# (DD06) Business Logic — UI.comboBox2() [7 LOC]

| Field | Value |
|-------|-------|
| Fully Qualified Name | `com.github.blaxk3.ui.UI` |
| Layer | UI / Presentation Component |
| Module | `ui` (Package: `com.github.blaxk3.ui`) |

## 1. Role

### UI.comboBox2()

This method constructs and prepares the second combo box UI control used by the screen. Its business purpose is not to perform domain calculations, but to provide a standardized selection input that is visually sized for the application layout and then populated through a dedicated currency-code initializer. In practice, this method acts as a presentation-layer factory: it creates the Swing `JComboBox`, applies a consistent width and height, and delegates option loading to `CurrencyCode`. The method supports the currency-selection use case only; there are no conditional branches or alternative business paths. Its role in the larger system is to encapsulate reusable UI composition so the screen-building code can request a ready-to-use dropdown component instead of assembling it inline.

## 2. Processing Pattern (Detailed Business Logic)

```mermaid
flowchart TD
    START["comboBox2()"]
    CREATE["Instantiate JComboBox component"]
    SIZE["Set preferred size to 300 x 30"]
    LOAD["new CurrencyCode(comboBox2).execute()"]
    RETURN_NODE["Return comboBox2 component"]
    START --> CREATE
    CREATE --> SIZE
    SIZE --> LOAD
    LOAD --> RETURN_NODE
```

## 3. Parameter Analysis

| No | Parameter Name | Type | Business Description |
|----|---------------|------|---------------------|
| - | (none) | - | This method takes no parameters. It relies on the UI object's internal `comboBox2` field as the target component instance and delegates population to `CurrencyCode`. |

External state read by the method: the instance field `comboBox2` in `UI`.

## 4. CRUD Operations / Called Services

### Pre-computed evidence from code analysis graph:

| CRUD | SC / CBS | SC Code | Entity / DB | Operation Description |
|------|----------|---------|-------------|----------------------|
| - | `UI.comboBox2` | UI | - | Calls `comboBox2` in `UI` |

Analyze all method calls within this method and classify each as a CRUD operation.

| CRUD | SC / CBS | SC Code | Entity / DB | Operation Description |
|------|----------|---------|-------------|----------------------|
| C | `CurrencyCode.execute` | UI | - | Populates the combo box with currency-code choices for display and selection |

## 5. Dependency Trace

### Pre-computed evidence from code analysis graph:

No screen/batch entry points found within 8 hops. Direct callers found: 1 methods.
Terminal operations from this method: `comboBox2` [-]

Trace who calls this method and what this method ultimately calls.

| # | Caller (Screen/Batch) | Call Chain (Full Path to this Method) | Terminal (SC / CRUD / Entity) |
|---|----------------------|--------------------------------------|-------------------------------|
| 1 | Unknown caller within `UI` | `caller -> UI.comboBox2` | `CurrencyCode.execute [C] currency selection list` |

## 6. Per-Branch Detail Blocks

**Block 1** — [SEQUENTIAL] (L103-L109)

> Builds a reusable currency combo box component and populates it before returning it to the caller.

| # | Type | Code |
|---|------|------|
| 1 | SET | `comboBox2 = new JComboBox<>();` // create the dropdown component |
| 2 | EXEC | `comboBox2.setPreferredSize(new Dimension(300, 30));` // apply fixed UI size for layout consistency |
| 3 | CALL | `new CurrencyCode(comboBox2).execute();` // load currency options into the component |
| 4 | RETURN | `return comboBox2;` // hand the configured component back to the caller |

## 7. Glossary

| Term | Type | Business Meaning |
|------|------|------------------|
| `comboBox2` | UI component | The second dropdown control on the screen, used here as the currency selection input. |
| `JComboBox` | Technical term | Swing dropdown component that lets the user select one value from a list. |
| `Dimension(300, 30)` | Technical term | Fixed component size used to keep the dropdown aligned with the screen layout. |
| `CurrencyCode` | Helper class | UI helper that populates the combo box with available currency values. |
| `execute()` | Method pattern | Initialization routine invoked to prepare the combo box contents. |
| UI | Layer | Presentation layer that builds and configures screen components. |