# Business Logic — KKW00816SF02DBean.listKoumokuIds() [7 LOC]

| Field | Value |
|-------|-------|
| Fully Qualified Name | `eo.web.webview.KKW00816SF.KKW00816SF02DBean` |
| Layer | Utility (Webview DBean — data type bean acting as schema/metadata provider) |
| Module | `KKW00816SF` (Package: `eo.web.webview.KKW00816SF`) |

## 1. Role

### KKW00816SF02DBean.listKoumokuIds()

This method serves as a **field metadata provider** for the optional service contract (オプションサービス契約) data view within the KKW00816SF screen module. It returns a static, ordered list of three field identifiers (written in Japanese) that represent the columns displayed in the option service contract list grid — namely the contract number, contract status, and service code.

The method implements a **registry pattern**: it acts as a centralized catalogue of valid field IDs for this particular DBean (data type bean). The Futurity Web X33 framework uses this metadata to dynamically render table columns, validate user input, and resolve field-to-value mappings at runtime. Other screen beans within the same module delegate to this method via the dispatcher logic in `KKW00816SFBean.java` to determine which fields belong to the "option service contract list" data type view.

As a `static` method with no conditional branches, no external calls, and no CRUD operations, its role in the larger system is purely that of a **shared configuration utility**. It is called whenever the framework needs to reconstruct the schema of the option service contract list without instantiating the full bean. The method is domain-neutral in its implementation — it simply enumerates field names — but its business significance is high because it defines the exact set of data points exposed to operators viewing option service contracts in the KKW00816SF screen.

## 2. Processing Pattern (Detailed Business Logic)

```mermaid
flowchart TD
    START(["listKoumokuIds()"])
    STEP1(["Initialize ArrayList<String> koumokuList"])
    STEP2(["Add 'Option Service Contract Number' to list"])
    STEP3(["Add 'Option Service Contract Status' to list"])
    STEP4(["Add 'Option Service Code' to list"])
    RETURN(["Return koumokuList"])
    END(["Return / Next"])

    START --> STEP1
    STEP1 --> STEP2
    STEP2 --> STEP3
    STEP3 --> STEP4
    STEP4 --> RETURN
    RETURN --> END
```

This method has **no conditional branches**, **no loops**, and **no method calls** beyond standard `ArrayList` operations. It follows a linear sequential pattern:
1. Create a new `ArrayList<String>`.
2. Add three Japanese field name strings in a fixed, deterministic order.
3. Return the populated list.

The absence of any branching or external calls makes this one of the simplest methods in the codebase — a pure factory method producing a constant data structure.

## 3. Parameter Analysis

| No | Parameter Name | Type | Business Description |
|----|---------------|------|---------------------|
| - | (none) | - | This is a `static` method with zero parameters. It takes no input and produces a fixed output based on compiled-in constants. |

**Instance fields or external state read:** None. This method is completely self-contained and does not reference any instance fields, static state, or external resources.

## 4. CRUD Operations / Called Services

| CRUD | SC / CBS | SC Code | Entity / DB | Operation Description |
|------|----------|---------|-------------|----------------------|
| - | (none) | - | - | This method makes no calls to external services, CBS components, or DAO layers. It only uses Java standard library `ArrayList` methods (`new ArrayList`, `add`, `return`). |

**Summary:** Zero CRUD operations. This method performs no database access, no service component invocations, and no data manipulation beyond constructing an in-memory list.

## 5. Dependency Trace

| # | Caller (Screen/Batch) | Call Chain (Full Path to this Method) | Terminal (SC / CRUD / Entity) |
|---|----------------------|--------------------------------------|-------------------------------|
| 1 | Screen:KKW00816SF | `KKW00816SFBean.getFieldName` → `KKW00816SF02DBean.listKoumokuIds()` | (none — returns metadata only) |

**Caller details:**
- The sole caller is `KKW00816SFBean.java` (line 2335), within the method that resolves field names for data type views. When the framework detects a data type of "option service contract list" (オプションサービス契約リスト) and a class name of "KKW00816SF02DBean", it dispatches to `KKW00816SF02DBean.listKoumokuIds()` to obtain the list of field identifiers. A second reference at line 2382 instantiates the bean for other processing but also references the same class.

## 6. Per-Branch Detail Blocks

This method has **no conditional branches**. The entire execution is a single linear block:

**Block 1** — [LINEAR EXECUTION] `(no condition)` (L273)

> Initialize an ArrayList and populate it with three fixed field name strings representing the columns of the option service contract list grid.

| # | Type | Code |
|---|------|------|
| 1 | SET | `ArrayList<String> koumokuList = new ArrayList<String>();` // Create new list container |
| 2 | EXEC | `koumokuList.add("オプションサービス契約番号");` // Add field name: Option Service Contract Number [-> Field ID: op_svc_kei_no] |
| 3 | EXEC | `koumokuList.add("オプションサービス契約ステータス");` // Add field name: Option Service Contract Status [-> Field ID: op_svc_kei_stat] |
| 4 | EXEC | `koumokuList.add("オプションサービスコード");` // Add field name: Option Service Code [-> Field ID: op_svc_cd] |
| 5 | RETURN | `return koumokuList;` // Return the populated list to the caller |

**Field ID mapping (inferred from bean field names):**
- "オプションサービス契約番号" → `op_svc_kei_no` (Option Service Contract Number)
- "オプションサービス契約ステータス" → `op_svc_kei_stat` (Option Service Contract Status)
- "オプションサービスコード" → `op_svc_cd` (Option Service Code)

## 7. Glossary

| Term | Type | Business Meaning |
|------|------|------------------|
| `op_svc_kei_no` | Field | Option Service Contract Number — the unique identifier for an option service contract line item |
| `op_svc_kei_stat` | Field | Option Service Contract Status — the current lifecycle status of the contract (e.g., active, terminated) |
| `op_svc_cd` | Field | Option Service Code — a code identifying the specific optional service product attached to the contract |
| オプションサービス契約番号 | Japanese Field | Option Service Contract Number — the human-readable display label for the contract number field |
| オプションサービス契約ステータス | Japanese Field | Option Service Contract Status — the human-readable display label for the contract status field |
| オプションサービスコード | Japanese Field | Option Service Code — the human-readable display label for the option service code field |
| DBean | Acronym | Data Bean — a Java class implementing the Futurity Web X33 framework's data type bean interface, responsible for holding and managing field values for a screen |
| X33VListedBeanInterface | Framework | Futurity Web X33 interface for beans that represent list/grid data views, requiring methods to supply field metadata |
| X33VDataTypeBeanInterface | Framework | Futurity Web X33 interface for beans that provide data type (column) definitions, requiring methods to return field names and types |
| KKW00816SF | Module | Screen module code — the K-Opticom internal screen for managing option service contracts (FC/CC change screen) |
| Koumoku (項目) | Japanese Term | Item / Field — a column or data field in a list view or form |
| FC/CC | Business term | Feature Code / Color Code — telecommunication line classification identifiers used in NTT FLET'S service contracts |