Apex Discovery Triggers

This trigger handler framework discovers classes that implement trigger handlers by querying ApexTypeImplementor.

That provides a slim trigger framework, with ordering, that does not require custom metadata or any other type of table to drive the triggers.

Here is an example trigger implementation:

public class MyTrigger implements BeforeInsert {
    
    public SObjectType getSObjectType() {
        return Account.SObjectType;
    }

    public void onBeforeInsert(List<Account> newRecords) {
        // do something
    }
}

If ordering is important, then you specify that with an extra interface. For a particular SObjectType and trigger event the handlers are run in ascending order of the numbers they declare with getOrder(). The absence of OrderedTriggerHandler implies an order value of 0.

public class MyTrigger implements BeforeInsert, OrderedTriggerHandler {
    
    public SObjectType getSObjectType() {
        return Account.SObjectType;
    }

    public Integer getOrder() {
        return 10;
    }
    
    public void onBeforeInsert(List<Account> newRecords) {
        // do something
    }
}

And an example trigger:

trigger AccountTrigger on Account (before insert, before update, before delete, after insert, after update, after delete, after undelete) {
    DiscoveryTriggerManager.getInstance(Account.SObjectType).handle();
}

Note that this library loads all trigger events for all SObjectTypes on first invocation and caches them in a static variable. So, the performance profile will be a relatively slow start at the beginning of a transaction, then fast performance for further triggers.

Installation

Either:

• Paste this onto the end of your My Domain URL: /packaging/installPackage.apexp?p0=04tWS000000HTQbYAO
• Include in your SFDX project as "Apex Discovery Triggers": "04tWS000000HTQbYAO"

Examples

See the unPackaged directory for a working example trigger.