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Domain-Specific Software Architecture (DSSA)

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Domain-Specific Software Architecture (DSSA)

Questions/Cues

  • Apa definisi DSSA dan apa komponen penyusunnya?
  • Apa lima stage proses DSSA?
  • Apa input/output tiap stage?
  • Apa itu reference architecture dan artefak penyusunnya?
  • Apa contoh reference architecture nyata dan keuntungan DSSA?

Reference Points

  • Domain Specific Software Architecture (Halaman 20-23, 35-39)
  • Domain Specific Software Architecture (Halaman 14-19, 41-50)

Definisi dan Komponen DSSA

DSSA pada dasarnya adalah ‘Software Architecture focused on a particular domain’ — untuk membatasi problem space dan memfasilitasi pengembangan terfokus.

Definisi software architecture (rujukan): Shaw & Garlan (“computational components and interactions”), Bass-Clements-Kazman (“structures… software elements, externally visible properties, relationships”), dan IEEE 2000 (“fundamental organization… components, relationships, principles guiding design & evolution”).

Sebuah DSSA comprises:

  • domain model
  • reference requirements
  • a reference architecture
  • a component library / software elements
  • an application configuration method untuk memilih & mengonfigurasi komponen
  • externally visible properties dari elemen-elemen tersebut

Lima Stage Proses DSSA

flowchart TD
    S1["Stage 1: Define the Scope of the Domain<br/>(emphasis: user's needs)"]
    S2["Stage 2: Define/Refine Domain-Specific<br/>Concepts/Requirements (emphasis: problem space)"]
    S3["Stage 3: Define/Refine Domain-Specific Design<br/>& Implementation Constraints (emphasis: solution space)"]
    S4["Stage 4: Develop Domain Architectures/Models<br/>(emphasis: module interfaces & semantics)"]
    S5["Stage 5: Produce/Gather Reusable Workproducts"]
    S1 --> S2 --> S3 --> S4 --> S5

Stage 1 — Define the Scope of the Domain (emphasis: user’s needs)

  • Inputs: Experts, Existing systems, Existing documentation (textbooks, articles).
  • Outputs: Block diagram domain (input/output & relasi high-level antar functional unit); daftar nama orang sebagai referensi/validasi; daftar proyek dengan pointer ke dokumentasi & source code; daftar needs yang harus dipenuhi aplikasi di domain.

Stage 2 — Define/Refine Domain-Specific Concepts/Requirements (emphasis: problem space; mirip Requirements Analysis)

  • Inputs: Outputs Stage 1, selected systems, selected documentation.
  • Outputs: Domain Models (Scenarios→Feature model; Domain Dictionary, Context Information/ER/Object Diagram→Information model; Data-Flow & State-Transition Diagram→Operational model) dan Functional requirements (Reference requirements).
  • Domain model = produk context analysis (mendefinisikan boundary domain & relasi entitas dalam vs luar) dan domain analysis (mengidentifikasi, menangkap, mengorganisasi domain assets).
  • Artefak contoh tiket: Scenarios (Ask, Look, Decide, Buy, Update), Domain Dictionary (mis. Customer), Context Information Diagram, ER Diagram (Theater–Section–Row–Seat; Person→Customer/Agent/Sales Manager), Object diagram (Seat/Row/Section/Theater + attributes & operations), Data-Flow Diagram, State-Transition Diagram (Seats Available ↔ Sold Out), dan Functional Requirements (Sell, Query, Transactions, Will Call-OPT).

Stage 3 — Define/Refine Domain-Specific Design and Implementation Constraints (emphasis: solution space)

  • Inputs: Outputs Stage 1 (terutama context diagram), Outputs Stage 2 (terutama control & data flow diagram + rationale).
  • Outputs: Non-Functional Requirements (mis. Security-OPT, Fault Tolerance, Multi-user Access-OPT, Safety, Response), Design Requirements (mis. User Interface ALT1/2/3: command line / menu driven / pulldown), Implementation Requirements (mis. Language: Ada; OS ALT1 Unix / ALT2 DOS; Size: ≤2000 seats/performance).

Stage 4 — Develop Domain Architectures/Models (mirip High-Level Design; emphasis: module/model interfaces & semantics)

  • Input: input & output stage sebelumnya.
  • Output: A Reference Architecture.

Stage 5 — Produce/Gather Reusable Workproducts

  • Input: interface specifications dari Stage 4 + artefak terkait dari sistem yang ada.
  • Output: Reusable components + test cases & dokumentasi; cross reference komponen ke requirements, constraints, dan architecture.

Reference Architecture

Reference Architecture = kumpulan principal design decisions yang secara simultan berlaku untuk multiple related systems, biasanya dalam satu application domain, dengan points of variation yang didefinisikan eksplisit. Kapan dikembangkan? Not too-early; not too-late.

Artefak penyusun reference architecture:

  • Reference Architecture Model — abstraksi awal berbasis architecture style (mis. layered: User Interface ↔ Functionality ↔ Data Structures).
  • Configuration Decision Tree — subset reference requirements dipilih; konfigurasi dilakukan saat reference architecture instantiation time (mis. Ticket→Price/Seat/Performance, Seating→Open/Reserved, UI→Command Line/Menus).
  • Architecture Schema / Design Record — titik kumpul pengetahuan tentang komponen DSSA: Name/Type, Description, Reference requirements satisfied, Data/control flow diagrams, Design rationale, Interface & architecture specifications and dependencies.
  • Reference Architecture Dependency Diagram — mengungkap koneksi komponen pada granularitas yang mencerminkan architecture style (mis. UI→Theater→Section→Row→Seat, dengan relasi Inherits & Calls).
  • Component Interface Descriptions — fokus pada bagaimana elemen berinteraksi dengan environment-nya (bukan implementasi); dideskripsikan dengan Interface Description Language (IDL) (mis. generic package Theater [...] is ... end Theater;).
  • Constraints and Rationale — constraints = range nilai parameter, relasi antar parameter/komponen yang harus diperhatikan sepanjang pengembangan.
flowchart LR
    RA["Reference Architecture"]
    RA --> RAM["Reference Architecture Model"]
    RA --> CDT["Configuration Decision Tree"]
    RA --> AS["Architecture Schema / Design Record"]
    RA --> DD["Dependency Diagram"]
    RA --> CID["Component Interface Descriptions (IDL)"]
    RA --> CR["Constraints and Rationale"]

Contoh Reference Architecture Nyata

Materi menampilkan beberapa reference architecture konkret (berlapis Presentation / Business / Data + Cross-Cutting: Security, Operational Management, Communication):

  • Web Application Architecture — Client (Browser/Rendering) + Web Server (Presentation/Business/Data Layer).
  • Rich Client Application — fokus local data sources + external data.
  • Rich Internet Application (RIA) — Plug-in Execution Container di client + Services Layer di server.
  • Mobile Apps Architecture — Mobile Client + Mobile Support Infrastructure (data synchronization, unreliable networks).
  • Retail Reference Architecture by WSO2 — API Management Layer, Integration, Business Services, dll.
  • API Management Reference Architecture by IBM — Capabilities for API Consumers/Providers, Marketplaces, Self-Service Portal.
  • Reference Architecture by Open Bank Project — solusi teruji untuk problem domain perbankan, mengurangi kompleksitas desain & mempercepat delivery dengan lebih sedikit error.

Keuntungan Utama DSSA

  • Overall cost minimized karena aset dapat di-reuse.
  • Market share meningkat dengan mengembangkan aplikasi terkait untuk berbagai user.

Summary

DSSA adalah software architecture yang difokuskan pada satu domain untuk membatasi problem space dan memfokuskan pengembangan; ia mencakup domain model, reference requirements, reference architecture, component library, application configuration method, dan externally visible properties. Prosesnya lima stage: (1) define scope domain → (2) refine concepts/requirements (problem space) → (3) refine design/implementation constraints (solution space) → (4) develop reference architecture → (5) gather reusable workproducts. Reference architecture = principal design decisions untuk banyak sistem terkait dengan points of variation, disusun atas model, configuration decision tree, architecture schema, dependency diagram, component interface (IDL), dan constraints/rationale. Contoh nyata mencakup Web/RIA/Mobile/Retail WSO2/API IBM/OpenBank. Keuntungannya: biaya minimal lewat reuse dan market share lebih luas. DSSA mengonsumsi Domain Model dan mewujudkan konsep DSSE Concepts and Three Key Factors.

Graph View

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