# Com / Fujitsu / Futurity / Web

## Overview

The `com.fujitsu.futurity.web` package is the web-facing tier of the Fujitsu Futurity application. It sits at the boundary between the servlet container (e.g., Tomcat, WebLogic) and the internal application logic, owning everything that touches the HTTP request/response lifecycle. Its responsibilities fall into two categories:

- **Request interception** — servlet filters that transform, inspect, or validate incoming HTTP requests before they reach the core application.
- **Application lifecycle management** — context listeners that initialize and tear down application-wide resources at deployment boundaries.

The package currently exists in a scaffolded state. Its constituent components are fully wired into the deployment descriptors (`web.xml` and `web-full.xml`) but contain no operational logic. They were put in place as structural placeholders so that the application can deploy and pass configuration-level integration tests even before the business logic is implemented.

This appears to be an older Japanese enterprise application (Shift JIS encoding hints, Japanese-language client support). The web tier's primary stated purpose is to normalize character encoding on requests from Japanese clients so that downstream servlets and JSP pages receive data in a consistent encoding.

## Sub-module Guide

The web package contains one sub-module:

### X33 — The Primary Web Sub-system

The **X33** package (`com.fujitsu.futurity.web.x33`) is the only sub-module and represents the web-facing layer of the X33 subsystem within Futurity. It is composed of two complementary pieces:

| Component | Class | Role |
|---|---|---|
| Filter | `X33JVRequestEncodingSjisFilter` | Intercepts incoming HTTP requests to normalize character encoding |
| Listener | `X33AppContextListener` | Reacts to servlet context start-up and shut-down events |

**How they relate.** The listener and filter address different time-scales within the same lifecycle:

- The **listener** fires once per application deployment cycle — at start-up and shut-down. It is the natural home for initializing shared state (configuration, caches, background threads) that the rest of the application, including the filter, will consume.
- The **filter** fires per-request, sitting in the servlet filter chain. It inspects or transforms each HTTP request before it propagates to downstream servlets or JSPs.

In a fully implemented system, the listener's `contextInitialized()` would load the encoding configuration that the filter reads during `doFilter()`. As written, there is no code connecting the two — they are independent stubs.

The X33 sub-module also illustrates a **double registration pattern**: both the filter and the listener are declared in both `web.xml` and `web-full.xml`. This suggests the application supports multiple deployment profiles (a "basic" and a "full" variant), and both profiles should activate the same infrastructure. This should be audited to confirm the dual entries are intentional and do not produce duplicate activations at runtime.

## Key Patterns and Architecture

### Stub-and-Wire

Every class in this package is registered in a deployment descriptor but contains no implementation. This is a deliberate development pattern: scaffolding goes in first so that deployment, XML validation, and integration tests can pass, and the business logic is filled in later. The consequence is that the servlet container will create, initialize, and destroy these objects with no observable effect on the running application.

### Request Flow (Intended)

Once implemented, the HTTP request path through this package would follow 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 (e.g., normalizes to UTF-8) and forwards the request via `chain.doFilter()`.
5. The request reaches the downstream servlets or JSP pages for business logic.
6. On undeploy, the container calls `X33AppContextListener.contextDestroyed()`.

### Structural Relationships

```mermaid
flowchart TD
    subgraph webConfig["Web Configuration"]
        xml1["web.xml"]
        xml2["web-full.xml"]
    end
    subgraph servletLayer["Servlet Layer"]
        filter["X33JVRequestEncodingSjisFilter
(Filter - no-op)"]
        contextListener["X33AppContextListener
(ServletContextListener - empty)"]
    end
    subgraph runtime["Runtime"]
        container["Servlet Container"]
        downstream["Downstream Servlets / JSP"]
    end
    xml1 --> filter
    xml2 --> filter
    xml1 --> contextListener
    xml2 --> contextListener
    filter --> container
    container --> downstream
```

## 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. |

No other internal modules reference these classes directly. The filter and listener are the outermost layer of the X33 subsystem, integrating with the system by reacting to events from the servlet container rather than by direct code-level coupling to downstream modules.

## Notes for Developers

- **Both 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. The only sub-modules are the `filter` and `listener` packages within X33, each containing a single class.