# Com / Fujitsu / Futurity

## Overview

The `com.fujitsu.futurity` package is the root namespace for the Fujitsu Futurity platform — an enterprise application system organized under the `com.fujitsu` Java package hierarchy. Futurity appears to be a multi-regional, Jakarta EE–based web application platform. At this point in the codebase, it exists as an organizational scaffold: the parent package and several intermediate levels serve as namespace containers, while the first concrete implementation materializes in the web tier under `com.fujitsu.futurity.web`.

The platform's architecture follows a layered model — web, domain, infrastructure — with regional variants identified by code prefixes (e.g. `X33JV` for X33 Japan). This package-level organization mirrors a typical Java enterprise application: top-level package groups logical subsystems, and the web tier defines the boundary where external HTTP traffic enters the system.

## Sub-module Guide

### com.fujitsu.futurity.web

The web package (`com.fujitsu.futurity.web`) is the only child module with substantive content. It functions as a parent namespace for web-layer subsystems, most notably the X33 Japan-focused variant. While the web package itself currently holds no indexed source files — serving as an organizational container — its children implement the HTTP request lifecycle.

This module sits at the boundary between external clients and the broader Futurity domain, defining the entry points through which HTTP traffic reaches application-level services. It follows a Jakarta EE servlet-based architecture, where filters intercept and transform requests, and application listeners manage bootstrap and teardown events.

#### X33: Japan Regional Variant

X33 (`com.fujitsu.futurity.web.x33`) is the primary concrete subsystem. It represents a Japan-targeted variant of the Futurity platform, identifiable by the `X33JV` (X33 Japan) naming convention throughout the codebase. X33 is organized into two leaf packages that serve complementary phases of the web-layer lifecycle:

| Sub-module | Component | Purpose |
|---|---|---|
| `com.fujitsu.futurity.web.x33.filter` | `X33JVRequestEncodingSjisFilter` | Handles Shift-JIS character encoding for Japanese form data |
| `com.fujitsu.futurity.web.x33.listener` | `X33AppContextListener` | Application bootstrap — loading config, initializing shared resources |

These two packages form a complete lifecycle pair. The listener's bootstrap work establishes shared state and configuration that the filter — and the rest of the application — consumes during request processing.

## How They Relate

The parent `com.fujitsu.futurity` namespace aggregates the web tier, which in turn contains the X33 subsystem. X33 is self-contained: its filter and listener packages are leaf packages with no further children. The interaction follows a linear web-layer pipeline:

```mermaid
flowchart TD
    subgraph Parent["com.fujitsu.futurity (Futurity Platform)"]
        direction TB
        subgraph Web["com.fujitsu.futurity.web"]
            direction TB
            subgraph X33["com.fujitsu.futurity.web.x33 (X33 Japan Variant)"]
                direction TB
                Listener["X33AppContextListener"] -->|contextInitialized| Bootstrap["Bootstrap: config, locale, shared resources"]
                Filter["X33JVRequestEncodingSjisFilter"] -->|doFilter| Encoding["setCharacterEncoding Shift_JIS"]
                Encoding -->|chain.doFilter| Target["Target Servlet / Controller"]
                Bootstrap --> Filter
            end
        end
        Listener -->|implements| ListenerIF["ServletContextListener / ApplicationListener"]
        Filter -->|implements| FilterIF["javax.servlet.Filter"]
        FilterIF -->|registered in| WebXML["web-full.xml deployment descriptor"]
    end
```

The data flow is sequential: the listener bootstraps shared resources at deployment time, and every subsequent HTTP request traverses the filter chain before reaching the target servlet. If the Shift-JIS encoding filter is fully implemented, it will decode request bodies before downstream components attempt to process Japanese form data.

## Key Patterns and Architecture

### Lifecycle-based separation of concerns

X33 follows the standard Jakarta EE pattern of separating bootstrap logic from request-time processing. The listener owns initialization code (`contextInitialized` / `contextDestroyed`), while the filter owns per-request cross-cutting logic. This separation makes the codebase easier to reason about: startup concerns are isolated from request-handling concerns, and each can be tested and modified independently.

### Stub-first development pattern

Both sub-modules in X33 are currently stubs — class declarations exist with correct package placement and naming, but no business logic is implemented. This suggests that the X33 subsystem is either new and under active development, or was scaffolded in anticipation of future requirements. The filter's `doFilter` method is a passthrough, and the listener's class body is empty. Developers should expect to add meaningful implementation before these components are functional.

### Filter chain delegation

The filter follows the standard Servlet Filter pattern: receive the HTTP request, optionally transform it, and delegate to the next link in the chain via `FilterChain.doFilter()`. The current implementation skips the transformation step entirely. When implemented, the expected transformation is setting the request character encoding to `Shift_JIS` before delegation, ensuring that downstream components receive properly decoded Japanese text.

### Package naming convention

The X33 identifier appears consistently across the module, reinforcing its identity as a regional variant:

| Pattern | Example | Meaning |
|---|---|---|
| `X33JV` | `X33JVRequestEncodingSjisFilter` | X33 Japan-specific variant |
| `X33` | `X33AppContextListener` | General X33 subsystem |
| `web.x33.*` | `filter`, `listener` | Leaf packages under X33 |

### Namespace hierarchy pattern

The parent package hierarchy (`com.fujitsu.futurity`) acts as a namespace container with no direct code — all substantive implementation lives in leaf packages below it. This is a common pattern in large enterprise Java projects where intermediate packages exist purely for organizational clarity and future growth.

## Dependencies and Integration

### Internal dependencies

- **No parent source files indexed**: The `com.fujitsu.futurity` parent and the intermediate `web` packages contain no indexed source files. They function as namespace containers for child modules.
- **X33 self-contained**: The `com.fujitsu.futurity.web.x33` module is the only child module with substantive code, with its `filter` and `listener` sub-packages having no further dependencies on other sibling modules.

### External dependencies

- **Jakarta Servlet API** (`javax.servlet`): Both the filter (`javax.servlet.Filter`) and the listener (likely `ServletContextListener` or Spring `ApplicationListener`) depend on the Servlet API. These are provided by the servlet container at runtime.
- **Spring Framework (potential)**: If the listener implements Spring's `ApplicationListener` rather than the standard `ServletContextListener`, it introduces a dependency on the Spring context.
- **`web-full.xml`**: The deployment descriptor wires the filter into the servlet container, making it part of the request processing pipeline.

### Integration with the broader system

The X33 web module appears to be a Japan-targeted variant of the Futurity platform. The Shift-JIS encoding requirement — visible in the filter name and intent — points to integration with Japanese legacy UIs or enterprise systems. The listener's bootstrap role suggests it may wire up encoding configuration, locale settings, or regional features consumed by other X33 domain components outside the web tier.

When fully implemented, the X33 web layer will serve as the HTTP-facing entry point for Japanese-language Futurity operations, ensuring that all incoming request data is correctly decoded before reaching domain logic.

## Notes for Developers

- **Both sub-modules are unimplemented.** The filter is a no-op passthrough and the listener is an empty class. If you are tasked with adding X33 functionality, these are the entry points.
- **To enable Shift-JIS encoding**, update `X33JVRequestEncodingSjisFilter.doFilter()` to cast the request to `HttpServletRequest` and call `request.setCharacterEncoding("Shift_JIS")` before `chain.doFilter(req, res)`.
- **To wire up the listener**, add the appropriate interface (`ServletContextListener` or Spring `ApplicationListener`) and implement the lifecycle methods. Register it in `web-full.xml` or via Spring component scanning as appropriate.
- **Thread safety**: The filter holds no instance state and is thread-safe by design. If state is added later, consider synchronization.
- **Shift-JIS vs UTF-8**: If the application is migrating away from Shift-JIS, consider whether the filter is still needed or should use UTF-8 instead. This has implications for compatibility with Japanese legacy systems.
- **No source files indexed for the parent package.** The parent `com.fujitsu.futurity` serves as a namespace container; all substantive code lives in the X33 child module under `com.fujitsu.futurity.web.x33`.
- **No child modules** exist for X33's `filter` or `listener` packages — they are leaf packages in the structure.