# Eo / Service / Client

## Overview

The `eo.service.client` package appears to represent a client-side service layer within the eo customer core system (`eo顧客基幹システム`), a telecommunications customer management platform originally developed by Fujitsu for K-Opticom (now part of KDDI's "eo" brand).

Based on the package naming convention observed across the eo codebase, this module appears responsible for encapsulating HTTP or REST client interactions — likely serving as an abstraction over external service calls (such as third-party APIs, gateway endpoints, or microservice clients) consumed by higher-level application layers. The name "client" in a service package typically indicates it wraps remote procedure calls or API invocations behind a local interface.

However, **no source files, classes, or child modules are currently indexed** for this module. The codebase tooling reports zero indexed source files, zero classes/interfaces/enums, zero methods/constructors, and no package dependencies or import patterns. This means either:

- The module has no code that matches the current indexing configuration.
- The source files exist but have not yet been added to the searchable codebase.
- The module is a thin or recently added package awaiting further implementation.

## Sub-module Guide

No child wiki pages or sub-modules are currently available for this module. The evidence shows:

- **Child wiki pages:** None (kkife335.md and kkife336.md were referenced but do not exist in the wiki index).
- **Direct child modules:** 0.
- **Indexed source files:** 0.

As the codebase index expands, this section will be updated with details on sub-modules such as REST clients, HTTP configuration, error handling, and retry strategies.

## Key Patterns and Architecture

Without indexed source code, the specific patterns and architecture of this module cannot be determined from the codebase itself. Based on the naming convention and the architectural patterns observed in sibling modules (such as `eo.ejb.cbs`), a client module in this system would likely follow these characteristics:

- **Template-based or schema-driven design:** The eo system uses structured message schemas (via `CAANSchemaInfo` and `CAANMsg`) for service contracts. A client layer in this context would likely consume or produce such structured messages.
- **External service wrapping:** If this module wraps REST or HTTP calls, it would likely follow the same pattern seen in `eo.ejb.cbs.mainproc` — reading configuration, building JSON payloads, setting headers, executing requests, and mapping responses.
- **Error code standardization:** The eo system uses a standardized error code convention (E1 through EC). Any client module in this package would likely propagate or translate errors using these codes.

This appears to be a potential client abstraction that would complement the CBS (Customer Business Service) layer by providing reusable, centralized HTTP or API client functionality.

## Dependencies and Integration

No package dependencies or cross-module relationships have been detected for this module in the current index. When indexed, this module would be expected to:

- **Depend on core libraries:** Java standard libraries, potentially Jackson (for JSON serialization/deserialization), Apache HttpClient or equivalent HTTP client libraries, and the Futurity framework (`com.fujitsu.futurity`) common to the eo system.
- **Be consumed by application services:** Higher-level service or business logic modules would likely use this client to interact with external services.
- **Integrate with configuration:** Following eo system conventions, client URLs, timeouts, and authentication parameters would likely be sourced from system settings tables rather than hardcoded.

## Notes for Developers

- **The module has no indexed code.** Any developer working in this area should check the actual source tree directly, as the wiki and code index may not yet reflect the current state of the codebase.
- **Follow existing eo patterns.** If adding code to this module, refer to `eo.ejb.cbs.mainproc` for established patterns around HTTP API calls, configuration loading, error handling, and message schemas.
- **Check source file version headers.** Files in this codebase typically include Fujitsu version history headers (e.g., `v75.00.00 2025/03/26`). New files should follow this convention.
- **Coordinate schema changes.** If this module deals with CBS message schemas, remember that schema changes require coordinated updates across all consumers — a change in one place must be reflected in every handler that reads or writes those fields.

## Module Structure

```mermaid
flowchart LR
    SVC["eo.service.client
(Client package — no indexed code)"]
    CBS["eo.ejb.cbs
(Customer Business Service)"]
    BP["koptBp
(BPM Operations)"]

    BP -->|"delegates to"| CBS
    CBS -->|"may use"| SVC
```

This diagram shows `eo.service.client` as a module with no indexed code, positioned to potentially serve as a shared client abstraction consumed by the CBS layer and, transitively, by BPM operations.