Building strong foundations apex enterprise patterns
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Developer "A" wrote an Apex controller without considering how it might be reused later by Developer "B" in a batch job, violating the principle of separation of concerns. The controller code used the ApexPages context inappropriately and lacked error handling. To properly structure code for reuse and extensibility, developers should follow patterns like separating concerns into distinct layers (service layer, domain layer, selector layer) with well-defined responsibilities and interfaces. This improves code quality, testability, and maintainability.
Building strong foundations apex enterprise patterns
- 1. Building Strong Foundations Apex Enterprise Patterns Andrew Fawcett FinancialForce.com, CTO @andyinthecloud
- 2. About GREAT ALONE. BETTER TOGETHER. âą Native to Salesforce1âą Platform since 2009 âą Investors include Salesforce Ventures âą 650+ employees, San Francisco based 2
- 3. Session Resources Follow the Session in the Dreamforce App, I will share this slide deck and other related links on the Feed Be social and feel free to ask follow up questions! ï
- 4. What's wrong with this picture?
- 5. What's wrong with this picture? Developer âAâ writes an Apex Controller first Developer âBâ writes an Apex Batch job later.
- 6. So what was wrong with that picture? Developer âAâ Developer âBâ MyControllerMyController Issue Use of ApexPages.currentPage() Unnecessary and fragile, utilize instead stdController.getId() method Error handling No try/catch error handling on controller method MyBatchJob Issue Use of ApexPages.currentPage() Is not available in a Batch Apex context, the constructor code will give an exception. SOQL Query and DML Governors Calling the controller method in a loop will cause a SOQL query and DML governor issues. Error Handling No try/catch error handling in the the execute method Separation of Concerns Developer A did not originally develop the controller logic expecting or anticipating Developer Bâs would in the future try to reuse it from a Batch Context as well. They did not consider correct Separation of ConcernsâŠ
- 7. selectById selectByXXX queryLocatorById SOQL new DomainClass(âŠ.) processRecords(âŠ) Domain Class Service Class Selector Class QueryLocator start(âŠ) execute(âŠ) Finish(âŠ) Batch Apex Service Boundary query queryquery Pattern Checklist Separation of Concerns â Service Layer â Domain Layer â Selector Layer â
- 8. So what is âSeparation of Concernsâ then? âThe goal is to design systems so that functions can be optimized independently of other functions, so that failure of one function does not cause other functions to fail, and in general to make it easier to understand, design and manage complex interdependent systemsâ Wikipedia, âSeparation of Concernsâ
- 9. Base Reference Material, Inspiration and Further Reading Service Layer Domain Layer âą Yet another Wrapper / Trigger pattern! Selector Layer Reference Martin Fowler âą http://martinfowler.com/eaaCatalog/ âą Author of âPatterns of Enterprise Application Architectureâ Salesforce Wiki Reference âą http://wiki.developerforce.com/page/Apex_Enterprise_Patterns_-_Separation_of_Concerns
- 10. Apex Enterprise Patterns Sample Application GitHub: financialforcedev/fflib-apex-common-samplecode
- 11. Apex Enterprise Patterns Architecture selectById selectByXXX queryLocatorById SOQL new DomainClass(âŠ.) processRecords(âŠ) Domain Class Service Class Selector Class QueryLocator start(âŠ) execute(âŠ) Finish(âŠ) Batch Apex Service Boundary query queryquery NOTE: You may also find Controllers consuming your Selector classes at times.
- 12. Brief introduction to the Factory pattern⊠⹠In class-based programming, the factory method pattern is a creational pattern which uses factory methods to deal with the problem of creating objects without specifying the exact class of object that will be created. http://en.wikipedia.org/wiki/Factory_metho d_pattern
- 13. With and without an Application Factory⊠Without With - Just use new operator whenever - Simpler code base, no Apex Interfaces - No mocking support - No polymorphic domain - Adhoc Unit of Work configuration - Use Application class instead of new operator - Must use Apex Interfaces to define SOC - ApexMocks support - Ability to leverage Polymorphic Domains - Standardized Unit of Work throughout When creating instances of Service, Domain, Selector and Unit of Work classesâŠ
- 14. Want to know more about Application factory? Just a regular class named Application with some public static final members in it! Further ReadingâŠ. Unit Testing, Apex Enterprise Patterns and ApexMocks â Part 1 Unit Testing, Apex Enterprise Patterns and ApexMocks â Part 2
- 15. selectById selectByXXX queryLocatorById SOQL new DomainClass(âŠ.) processRecords(âŠ) Domain Class Service Class Selector Class QueryLocator start(âŠ) execute(âŠ) Finish(âŠ) Batch Apex Service Boundary query queryquery Pattern Checklist Separation of Concerns ïŸ Service Layer â Domain Layer â Selector Layer â
- 16. Introducing the Service Layer
- 17. Introducing the Service Layer : Naming and Methods Naming Convention ï§ Suffix with âServiceâ, e.g. OpportunitiesService ï§ Methods named by purpose not usage, e.g. applyDiscounts ï§ Stateless, uses with sharing and global optional for API readyness
- 18. Introducing the Service Layer : Caller Benefits Clear Code Factoring ï§ Encapsulates Processes / Tasks ï§ Caller Context Agnostic, Controller class calling it exampleâŠ
- 19. Introducing the Service Layer : Example Method Defined Responsibilities ï§ Supports Bulkifcation ï§ Transaction management
- 20. Developing and calling a Service Layer Service Contract Developer âAâ follows Service Layer pattern. Developer âAâ writes Controller code to consume the Service. Developer âBâ then reuses the Developer âAâ code safely. AccountService.cls MyController.cls MyBatch.cls
- 21. Code Walkthrough : Sample Services Managing DML and Transactions âą Unit of Work Pattern Classes OpportunitiesServiceImpl.cls
- 22. Code Walkthrough : Custom Buttons Custom Buttons âą Detail and List View âą Calling Visualforce Controller Code Visualforce Controllers and Pages âą Error Handling âą Interacts with Service Layer âą Utilize bulkified methods âą Assume transaction containment âą Catch exceptions and display them on the page Classes and Pages OpportunityApplyDiscountController.cls âą opportunityapplydiscount.page âą opportunityapplydiscounts.page OpportunityCreateInvoiceController.cls âą opportunitycreateinvoice.page âą opportunitycreateinvoices.page
- 23. Code Walkthrough : Batch Apex Classes CreatesInvoicesJob.cls ï§ Error Handling ï§ Interacts with Service Layer âą Utilize bulkified methods, Assume transaction containment âą Catch exceptions and logs them for later notification
- 24. selectById selectByXXX queryLocatorById SOQL new DomainClass(âŠ.) processRecords(âŠ) Domain Class Service Class Selector Class QueryLocator start(âŠ) execute(âŠ) Finish(âŠ) Batch Apex Service Boundary query queryquery Pattern Checklist Separation of Concerns ïŸ Service Layer ïŸ Domain Layer â Selector Layer â
- 25. Introducing the Domain Layer Domain Class Service Layer Visualforce Controller Apex Webservice Inbound Email Handler Batch Apex Scheduled Apex JavaScript Remo ng Apex Rest Service Class Domain Class Domain Class Domain Class Domain Layer Database Manipula on via Apex Trigger Service Opera ons via Apex Calls Custom Objects Standard UI Layouts Formulas Reports Dashboards Workflow Custom Object Custom Object Bulkifica on of DML Unit of Work Service Class Custom Object Service Class
- 26. Introducing the Domain Layer Naming Convention ï§ Name uses plural name of object, e.g. Opportunities NOTE: This class implements an interface and the newInstance method, required only if using Application factory
- 27. Introducing the Domain Layer Clear Code Factoring ï§ Encapsulates Validation / Defaulting of Fields ï§ Wraps Apex Trigger Logic in Apex Class (Trigger/Wrapper Pattern)
- 28. Introducing the Domain Layer Defined Responsibilities ï§ Enforces Bulkifcation for logic ï§ Platform security best practice (honors Users profile) ï§ Encapsulates ALL logic / behavior for each object âą e.g. onValidate, onBeforeInsert and applyDiscount
- 29. Introducing the Domain Layer : Apex Trigger Flow
- 30. Code Walkthrough : Domain Layer : Apex Triggers What no code?!? ï Triggers OpportunitiesTrigger.trigger OpportunityLineItemsTrigger.trigger
- 31. selectById selectByXXX queryLocatorById SOQL new DomainClass(âŠ.) processRecords(âŠ) Domain Class Service Class Selector Class QueryLocator start(âŠ) execute(âŠ) Finish(âŠ) Batch Apex Service Boundary query queryquery Pattern Checklist Separation of Concerns ïŸ Service Layer ïŸ Domain Layer ïŸ Selector Layer â
- 32. Introducing the Selector Layer selectById selectByXXX queryLocatorById SOQL new DomainClass(âŠ.) processRecords(âŠ) Domain Class Service Class Selector Class QueryLocator start(âŠ) execute(âŠ) Finish(âŠ) Batch Apex Service Boundary query queryquery NOTE: You may also find Controllers consuming your Selector classes at times.
- 33. Introducing the Selector Layer Naming Convention ï§ Plural object name suffixed by Selector âą e.g. OpportunitiesSelector NOTE: Interface and newInstance method not required if your not using the Application factory
- 34. Introducing the Selector Layer Clear Code Factoring ï§ Encapsulates Query Logic
- 35. Introducing the Selector Layer Defined Responsibilities ï§ Consistency over queried fields ï§ Platform security best practice âą Configurable ï§ Encapsulates ALL query logic
- 36. Code Walkthrough : Selector Layer : Callers Service Layer Logic : OpportunitiesSelector.selectByIdWithProducts Domain Layer Logic : AccountsSelector.selectByOpportunity Apex Class OpportunitiesServiceImpl.cls Apex Class Opportunities.cls NOTE: Above example leverages feature of Selector factory
- 37. selectById selectByXXX queryLocatorById SOQL new DomainClass(âŠ.) processRecords(âŠ) Domain Class Service Class Selector Class QueryLocator start(âŠ) execute(âŠ) Finish(âŠ) Batch Apex Service Boundary query queryquery Pattern Checklist Separation of Concerns ïŸ Service Layer ïŸ Domain Layer ïŸ Selector Layer ïŸ
- 38. Summary
- 39. Summary
- 40. When is SOC / DRY appropriate (a rough guide)? Solution / Code Base Size Developers Requirements Scope Number of Client Types and Interactions SOC/DRY Appropriate? Small 1 to 2 âą Well known and unlikely to change âą One off solutions âą Limited number of objects âą Standard UI âą Simple VF / Triggers âą No Batch Mode âą No API âą No Mobile Typically not Small to Medium 1 to 6 âą Well known but may need to evolve rapidly âą Growing number objects and processes interacting âą Product deliverable or larger duration projects âą Standard UI âą Advanced VF / JQuery âą Batch Mode âą API (on roadmap) âą Mobile (on roadmap) Worth considering Large > 6 âą Scope driven by multiple customers and user types âą Large number of objects âą Generic product or solution aimed at Mid to Enterprise market with Customer or Partner Integrations. âą Growing development team! âą Standard UI âą Advanced VF / JQuery âą Batch Mode âą Developer / Partner API âą Mobile Clients âą New Platform Feature Ready, Chatter Actions! Definite benifits
- 41. Session Resources Follow the Session in the Dreamforce App, I will share this slide deck and other related links on the Feed Be social and feel free to ask follow up questions! ï
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