# Com / Fujitsu

## Overview

The `com.fujitsu` package serves as the packaging root for the **Fujitsu Futurity** suite — a family of Java EE web applications. At this level, the module represents an organizational boundary rather than an operational one: it contains no source files, classes, or dependencies directly indexed at the root itself. All operational content lives in its child sub-packages.

The primary (and currently only) sub-package is **Futurity** (`com.fujitsu.futurity`), which functions as the top-level application module. Futurity is a web-tier infrastructure scaffold, specifically built for the **X33** variant — a Japan-focused application variant. Its responsibility is to provide the structural hooks for intercepting, transforming, and managing HTTP traffic lifecycle before requests reach any business logic. As of the current state, this is largely a **structural skeleton**: servlet filters, context listeners, and deployment descriptors are declared and wired, but their implementations are empty or no-op stubs.

This module is essentially a **foundational framework** — the plumbing has been built, but the pipes are not yet carrying any signal.

## Sub-module Guide

The `com.fujitsu` package currently contains one sub-module:

### `futurity` — The Futurity Application

The Futurity module is the only child of `com.fujitsu` and represents the full application stack today. It is a Japan-focused Java EE web application (the X33 variant) whose current role is infrastructure scaffolding.

Within Futurity, the only child package is `com.fujitsu.futurity.web`, which in turn contains the `x33` application sub-module. This sub-module defines two servlet-tier components:

| Component | Concern | Scope |
|---|---|---|
| `X33JVRequestEncodingSjisFilter` | Sets character encoding (MS932 / Shift JIS) on incoming requests | Per-request |
| `X33AppContextListener` | Provides startup and shutdown hooks for application-scoped resources | Application lifecycle |

Together, these two components form the complete servlet-tier hook set for X33. The listener operates at application deployment time (once), while the filter operates per HTTP request (repeatedly). Both are currently no-op stubs.

**How this fits the bigger picture:** The `com.fujitsu` module acts as the organizational root, Futurity is the application container, the `web` package is the web-tier layer, and `x33` is the concrete application living inside that layer. Each level adds a layer of specificity — from brand (Fujitsu) to product (Futurity) to tier (web) to variant (X33).

## Key Patterns and Architecture

```mermaid
flowchart TD
  subgraph FUJITSU["com.fujitsu"]
    subgraph FUT["com.fujitsu.futurity"]
      subgraph WEB["com.fujitsu.futurity.web"]
        X33["X33 Sub-module"]
      end
    end
  end
  WEB --> X33
  X33 --> FILTER["X33JVRequestEncodingSjisFilter
Request encoding filter"]
  X33 --> LISTENER["X33AppContextListener
Lifecycle listener"]
  WEB --> DESC["Deployment descriptors
web.xml / web-full.xml"]
  DESC -->|Registers| FILTER
  DESC -->|Registers| LISTENER
```

### Key architectural patterns

- **Lifecycle-Request Separation:** The X33 module cleanly separates application lifecycle concerns (listener) from per-request concerns (filter). This is the standard Java EE servlet architecture pattern.

- **Stub Scaffolding:** Both servlet components implement their respective interfaces with empty or no-op bodies. This pattern suggests early-stage scaffolding — infrastructure hooks built ahead of business logic — or a decommissioned application where the structural skeleton remains as a foundation.

- **Deployment Descriptor-Driven:** Components are explicitly declared in `web.xml` and `web-full.xml` rather than discovered via Servlet 3.0+ annotations. This means deployment configuration is XML-centric, not annotation-driven.

- **Dual-Profile Deployment:** Both `web.xml` (basic profile) and `web-full.xml` (full Java EE profile) register the same components. Any implementation changes must be reflected in both descriptors to avoid environment-specific behavior divergence.

- **Isolation:** No cross-module integration exists yet. The X33 package imports no other internal modules, and no other modules reference X33 classes. It operates as a standalone web module within the broader Futurity ecosystem.

- **Character Encoding Focus:** The sole non-trivial design decision so far is the character encoding filter targeting MS932 / Shift JIS, indicating Japanese language support as a first-class requirement.

## Dependencies and Integration

### Internal Dependencies

The module has no internal cross-module dependencies at this time. No source files from `com.fujitsu` or its children import classes from other packages, and no external modules import from `com.fujitsu`. This reflects the stub status of all components.

### External Dependencies

All functionality within the Futurity/X33 components depends solely on the standard **Java Servlet API**:

| Dependency | Component | Purpose |
|---|---|---|
| `javax.servlet.Filter` | `X33JVRequestEncodingSjisFilter` | Servlet filter interface |
| `javax.servlet.ServletRequest` / `ServletResponse` | `X33JVRequestEncodingSjisFilter` | Request/response handling |
| `javax.servlet.FilterChain` | `X33JVRequestEncodingSjisFilter` | Filter chain delegation |
| `javax.servlet.FilterConfig` | `X33JVRequestEncodingSjisFilter` | Initialization parameters |
| `javax.servlet.ServletContextListener` | `X33AppContextListener` | Application lifecycle |
| `javax.servlet.ServletContextEvent` | `X33AppContextListener` | Lifecycle event payloads |

The code uses `javax.servlet` (Java EE / Servlet 3.x) package naming. Developers should confirm whether the build has migrated to `jakarta.servlet` (Jakarta EE / Servlet 5.x+), as this would require updating imports before any implementation work.

### Deployment

Both deployment descriptors (`web.xml` and `web-full.xml`) are responsible for wiring the X33 components. Any changes to component registration must be reflected in both files.

## Notes for Developers

- **Everything is a stub.** Neither the filter nor the listener contains executable logic. Adding implementation is safe — there is no existing behavior to break.

- **Character encoding is a priority area.** If the X33 application handles Japanese content, implementing `X33JVRequestEncodingSjisFilter` is likely one of the first practical tasks. A recommended approach is to check `req.getCharacterEncoding() == null` before setting the encoding, to avoid overriding an explicit client-specified `Content-Type` header.

- **Servlet API version matters.** The code references `javax.servlet` (Java EE / Servlet 3.x). Confirm whether the project has migrated to `jakarta.servlet` (Jakarta EE / Servlet 5.x+) before implementing any interface methods, as the package name will differ.

- **Coordinate across deployment profiles.** Changes to `web.xml` should be mirrored in `web-full.xml`. Divergence between these profiles is a common source of environment-specific bugs.

- **This appears to be a structural foundation.** The presence of properly named and deployed stubs suggests this package is intended to grow into a fully functional web tier. Treat these classes as extension points rather than dead code.

- **Indexing caveat:** Static analysis reports zero indexed classes and methods for the `com.fujitsu` root because the stub classes are minimal. Once implementation is added, the code index should be refreshed to capture new symbols.