I'm getting an error and not able to find solution . I'm trying to use best practice of trigger using trigger handler . Following is what I did uptil now . Anyone please help me to structure or help me with modification .Thanks in advance.



===Trigger===

trigger OpportunityTrigger on Opportunity (after update) {
   new OpportunityTriggerHandler().run();
}

=== Trigger Handler class ===

public virtual class TriggerHandler {

  public TriggerHandler() { }
  
  // main method that will be called during execution
  public void run() {

     // dispatch to the correct handler method
      if(Trigger.isAfter && Trigger.isUpdate) {
      this.afterUpdate();
    } 
  }

  // context-specific methods for override
  protected virtual void afterUpdate(){}
  protected virtual void afterDelete(){}
    
  // exception class
  public class TriggerHandlerException extends Exception {}

}

== OpportunityTriggerHancler Class== 

I'm getting error in this class .

public class OpportunityTriggerHandler extends TriggerHandler {

   List<Task> tasks = new List<Task>();
   List<Opportunity> Opps = Trigger.new;
   Map <Id, String> oppsOwner = new Map <Id, String> ();
   
   public OpportunityTriggerHandler() {}
  
   protected override void afterUpdate()
  {
    for (Opportunity opp : trigger.new)
    {
        // Check if the StageName has been changed
        if (opp.StageName != trigger.oldMap.get(opp.Id).StageName)
        {
            // get the owner ID's that have been affected
            oppsOwner.put(opp.ownerId, null);
        }
    }

    // Map the owner ID to it's email address
    for (User owner : [SELECT Id, Email FROM User WHERE Id = :oppsOwner.keySet()])
    {
        oppsOwner.put(owner.Id, owner.Email);
    }
        
  }
   
  }