classes, services) - Immutability: records, final fields, transformations produce new instances - Pure data transformations: functions depending only on inputs, no side effects - Flat and denormalized data: ID references instead of deep nesting - Generic until specific: Map<String,Object> for dynamic data, convert to records when processing - Data integrity: pure validation functions returning validation results - Flexible generic data access: generic CRUD interfaces, interchangeable implementations **Scope:** The reference is organized by examples (good/bad code patterns) for each core area. Apply recommendations based on applicable examples. ## Constraints Before applying any data-oriented programming recommendations, ensure the project compiles. Compilation failure is a blocking condition. After applying improvements, run full verification. - **MANDATORY**: Run `./mvnw compile` or `mvn compile` before applying any change - **SAFETY**: If compilation fails, stop immediately — do not proceed until resolved - **VERIFY**: Run `./mvnw clean verify` or `mvn clean verify` after applying improvements - **BEFORE APPLYING**: Read the reference for detailed good/bad examples, constraints, and safeguards for each data-oriented programming pattern ## When to use this skill - Improve the code with Data-Oriented Programming - Apply Data-Oriented Programming - Refactor the code with Data-Oriented Programming - Apply Data-Oriented Programming - Refactor the code with Data-Oriented Programming - Apply Data-Oriented Programming ## Workflow 1. **Compile project before data-oriented changes** Run `./mvnw compile` or `mvn compile` and stop immediately if compilation fails. 2. **Read data-oriented reference and assess model design** Read `references/144-java-data-oriented-programming.md` and identify candidates for data/behavior separation and immutable transformations. 3. **Apply data-oriented refactorings** Implement selected improvements using records, pure transformation functions, flat structures, and explicit validation. 4. **Verify with full build** Run `./mvnw clean verify` or `mvn clean verify` after applying improvements. ## Reference For detailed guidance, examples, and constraints, see [references/144-java-data-oriented-programming.md](references/144-java-data-oriented-programming.md).
Use when you need to generate a checklist document with Java system prompts, following the embedded template exactly and producing INVENTORY-SKILLS-JAVA.md in the project root. This should trigger for requests such as Create Java system prompts checklist; Generate INVENTORY-SKILLS-JAVA.md; Use @001-skills-inventory. Part of cursor-rules-java project
Use when you need to generate a checklist document with embedded agents inventory, following the embedded template exactly and producing INVENTORY-AGENTS-JAVA.md in the project root. This should trigger for requests such as Create embedded agents inventory checklist; Generate INVENTORY-AGENTS-JAVA.md; Use @002-agents-inventory. Part of cursor-rules-java project
Use when you need to install the embedded robot agents into either .cursor/agents or .claude/agents, selecting the destination interactively and copying the embedded agent definitions from project assets. This should trigger for requests such as Install embedded agents; Bootstrap .cursor/agents; Bootstrap .claude/agents; Copy robot agents. Part of cursor-rules-java project
Guides the creation of agile epics with comprehensive definition including business value, success criteria, and breakdown into user stories. Use when the user wants to create an agile epic, define large bodies of work, break down features into user stories, or document strategic initiatives. This should trigger for requests such as Create an agile epic; Write an epic; I need to create an epic; Define an epic; Epic definition. Part of cursor-rules-java project
Guides the creation of detailed agile feature documentation from an existing epic. Use when the user wants to split an epic into feature files, derive features with scope and acceptance criteria, or plan feature documentation for stakeholders or engineering. This should trigger for requests such as Create features from an epic; Split epic into features; Feature files from epic; Derive features from epic. Part of cursor-rules-java project
Guides the creation of agile user stories and Gherkin feature files. Use when the user wants to create a user story, write acceptance criteria, define Gherkin scenarios, or author BDD feature files. This should trigger for requests such as Create a user story; Write a user story; I need to write a user story. Part of cursor-rules-java project
Use when you need to generate Architecture Decision Records (ADRs) for a Java project through an interactive, conversational process that systematically gathers context, stakeholders, options, and outcomes to produce well-structured ADR documents. This should trigger for requests such as Generate ADR; Create Architecture Decision Record; Document architecture decision; Architecture Decision Record for Java. Part of cursor-rules-java project
Facilitates conversational discovery to create Architectural Decision Records (ADRs) for functional requirements covering CLI, REST/HTTP APIs, or both. Use when the user wants to document command-line or HTTP service architecture, capture functional requirements, create ADRs for CLI or API projects, or design interfaces with documented decisions. This should trigger for requests such as Create ADR for functional requirements; Document functional requirements; Capture functional requirements; Generate functional requirements in an ADR. Part of cursor-rules-java project