Domain Identification and Grouping

This skill groups architectural components into logical domains (business areas) to prepare for creating domain services in a service-based architecture.

How to Use

Quick Start

Request analysis of your codebase:

"Group components into logical domains"

"Identify component domains for service-based architecture"

"Create domain groupings from components"

"Analyze which components belong to which domains"

Usage Examples

Example 1: Domain Identification

User: "Group components into logical domains"

The skill will:

1. Analyze component responsibilities and relationships

2. Identify business domains based on functionality

3. Group components into domains

4. Create domain diagrams

5. Suggest namespace refactoring for domain alignment

Example 2: Domain Analysis

User: "Which domain should the billing components belong to?"

The skill will:

1. Analyze billing component functionality

2. Check relationships with other components

3. Identify appropriate domain (e.g., Customer or Financial)

4. Recommend domain assignment

Example 3: Domain Refactoring

User: "What namespace refactoring is needed to align components with domains?"

The skill will:

1. Compare current component namespaces to identified domains

2. Identify misaligned components

3. Suggest namespace changes

4. Create refactoring plan

Step-by-Step Process

Identify Domains

Analyze business capabilities and component relationships

Group Components

Assign components to appropriate domains

Validate Groupings

Ensure components fit well in their domains

Refactor Namespaces

Align component namespaces with domains

Create Domain Map

Visualize domain structure and component groupings

When to Use

Apply this skill when:

After identifying, sizing, and analyzing component dependencies

Before creating domain services (Pattern 6)

When planning service-based architecture migration

Analyzing component relationships and business alignment

Preparing for domain-driven design implementation

Grouping components for better organization

Core Concepts

Domain Definition

A

domain

is a logical grouping of components that:

Represents a distinct business capability or area

Contains related components that work together

Has clear boundaries and responsibilities

Can become a domain service in service-based architecture

Examples

:

Customer Domain

Customer profile, billing, support contracts

Ticketing Domain

Ticket creation, assignment, routing, completion

Reporting Domain

Ticket reports, expert reports, financial reports
Component Domain Relationship
One-to-Many: A single domain contains multiple components Domain: Customer ├── Component: Customer Profile ├── Component: Billing Payment ├── Component: Billing History └── Component: Support Contract Domain Manifestation Domains are physically manifested through namespace structure : Before Domain Alignment : services/billing/payment services/billing/history services/customer/profile services/supportcontract After Domain Alignment : services/customer/billing/payment services/customer/billing/history services/customer/profile services/customer/supportcontract Notice how all customer-related functionality is grouped under .customer domain. Analysis Process Phase 1: Identify Business Domains Analyze the codebase to identify distinct business domains: Examine Component Responsibilities Read component names and descriptions Understand what each component does Identify business capabilities Look for Business Language Group components by business vocabulary Example: "billing", "payment", "invoice" → Financial domain Example: "customer", "profile", "contract" → Customer domain Identify Domain Boundaries Where do business concepts change? What are the distinct business areas? How do components relate to business capabilities? Collaborate with Business Stakeholders Validate domain identification with product owners Ensure domains align with business understanding Get feedback on domain boundaries Example Domain Identification :

Identified Domains 1. ** Ticketing Domain ** (ss.ticket) - Ticket creation, assignment, routing, completion - Customer surveys - Knowledge base 2. ** Customer Domain ** (ss.customer) - Customer profile - Billing and payment - Support contracts 3. ** Reporting Domain ** (ss.reporting) - Ticket reports - Expert reports - Financial reports 4. ** Admin Domain ** (ss.admin) - User maintenance - Expert profile management 5. ** Shared Domain ** (ss.shared) - Login - Notification Phase 2: Group Components into Domains Assign each component to an appropriate domain: Analyze Component Functionality What business capability does it support? What domain vocabulary does it use? What other components does it relate to? Check Component Relationships Which components are frequently used together? What are the dependencies between components? Do components share data or workflows? Assign to Domain Place component in domain that best fits its functionality Ensure component aligns with domain's business language Verify component relationships support domain grouping Handle Edge Cases Components that don't fit clearly: Analyze more deeply Components that fit multiple domains: Choose primary domain Shared components: May belong to Shared domain Example Component Grouping :

Component Domain Assignment

Ticketing Domain (ss.ticket)

Ticket Shared (ss.ticket.shared)

Ticket Maintenance (ss.ticket.maintenance)

Ticket Completion (ss.ticket.completion)

Ticket Assign (ss.ticket.assign)

Ticket Route (ss.ticket.route)

KB Maintenance (ss.ticket.kb.maintenance)

KB Search (ss.ticket.kb.search)

Survey (ss.ticket.survey)

Customer Domain (ss.customer)

Customer Profile (ss.customer.profile)

Billing Payment (ss.customer.billing.payment)

Billing History (ss.customer.billing.history)

Support Contract (ss.customer.supportcontract)

Reporting Domain (ss.reporting)

Reporting Shared (ss.reporting.shared)

Ticket Reports (ss.reporting.tickets)

Expert Reports (ss.reporting.experts)

Financial Reports (ss.reporting.financial) Phase 3: Validate Domain Groupings Ensure components fit well in their assigned domains: Check Cohesion Do components in domain share business language? Are components frequently used together? Do components have direct relationships? Verify Boundaries Are domain boundaries clear? Do components belong to only one domain? Are there components that don't fit anywhere? Assess Completeness Are all components assigned to a domain? Are domains cohesive and well-formed? Do domains represent distinct business capabilities? Get Stakeholder Validation Review domain groupings with product owners Ensure domains align with business understanding Get feedback on domain boundaries Validation Checklist : All components assigned to a domain Domains have clear boundaries Components fit well in their domains Domains represent distinct business capabilities Stakeholders validate domain groupings Phase 4: Refactor Namespaces for Domain Alignment Align component namespaces with identified domains: Compare Current vs Target Namespaces Current: services/billing/payment Target: services/customer/billing/payment Change: Add .customer domain node Identify Refactoring Needed Which components need namespace changes? What domain nodes need to be added? Are there components already aligned? Create Refactoring Plan List components needing namespace changes Specify target namespace for each Prioritize refactoring work Execute Refactoring Update component namespaces Update imports/references Verify all references updated Example Namespace Refactoring :

Namespace Refactoring Plan

|

|

| | KB Maintenance | ss.kb.maintenance | ss.ticket.kb.maintenance | Add .ticket | | KB Search | ss.kb.search | ss.ticket.kb.search | Add .ticket | | Survey | ss.survey | ss.ticket.survey | Add .ticket | Phase 5: Create Domain Map Visualize domain structure and component groupings: Create Domain Diagram Show domains as boxes Show components within each domain Show relationships between domains Document Domain Structure List domains and their components Describe domain responsibilities Note domain boundaries Create Domain Inventory Table of domains and components Component counts per domain Size metrics per domain Example Domain Map :

Domain Map ┌─────────────────────────────────────┐ │ Ticketing Domain (ss.ticket) │ ├─────────────────────────────────────┤ │ • Ticket Shared │ │ • Ticket Maintenance │ │ • Ticket Completion │ │ • Ticket Assign │ │ • Ticket Route │ │ • KB Maintenance │ │ • KB Search │ │ • Survey │ └─────────────────────────────────────┘ │ │ uses ▼ ┌─────────────────────────────────────┐ │ Customer Domain (ss.customer) │ ├─────────────────────────────────────┤ │ • Customer Profile │ │ • Billing Payment │ │ • Billing History │ │ • Support Contract │ └─────────────────────────────────────┘

Output Format

Domain Identification Report

```markdown

Domain Identification

Domain: Customer (ss.customer)

Business Capability: Manages customer relationships, billing, and support contracts Components: - Customer Profile (ss.customer.profile) - Billing Payment (ss.customer.billing.payment) - Billing History (ss.customer.billing.history) - Support Contract (ss.customer.supportcontract) Component Count: 4 Total Size: ~15,000 statements (18% of codebase) Domain Cohesion: ✅ High - Components share customer-related vocabulary - Components frequently used together - Direct relationships between components Boundaries: - Clear separation from Ticketing domain - Clear separation from Reporting domain - Shared components (Notification) used by all domains Component Domain Assignment Table

|

Namespace Refactoring Plan

Priority: High ** Customer Domain Alignment ** ** Components to Refactor ** : 1. Billing Payment: ss.billing.payment → ss.customer.billing.payment 2. Billing History: ss.billing.history → ss.customer.billing.history 3. Support Contract: ss.supportcontract → ss.customer.supportcontract ** Steps ** : 1. Update namespace declarations in source files 2. Update import statements in dependent components 3. Update directory structure 4. Run tests to verify changes 5. Update documentation ** Expected Impact ** : - All customer-related components aligned under .customer domain - Clearer domain boundaries - Easier to identify domain components Domain Map Visualization

Domain Map

Domain Structure Customer Domain (ss.customer) ├── Customer Profile ├── Billing Payment ├── Billing History └── Support Contract Ticketing Domain (ss.ticket) ├── Ticket Shared ├── Ticket Maintenance ├── Ticket Completion ├── Ticket Assign ├── Ticket Route ├── KB Maintenance ├── KB Search └── Survey Reporting Domain (ss.reporting) ├── Reporting Shared ├── Ticket Reports ├── Expert Reports └── Financial Reports Admin Domain (ss.admin) ├── User Maintenance └── Expert Profile Shared Domain (ss.shared) ├── Login └── Notification

Domain Relationships

Ticketing Domain

│ uses

├─→ Shared Domain (Login, Notification)

└─→ Customer Domain (Customer Profile)

Customer Domain

│ uses

└─→ Shared Domain (Login, Notification)

Reporting Domain

│ uses

├─→ Ticketing Domain (Ticket data)

├─→ Customer Domain (Customer data)

└─→ Shared Domain (Login)

Analysis Checklist

Domain Identification

:

Analyzed component responsibilities

Identified business capabilities

Identified distinct business domains

Validated domains with stakeholders

Component Grouping

:

Assigned each component to a domain

Analyzed component relationships

Ensured components fit domain vocabulary

Handled edge cases (shared components, unclear assignments)

Domain Validation

:

Checked cohesion within domains

Verified domain boundaries are clear

Ensured all components assigned

Validated with stakeholders

Namespace Refactoring

:

Compared current vs target namespaces

Identified components needing refactoring

Created refactoring plan

Prioritized refactoring work

Domain Mapping

:

Created domain diagram

Documented domain structure

Created domain inventory table

Documented domain relationships

Implementation Notes

For Node.js/Express Applications

Domains typically organized in

services/

directory:

services/

├── customer/ ← Customer Domain

│ ├── profile/

│ ├── billing/

│ │ ├── payment/

│ │ └── history/

│ └── supportcontract/

├── ticket/ ← Ticketing Domain

│ ├── shared/

│ ├── maintenance/

│ ├── assign/

│ └── route/

└── reporting/ ← Reporting Domain

├── shared/

├── tickets/

└── experts/

For Java Applications

Domains identified by package structure:

com.company.customer ← Customer Domain

├── profile

├── billing

│ ├── payment

│ └── history

└── supportcontract

com.company.ticket ← Ticketing Domain

├── shared

├── maintenance

├── assign

└── route

Domain Identification Strategies

Strategy 1: Business Capability Analysis

Identify what business capabilities the system provides

Group components by capability

Example: "Customer Management" capability → Customer Domain

Strategy 2: Vocabulary Analysis

Identify business vocabulary used by components

Group components sharing same vocabulary

Example: Components using "billing", "payment", "invoice" → Financial Domain

Strategy 3: Relationship Analysis

Identify components frequently used together

Group components with strong relationships

Example: Components that share data/workflows → Same Domain

Strategy 4: Stakeholder Collaboration

Work with product owners/business analysts

Use their understanding of business areas

Validate domain boundaries with them

Fitness Functions

After creating domains, create automated checks:

Domain Namespace Governance

// Ensure components belong to correct domain

function

validateDomainNamespaces

(

components

,

domainRules

)

{

const

violations

=

[

]

components

.

forEach

(

comp

)

=>

{

const

domain

=

identifyDomain

(

comp

.

namespace

)

const

expectedDomain

=

domainRules

[

comp

.

name

]

if

(

domain

!==

expectedDomain

)

{

violations

.

push

(

{

component

:

comp

.

name

,

currentDomain

:

domain

,

expectedDomain

:

expectedDomain

,

namespace

:

comp

.

namespace

,

}

)

}

)

return

violations

}

Domain Boundary Enforcement

// Prevent components from accessing other domains directly

function

enforceDomainBoundaries

(

components

)

{

const

violations

=

[

]

components

.

forEach

(

comp

)

=>

{

comp

.

imports

.

forEach

(

imp

)

=>

{

const

importedDomain

=

identifyDomain

(

imp

)

const

componentDomain

=

identifyDomain

(

comp

.

namespace

)

if

(

importedDomain

!==

componentDomain

&&

importedDomain

!==

'shared'

)

{

violations

.

push

(

{

component

:

comp

.

name

,

domain

:

componentDomain

,

importsFrom

:

imp

,

importedDomain

:

importedDomain

,

issue

:

'Cross-domain direct dependency'

,

}

)

}

)

}

)

return

violations

}

Best Practices

Do's ✅

Collaborate with business stakeholders to identify domains

Group components by business capability, not technical layers

Ensure domains represent distinct business areas

Validate domain boundaries with stakeholders

Refactor namespaces to align with domains

Create clear domain documentation

Use business language in domain names

Don'ts ❌

Don't create domains based on technical layers (services, controllers, models)

Don't force components into domains where they don't fit

Don't skip stakeholder validation

Don't create too many small domains (aim for 3-7 domains)

Don't create domains that are too large (monolithic domains)

Don't ignore components that don't fit (analyze why)

Don't skip namespace refactoring (critical for clarity)

Common Domain Patterns

Typical Domains in Business Applications

Customer Domain

Customer management, profiles, relationships

Product Domain

Product catalog, inventory, pricing

Order Domain

Order processing, fulfillment, shipping

Billing Domain

Invoicing, payments, financial transactions

Reporting Domain

Reports, analytics, dashboards

Admin Domain

User management, system configuration

Shared Domain

Common functionality (login, notification, utilities)

Domain Size Guidelines

Small Domain

2-4 components

Medium Domain

5-8 components

Large Domain

9-15 components
Too Large: 15 components (consider splitting) Next Steps After creating component domains: Apply Create Domain Services Pattern - Extract domains to separate services Plan Service Extraction - Create migration plan for domain services Implement Domain Services - Move domains to separately deployed services Monitor Domain Boundaries - Use fitness functions to enforce boundaries Notes Domains should represent business capabilities, not technical layers Domain identification requires collaboration with business stakeholders Namespace refactoring is critical for domain clarity Domains prepare the codebase for service-based architecture Well-formed domains make service extraction easier Domain boundaries should be clear and well-documented

domain-identification-grouping

安装

Ticketing Domain (ss.ticket)

Ticket Shared (ss.ticket.shared)

Ticket Maintenance (ss.ticket.maintenance)

Ticket Completion (ss.ticket.completion)

Ticket Assign (ss.ticket.assign)

Ticket Route (ss.ticket.route)

KB Maintenance (ss.ticket.kb.maintenance)

KB Search (ss.ticket.kb.search)

Customer Domain (ss.customer)

Customer Profile (ss.customer.profile)

Billing Payment (ss.customer.billing.payment)

Billing History (ss.customer.billing.history)

Reporting Domain (ss.reporting)

Reporting Shared (ss.reporting.shared)

Ticket Reports (ss.reporting.tickets)

Expert Reports (ss.reporting.experts)

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Output Format

Domain Identification Report

Domain Identification

Domain: Customer (ss.customer)

|

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|

Domain Relationships