book

Mastering Apex Programming - Second Edition

by Paul Battisson

November 2023

Intermediate to advanced

394 pages

10h 14m

English

Packt Publishing

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Who this book is forWhat this book coversTo get the most out of this bookConventions usedGet in touchShare Your ThoughtsDownload a free PDF copy of this book
Null pointer exceptionsExceptions on object instancesExceptions when working with mapsSafe navigation operatorRetrieving configuration data in a bulkified wayHot and cold dataBulkification – querying within loopsBulkification – DML within loopsHardcodingSummary
Technical requirementsDebugging on SalesforcePrevention is better than cureLog levelsSFDX and streaming logsDebugging using the Apex Replay DebuggerApex Interactive DebuggerISV Customer DebuggerWhich tool to use?Summary
The Salesforce order of executionAn example scenarioThe save order of executionClicks and codeTrigger architectureUsing trigger handler frameworksControlling trigger executionSummary
Understanding the different types of exceptionsExpected exceptionsUnexpected exceptionsUnknown exceptionsCatching errorsUsing the finally blockException loggingCapturing stateUsing custom exception typesSummary
Understanding the importance of testingUsing a test data factory to create dataLoading test data using Test.loadDataThe TestSetup annotationMocking test dataTesting RESTful web services with static resourcesTesting RESTful web services with a custom mockTesting best practicesUsing Test.startTest and Test.stopTest to demarcate the code under testUsing assertions to validate behaviorWriting a test for any bug that occursSummary
How permissions and sharing work on SalesforceSharing and performanceEnforcing sharingSharing records using ApexEnforcing object and field permissionsUnderstanding Apex class securityEnforcing permissions and security within SOQLEnforcing user mode for all database operationsAvoiding SOQL injection vulnerabilitiesSummary

When to use a future methodMixed DMLOther use cases for future methodsDefining future methodsPassing state and coordinating dataCalling future methodsMonitoring the execution of future method invocationsTesting future methodsSummary
When to use Batch ApexLarge data volumesComplex logical manipulation processesHigh-volume web service calloutsAsynchronous queue processingDefining a Batch Apex classThe base interfaceInvoking Batch ApexUsing Database.executeBatchMonitoring Batch ApexException handling and platform eventsTesting Batch ApexSummary
What is Queueable Apex?Queueable versus futureQueueable versus BatchWhen to use Queueable ApexExtensive or complex processesCalloutsChained processesDefining Queueable Apex implementationsAllowing calloutsInvoking Queueable ApexEnqueuing child/chained jobsTesting Queueable ApexSummary
When to use Scheduled Apex jobsOne-off executionsRepeating jobsDefining a schedulable Apex classScheduling an Apex classUsing the Apex SchedulerUsing the System.schedule methodSystem.schedule versus System.scheduleBatch for Batch Apex classesSuicidal schedulingMonitoring a scheduled jobScheduled job limitsTesting scheduled jobs and Apex schedulingSummary
What is an API?Types of APIsPublic APIsPartner APIsPrivate APIsComposite APIsSOAP versus REST versus gRPC versus GraphQLSOAPRESTgRPCGraphQLEvent/message bus integrationCustom code versus toolsSummary
An overview of the event-driven architecture and the event busExploring event-driven architectureThe event busWhen to use platform eventsDefining and publishing a platform eventUsing ApexPublishing platform events through FlowUsing the REST APISubscribing to and handling platform eventsHandling platform events using Apex triggersSubscribing to platform events in FlowChange Data Capture and platform eventsTesting platform eventsTesting whether platform events are publishingTesting the consumption of platform eventsLogging using platform eventsA discussion of the CometD protocol and handling events externallyThe Pub/Sub APIIntegrations using platform eventsSummary
Apex and FlowInvocable actionsTesting invocable actionsInternal APIsCallouts from invocable methodsExternal Services in FlowSummary
An overview of RESTHTTP methodsREST and Apex – when to use custom endpointsDefining endpointsA more detailed exampleDynamic parsing using custom metadataTesting endpoints using WorkbenchExposing endpointsPublic APIs and Sites pagesAn alternative using URL Rewriter and Visualforce pagesHandling request body dataHandling JSONHandling XMLTesting Apex REST codeSummary
Basic REST calloutsRemote Site SettingsAuthentication and named credentialsUsing certificatesTestingOpenAPI and external servicesSummary
SOAP overviewWSDL filesGenerating ApexMaking asynchronous calloutsTesting calloutsSummary
An overview of DataWeaveScript structureUsing DataWeave in ApexCreating a DataWeave script for useCalling a DataWeave script from ApexTesting Apex containing DataWeaveWhen to use DataWeaveSummary
Understanding the Salesforce application request life cycleMulti-tenancy and performanceGovernor limits and why we should embrace themThinking about performanceSummary
Measure twice, cut onceThe OODA methodologyObserveOrientDecideActBig O notation and magnitude analysisProfiling Apex performanceUsing the Limits classA utility class to profile ApexProfiling Visualforce page performanceProfiling LWC performanceSummary
Improving CPU timeFaster for loopsUsing maps to remove and reduce loopingReducing the use of expensive operationsReducing heap size usageBatched for loopsUsing scopingRemoving unwanted itemsImproving query selectivityThe number of queriesRetrieving child records with a sub-queryCache resultsPlatform CacheUnderstanding when to make some of these improvementsSummary
Using clicks with codeWhether to use clicks or codeClicks, code, and performance implicationsCode structure and lintingObject-oriented programming in ApexCommon Salesforce architectural trade-offsSynchronous versus asynchronousWizards to help chunkClient-side versus server-side processing of dataEnterprise patterns versus flexibilityManaging long-term performance of an applicationSummary
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Content preview from Mastering Apex Programming - Second Edition

9 Working with Queueable Apex

So far in this section on asynchronous processing in Apex, we have dealt with both future methods and Batch Apex, two different ways of processing data asynchronously with different use cases and benefits. In this chapter, we are going to discuss another asynchronous processing option that is somewhat of a hybrid of both – Queueable Apex.

We will discuss what Queueable Apex is and how it compares to both Batch Apex and future methods. This will help us define and understand use cases for Queueable Apex before we learn how to define a Queueable Apex implementation. After defining a Queueable Apex implementation, we will learn how to invoke a queueable job and how to chain jobs. We’ll finish this chapter by reviewing ...