# ACA001SFBean

## Purpose

`ACA001SFBean` is a minimal JavaServer Faces (JSF) data bean used within the [Futurity](https://fujitsu.github.io/futurity/) framework to hold transient view-state data for the ACA001 screen. It acts as a simple value carrier — a single `String value` field exposed through a standard JavaBean getter — enabling JSP pages and XML-based screen definitions to bind and exchange data during the request lifecycle. This appears to be a placeholder or fixture bean, given its trivial structure (one field, one getter, no logic).

## Design

`ACA001SFBean` is a **plain data bean** (sometimes called a value object or form bean) in the Futurity framework's MVC-like architecture. In Futurity, each screen definition XML file declares a `<SERVICEFORM>` or `<FORM>` element that references a bean class; the framework instantiates the bean, populates its properties from form data, and makes it available to both the view (JSP) and the business logic class (paired via the `<BL>` or `<項目>` elements).

The class follows the JavaBeans convention of a private field with a public getter, making it usable in JSP Expression Language (EL) and tag libraries without explicit setters. Since no setter is defined, the bean is effectively **read-only from the view's perspective** — data flows into it via framework injection or direct instantiation, and out via `getValue()`.

```
┌─────────────────────────────────────────────────┐
│  ACA001SFBean                                   │
├─────────────────────────────────────────────────┤
│  - value : String                               │
├─────────────────────────────────────────────────┤
│  + getValue() : String                          │
└─────────────────────────────────────────────────┘
```

## Key Methods

### `getValue() → String`

**Lines 4–4**

Returns the current value of the `value` field.

| Property     | Value               |
|-------------|---------------------|
| **Visibility** | `public`            |
| **Parameters** | None                |
| **Return type** | `String`            |
| **Side effects** | None (pure read)   |

This method is the sole public API of the class. It returns the `value` field directly without any transformation, null-checking, or defensive copying. Callers should be aware that `getValue()` may return `null` if the field was never assigned. In the context of the Futurity framework, the `value` field would typically be populated by the framework's form-binding machinery from request parameters or session data associated with the ACA001 screen.

Because there is no setter (`setValue(String)`), this bean is designed as a **consumer of data** rather than a mutator — the framework or a logic class sets the value, and the view reads it.

## Relationships

### Who uses ACA001SFBean (5 inbound connections)

The bean is referenced across configuration files and JSP views that define the ACA001 screen hierarchy:

| Dependent | Type | How it references ACA001SFBean |
|-----------|------|-------------------------------|
| `WEBGAMEN_FULL_ACA001.xml` | XML screen definition | Declares `<SERVICEFORM bean="eo.web.webview.ACA001SF.ACA001SFBean"/>` |
| `faces-config.xml` | JSF configuration | References the bean class (likely as a managed bean or navigation rule association) |
| `WEBGAMEN_ACA001010PJP.xml` | XML screen definition | Declares `<SERVICEFORM bean="eo.web.webview.ACA001SF.ACA001SFBean">` with an associated button action |
| `x33S_ACA001.xml` | XML screen definition (Japanese elements) | Declares `<フォーム bean="eo.web.webview.ACA001SF.ACA001SFBean"/>` (using Japanese XML element names) |
| `FULL_ACA001010PJP.jsp` | JSP view | Uses `<jsp:useBean id="logic" class="eo.web.webview.ACA001SF.ACA001SFBean" scope="request"/>` and imports the class |

### Dependency diagram

```
flowchart TD
    subgraph Controllers["Controllers / Logic"]
        ACA001SFLogic["ACA001SFLogic
Business Logic"]
        ACA001SFAction["ACA001SFAction
Button Handler"]
    end

    subgraph Data["Data Binding"]
        ACA001SFBean["ACA001SFBean
Data Bean"]
    end

    subgraph Views["Views"]
        FULL_ACA001010PJP["FULL_ACA001010PJP.jsp
JSP View"]
    end

    subgraph Config["Configuration Files"]
        WEBGAMEN_FULL["WEBGAMEN_FULL_ACA001.xml
Screen Definition"]
        WEBGAMEN_ACA001010["WEBGAMEN_ACA001010PJP.xml
Screen Definition"]
        x33S_ACA001["x33S_ACA001.xml
Japanese Screen Def"]
    end

    WEBGAMEN_FULL -->|configures SERVICEFORM bean| ACA001SFBean
    WEBGAMEN_ACA001010 -->|configures SERVICEFORM bean| ACA001SFBean
    x33S_ACA001 -->|configures FORM bean| ACA001SFBean
    FULL_ACA001010PJP -->|jsp:useBean scope=request| ACA001SFBean
    ACA001SFLogic -->|paired with| ACA001SFBean
    ACA001SFAction -->|paired with| ACA001SFBean
```

### Outbound dependencies

`ACA001SFBean` has **no outbound references** — it does not import or depend on any other classes beyond the Java standard library (`String`). This makes it a leaf node in the dependency graph, which is typical for data beans that exist purely as data carriers.

## Usage Example

The typical usage pattern for `ACA001SFBean` is as follows:

1. **Configuration**: A screen definition XML file (e.g., `WEBGAMEN_FULL_ACA001.xml`) declares the bean as the `<SERVICEFORM>` for a screen:

   ```xml
   <SCREEN id="FULL_ACA001">
     <BL class="eo.web.webview.ACA001SF.ACA001SFLogic"/>
     <SERVICEFORM bean="eo.web.webview.ACA001SF.ACA001SFBean"/>
   </SCREEN>
   ```

2. **Instantiation**: The Futurity framework instantiates the bean (typically in `request` scope) and populates its `value` field from the incoming HTTP request.

3. **JSP Access**: In the JSP view (`FULL_ACA001010PJP.jsp`), the bean is accessed via `<jsp:useBean>` or EL:

   ```jsp
   <jsp:useBean id="logic" class="eo.web.webview.ACA001SF.ACA001SFBean" scope="request"/>
   ```

4. **Data Read**: The view or a paired action class reads the value:

   ```java
   ACA001SFBean bean = ...; // injected or looked up
   String val = bean.getValue();
   ```

5. **Button Action**: The paired `ACA001SFAction` (declared in `WEBGAMEN_ACA001010PJP.xml`) can also access the bean to read or process the submitted form data.

## Notes for Developers

- **Read-only from the view**: Since there is no `setValue(String)` method, the bean cannot be directly modified by JSP EL expressions or tag libraries. If write-back is needed, a setter must be added.
- **No null safety**: `getValue()` returns the raw `String` which may be `null`. Callers must handle null checks before using the return value (e.g., `if (bean.getValue() != null)`).
- **No serialization**: The class does not explicitly implement `Serializable`. If it is used across request boundaries that require serialization (e.g., session-scoped beans in certain containers), this could cause issues.
- **No business logic**: This bean is purely a data carrier. All business logic for the ACA001 screen is delegated to `ACA001SFLogic` (declared as the `<BL class="...">` in the same screen definitions).
- **Framework dependency**: The bean's role and lifecycle are managed by the [Futurity](https://fujitsu.github.io/futurity/) framework's screen-definition machinery. Its behavior (when it is instantiated, populated, and discarded) is determined by the framework, not by application code.
- **Part of a screen group**: This bean is associated with the ACA001 screen family, which appears in multiple configurations — standard XML (`WEBGAMEN_FULL_ACA001.xml`), extended XML with action (`WEBGAMEN_ACA001010PJP.xml`), and Japanese-element XML (`x33S_ACA001.xml`). This suggests the ACA001 screen has multiple variants or deployment profiles that share the same data bean.