Enterprise LITE - a micro-framework for APEX

This is a lightweight framework which makes your APEX code more readable and more structured. Currently it is used in unmanaged packages, however it can be implemented in managed packages, too.

TriggerHandler

Centralizing your trigger fired business logic is a good practice. Use one trigger per object, and forward the delegate the execution to the TriggerHandler.

trigger Attendee_Handler on bt_events__Attendee__c (
    before insert, 
    after insert, 
    before delete, 
    after delete, 
    before update, 
    after update) {
	    new TriggerHandler(bt_events__Attendee__c.sObjectType).manage();
}

Define Events

TriggerHandler.cls is a pre-defined class, which is responsible for calling the logic on trigger events. In its construct method you are binding trigger classes to events and objects. For example,

    private void construct() {
        bind(bt_events__Attendee__c.sObjectType, evt.beforeinsert, new Attendee_PopulateParent());
        bind(Contact.sObjectType, Evt.afterinsert, new Contact_CopyParentPhone());
    }

here we are binding a trigger classes to bt_events__Attendee__c object on a beforeinsert event, and another class to the Contact object on the afterevent database event.

TriggerHandler.IHandlerInterface

Any class can be bound to a trigger event. The only requirement is to implement a common interface.

    public interface IHandlerInterface {
        void handle(Schema.SObjectType sObjectType);  
    } 

The handle() method is called by the TriggerHandler class every time, when an event is bound to an object.

You can run your trigger logic from the handle() method or you can extend the SObjectTrigger class.

SObjectTrigger class

The purpose of this class is to standardize the trigger logic. The class implements the IHandlerInterface interface, so you can bind this class' children directly to events in the TriggerHandler.

The class has 2 methods to override:

	public virtual Boolean getIsToProcess(SObject oldRecord, SObject newRecord) {
		return true;
	}

	public abstract void executeTrigger(SObject[] sObjectList);

executeTrigger method is called with the list of records to process by the trigger logic, so this is the place to implement business logic for a given object. For example, if the class is bound to Contact object, it is called with a list of Contacts.

getIsToProcess method is used to filter the list of records to process. For example, if we want to fire a trigger logic ONLY if a Contact Email has been changed, we can implement this logic the following way:

	public override Boolean getIsToProcess(SObject oldRecord, SObject newRecord) {
		return oldRecord.get('Email') != newRecord.get('Email');
	}

	public override void executeTrigger(SObject[] sObjectList) {
	}

The filtering method has 2 parameters -- oldRecord is the old state of the record, newRecord is the updated one. Please note that in an insert context the oldRecord parameter is null, while in delete context the newRecord is null.

The sObjectList which is passed to the executeTrigger is constructed from the trigger.new list, but on delete event it has records from the trigger.old list.