# Com / Fujitsu / Futurity

## Overview

The `com.fujitsu.futurity` package represents the top-level application module of the Fujitsu Futurity suite. It serves as the packaging root for a Java EE web application — in particular, a Japan-focused variant (X33) within the Futurity product family. The module's primary responsibility is to provide the **web-tier infrastructure layer**: the structural hooks through which the application intercepts, transforms, and manages the lifecycle of HTTP traffic before requests reach any business logic or data access components.

At its current stage, Futurity functions as an **infrastructure scaffold**. No business logic, controllers, or views have been implemented yet. Instead, the module provides the foundational servlet-tier components — request encoding filters and application lifecycle listeners — wired through XML-based deployment descriptors (`web.xml`, `web-full.xml`). This pattern suggests either early-stage scaffolding (infrastructure hooks built ahead of business logic) or a decommissioned application where the structural skeleton remains as a foundation for future development.

## Sub-module Guide

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

The `web` package is the sole child module of Futurity and contains the entire web-layer implementation today. It acts as the entry point for all HTTP traffic, providing servlet filters, context listeners, and deployment descriptor wiring.

Within the web package, **X33** (`com.fujitsu.futurity.web.x33`) is the primary (and currently only) application sub-module. It represents a distinct application — likely Japan-focused — and decomposes into two servlet API components:

| Component | Class | Concern | Boundary |
|---|---|---|---|
| Request encoding filter | `X33JVRequestEncodingSjisFilter` | Sets character encoding (MS932 / Shift JIS) on incoming requests | Per-request |
| Application listener | `X33AppContextListener` | Provides startup and shutdown hooks for application-scoped resources | Application lifecycle |

These two components follow a clean **lifecycle-vs-request separation**: the listener fires once when the web container deploys or undeploys the application, while the filter fires for every HTTP request. In a fully implemented application, the listener would bootstrap shared state (data sources, cached lookups) at deploy time, and the filter would transform each request (e.g., setting character encoding) before forwarding it to controllers. Today, both are stubs with empty or no-op implementations.

**How the sub-modules relate:** The `web` package is the container; `x33` is the application living inside it. The filter and listener within `x33` operate at complementary boundaries — one is a singleton per application lifetime, the other is invoked per request. Together they form the complete set of servlet-tier hooks (lifecycle-level and request-level), but as stubs they represent a structural skeleton: the scaffolding is in place, the plumbing is wired through `web.xml`, but the pipes are not yet carrying any signal.

## Key Patterns and Architecture

```mermaid
flowchart TD
  subgraph FUT["com.fujitsu.futurity
Futurity Application"]
    WEB["com.fujitsu.futurity.web
Web Tier"]
  end
  WEB --> X33["X33 Sub-module
com.fujitsu.futurity.web.x33"]
  X33 --> FILTER["X33JVRequestEncodingSjisFilter
Request encoding filter"]
  X33 --> LISTENER["X33AppContextListener
Lifecycle listener"]
  FILTER --> FILTER_BEHAVIOR["Pass-through / no-op
Today: empty implementation"]
  LISTENER --> LISTENER_BEHAVIOR["Lifecycle hooks
Today: no-op"]
  WEB --> DEPLOY["web.xml / web-full.xml
Deployment descriptors"]
  DEPLOY --> REG["Registers FILTER and LISTENER"]
```

### Architectural patterns

- **Lifecycle-Request separation:** The filter and listener cleanly separate concerns — one handles the application lifecycle, the other handles per-request transformation. This is the standard servlet architecture pattern in Java EE.
- **Stub scaffolding:** Both components follow an identical skeleton pattern: a class implementing a servlet API interface with empty or no-op method bodies. This pattern typically indicates either early-stage scaffolding where infrastructure hooks are created before business logic is written, or a decommissioned component whose logic was migrated elsewhere.
- **Deployment descriptor-driven:** Neither component is discovered via annotation scanning or programmatic registration. They are explicitly declared in `web.xml` and `web-full.xml`, meaning the X33 application uses XML-based deployment configuration rather than Servlet 3.0+ annotation-based discovery.
- **Dual-profile deployment:** Both `web.xml` and `web-full.xml` register the same components, suggesting support for multiple deployment profiles (e.g., basic vs. full Java EE server). Any implementation work should be reflected in both descriptors to avoid environment-specific behavior.
- **No cross-module integration yet:** No imports flow into or out of the X33 package, and no other modules reference classes from `com.fujitsu.futurity.web.x33`. This isolation suggests the X33 application may currently operate as a standalone web module within the broader Futurity ecosystem, with integration points not yet wired.

## Dependencies and Integration

### Internal dependencies

The X33 web package has **no Java-level dependencies** on other internal modules. Neither the filter nor the listener imports any classes from within the Futurity application. This is consistent with their stub status — there is no executable logic to require imports.

### External dependencies

Both components depend only on the standard Java Servlet API:

| Dependency | Used by | Purpose |
|---|---|---|
| `javax.servlet.Filter` | `X33JVRequestEncodingSjisFilter` | Servlet filter interface |
| `javax.servlet.ServletRequest` / `ServletResponse` | `X33JVRequestEncodingSjisFilter` | Request/response objects in `doFilter()` |
| `javax.servlet.FilterChain` | `X33JVRequestEncodingSjisFilter` | Passes requests through the filter chain |
| `javax.servlet.FilterConfig` | `X33JVRequestEncodingSjisFilter` | Init parameters and context reference |
| `javax.servlet.ServletContextListener` / `ServletContextEvent` | `X33AppContextListener` | Application lifecycle hooks |

### Deployment configuration

| File | Component registered |
|---|---|
| `web.xml` | Both `X33JVRequestEncodingSjisFilter` and `X33AppContextListener` |
| `web-full.xml` | Both `X33JVRequestEncodingSjisFilter` and `X33AppContextListener` |

## Notes for Developers

- **Everything is a stub.** Neither the filter nor the listener has executable logic. Adding implementation is safe — there is no existing behavior to break.
- **Character encoding is a priority area.** If the X33 application handles Japanese content, implementing the `X33JVRequestEncodingSjisFilter` is likely one of the first practical tasks. The recommended approach is to check `req.getCharacterEncoding() == null` before setting the encoding, to avoid overriding an explicit client-specified `Content-Type` header.
- **Servlet API version matters.** The code comments reference `javax.servlet` (Java EE / Servlet 3.x), but the project may have migrated to `jakarta.servlet` (Jakarta EE / Servlet 5.x+). Confirm the build configuration before implementing any interface methods.
- **Coordinate across profiles.** Any changes to `web.xml` or `web-full.xml` should be kept in sync. Divergence between these profiles is a common source of environment-specific bugs.
- **This appears to be a structural foundation.** The presence of properly named and deployed stubs suggests this package is intended to grow into a fully functional web tier. Developers working on X33 should treat these classes as extension points rather than dead code.
- **Indexing caveat:** Static analysis of this module reports zero indexed classes and methods, because the stub classes are minimal (interfaces are implemented but method bodies are empty). When implementation is added, the index will need to be refreshed to capture the new symbols.