What is the “Enterprise application”? Enterprise application does: ● store vary data ● manage huge data ● accept many requests at a time ● collaborate with other Enterprise applications 4 エンタープライズアプリケーションとは
Contents 7 About MakeInvoice The way we have managed such a large, complex application Architecture in MakeInvoice Service description about MakeInvoice, invoice creation and management SaaS Design patterns that will be worthwhile to adopt to MakeInvoice Adoptable Patterns 1 2 3 目次
This logic has to consider: ● difference between regular and discount item ● tax calculation ● to manipulate a template of document Invoice Creation 請求書生成のビジネスロジック
This logic has to consider: ● resending invoice ● how to handling old invoice ● difference between total price and price paid partially Demand for Payment 支払催促のビジネスロジック
Large domain model structure Complex business logic Requests from dashboard, from Salesforce, from other services using MakeInvoice Some other SaaS to have to connect 18 Characteristics of MakeInvoice backend API MakeInvoiceのバックエンドAPIの特徴
Domain Layer UseCase Layer Primary / Secondary Adapter Code for technical interest and implementation i.e: Http, gRPC, RDB, KVS Represents common use-cases using domain model Contains only “pure” domain concepts and logic Dependency direction 各レイヤーの責務 依存の方向性
Hexagonal architecture This architecture aims to: ● receive request from variety of clients ● reuse essential application code ● write data on several data storages or send to other system 22 https://blog.tai2.net/hexagonal_architexture.html ヘキサゴナルアーキテクチャ
Hexagonal architecture ● Primary Adapters are adapters to communicate with primary actor. ● Secondary Adapters are adapters to communicate with supporting actor (also known as secondary actor). 23 https://blog.tai2.net/hexagonal_architexture.html プライマリアダプターと主アクター セカンダリアダプターと支援アクター
“We wondered why people were so against using regular objects in their systems and concluded that it was because simple objects lacked a fancy name. ” 28 https://martinfowler.com/bliki/POJO.html Plain Old Java Object (POJO) 昔からある単なるJavaオブジェクト
“An object model of the domain that incorporates both behavior and data.” 30 Domain Model https://www.martinfowler.com/eaaCatalog/domainModel.html ドメインモデル
“A small simple object, like money or a date range, whose equality isn't based on identity.” 32 Value Object https://www.martinfowler.com/eaaCatalog/valueObject.html 値オブジェクト
“Mediates between the domain and data mapping layers using a collection-like interface for accessing domain objects.” 36 https://www.martinfowler.com/eaaCatalog/repository.html Repository リポジトリ
“By pulling all the behavior out into services, however, you essentially end up with Transaction Scripts, and thus lose the advantages that the domain model can bring. ” 42 https://martinfowler.com/bliki/AnemicDomainModel.html AnemicDomainModel ドメインモデル貧血症
Secondary Adapter Main concern in this layer probably is mapping objects to/from relational database. Also clients to request to external service is in this layer. セカンダリアダプター
“A layer of Mappers that moves data between objects and a database while keeping them independent of each other and the mapper itself.” 46 https://www.martinfowler.com/eaaCatalog/dataMapper.html Data Mapper データマッパー
“Represents an inheritance hierarchy of classes as a single table that has columns for all the fields of the various classes.” 54 https://www.martinfowler.com/eaaCatalog/singleTableInheritance.html Single Table Inheritance シングルテーブル継承
“Represents an inheritance hierarchy of classes with one table for each class.” 59 https://www.martinfowler.com/eaaCatalog/classTableInheritance.html Class Table Inheritance クラステーブル継承
“Saves a graph of objects by serializing them into a single large object (LOB), which it stores in a database field.” 67 https://www.martinfowler.com/eaaCatalog/serializedLOB.html Serialized LOB シリアライズドLOB
● Managing scheme is difficult. ● Adding and removing property is problematic. ● Result of SQL is not human friendly. ● Managing scheme is almost unnecessary. ● New table is not needed. ● Table joining does not occur. ● Object count is unlimited. Using serialized field has pros and cons Pros Cons シリアライズされたフィールドの功罪
“Has one class perform the database mapping for a child class.” 72 https://www.martinfowler.com/eaaCatalog/dependentMapping.html Dependent Mapping 依存マッピング
● When owner object is updated, dependent objects are all deleted then re-inserted. ● When owner object is deleted, dependent objects are deleted cascadingly. ● Any object except for owner cannot associate with dependent object. ● Dependent object's table has foreign key for owner's table. Dependent object's characteristic Association/Relation Update/Delete 依存オブジェクトの特徴
“Removes dependence upon problematic services during testing. WSDL ” 75 https://www.martinfowler.com/eaaCatalog/dependentMapping.html Service Stub サービススタブ
Primary Adapter This layer is so-called "Presentation Layer". To parse request from client and to compose response are its responsibility. Also main App for running batch program is contained here. プライマリアダプター
“Provides a coarse-grained facade on fine-grained objects to improve efficiency over a network.” 78 https://www.martinfowler.com/eaaCatalog/remoteFacade.html Remote Facade
“An object that carries data between processes in order to reduce the number of method calls.” 81 https://www.martinfowler.com/eaaCatalog/dataTransferObject.html Data Transfer Object データ変換オブジェクト
Domain Model Repository ValueObject DataMapper SingleTableInheritanse ClassTableInheritanse EmbededValue SerializedLOB DependentMapping DTO Remote Facade Putting It All Together 全てのパターンをひとつに SPA DB UseCase Service Stub Other SaaS
Conclusion 86 PofEAA put forward many useful patterns for complex web application. But , as Fowler writes, these patterns have pros and cons. So we have to keep thinking which patterns to use or not use any pattern. Use this advice to prod your thinking. In the end you have to make, and live with, the decisions yourself. One good thing is that your decisions are not cast forever in stone. - Martin Fowler 結論
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