14) Implementing the Selector Layer with the Apex Common Library

Implementing the Selector Layer with the Apex Common Library

The Template for every Selector Class you create

Every Selector layer class you create should at least implement the following methods for it to work as anticipated.

//Selector layer classes should all use the inherited sharing keyword so that the caller determines to context it operates in.
//It should also always extend the fflib_SObjectSelector so it can inherit that classes methods and functionality.
public inherited sharing class Contact_Selector extends fflib_SObjectSelector
{
	public Contact_Selector(){
                /*This is calling the fflib_SObjectSelector classes constructor and setting the following booleans:
                  1) If the selector queries should use field sets
                  2) If you would like to enforce CRUD security
                  3) If you would like to enforce FLS
                  4) If you would like to sort selected fields
                */
		super(false, true, true, false);
	}

        //Add the base fields for the object that should just be used in absolutely every query done by this class
	public List<Schema.SObjectField> getSObjectFieldList(){
		return new List<Schema.SObjectField>{
				Contact.Id,
				Contact.Name,
				Contact.FirstName,
				Contact.LastName
		};
	}

        //Allows you to easily get the object type for the object being queried by this class
	public Schema.SObjectType getSObjectType(){
		return Contact.SObjectType;
	}

        //Allows you to create a query that selects records by a set of ids (basically adds the WHERE Id IN :ContactIds to the query)
	public List<Contact> selectById(Set<Id> contactIds){
		return (List<Contact>) selectSObjectsById(contactIds);
	}
}

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The fflib_SObjectSelector Constructor Parameters and what each of them mean

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How to set the default field selection for your Selector Class

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How to set your default OrderBy clause in your Selector Class

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The fflib_SObjectSelector Class methods Cheat Sheet

While there are many other methods within the fflib_SObjectSelector class below are the methods most commonly utilized in implementations.

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The fflib_QueryFactory class