# Com / Fujitsu / Futurity

## Overview

The `com.fujitsu.futurity` package serves as the top-level namespace for the Fujitsu Futurity application, a Java EE web application designed to handle HTTP-based workflows, with explicit support for Japanese-language input. This module represents the boundary between the servlet container and the application's internal logic, acting as the entry point for all HTTP traffic.

At present, the module is in a scaffolding phase. The web tier (`com.fujitsu.futurity.web`) declares the infrastructure hooks it will need — application lifecycle listeners and request-level filters — but leaves them as no-ops. This suggests the application is either in early development or was initialized as a module reservation ahead of active implementation. The package structure follows a standard Java EE convention: a top-level namespace under `com.fujitsu`, a project-level group (`futurity`), and a web package containing servlet-level concerns.

The module is a leaf in the dependency graph — it imports nothing beyond `javax.servlet` and is imported by nothing. This means it is currently isolated from the rest of the codebase, with changes here having no downstream ripple effects.

## Sub-module Guide

### `web` — Servlet-Tier Entry Points

The `com.fujitsu.futurity.web` package is the sole documented child module and serves as the web-tier boundary for the Futurity application. It provides the infrastructure hooks that govern how HTTP requests enter the application and how the application initializes and shuts down within the servlet container.

#### `x33` — Lifecycle and Encoding Scaffolding

Within the `web` package, the `x33` sub-package is the only active entry point today. It declares two servlet-level components, both registered via deployment descriptors (`web.xml` and `web-full.xml`):

- **`listener.X33AppContextListener`** — An empty stub for application startup and shutdown logic. Registered as a `<listener>` in deployment descriptors, it follows the Java EE `ServletContextListener` pattern. When implemented, this would bootstrap application state such as configuration loading, Spring context initialization, or resource pool setup.

- **`filter.X33JVRequestEncodingSjisFilter`** — A servlet filter intended to handle Shift JIS (SJIS / cp932) character encoding for Japanese-language HTTP requests. The name encodes its localization intent: `JV` for Japan and `Sjis` for the character set. Currently a pass-through (delegates every request to the next chain element without modification), it means Japanese input parameters rely on the container's default encoding — a risk for mojibake if the server is misconfigured.

**How these components relate:** Both sub-components share a common parent package and deployment-time registration but have no direct code-level relationship. They operate at different points in the request lifecycle: the listener fires once at container startup, while the filter intercepts every subsequent HTTP request. Together they form a minimal scaffolding pattern — the listener prepares the environment, the filter normalizes incoming data. Neither imports from or communicates with the other.

## Key Patterns and Architecture

### Deployment Descriptor-Driven Registration

Both `x33` components are wired exclusively through deployment descriptors (`web.xml` and `web-full.xml`) rather than programmatic annotations like `@WebListener` or `@WebFilter`. This dual-registration across both the servlet-only profile and the full Java EE profile ensures the hooks activate regardless of which container profile the application runs on (e.g., Tomcat vs. a full Jakarta EE server).

### Scaffold / Stub Pattern

The `x33` module follows a "declare the hook, leave the body empty" pattern. Both the listener and the filter are no-ops at the code level, suggesting this module was either planned for future implementation or its functionality was deferred. This is a common practice when setting up a new module or reserving extension points ahead of a sprint or release.

### Request Processing Flow

The web package's architecture follows a standard Java EE servlet pipeline: the container invokes the listener once at startup, then routes each HTTP request through any registered filters before reaching the target servlet. The `x33` filter is positioned at the entry of this pipeline, making it the right place for request-level concerns like encoding normalization, though it currently performs no transformation.

```mermaid
flowchart TD
    subgraph DEP["Deployment Descriptors"]
        web["web.xml / web-full.xml"]
    end

    subgraph STAGE1["Startup Phase"]
        regL["Registers X33AppContextListener"]
    end

    subgraph STAGE2["Request Phase"]
        regF["Registers X33JVRequestEncodingSjisFilter"]
    end

    DEP --> regL
    DEP --> regF
    regL --> emptyL["Empty stub - no-op"]
    regF --> emptyF["Delegates to chain - no-op"]
```

```mermaid
sequenceDiagram
    autonumber
    participant C as "Servlet Container"
    participant L as "X33AppContextListener"
    participant RQ as "X33JVRequestEncodingSjisFilter"
    participant FC as "FilterChain"
    participant S as "Target Servlet"

    C->>L: contextInitialized event
    activate L
    note right of L: No-op: empty class body
    deactivate L
    loop "For each HTTP request"
        C->>RQ: request arrives
        activate RQ
        RQ->>FC: chain.doFilter req, res
        RQ->>RQ: returns immediately
        deactivate RQ
        FC->>S: pass through unchanged
        S-->>C: response
    end
```

## Dependencies and Integration

### External Dependencies

This module has no Java-level imports beyond the standard `javax.servlet` API. There are no framework dependencies (Spring, Guice, CDI, etc.) declared or detected. The module is entirely self-contained within the Java EE servlet specification.

### Inbound Relationships

| Artifact | Role |
|---|---|
| `web.xml` | Declares `X33AppContextListener` as a `<listener>` and `X33JVRequestEncodingSjisFilter` as a `<filter>` with associated `<filter-mapping>` entries. |
| `web-full.xml` | Duplicate declarations for full-profile deployment environments. |
| `com.fujitsu.futurity` (parent namespace) | The web package is a child of the top-level `com.fujitsu.futurity` namespace, which likely contains the business logic and service layer this web tier communicates with. |

### Outbound Relationships

No classes from the `com.fujitsu.futurity` package are imported or referenced by other packages in the codebase. The module is a leaf in the dependency graph — it depends on nothing beyond the servlet API and is depended upon by nothing explicitly.

### Package Structure

```
com.fujitsu.futurity.web
└── x33
    ├── listener/
    │   └── X33AppContextListener.java      — empty lifecycle stub
    └── filter/
        └── X33JVRequestEncodingSjisFilter.java  — no-op request filter
```

## Module Interaction Map

The following diagram shows how the documented sub-modules interact at runtime:

```mermaid
flowchart LR
    subgraph CONTAINER["Servlet Container"]
        REQ["HTTP Request"]
    end

    subgraph WEB["com.fujitsu.futurity.web"]
        subgraph X33["x33 sub-package"]
            L["X33AppContextListener"]
            F["X33JVRequestEncodingSjisFilter"]
        end
    end

    subgraph DESC["Deployment Descriptors"]
        WD["web.xml / web-full.xml"]
    end

    WD -->|registers| L
    WD -->|registers| F
    REQ -->|lifecycle| L
    REQ -->|routing| F
    F -->|delegates| L
```

## Notes for Developers

- **Everything is currently a stub.** The listener class has no class body, and the filter's `doFilter`, `init`, and `destroy` methods are no-ops. Nothing at runtime depends on these components performing work.

- **Japanese encoding is a known gap.** If the Futurity application serves Japanese-language users, the unhandled Shift JIS encoding is a real risk. To address this, `X33JVRequestEncodingSjisFilter.doFilter` should call `((HttpServletRequest) req).setCharacterEncoding("cp932")` before delegating to the chain. For robustness, wrap the request in a custom `HttpServletRequestWrapper` so that `getParameter` calls throughout the application respect the encoding.

- **Listener implementation requires a design decision.** Before adding behavior to `X33AppContextListener`, determine whether it should implement `javax.servlet.ServletContextListener` (generic container lifecycle, receiving `contextInitialized`/`contextDestroyed`) or integrate with Spring (e.g., extend `ContextLoaderListener`). This choice dictates the API to implement and the `web.xml` configuration required.

- **Thread-safety.** The filter is stateless, so thread-safety is not a concern today. Any future state added to either component should be handled with care, especially if the listener begins storing application-scoped resources.

- **Low-risk area to modify.** Since no other package references classes from this module, changes here have no downstream impact. This module can be safely extended, refactored, or removed.

- **Possible deprecation.** Given that both components are empty stubs with no cross-module references, it is worth verifying with the team whether the X33 module is still in scope. If not, the `x33` package and its `web.xml` entries can be cleaned up to reduce deployment confusion.