# Com / Fujitsu

## Overview

The `com.fujitsu` package serves as the root namespace for **Futurity** — an older Japanese enterprise application built on the Java Servlet/JSP stack. The module name, the naming conventions used internally, and the explicit use of Shift JIS character encoding all point to a system designed to serve Japanese-language clients.

At the current stage of development, this package is entirely **scaffolded**: the infrastructure has been wired into deployment descriptors so the application can deploy cleanly, but no business logic has been implemented yet. The purpose is structural — to establish a stable deployment baseline that passes configuration-level integration tests before core functionality is added.

The only active capability in the module right now is the **web-facing tier**, which intercepts HTTP requests, normalizes character encoding for Japanese clients, and manages application lifecycle events. This layer sits as the outermost boundary of the system, between the servlet container and whatever business-layer packages will be developed inside this module in the future.

## Sub-module Guide

Futurity contains a single sub-module that owns the web infrastructure:

### `com.fujitsu.futurity.web` — The Web Tier

The web sub-package is the sole active component in the entire `com.fujitsu` module. It owns everything that touches the HTTP request/response lifecycle and serves as the entry point for all external traffic.

Within the web package sits the **X33** sub-package (`com.fujitsu.futurity.web.x33`), which appears to be the web-facing layer of an internal subsystem named "X33" (a common naming convention in Japanese enterprise software, possibly referencing a product line or client code). X33 is composed of two complementary components:

- **`X33AppContextListener`** — A `ServletContextListener` that reacts to application start-up and shut-down events. It is the natural home for initializing shared state (configuration, caches, background threads) that the rest of the application depends on.
- **`X33JVRequestEncodingSjisFilter`** — A servlet filter that intercepts incoming HTTP requests. Its intended purpose is to normalize character encoding (e.g., from the client's Shift JIS to a consistent internal encoding like UTF-8) before requests reach downstream servlets or JSP pages.

#### How the sub-modules relate

These two components address different time-scales within the same application lifecycle:

- The **listener** fires once per deployment cycle (start-up and shut-down), handling bootstrap and teardown.
- The **filter** fires per-request, sitting in the servlet filter chain for every incoming HTTP call.

In a fully implemented system, the listener's `contextInitialized()` method would load configuration (such as the target encoding) that the filter reads during `doFilter()`. Currently, they are independent stubs with no connecting logic.

### The Double Registration Pattern

Both the filter and the listener 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 are expected to activate the same web infrastructure. This duplication should be audited to confirm it is intentional and does not cause duplicate filter/listener activations at runtime.

## Key Patterns and Architecture

### Stub-and-Wire

Every class in the `com.fujitsu.futurity` package follows a **stub-and-wire** pattern: they are registered in deployment descriptors and can be instantiated by the servlet container, but they contain no implementation logic. This is a deliberate development strategy — scaffolding goes in first so that deployment, XML validation, and integration tests pass, and the business logic is filled in later. The consequence is that the servlet container creates, initializes, and destroys these objects with no observable effect on the running application.

### Request Flow (Intended)

Once implemented, the HTTP request path through this package follows 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()`.

### Architecture Diagram

```mermaid
flowchart TD
    subgraph config["Web Configuration"]
        xml1["web.xml"]
        xml2["web-full.xml"]
    end
    subgraph webTier["Web Tier - com.fujitsu.futurity.web"]
        listener["X33AppContextListener
(ContextListener - empty)"]
        filter["X33JVRequestEncodingSjisFilter
(Filter - no-op)"]
    end
    subgraph future["Business Layer
(Not yet implemented)"]
        servlets["Downstream Servlets / JSP"]
        logic["Application Business Logic"]
    end
    subgraph runtime["Runtime Environment"]
        container["Servlet Container
(Tomcat / WebLogic)"]
    end
    xml1 --> filter
    xml2 --> filter
    xml1 --> listener
    xml2 --> listener
    filter --> container
    container --> listener
    container --> servlets
    servlets --> logic
```

The diagram above shows how the web-tier components integrate with the broader system. Both deployment descriptors register the filter and listener, which communicate with the servlet container at runtime. The business layer (currently unimplemented) sits downstream of the container, connected through the servlet/JSP dispatch mechanism.

## Dependencies and Integration

| Dependency | Purpose |
|---|---|
| `javax.servlet` | The standard Servlet API — both classes depend on `Filter`, `FilterChain`, `FilterConfig`, `ServletContextListener`, `ServletRequest`, `ServletResponse`, and related interfaces. |
| `web.xml` / `web-full.xml` | Deployment descriptors that register the filter and listener, including URL patterns and listener declarations. |
| `com.fujitsu.futurity.web.x33` | The X33 sub-package, which holds the two concrete classes. |

No other internal modules currently reference these classes directly. The filter and listener are the outermost layer of the system, integrating by reacting to events from the servlet container rather than through direct code-level coupling to downstream modules. Future business-layer packages developed inside `com.fujitsu.futurity` will likely be accessed by these components via shared configuration objects or dependency injection.

## Notes for Developers

- **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 is a stub-only package.** No source files are currently indexed under this module at the package level. The only sub-modules are within the `web.x33` sub-package, which contains a single filter class and a single listener class.

- **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.