The purpose of this framework is to manage APEX triggers and SOQL queries.

To create a trigger handler, you simply need to create a class that inherits from AbstractTriggerHandler.cls. Here is an example for creating an Opportunity trigger handler.

public class OpportunityTriggerHandler extends AbstractTriggerHandler {

In your trigger handler, to add logic to any of the trigger contexts, you only need to override them in your trigger handler. Here is how we would add logic to a beforeUpdate trigger.

public class OpportunityTriggerHandler extends AbstractTriggerHandler {
  
  override
  public void beforeInsert(List<SObject> newSObjects) {
    for(Opportunity o : (List<Opportunity>) newSObjects) {
      // do something
    }  
  }

  // add overrides for other contexts

}

To use the trigger handler, you only need to call the TriggerDispatcher.cls within the trigger handler itself and call the run() method. Here is an example of the Opportunity trigger.

trigger OpportunityTrigger on Opportunity (before insert, before update) {
  OpportunityTriggerHandler handler = new OpportunityTriggerHandler();
  TriggerDispatcher.run(handler);
}

To prevent recursion, you can set a max loop count for Trigger Handler. If this max is exceeded, and exception will be thrown. A great use case is when you want to ensure that your trigger runs once and only once within a single execution. Example:

public class OpportunityTriggerHandler extends AbstractTriggerHandler {

  public OpportunityTriggerHandler() {
    this.setMaxLoopCount(1);
  }
  
  override
  public void beforeInsert(List<SObject> newSObjects) {
  for(Opportunity o : (List<Opportunity>) newSObjects) {
    // do something
  }

}

You can also block recursive call this way:

override
public void beforeInsert(List<SObject> newSObjects) {
    if (hasNotRan('before insert')) {
        TriggerDispatcherTest.LAST_METHOD_CALLED = 'beforeInsertNoRecursionTestHandler';
        setHasRan('before insert');
    }
}

⚠️ BE AWARE OF:

• A transaction that does DML on more than 200 records (e.g. execute anonymous, VF controller, REST service, …) One don’t want the execution of records 201-… to be halted because of a recursion Boolean set during records 1-200.

• A transaction that uses Database.insert(someList,false) where the allOrNothing argument allows partial successes. Per the SFDC APEX doc, if any errors occur, the triggers will be re-executed a second and possibly a third time on the records that succeeded on pass 1. Again, one don’t want the trigger recursion Boolean to prevent execution of the handler on pass 2 (3) just because on pass 1 the recursion Boolean was enabled.

With the custom setting "Trigger Setting", you can enable or disable a specific trigger:

Custom Settings: (Trigger Setting)

Trigger Setting Data: (Create record for each trigger, optional)

⚠️ If the setting do not exist, it will be enable by default.

What if you want to tell other trigger handlers to halt execution? That's easy with the bypass api:

public class OpportunityTriggerHandler extends AbstractTriggerHandler {
  
  public override void afterUpdate() {
    List<Opportunity> opps = [SELECT Id, AccountId FROM Opportunity WHERE Id IN :Trigger.newMap.keySet()];
    
    Account acc = [SELECT Id, Name FROM Account WHERE Id = :opps.get(0).AccountId];

    TriggerDispatcher.bypass('AccountTriggerHandler');

    acc.Name = 'No Trigger';
    update acc; // won't invoke the AccountTriggerHandler

    TriggerDispatcher.removeBypass('AccountTriggerHandler');

    acc.Name = 'With Trigger';
    update acc; // will invoke the AccountTriggerHandler

  }

}

If you need to check if a handler is bypassed, use the isBypassed method:

if (TriggerDispatcher.isBypassed('AccountTriggerHandler')) {
  // ... do something if the Account trigger handler is bypassed!
}

If you want to clear all bypasses for the transaction, simple use the clearAllBypasses method, as in:

// ... done with bypasses!

TriggerDispatcher.clearAllBypasses();

// ... now handlers won't be ignored!