Apex trigger framework

OpportunityTrigger.trigger

trigger OpportunityTrigger on Opportunity (before insert, before update, before delete, 
                                           after insert, after update, after delete, after undelete) {
  (new OpportunityTriggerHandler()).run();
}

OpportunityTriggerHandler.cls

public class OpportunityTriggerHandler extends TriggerHandler {

  public OpportunityTriggerHandler() { 
    // any custom constructor stuff goes here
    
    // call the constructor of the parent
    super(); 
  }

  /****************************************
   * context method overrides
   ****************************************/

  public override void beforeInsert() {
    runValidations();
  } 

  /****************************************
   * private processing methods
   ****************************************/

  private void runValidations() {

  }

}

TriggerHandler.cls

public virtual class TriggerHandler {

  private TriggerHandlerSettings__c settings;
  
  public TriggerHandler() {
    this.settings = TriggerHandlerSettings__c.getOrgDefaults();
  }

  public void run() {

    // bail out of the handler if triggers are disabled or this is running
    // outside of the Trigger context
    if(this.settings.Disable_All_Triggers__c) {
      return;
    }

    // throw an exception if the trigger handler is called when a trigger 
    // is not executing
    if(!Trigger.isExecuting) {
      throw new TriggerHandlerException('Trigger handler called outside of Trigger execution');
    }

    // dispatch to the correct handler method
    if(Trigger.isBefore && Trigger.isInsert) {
      this.beforeInsert();
    } else if(Trigger.isBefore && Trigger.isUpdate) {
      this.beforeUpdate();
    } else if(Trigger.isBefore && Trigger.isDelete) {
      this.beforeDelete();
    } else if(Trigger.isAfter && Trigger.isInsert) {
      this.afterInsert();
    } else if(Trigger.isAfter && Trigger.isUpdate) {
      this.afterUpdate();
    } else if(Trigger.isAfter && Trigger.isDelete) {
      this.afterDelete();
    } else if(Trigger.isAfter && Trigger.isUndelete) {
      this.afterUndelete();
    }
  }

  // context-specific methods for override
  public virtual void beforeInsert(){}
  public virtual void beforeUpdate(){}
  public virtual void beforeDelete(){}
  public virtual void afterInsert(){}
  public virtual void afterUpdate(){}
  public virtual void afterDelete(){}
  public virtual void afterUndelete(){}

  // utility exception class
  public class TriggerHandlerException extends Exception {}

}