Trigger Handler

An opinionated trigger handler framework. Contains a single virtual class that can be extended to create a trigger handler without a lot of boilerplate code.

Credit to https://github.com/trailheadapps
Originally by Kevin O'Hara github.com/kevinohara80/sfdc-trigger-framework

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Usage Guide

Extension Class

Create a class which extends the base Trigger Handler class and overrides at least one of its operation methods

// AccountTriggerHandler.cls
public with sharing class AccountTriggerHandler extends TriggerHandler {
    public override void beforeInsert() {
        // Code here will run when in the "Before Insert" Context
        System.debug('Overriding Before Insert Trigger...');

        // Records from the Trigger Context need to be cast to the correct SObject before using
        List<Account> triggerOld = (List<Account>) Trigger.old;
        List<Account> triggerNew = (List<Account>) Trigger.new;
        Map<Id, Account> triggerMapNew = (Map<Id, Account>) Trigger.newMap;
        Map<Id, Account> triggerMapOld = (Map<Id, Account>) Trigger.oldMap;
    }
}

Overridable Operation Methods

• beforeInsert
• beforeUpdate
• beforeDelete
• afterInsert
• afterUpdate
• afterDelete
• afterUndelete

Trigger

// AccountTrigger.trigger
trigger AccountTrigger on Account(
   before insert
) {
   new AccountTriggerHandler().run();
}

Max Loop Count

A Max Loop Count can be set to ensure that a trigger only runs once in the current transaction (though this should not normally be necessary)

trigger Account on Account (after update) {
   AccountTriggerHandler handler = new AccountTriggerHandler();
   // Set the max number of executions
   handler.setMaxLoopCount(1);
   try {
      handler.run();
   } catch(TriggerHandler.TriggerHandlerException e) {
      // Exceeding the max loop count will throw an exception.
      System.debug(LoggingLevel.WARN, e.getMessage());
   }
}

Bypassing a Trigger

Calling the TriggerHandler.bypass static method will ensure that the specified trigger does not run for the current transaction

TriggerHandler.bypass('AccountTriggerHandler');