# Root

## Overview

The root (`""`) of this codebase is the top-level organizational container — a package-free namespace that groups together multiple, loosely related top-level namespaces. Rather than representing a single application or domain, the root serves as a **structural scaffold** where distinct subsystems coexist: an enterprise Fujitsu platform, an `eo` web application layer, and Java EE standard packages (`javax`).

This codebase appears to be a large, legacy Java EE (Jakarta EE) web application system. At its core is the **Futurity platform** — a multi-regional web application targeting specific markets (notably Japan via the X33 variant). The `eo.web` package provides an additional web-facing MVC layer, likely for a separate application or feature set. The `javax` packages represent standard Java EE frameworks integrated into the system, with JavaServer Faces (JSF) being the documented web framework.

All three namespaces share a common characteristic: they are largely **scaffolding** at this stage. Source code under `com.fujitsu`, `eo`, and `javax` consists primarily of empty class declarations, stub methods, and namespace containers. The substantive implementation is either pending, or lives in modules not yet indexed. This suggests the project is in an early construction or migration phase, where the architectural skeleton has been established but business logic has not yet been added.

## Sub-module Guide

The root encompasses three top-level namespaces that operate largely independently, each serving a different concern:

### com.fujitsu — The Fujitsu Enterprise Platform

The `com.fujitsu` namespace is the root for the Fujitsu enterprise application ecosystem. It contains the **Futurity platform** (`com.fujitsu.futurity`), a multi-regional Jakarta EE web application. The only concrete implementation so far is the **X33 Japan regional variant** (`com.fujitsu.futurity.web.x33`), which includes two stub components:

- **`X33AppContextListener`** — a servlet lifecycle listener intended to bootstrap configuration, locale settings, and shared resources at deployment time.
- **`X33JVRequestEncodingSjisFilter`** — a servlet filter intended to apply Shift-JIS character encoding to incoming HTTP requests, supporting legacy Japanese enterprise systems.

The hierarchy is strictly vertical: namespace (com.fujitsu) → platform (futurity) → web tier (web) → regional variant (x33) → components (filter, listener). X33 is the sole regional variant, and both its filter and listener are class-stubs with empty bodies.

### eo — The Web Application Layer

The `eo` domain houses the **web-facing surface area** (`eo.web`) of what appears to be a separate web application or feature set. Its primary sub-module is **`eo.web.webview`**, which organizes web pages as self-contained MVC modules following the Apache Struts 1.x pattern.

The sole documented page module is **`ACA001SF`**, which consists of four tightly coupled files:

| Artifact | Role |
|---|---|
| `ACA001SFBean.java` | JavaBean view-model exposing properties for JSP consumption |
| `ACA001SFLogic.java` | Controller class that handles requests and populates the bean |
| `WEBGAMEN_FULL_ACA001.xml` | Struts XML config mapping action names to logic classes |
| `FULL_ACA001010PJP.jsp` | JSP template rendering the page from bean data |

The `eo.web` namespace is designed for future expansion — new page modules would follow the same flat sub-package pattern under `eo.web.webview` (e.g., `eo.web.webview.NEXTSF`).

### javax — Java EE Standard Packages

The `javax` package group represents the Java EE standard framework integration within this codebase. The documented sub-module is **`javax.faces`**, the root namespace for the **JavaServer Faces (JSF)** reference implementation. Its child `javax.faces.webapp` contains `FacesServlet` — the central request controller that routes HTTP requests through the JSF six-phase lifecycle (Restore View, Apply Request Values, Process Validations, Update Model Values, Invoke Application, Render Response).

Like the other namespaces, `javax.faces` here is a **stub**: the class is declared but contains no implementation. In production, this would be provided by a JSF reference implementation (Mojarra or MyFaces).

### How the sub-modules relate

While the three namespaces share the root as their parent, they operate in **parallel lanes** rather than in a parent-child relationship with each other:

- **`com.fujitsu`** provides the enterprise application platform with regional variants (X33 Japan).
- **`eo`** provides the MVC web layer with page-level controllers, likely for the same or a related application.
- **`javax`** provides the Java EE infrastructure layer — the frameworks and standard APIs the application builds on.

There is no direct code-level dependency between `com.fujitsu`, `eo`, and `javax` in the current index. However, the architectural intent is clear: the `eo.web` Struts-based MVC pages (and potentially future `com.fujitsu` domain logic) would consume or replace the `javax.faces` infrastructure to serve web requests. The X33 filter in `com.fujitsu` acts as a servlet-level cross-cutting concern that sits below both MVC approaches in the request processing chain.

```mermaid
flowchart TD
    subgraph Fujitsu["com.fujitsu<br/>Enterprise Platform"]
        Futurity["com.fujitsu.futurity<br/>Platform Namespace"] --> X33["com.fujitsu.futurity.web.x33<br/>X33 Japan Variant"]
        X33 --> Listener["X33AppContextListener<br/>(lifecycle bootstrap)"]
        X33 --> Filter["X33JVRequestEncodingSjisFilter<br/>(Shift-JIS encoding)"]
        Listener -->|"delegates"| Bootstrap["config, locale, shared resources"]
        Filter -->|"setCharacterEncoding"| Encoding["Shift_JIS"]
        Encoding -->|"chain.doFilter"| TargetServlet["Target Servlet"]
    end

    subgraph Eo["eo<br/>Web Domain"]
        EoWeb["eo.web<br/>Web Surface Area"] --> Webview["eo.web.webview<br/>Struts MVC Pages"]
        Webview --> ACA001SF["ACA001SF page module<br/>Bean + Logic + XML + JSP"]
    end

    subgraph Javax["javax<br/>Java EE Standard Packages"]
        Faces["javax.faces<br/>JSF Root Package"] --> Webapp["javax.faces.webapp<br/>JSF Web Integration"]
        Webapp --> Servlet["FacesServlet<br/>Request Controller<br/>(stub)"]
        Servlet -->|"delegates to"| Lifecycle["JSF Six-Phase<br/>Request Lifecycle"]
    end

    Filter -->|"registered via"| WebXML["web-full.xml<br/>deployment descriptor"]
    Servlet -->|"registered via"| WebXML
    TargetServlet -->|"receives from"| Filter
    ACA001SF -->|"routes via"| StrutsXML["Struts XML Config"]
    StrutsXML -->|"executes"| ACA001SFLogic["ACA001SFLogic<br/>(controller)"]
```

## Key Patterns and Architecture

### Stub-First Development Across All Namespaces

All three namespaces share a common development pattern: **classes are declared, but bodies are empty or skeletal**. This is not a coincidence — it indicates a systematic "scaffold-first" approach where the architectural skeleton is established before business logic. The stubs serve as compile-time contracts (correct interfaces, correct naming, correct package placement) while deferring implementation.

### Namespace-Hollow Hierarchy

`com.fujitsu` and its `futurity` child contain no indexed source files directly. They exist purely for namespace isolation and to support future growth. This is common in large enterprise Java projects where top-level packages exist as organizational containers. Similarly, `javax.faces` is a namespace group whose actual implementation (`FacesServlet`) lives in the `webapp` subpackage.

### Dual MVC Paradigms

The codebase exhibits **two competing MVC approaches** that have not yet been reconciled:

1. **Struts 1.x** (`eo.web.webview`) — The classic XML-configured, action-based MVC pattern. Each page is a self-contained module of Bean + Logic + XML + JSP. This is a legacy but well-understood framework.
2. **JSF** (`javax.faces`) — The component-based MVC paradigm. `FacesServlet` orchestrates a six-phase lifecycle to manage component trees, converters, validators, and view rendering.

The codebase appears to be in an undecided state — possibly migrating from Struts to JSF, or maintaining both for different feature sets. There is no cross-wiring documented between them in the current index.

### Regional Variant Through Package Scoping

The `com.fujitsu.futurity.web.x33` module demonstrates a **package-level regional variant** pattern. Rather than using feature flags or runtime configuration to distinguish the Japan variant, X33 is expressed through its own package (`x33`) and class naming convention (`X33JV`). This makes the variant's boundaries explicit at compile time and supports clean separation between shared platform code and region-specific logic.

### Write-Once Bean Discipline

In the `eo.web.webview` module, the `ACA001SFBean` class defines only a getter (`getValue()`) with no setter. This **output-only bean discipline** enforces immutability after the logic phase — data flows from the controller into the bean once, and the JSP consumes it without the risk of the view triggering unwanted side-effects through property setters.

### Servlet Lifecycle Bootstrap Pattern

The `com.fujitsu` X33 module follows the standard Jakarta EE bootstrap-and-filter pattern:

- **Listener** (`ServletContextListener` / `ApplicationListener`): Runs once at deployment to initialize shared resources.
- **Filter** (`javax.servlet.Filter`): Runs for every HTTP request to apply cross-cutting transformations.
- **Delegation**: The filter delegates to the next link in the chain, and the listener primes the context that downstream components consume.

## Dependencies and Integration

### Internal Dependencies

| Dependency | Type | Description |
|---|---|---|
| `com.fujitsu.futurity` | child namespace | Sole concrete platform under `com.fujitsu`. Currently a namespace container. |
| `com.fujitsu.futurity.web.x33` | leaf package | Only module with substantive (stub) code under `com.fujitsu`. Contains the X33 Japan filter and listener. |
| `eo.web.webview` | child package | Primary functional child of `eo.web`. Contains Struts MVC page modules. |
| `javax.faces.webapp` | child package | Sole JSF web integration module. Contains the `FacesServlet` stub. |

### External Dependencies

| Dependency | Used By | Role |
|---|---|---|
| `javax.servlet.*` | X33 Filter, X33 Listener, FacesServlet | Core Servlet API for HTTP request/response handling. Provided at runtime by the servlet container. |
| `org.apache.struts.*` | `eo.web.webview` | Apache Struts 1.x framework. Expected but not yet indexed. |
| JSF Reference Implementation (Mojarra/MyFaces) | `javax.faces.webapp` | Production `FacesServlet` implementation. The stub here delegates to one of these. |
| Spring Framework (potential) | X33 Listener | If the listener implements Spring's `ApplicationListener`, it introduces a Spring context dependency. |
| `web-full.xml` | X33 Filter, FacesServlet | Deployment descriptor that wires servlets, filters, and listeners into the container. |

### Integration with the Broader System

```mermaid
flowchart LR
    Client["Browser / Client"] -->|"HTTP Request"| Chain["Servlet Filter Chain"]
    Chain -->|"Shift-JIS decode"| X33Filter["X33JVRequestEncodingSjisFilter"]
    X33Filter -->|"chain.doFilter"| Router{"Which MVC?"}
    Router -->|"Struts Action"| Struts["Struts XML Config"]
    Router -->|"JSF URL pattern"| JSF["FacesServlet"]
    Struts -->|"execute()"| StrutsLogic["*Logic Controller"]
    JSF -->|"lifecycle"| JSFLifecycle["JSF Six-Phase Lifecycle"]
    StrutsLogic -->|"populates"| StrutsBean["*Bean"]
    JSFLifecycle -->|"renders"| JSFView["JSF Component Tree"]
    StrutsBean -->|"reads properties"| StrutsJSP["JSP Template"]
    JSFView -->|"renders HTML"| Client
    StrutsJSP -->|"renders HTML"| Client
```

The request processing pipeline, when fully implemented, would flow:

1. **Incoming HTTP request** → passes through X33's `X33JVRequestEncodingSjisFilter` for Shift-JIS encoding (if targeting the Japan variant).
2. **Routing** → determined by the URL pattern and deployment descriptor (`web-full.xml`), the request is dispatched to either the Struts action layer (`eo.web.webview`) or the JSF lifecycle (`javax.faces.webapp`).
3. **MVC processing** → Struts routes via XML config to `*Logic` controllers; JSF routes through its six-phase lifecycle to component trees.
4. **View rendering** → Struts uses JSP templates reading from `*Bean` properties; JSF renders from its component tree to HTML.
5. **Response** → HTML is returned to the client.

### Indexing Status

The root-level index reports **zero source files, zero classes, and zero methods**. This is expected for a root package — it contains no code directly. However, it also means the root module documentation must be synthesized entirely from its child modules. The child modules themselves report varying levels of coverage: `com.fujitsu` (no indexed files, but child `fujitsu.md` documents X33 stubs), `eo` (zero indexed files, but `eo/web.md` documents Struts stubs), and `javax` (no indexed files, but `javax/faces.md` documents the JSF stub). This indexing gap should be verified — some files may exist but fall outside the indexing scope.

## Notes for Developers

- **Everything is scaffolding.** All documented classes are skeletal with empty method bodies. Before building on top of any of these, verify whether real logic should already exist by checking the corresponding source files directly.
- **Two MVC frameworks, no reconciliation.** The codebase has both Struts 1.x (`eo.web.webview`) and JSF (`javax.faces`) in place, with no documented integration between them. If you're working on a new feature, determine which framework it should target before writing code.
- **Shift-JIS encoding is legacy.** The `X33JVRequestEncodingSjisFilter` in `com.fujitsu` explicitly handles Shift-JIS encoding for the Japan variant. If the application is modernizing, evaluate whether UTF-8 is a viable replacement and what impact this has on compatibility with Japanese legacy systems.
- **Bean asymmetry in `eo.web.webview`.** The `ACA001SFBean` class defines only a getter with no setter. If you need to modify a bean's value from your own code, you must add a setter explicitly. This is by design — beans are output-only models.
- **To implement the X33 filter**, the filter should cast the request to `HttpServletRequest` and call `request.setCharacterEncoding("Shift_JIS")` before delegating via `chain.doFilter(req, res)`.
- **Thread safety.** The X33 filter holds no instance state and is thread-safe by design. If state is added later, consider synchronization or thread-local storage.
- **`web-full.xml` is the wiring hub.** Both the X33 filter and the JSF `FacesServlet` are registered through this deployment descriptor. This is the central configuration file for servlet lifecycle wiring.
- **Indexing gaps.** The code index reports zero source files across all root-level packages. This may be an oversight in the indexing scope. Consider expanding the scope to verify whether additional files exist under `com.fujitsu`, `eo`, and `javax` that were not captured.
- **Namespace-hollow packages are intentional.** `com.fujitsu`, `com.fujitsu.futurity`, and `javax.faces` are all namespace containers with no direct source files. This is the expected pattern — all implementation lives in leaf packages. Do not attempt to add code directly to these hollow packages.