MetadataTriggerHandler

MetadataTriggerHandler Class

This class exists as a unified, trigger handler class. It uses Custom Metadata, and introspection of the Trigger.new variable to determine what trigger handler classes should be called, and in what order.

Metadata_Driven_Trigger__mdt has three fields:

Object__c - is a metadata entity look up to an sObject ie: Account
Execution_Order__c - is an integer and determines the order the trigger
handlers are executed
Class__c - is a String holding the name of the Trigger Handler to execute

Note: This Trigger framework works like this:

An .trigger for a sObject invokes this class via: new MetadataTriggerHandler().run();

This trigger handler class extends TriggerHandler - all the trigger handler classes must extend trigger handler. Most classes will only overwrite the context methods like afterUpdate(). This class, however, overrides the run method. This class is responsible for determining which other trigger handler classes to instantiate and run.

Concrete example: AccountTrigger.trigger (in this org) - invokes this class. This class queries the custom metadata and will find (at least) one metadata record tied to Account and the metadata record's Class__c specifies AccountTriggerHandler. This class then loops over the returned metadata records, instantiating the classes specified. It then calls the appropriate context methods on those classes.

Note: The TriggerHandler framework below does not give you the ability to order, or re-arrange the trigger work of managed packages. It also does not allow you to declare the order of methods within the triggerHandler classes themselves. When using the MetadataTriggerHandler, it's better to have a high number of singularly focused trigger handler classes than a few classes with multiple methods.

Group Trigger Recipes

See TriggerHandler

Inheritance

TriggerHandler

Fields

`mts`

TESTVISIBLE

Signature

private mts

Type

MetadataTriggerService

`tryggers`

TESTVISIBLE

Signature

private tryggers

Type

List<Metadata_Driven_Trigger__mdt>

`activeHandler`

TESTVISIBLE

Signature

private activeHandler

Type

TriggerHandler

`context`

Inherited

TESTVISIBLE

Signature

protected context

Type

TriggerContext

Constructors

`MetadataTriggerHandler()`

Constructor used by live triggers.

Signature

public MetadataTriggerHandler()

`MetadataTriggerHandler(mts)`

Signature

public MetadataTriggerHandler(MetadataTriggerService mts)

Parameters

Name	Type	Description
mts	MetadataTriggerService

Methods

`run()`

SUPPRESSWARNINGS

Overrides the standard Run() method, which allows this metadata based trigger handler can be an incremental update / sit beside other trigger handlers classes that are directly invoked by a trigger

Signature

public override void run()

Return Type

void

`setMaxLoopCount(max)`

Inherited

Allows developers to prevent trigger loops, or allow a limited number of them by setting the maximum number of times this trigger is called.

Signature

public void setMaxLoopCount(Integer max)

Parameters

Name	Type	Description
max	Integer	A valid number (generally 1) of times you'd like
to allow the trigger to run.

Return Type

void

Example

In the context of a TriggerHandler class:

this.setMaxLoopCount(5);

`clearMaxLoopCount()`

Inherited

Allows developers to turn off the max loop count

Signature

public void clearMaxLoopCount()

Return Type

void

Example

In the context of a TriggerHandler class:

this.clearMaxLoopCount();

`bypass(handlerName)`

Inherited

Allows developers to conditionally bypass (disable) other triggers that also implement this triggerHandler

Signature

public static void bypass(String handlerName)

Parameters

Name	Type	Description
handlerName	String	Class name (String) of the trigger handler to bypass

Return Type

void

Example

TriggerHandler.bypass('AccountTriggerHandler');

`clearBypass(handlerName)`

Inherited

Removes a given trigger handler class name from the list of bypassed trigger handlers.

Signature

public static void clearBypass(String handlerName)

Parameters

Name	Type	Description
handlerName	String	Handler class name to remove from the bypass list

Return Type

void

Example

TriggerHandler.clearBypass('AccountTriggerHandler');

`isBypassed(handlerName)`

Inherited

Allows developers to check whether a given trigger handler class is currently bypassed.

Signature

public static Boolean isBypassed(String handlerName)

Parameters

Name	Type	Description
handlerName	String	The name of the trigger handler class to check for

Return Type

Boolean

Example

TriggerHandler.isBypassed('AccountTriggerHandler');

`clearAllBypasses()`

Inherited

removes all classes from the bypass list

Signature

public static void clearAllBypasses()

Return Type

void

Example

Triggerhandler.clearAllBypasses();

`addToLoopCount()`

Inherited

TESTVISIBLE

increment the loop count

Signature

protected void addToLoopCount()

Return Type

void

Throws

Throws: loop count exception if the max loop count is reached

`validateRun()`

Inherited

TESTVISIBLE

make sure this trigger should continue to run

Signature

protected Boolean validateRun()

Signature

protected virtual void afterUndelete()

Return Type

void