# Com

## Overview

The `com` root namespace is a top-level Java package that currently contains two entirely unrelated sub-modules:

- **`com.example`** — A fixture package that exists solely to support static analysis tooling. It provides minimal, empty classes that linting rules (specifically the **bug-ca-002** Sonar rule) can resolve against when validating import ordering in JSP and JSF files.
- **`com.fujitsu`** — The root namespace for **Futurity**, an older Japanese enterprise application built on the Java Servlet/JSP stack. This module is currently in scaffold-only mode: deployment descriptors are configured, but no business logic has been implemented. Its web-tier components (a context listener and character-encoding filter) form the outermost request boundary for Japanese-language clients using Shift JIS encoding.

These two sub-modules have no relationship to each other. `com.example` is infrastructure for code quality checks, while `com.fujitsu` is the start of a production application (albeit an empty one at this stage). The `com` package itself contains no source files and no classes of its own — it acts purely as a namespace container.

## Sub-module Guide

### `com.example` — Static Analysis Fixtures

This package exists as scaffolding for the project's code quality pipeline. Rather than containing any runtime behavior, it provides well-known, importable classes that static analysis rules can resolve against. The current child sub-module is:

- **`com.example.bugca002`** — Contains a single empty class (`KnownClass`) that serves as an import resolution target for the **bug-ca-002** Sonar rule. The rule validates that JSP import directives appear in a canonical order (e.g., alphabetical). `KnownClass` gives the rule a concrete, resolvable class to check against.

### `com.fujitsu` — Futurity Enterprise Application

This package is the root for Futurity, a Japanese enterprise application. Its web-tier infrastructure is scaffolded but not yet implemented. The active child sub-module is:

- **`com.fujitsu.futurity.web.x33`** — Contains two servlet-lifecycle components:
  - **`X33AppContextListener`** — A `ServletContextListener` stub that will handle application startup and shutdown events (currently a no-op).
  - **`X33JVRequestEncodingSjisFilter`** — A servlet filter stub that will intercept HTTP requests to normalize character encoding from Shift JIS to the internal encoding (currently a no-op).

### How the Sub-Modules Relate

Within `com.fujitsu`, the listener and filter address different points in the application lifecycle: the listener fires once per deployment cycle (bootstrap and teardown), while the filter fires per-request in the servlet filter chain. In a fully implemented system, the listener would initialize shared configuration (such as the target encoding) that the filter reads during request processing. Currently, they are independent stubs with no connecting logic.

`com.example` and `com.fujitsu` share no code, no dependencies, and no architectural pattern beyond the coincidental use of minimal, scaffolded classes.

## Key Patterns and Architecture

### Fixture-Based Testing (com.example)

The `com.example` package follows a fixture-based testing pattern. Classes here are structural scaffolding, not production code:

- **Predictability** — Empty classes with no dependencies are fully deterministic for static analysis to resolve.
- **Isolation** — Each Sonar rule gets its own sub-package (e.g., `bugca002`), preventing cross-rule interference.
- **Minimal footprint** — Classes are intentionally empty, so they cannot introduce production bugs into the analysis pipeline.

### Stub-and-Wire (com.fujitsu)

Every class in `com.fujitsu` follows a **stub-and-wire** pattern: they are registered in deployment descriptors (`web.xml` and `web-full.xml`) so they can be instantiated by the servlet container, but contain no implementation logic. This is a deliberate strategy — the deployment baseline goes in first so configuration-level integration tests pass, with business logic to be added later.

### Request Flow (Intended, com.fujitsu)

Once the Futurity business layer is implemented, the HTTP request path will follow this sequence:

1. The servlet container deploys the application and calls `X33AppContextListener.contextInitialized()`.
2. An incoming HTTP request arrives at the container.
3. The container dispatches the request through the filter chain, invoking `X33JVRequestEncodingSjisFilter.doFilter()`.
4. The filter sets the request character encoding and forwards the request via `chain.doFilter()`.
5. The request reaches downstream servlets or JSP pages for business logic.
6. On undeploy, the container calls `X33AppContextListener.contextDestroyed()`.

### Deployment Descriptor Duplication

Both the filter and the listener in `com.fujitsu` are declared in two deployment descriptors — `web.xml` and `web-full.xml`. This suggests the application supports multiple deployment profiles (a "basic" and a "full" variant) and both profiles should activate the same web infrastructure. This duplication should be audited to confirm it is intentional and does not cause duplicate activations at runtime.

### Module Interaction Diagram

```mermaid
flowchart TD
  subgraph com["Root Namespace: com"]
    subgraph example["com.example"]
      sub1["Static Analysis
Fixtures"]
      bugca["com.example.bugca002
KnownClass
(import target)"]
    end
    subgraph fujitsu["com.fujitsu"]
      sub2["Futurity
Enterprise App"]
      web["com.fujitsu.futurity.web.x33
Web Tier
(listener + filter)"]
    end
  end
  example -->|"supports"| analysis["Static Analysis
(SonarQube bug-ca-002)"]
  fujitsu -->|"provides"| runtime["Fujitsu Enterprise
Runtime (JSP/Servlet)"]
```

## Dependencies and Integration

### Inbound Dependencies

The `com` namespace has no inbound dependencies from other packages in the index — it is a leaf in the module dependency graph. Neither `com.example` nor `com.fujitsu` are consumed by other packages as imports.

### Outbound Dependencies

| Package | Dependency | Purpose |
|---|---|---|
| `com.example.bugca002` | None | `KnownClass` has no dependencies; it is entirely self-contained. |
| `com.fujitsu.futurity.web.x33` | `javax.servlet` | Both classes depend on `Filter`, `FilterChain`, `FilterConfig`, `ServletContextListener`, `ServletRequest`, and `ServletResponse` interfaces. |

### Cross-Module Context

`com.example` is consumed by the JSP file `BugCa002Language Before Import.jsp`, which imports `KnownClass` for the **bug-ca-002** rule's import-resolution validation. `com.fujitsu` does not currently integrate with any other modules — its web-tier components are the outermost layer of the (not yet built) application, integrating by reacting to events from the servlet container rather than through direct code-level coupling to downstream modules.

## Notes for Developers

### Working with `com.example`

- **Do not remove.** Despite its simplicity, this package is required by the `bug-ca-002` analysis fixtures. Deleting `KnownClass` or its package would break the JSP file that references it and likely cause import-resolution failures in the static analysis pipeline.
- **Keep it minimal.** Classes in this area are intentionally stubs. Adding business logic, dependencies, or side effects would turn a test fixture into production code, introducing unnecessary risk and maintenance burden.
- **Package naming convention.** The `bugca002` package name follows the pattern `<rule-id-classifier>` used across the project to group classes that exist solely as test data for specific SonarQube rules. New test fixtures should follow the same pattern: create a package named after the rule, place a minimal class inside, and reference it from the appropriate fixture JSP/JSF file.
- **No runtime behavior.** This area does not execute at runtime, does not participate in request lifecycles, and does not manage data. Any developer encountering these classes in a runtime stack trace should investigate why test infrastructure code is being loaded outside of analysis.

### Working with `com.fujitsu`

- **All components are no-ops.** If you are tasked with implementing the filter's encoding logic, the standard approach is to cast the `ServletRequest` to `HttpServletRequest`, call `setCharacterEncoding()` with the target encoding (e.g., `"SJIS"` or `"UTF-8"`), and then pass the request down the chain. For the listener, implement `contextInitialized()` and `contextDestroyed()` with appropriate initialization and teardown logic.
- **Verify the deployment configuration.** The dual registration in `web.xml` and `web-full.xml` should be audited. If both descriptors are deployed simultaneously, the servlet container may issue warnings or behave unpredictably due to duplicate registrations.
- **The filter may be removable.** Since it performs no work, check whether the `<filter-mapping>` entries are still needed. If Japanese client encoding is handled elsewhere (e.g., by the servlet container, a front-end proxy, or a different filter), this filter and its mappings could be safe to delete.
- **This appears to be a greenfield project.** The stub-and-wire pattern, combined with the complete absence of business logic, suggests this package was scaffolded as a foundation for future development. The naming convention (X33) and Shift JIS encoding hints suggest this may be part of a larger Fujitsu enterprise product line targeting the Japanese market.