# Getting Started

## What This Project Does

This is a small Java codebase built around a handful of domain classes and simple processing/service entry points. The code appears to model order and product workflows alongside several data-holder classes that contain labeled fields, patterns, and encoding-related examples.

If you are new here, the fastest way to understand the project is to start with the orchestration classes, then move into the data structures they manipulate.

## Recommended Reading Order

1. **[overview.md](../overview.md)** — start here for the high-level map of the repository.
2. **[root.md](../root.md)** — review the module page to see how the codebase is organized.
3. **[OrderProcessor](../../src/main/java/OrderProcessor.java)** and **[ProductService](../../src/main/java/ProductService.java)** — read the main behavior-oriented classes first.
4. **[LargeBusinessLabelClass](../../src/main/java/LargeBusinessLabelClass.java)**, **[LargeFieldMap](../../src/main/java/LargeFieldMap.java)**, **[MixedLabelClass](../../src/main/java/MixedLabelClass.java)**, **[PartialLabelEntity](../../src/main/java/PartialLabelEntity.java)** — then inspect the primary data shapes.
5. **[MultiPattern](../../src/main/java/MultiPattern.java)** and **[EucJpClass](../../src/main/java/EucJpClass.java)** — read these when you need to understand pattern or encoding-related examples.

## Key Entry Points

There are no highly-referenced classes in the current reference catalog, so use the following classes as practical entry points:

- **[OrderProcessor](../../src/main/java/OrderProcessor.java)** — likely the clearest workflow-oriented starting point.
- **[ProductService](../../src/main/java/ProductService.java)** — the main service-style class in the repository.
- **[LargeBusinessLabelClass](../../src/main/java/LargeBusinessLabelClass.java)** — a representative example of the label-heavy data model style used here.
- **[LargeFieldMap](../../src/main/java/LargeFieldMap.java)** — a compact example of the mapped-field naming conventions.
- **[MultiPattern](../../src/main/java/MultiPattern.java)** — shows pattern-style field grouping and comment-based annotations.

## Project Structure

The repository is very flat:

- **`src/main/java/`** contains all Java source files.
- There is no obvious package hierarchy in the current snapshot, so classes live side by side at the root of the Java source tree.
- The code is centered on a few top-level classes rather than many layered modules.

A few useful waypoints:

- **Behavior classes:** `OrderProcessor`, `ProductService`
- **Data classes:** `LargeBusinessLabelClass`, `LargeFieldMap`, `MixedLabelClass`, `PartialLabelEntity`, `EucJpClass`
- **Pattern/example class:** `MultiPattern`
- **Placeholder/minimal class:** `A`

## Configuration

No dedicated build or runtime configuration files were visible in the current repository snapshot. That usually means one of two things:

- configuration lives outside the extracted source tree, or
- this project is intentionally minimal and source-driven.

If you need to orient yourself further, check first for common Java project files such as:

- `pom.xml` for Maven
- `build.gradle` or `build.gradle.kts` for Gradle
- `settings.gradle` for multi-module Gradle builds
- `.editorconfig` for formatting rules
- `.gitignore` for local build/output conventions

## Common Patterns

A few patterns show up repeatedly across the source:

- **Simple POJO-style classes** with private fields and minimal behavior.
- **Inline field comments** used as labels or annotations, often in Japanese.
- **Very small methods** that return stored values or echo inputs.
- **Naming-by-domain** rather than deep abstraction; the class names themselves carry most of the meaning.
- **Comment markers for change blocks** such as `// ... ADD START` and `// ... ADD END` in `MultiPattern`.

## Suggested First Pass Through the Code

When you begin reading the implementation, follow this order:

1. Open **[OrderProcessor](../../src/main/java/OrderProcessor.java)** and identify the main flow.
2. Open **[ProductService](../../src/main/java/ProductService.java)** and compare its role with the processor.
3. Scan the field-heavy classes to learn the naming and labeling style.
4. Only then dig into the smaller examples like **[MultiPattern](../../src/main/java/MultiPattern.java)** and **[A](../../src/main/java/A.java)**.

If you are looking for the quickest mental model, focus on the small number of classes first and treat the rest as supporting examples of the same style.