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A simple and minimal framework for Salesforce Apex triggers with declarative trigger handlers management - in accordance with Salesforce development best practices, defines a single entry point for sObject trigger with dispatching handler functions by a specific trigger event. Also gives an ability to manage trigger handlers with the no-code approach, just managing custom metadata definitions via point and clicks.

There are three main blocks of functionality:

• Trigger handler backbone with event handlers and dispatcher logic.
• Trigger enablement logic, which allows you to disable the trigger hanler globally or by for a specific event (optionally).
• Trigger handler logic management for determining the handlers and order of their execution for specific event (optionally).

• List<SObject> newList - readonly, returns the Trigger.new records.
• Map<Id, SObject> newMap - readonly, returns the Trigger.newMap records.
• List<SObject> oldList - readonly, returns the Trigger.old records.
• Map<Id, SObject> oldMap - readonly, returns the Trigger.oldMap records.
• Integer size - readonly, returns the quantity of trigger records.

• TriggerHandlerException - will be thrown in the next cases:
  1. Call of thenewList property onBefore Delete orAfter Delete trigger events.
  2. Call of thenewMap property onBefore Insert,Before Delete orAfter Delete trigger events.
  3. Call of theoldList property onBefore Insert,After Insert orAfter Undelete trigger events.
  4. Call of theoldMap property onBefore Insert,After Insert orAfter Undelete trigger events.

Also, you can directly define all your logic in your sObject trigger handler just overriding the next methods:

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

But keep in mind - to prevent blocking of other features your method overrides must include base class method call, also your overriden functionality will be executed after all declarative handler methods (see here).

First, create an Apex trigger for sObject:

triggerAccountTriggeronAccount (beforeinsert,beforeupdate,beforedelete,afterinsert,afterupdate,afterdelete,afterundelete) {newAccountTriggerHandler(Trigger.operationType,Trigger.new,Trigger.newMap,Trigger.old,Trigger.oldMap,Trigger.size    ).dispatch();}

Then, extend the baseTriggerHandler class and create a trigger handler for your sObject:

publicclassAccountTriggerHandlerextendsTriggerHandler {publicAccountTriggerHandler(System.TriggerOperationtriggerOperation,List<Account>newList,Map<Id,Account>newMap,List<Account>oldList,Map<Id,Account>oldMap,Integersize) {super(triggerOperation,newList,newMap,oldList,oldMap,size        );    }}

Finally, override the base methods with logic you need:

publicclassAccountTriggerHandlerextendsTriggerHandler {    ...publicoverridevoidbeforeInsert() {// base method callsuper.beforeInsert();// put your overriden logic here...    }}

Create aTrigger_Handler_Settings__mdt record to describe the sObject trigger behavior globally or on the specific event:By default the trigger handler enabled globally with all events.

Define the handler with the next pattern (implement theCallable interface):

publicclassAccountTriggerHandlerMethodBeforeInsertimplementsCallable {/**     * See possible params values below:     * @param action - will contain the string name of TriggerOperation enum value for the current context     * @param args - will contain a map of Trigger props with the prop names as keys     *               For example, you can retrieve newList by the key 'newList' for BEFORE_INSERT event handler     */Objectcall(Stringaction,Map<String,Object>args) {// put your logic here...    }}

... and register it in the Custom metadata by creating the correspondentTrigger_Handler_Method__mdt record:

Please seeCHANGELOG for more information what has changed recently.

The idea of this framework was based on the main concepts ofTDTM framework and Kevin O'Hara`ssfdc-trigger-framework.

The MIT License (MIT). Please seeLicense File for more information.