# Com / Fujitsu / Futurity / Web

## Overview

The `com.fujitsu.futurity.web` package serves as the **web-tier integration layer** for the Fujitsu Futurity application. It sits at the boundary between the Java servlet container and the application's business subsystems, responsible for handling incoming HTTP requests, managing request-level concerns such as character encoding, and orchestrating application lifecycle events through servlet listeners.

This module appears to function as the outermost web-facing package for the Futurity application. Its primary concern is not business logic itself, but rather the translation, encoding, filtering, and lifecycle management of HTTP traffic before it reaches downstream service layers. The package follows a traditional Java EE / XML-based deployment descriptor pattern (using `web-full.xml` for wiring) rather than relying on Spring or annotation-based auto-discovery.

At present, this module exists primarily as **scaffolding**. The source index returned no compiled classes or methods, which indicates either that the code has not yet been compiled/indexed, or that the implementations are minimal placeholder stubs. The single child package (`x33`) confirms this: it contains class declarations and filter registrations, but no functional behavior has been implemented yet.

## Sub-module Guide

### `x33` — X33 Web Integration Subsystem

The `com.fujitsu.futurity.web.x33` sub-package is dedicated to handling the **X33 subsystem**'s web-facing concerns. X33 appears to be a Japanese-facing component (possibly a JV — Japan Version — integration), which explains the Shift-JIS (MS932) encoding focus.

The x33 package contains two complementary sub-packages:

- **`filter`** — Hosts `X33JVRequestEncodingSjisFilter`, a servlet filter registered via `web-full.xml`. Intended to enforce Shift-JIS encoding on incoming X33 JV requests. Currently a pass-through no-op.
- **`listener`** — Hosts `X33AppContextListener`, a stub class intended to serve as a servlet context listener for X33-specific startup/shutdown lifecycle management. Currently an empty class with no implementation.

These two sub-packages cover the two fundamental axes of the web request lifecycle:

| Sub-package | Lifecycle scope | Responsibility |
|---|---|---|
| `listener` | Application-wide | Startup, shutdown, context attribute events |
| `filter` | Per-request | Character encoding on incoming HTTP requests |

In a fully implemented system, the listener would initialize shared X33 resources at application startup (e.g., connection pools, configuration lookups), while the filter would ensure every incoming X33 request is processed with the correct Shift-JIS character encoding.

## Key Patterns and Architecture

### Registration-based wiring (XML-declarative)

Both sub-modules rely on **declarative registration** through `web-full.xml` rather than annotations:

- The filter is declared and mapped to URL patterns in `web-full.xml`.
- The listener, if implemented, would similarly be declared in `web.xml` (or annotated with `@WebListener`).

This reflects the application's use of a traditional Java EE deployment model where the deployment descriptor is the source of truth for servlet wiring.

### Filter chain architecture

The filter sub-package follows the standard `javax.servlet.Filter` pattern with three lifecycle methods (`doFilter`, `init`, `destroy`). The filter chain architecture allows multiple filters to be stacked, each able to inspect, modify, or short-circuit the request before it reaches the target servlet. Currently, the `X33JVRequestEncodingSjisFilter` delegates directly to the next link in the chain without any processing.

### Placeholder (scaffold) pattern

The entire `com.fujitsu.futurity.web` module follows a scaffold pattern. Class names and package structure are correctly named and registered, but the behavior is not yet implemented. This suggests one of:

1. The X33 web integration work was started but not completed.
2. The encoding and listener concerns are handled elsewhere in the application (e.g., a global character encoding filter or Spring-based lifecycle beans), making these X33-specific placeholders temporary.

### Request flow

The following diagram shows where the X33 web sub-modules sit in the request lifecycle:

```mermaid
flowchart TD
    A["Servlet Container"] -->|"dispatches HTTP request"| B["X33JVRequestEncodingSjisFilter.doFilter"]
    B -->|"passes through chain"| C["Next filter or target servlet"]
    D["web-full.xml"] -->|"declares filter and URL mapping"| B
    E["X33AppContextListener"] -->|"empty stub awaiting implementation"| F["X33 web subsystem"]
```

### Cross-module request path (inferred)

When the application is fully implemented, the request flow through the web tier is expected to follow this pattern:

```mermaid
flowchart LR
    A["Client"] -->|"HTTP request"| B["web-full.xml"]
    B -->|"routes to filter"| C["X33JVRequestEncodingSjisFilter"]
    C -->|"applies SJIS encoding"| D["Encoding wrapper"]
    D -->|"forwarded downstream"| E["X33 backend subsystem"]
    F["ServletContext startup"] -->|"initializes resources"| G["X33AppContextListener"]
    G -->|"shared config/pools"| E
```

## Dependencies and Integration

### External dependencies

| Dependency | Role |
|---|---|
| `javax.servlet.Filter` | Implemented by `X33JVRequestEncodingSjisFilter` for `doFilter`, `init`, and `destroy` methods |
| `javax.servlet.ServletRequest` / `ServletResponse` | Types used in `doFilter()` for request/response handling |
| `javax.servlet.FilterChain` | Used by the filter to pass requests down the chain |
| `web-full.xml` | Declares the filter registration and associates it with URL patterns |

### Internal relationships

No internal application package dependencies have been detected. This module does not import or reference any classes from other parts of the Futurity codebase. It is a **leaf module** at the `com.fujitsu.futurity.web.x33` level, meaning it is designed to be the outermost web-facing layer for the X33 subsystem — it receives external traffic and delegates inward.

### Cross-module integration

No cross-module relationships were detected in the index. If the listener were implemented (e.g., as a `ServletContextListener`), it would naturally integrate with the broader application lifecycle — potentially initializing beans, registering JNDI resources, or triggering X33-specific startup routines. As-is, it does not participate in any request flow or event handling.

## Notes for Developers

### Encoding is not applied

The `X33JVRequestEncodingSjisFilter` does not set any character encoding on incoming requests. If the X33 JV subsystem handles Japanese input (Shift-JIS / MS932), requests may arrive with incorrect character encoding, potentially corrupting multi-byte characters in parameters or headers.

**Recommended next steps:**
- Verify with the team whether this filter should (a) implement the SJIS encoding logic, (b) delegate encoding to a site-wide `CharacterEncodingFilter`, or (c) be removed entirely.
- If encoding should be applied, `req.setCharacterEncoding("MS932")` should be called before `chain.doFilter(...)` in `doFilter()`.

### Listener is a stub

`X33AppContextListener` has no implementation and is not registered with the servlet container. If X33 requires any startup or shutdown logic, this class is the intended location — but it needs to be:

1. Wired to an appropriate listener interface (`ServletContextListener`, `HttpSessionListener`, etc.).
2. Annotated with `@WebListener` or registered in `web.xml`.
3. Implemented with the actual initialization or cleanup logic.

### Thread safety

The filter is thread-safe by design — it holds no instance fields and is entirely stateless. No synchronization is needed for concurrent request handling.

### No child packages

Both the filter and listener packages contain exactly one file each, with no child subpackages. Any future extensions (additional filters, listener variants, or utility classes) would be added directly within these packages.

### Configuration extensibility

The filter's `init(FilterConfig)` method ignores its `config` parameter. If encoding rules ever need to become configurable (e.g., selectable character sets per deployment environment), the `init` method would be the extension point to read initialization parameters from the deployment descriptor.

### General guidance for working in this module

- The entire module is currently scaffolding. Before implementing behavior, coordinate with the team to understand whether X33-specific encoding and lifecycle handling is still needed, or if it has been superseded by application-wide mechanisms.
- Any new code should follow the existing XML-declarative wiring pattern for consistency with the deployment model.
- Character encoding is a critical concern for the X33 subsystem. Misconfigured encoding in production could silently corrupt user input — prioritize verifying and implementing the filter's encoding logic.