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Great Contributions to Apex Enterprise Patterns!

Just one week before the start of Dreamforce 2015, the Apex Enterprise Pattern library will be 2 years old since it was first published. My community time is increasingly busy these days not only answering questions around this and other GitHub repositories, but also reviewing Pull Requests. Both are a sign of a healthy open source project for sure! In this short blog i just wanted to call out some of the new features added by the community. So lets get started…

  • Unit of Work, register Method flexibility.  
    The initial implementation of Unit Of Work used a List to contain the records registered with it. This ment that in some cases if the code path registered the same record twice an error would occur. This change means you don’t have to worry about this and if complex code paths happen to register the same record again, it will be handled without error.Thanks to: Thomas Fuda for this enhancement!
  • Unit of Work, customisable DML implementation via IDML interface. 
    This improvement allows you to implement the IDML interface to implement your own calls to the platforms DML methods. The use case that prompted this enhancement was to allow for fine grained control using the Database methods that permit options such as all or nothing control (the default being all).Thanks to: David Esposito for this enhancement!
  • Unit of Work and Application Factory, new newInstance(Set<SObjectType> types) method
    This enhancement provides the ability to leverage the factory but have it provide Unit of Work instances configured using a specific set of SObjectType’s and not the default one. In cases where you have only a few objects to register, perhaps dynamically or those different from the default Application set for a specific use case. Please read the comments for this method for more details.Thanks to: John Davis for this enhancement!
  • Unit of Work, Eventing API
    New virtual methods have been added to the Unit of Work class, allowing those that want to subclass it, to hook special handling code to be executed during commitWork. This allows you to extend in very custom way your application or services own work to be done at various stages, start, end and during the DML operations. For example common validation that can only occur once everything has been written but not before the request ends.Thanks to: John Davis for this enhancement!
  • Unit of Work, Bulkified Register Methods
    Its now possible to register lists of SObject’s with the Unit of Work in one method call rather than one per call. While the Unit of Work has always been internally bulkified, this enhancement helps callers who are dealing with lists or maps interact with the Unit Of Work more easily.Thanks to: MayTheSForceBeWithYou (now a FinancialForce employee) for this enhancement!
  • Selector, Better default Order By handling
    Not all Standard objects have a Name field, this excellent enhancement helped ensure that if this was the case the base class would look for the next best thing to sequence your records against by default. Alex has also made numerous other tweaks to the Selector layer in addition to this btw!Thanks to: Alex Tennant for this enhancement!

In addition to the above there has been numerous behind the scenes improvements to library as well, making it more stable, support various non standard aspects of standard objects and such like. I based the above on GitHub’s report of commits to the repository here.

In addition to code changes, there are also some great discussions and ideas in the pipeline…

  • Unit of Work and Cyclic Dependencies
    This limitation doesn’t come up often, but for complex situations is causing fans of the UOW some pain having to leave it behind when it does. This is the long standing request by Seth Stone, but has seen a few attempts since via Alex Tennant and more recently some upcoming efforts by john-m in the pipeline. Watch this space!
  • Helper methods to fflib_SObjectDomain for Changed Fields
    Another Force.com MVP, Daniel Hoechst, suggested this feature, inspired from those present in other trigger frameworks, join the conversation here.
  • Support for undelete Trigger events to Domain layer
    This idea raised by our good friends over at BigAssForce, is seeing some recent interest for contribution by Autobat, see here for more discussion.

Thank you one and all for being social and contributing to a growing community around this library!


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Where to place Validation code in an Apex Trigger?

Quite often when i answer questions on Salesforce StackExchange they prompt me to consider future blog posts. This question has been sat on my blog list for a while and i’m finally going to tackle the ‘performing validation in the after‘ comment in this short blog post, so here goes!

Salesforce offers Apex developers two phases within an Apex Trigger, before and after. Most examples i see tend to perform validation code in the before phase of the trigger, even the Salesforce examples show this. However there can be implications with this, that is not at first that obvious. Lets look at an example, first here is my object…

Screen Shot 2015-04-19 at 09.31.05

Now the Apex Trigger doing some validation…

trigger LifeTheUniverseAndEverythingTrigger1 on LifeTheUniverseAndEverything__c
   (before insert) {

	// Make sure if there is an answer given its always 42!
	for(LifeTheUniverseAndEverything__c record : Trigger.new) {
		if(record.Answer__c!=null && record.Answer__c != 42) {
			record.Answer__c.addError('Answer is not 42!');
		}
	}
}

The following test method asserts that a valid value has been written to the database. In reality you would also have tests that assert invalid values are rejected, though the test method below will suffice for this blog.

	@IsTest
	private static void testValidSucceeds() {

		// Insert a valid answer
		LifeTheUniverseAndEverything__c
			lifeTheUniverseAndEverything = new LifeTheUniverseAndEverything__c();
		lifeTheUniverseAndEverything.Answer__c = 42;
		insert lifeTheUniverseAndEverything;

		// Is the answer still the same, surely nobody could have changed it right?
		System.assertEquals(42,
			[select Answer__c
			   from LifeTheUniverseAndEverything__c
			   where Id = :lifeTheUniverseAndEverything.Id][0].Answer__c);
	}

This all works perfectly so far!

Screen Shot 2015-04-19 at 10.46.51

What harm can a second Apex Trigger do?

Once developed Apex Triggers are either deployed into a Production org or packaged within an AppExchange package which is then installed. In the later case such Apex Triggers cannot be changed. The consideration being raised here arises if a second Apex Trigger is created on the object. There can be a few reasons for this, especially if the existing Apex Trigger is managed and cannot be modified or a developer simply chooses to add another Apex Trigger.

So what harm can a second Apex Trigger on the same object really cause? Well, like the first Apex Trigger it has the ability to change field values as well as validate them. As per the additional considerations at the bottom of the Salesforce trigger invocation documentation, Apex Triggers are not guaranteed to fire in any order. So what would happen if we add a second trigger like the one below which attempts to modify the answer to an invalid value?

trigger LifeTheUniverseAndEverythingTrigger2 on LifeTheUniverseAndEverything__c
  (before insert) {

	// I insist that the answer is actually 43!
	for(LifeTheUniverseAndEverything__c record : Trigger.new) {
		record.Answer__c = 43;
	}
}

At time of writing in my org, it appears that this new trigger (despite its name) is actually being run by the platform before my first validation trigger. Thus since the validation code gets executed after this new trigger changes the value we can see the validation is still catching it. So while thats technically not what this test method was testing, it shows for the purposes of this blog that the validation is still working, phew!

Screen Shot 2015-04-19 at 10.50.12

Apex Trigger execution order matters…

So while all seems well up until this point,  remember that we cannot guarantee that Salesforce will always run our validation trigger last. What if ours validation trigger ran first? Since we cannot determine the order of invocation of triggers, what we can do to illustrate the effects of this is simply switch the code in the two examples triggers like this so.

trigger LifeTheUniverseAndEverythingTrigger2 on LifeTheUniverseAndEverything__c
  (before insert) {

  	// Make if there is an answer given its always 42!
	for(LifeTheUniverseAndEverything__c record : Trigger.new) {
		if(record.Answer__c!=null && record.Answer__c != 42) {
			record.Answer__c.addError('Answer is not 42!');
		}
	}
}

trigger LifeTheUniverseAndEverythingTrigger1 on LifeTheUniverseAndEverything__c
  (before insert, before update) {

	// I insist that the answer is actually 43!
	for(LifeTheUniverseAndEverything__c record : Trigger.new) {
		record.Answer__c = 43;
	}
}

Having effectively emulated the platform running the two triggers in a different order, validation trigger first, then the field modify trigger second. Our test asserts are now showing the validation logic in this scenario failed to do its job and invalid data reached the database, not good!

Screen Shot 2015-04-19 at 10.53.51

So whats the solution to making my triggers bullet proof?

So what is the solution to avoiding this, well its pretty simple really, move your logic into the after phase. Even though the triggers may still fire in different orders, one thing is certain. Nothing and i mean nothing, can change in the after phase of a trigger execution, meaning you can reliably check the field values without fear of them changing later!

trigger LifeTheUniverseAndEverythingTrigger2 on LifeTheUniverseAndEverything__c
  (after insert) {

  	// Make if there is an answer given its always 42!
	for(LifeTheUniverseAndEverything__c record : Trigger.new) {
		if(record.Answer__c!=null && record.Answer__c != 42) {
			record.Answer__c.addError('Answer is not 42!');
		}
	}
}

Thus with this change in place, even though the second trigger fires afterwards and attempts to change the value an inserted to 43, the first trigger validation still prevents records being inserted to the database, success!

Screen Shot 2015-04-19 at 10.50.12

Summary

This approach is actually referenced in a few Trigger frameworks such as Tony Scott’s ‘Trigger Pattern for Tidy, Streamlined, Bulkified Triggers‘ and the Apex Enterprise Patterns Domain pattern.

One downside here is that for error scenarios the record is executing potentially much more platform features (for workflow and other processes) before your validation eventually stops proceedings and asks for the platform to roll everything back. That said, error scenarios, once users learn your system are hopefully less frequent use cases.

So if you feel scenario described above is likely to occur (particularly if your developing a managed package where its likely subscriber developers will add triggers), you should seriously consider leveraging the after phase of triggers for validation. Note this also applies with the update and delete events in triggers.

 


6 Comments

Unit Testing, Apex Enterprise Patterns and ApexMocks – Part 2

In Part 1 of this blog series i introduced a new means of applying true unit testing to Apex code leveraging the Apex Enterprise Patterns. Covering the differences between true unit testing vs integration testing and how the lines can get a little blurred when writing Apex test methods.

If your following along you should be all set to start writing true unit tests against your controller, service and domain classes. Leveraging the inbuilt dependency injection framework provided by the Application class introduced in the last blog. By injecting mock implementations of service, domain, selector and unit of work classes accordingly.

What are Mock classes and why do i need them?

Depending on the type of class your unit testing you’ll need to mock different dependencies so that you don’t have to worry about the data setup of those classes while your busy putting your hard work in to testing your specific class.

Unit Testing

In object-oriented programming, mock objects are simulated objects that mimic the behavior of real objects in controlled ways. A programmer typically creates a mock object to test the behavior of some other object, in much the same way that a car designer uses a crash test dummy to simulate the dynamic behavior of a human in vehicle impacts. Wikipedia.

In this blog we are going to focus on an example unit test method for a Service, which requires that we mock the unit of work, selector and domain classes it depends on (unit tests for these classes will of course be written as well). Lets take a look first at the overall test method then break it down bit by bit. The following test method makes no SOQL queries or DML to accomplish its goal of testing the service layer method.

	@IsTest
	private static void callingServiceShouldCallSelectorApplyDiscountInDomainAndCommit()
	{
		// Create mocks
		fflib_ApexMocks mocks = new fflib_ApexMocks();
		fflib_ISObjectUnitOfWork uowMock = new fflib_SObjectMocks.SObjectUnitOfWork(mocks);
		IOpportunities domainMock = new Mocks.Opportunities(mocks);
		IOpportunitiesSelector selectorMock = new Mocks.OpportunitiesSelector(mocks);

		// Given
		mocks.startStubbing();
		List<Opportunity> testOppsList = new List<Opportunity> {
			new Opportunity(
				Id = fflib_IDGenerator.generate(Opportunity.SObjectType),
				Name = 'Test Opportunity',
				StageName = 'Open',
				Amount = 1000,
				CloseDate = System.today()) };
		Set<Id> testOppsSet = new Map<Id, Opportunity>(testOppsList).keySet();
		mocks.when(domainMock.sObjectType()).thenReturn(Opportunity.SObjectType);
		mocks.when(selectorMock.sObjectType()).thenReturn(Opportunity.SObjectType);
		mocks.when(selectorMock.selectByIdWithProducts(testOppsSet)).thenReturn(testOppsList);
		mocks.stopStubbing();
		Decimal discountPercent = 10;
		Application.UnitOfWork.setMock(uowMock);
		Application.Domain.setMock(domainMock);
		Application.Selector.setMock(selectorMock);

		// When
		OpportunitiesService.applyDiscounts(testOppsSet, discountPercent);

		// Then
		((IOpportunitiesSelector)
			mocks.verify(selectorMock)).selectByIdWithProducts(testOppsSet);
		((IOpportunities)
			mocks.verify(domainMock)).applyDiscount(discountPercent, uowMock);
		((fflib_ISObjectUnitOfWork)
			mocks.verify(uowMock, 1)).commitWork();
	}

First of all, you’ll notice the test method name is a little longer than you might be used to, also the general layout of the test splits code into Given, When and Then blocks. These conventions help add some documentation, readability and consistency to test methods, as well as helping you focus on what it is your testing and assuming to happen. The convention is one defined by Martin Fowler, you can read more about GivenWhenThen here. The test method name itself, stems from a desire to express the behaviour the test is confirming.

Generating and using Mock Classes

UPDATE: Since the Apex Stub API was released you do not need this, see here!

The Java based Mockito framework leverages the Java runtimes capability to dynamically create mock implementations. However the Apex runtime does not have any support for this. Instead ApexMocks uses source code generation to generate the mock classes it requires based on the interfaces you defined in my earlier post.

The patterns library also comes with its own mock implementation of the Unit of Work for you to use, as well as some base mock classes for your selectors and domain mocks (made know to the tool below). The following code at the top of the test method creates the necessary mock instances that will be configured and injected into the execution.

// Create mocks
fflib_ApexMocks mocks = new fflib_ApexMocks();
fflib_ISObjectUnitOfWork uowMock = new fflib_SObjectMocks.SObjectUnitOfWork(mocks);
IOpportunities domainMock = new Mocks.Opportunities(mocks);
IOpportunitiesSelector selectorMock = new Mocks.OpportunitiesSelector(mocks);

To generate the Mocks class used above use the ApexMocks Generator, you can run it via the Ant tool. The apex-mocks-generator-3.1.2.jar file can be downloaded from the ApexMocks repo here.

<?xml version="1.0" encoding="UTF-8"?>
<project name="Apex Commons Sample Application" default="generate.mocks" basedir=".">

	<target name="generate.mocks">
		<java classname="com.financialforce.apexmocks.ApexMockGenerator">
			<classpath>
				<pathelement location="${basedir}/bin/apex-mocks-generator-3.1.2.jar"/>
			</classpath>
			<arg value="${basedir}/fflib-sample-code/src/classes"/>
			<arg value="${basedir}/interfacemocks.properties"/>
			<arg value="Mocks"/>
			<arg value="${basedir}/fflib-sample-code/src/classes"/>
		</java>
	</target>

</project>

You can configure the output of the tool using a properties file (you can find more information here).

IOpportunities=Opportunities:fflib_SObjectMocks.SObjectDomain
IOpportunitiesSelector=OpportunitiesSelector:fflib_SObjectMocks.SObjectSelector
IOpportunitiesService=OpportunitiesService

The generated mock classes are contained as inner classes in the Mocks class and also implement the interfaces you define, just as the real classes do. You can choose to add the above Ant tool call into your build scripts or just simply retain the class in your org refreshing it by re-run the tool whenever your interfaces change.

</pre>
<pre>/* Generated by apex-mocks-generator version 3.1.2 */
@isTest
public class Mocks
{
	public class OpportunitiesService
		implements IOpportunitiesService
	{
		// Mock implementations of the interface methods...
	}

	public class OpportunitiesSelector extends fflib_SObjectMocks.SObjectSelector
		implements IOpportunitiesSelector
	{
		// Mock implementations of the interface methods...
	}

	public class Opportunities extends fflib_SObjectMocks.SObjectDomain
		implements IOpportunities
	{
		// Mock implementations of the interface methods...
	}
}

To make it easier for those wanting to try out the sample application i have committed the generated Mocks class here, so you can review the full generated code if you wish. Though you can of course edit it, i would recommend against it as you will not be able to re-run the generator again without loosing changes.

Mocking method responses

Mock classes are dumb by default, so of course you cannot inject them into the upcoming code execution and expect them to work. You have to tell them how to respond when called. They will however record for you when their methods have been called for you to check or assert later. Using the framework you can tell a mock method what to return or exceptions to throw when the class your testing calls it.

So in effect you can teach them to emulate their real counter parts. For example when a Service method calls a Selector method it can return some in memory records as apposed to having to have them setup on the database. Or when the unit of work is used it will record method invocations as apposed to writing to the database.

Here is an example of configuring a Selector mock method to return test record data. Note that you also need to inform the Selector mock what type of SObject it relates to, this is also the case when mocking the Domain layer. Finally be sure to call startStubbing and stopStubbing between your mock configuration code. You can read much more about the ApexMocks API here, which resembles the Java Mockito API as well.

// Given
mocks.startStubbing();
List<Opportunity> testOppsList = new List<Opportunity> {
	new Opportunity(
		Id = fflib_IDGenerator.generate(Opportunity.SObjectType),
		Name = 'Test Opportunity',
		StageName = 'Open',
		Amount = 1000,
		CloseDate = System.today()) };
Set<Id> testOppsSet = new Map<Id, Opportunity>(testOppsList).keySet();
mocks.when(domainMock.sObjectType()).thenReturn(Opportunity.SObjectType);
mocks.when(selectorMock.sObjectType()).thenReturn(Opportunity.SObjectType);
mocks.when(selectorMock.selectByIdWithProducts(testOppsSet)).thenReturn(testOppsList);
mocks.stopStubbing();

TIP: If you want to mock sub-select queries returned from a selector take a look at this.

Injecting your mock implementations

Finally before you call the method your wanting to test, ensure you have injected the mock implementations. So that the calls to the Application class factory methods will return your mock instances over the real implementations.

Application.UnitOfWork.setMock(uowMock);
Application.Domain.setMock(domainMock);
Application.Selector.setMock(selectorMock);

Testing your method and asserting the results

Calling your method to test is a straight forward as you would expect. If it returns values or modifies parameters you can assert those values. However the ApexMocks framework also allows you to add further behavioural assertions that add further confidence the code your testing is working the way it should. In this case we are wanting to assert or verify (to using mocking speak) the correct information was passed onto the domain and selector classes.

// When
OpportunitiesService.applyDiscounts(testOppsSet, discountPercent);

// Then
((IOpportunitiesSelector)
	mocks.verify(selectorMock)).selectByIdWithProducts(testOppsSet);
((IOpportunities)
	mocks.verify(domainMock)).applyDiscount(discountPercent, uowMock);
((fflib_ISObjectUnitOfWork)
	mocks.verify(uowMock, 1)).commitWork();

TIP: You can verify method calls have been made and also how many times. For example checking a method is only called a specific number of times can help add some level of performance and optimisation checking into your tests.

Summary

The full API for ApecMocks is outside the scope of this blog series, and frankly Paul Hardaker and Jessie Altman have done a much better job, take a look at the full list of documentation links here. Finally keep in mind my comments at the start of this series, this is not to be seen as a total alternative to traditional Apex test method writing. Merely another option to consider when your wanting a more focused means to test specific methods in more varied ways without incurring the development and execution costs of having to setup all of your applications data in each test method.


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Unit Testing, Apex Enterprise Patterns and ApexMocks – Part 1

If you attended my Advanced Apex Enterprise Patterns session at Dreamforce 2014 you’ll have heard me highlight the different between Apex tests that are either written as true unit test vs those written in a way that more resembles an integration test. As Paul Hardaker (ApexMocks author) once pointed out to me, technically the reality is Apex developers often only end up writing only integration tests.

Lets review Wikipedia’s definition of unit tests

Intuitively, one can view a unit as the smallest testable part of an application. In procedural programming, a unit could be an entire module, but it is more commonly an individual function or procedure. In object-oriented programming, a unit is often an entire interface, such as a class, but could be an individual method. Unit tests are short code fragments created by programmers or occasionally by white box testers during the development process

Does this describe an Apex Test you have written recently?

Lets review what Apex tests typically require us to perform…

  • Setup of application data for every test method
  • Executes the more code than we care about testing at the time
  • Tests often not very varied enough, as they can take a long time to run!

Does the following Wikipedia snippet describing integration tests more accurately describe this?

Integration testing (sometimes called integration and testing, abbreviated I&T) is the phase in software testing in which individual software modules are combined and tested as a group. It occurs after unit testing and before validation testing. Integration testing takes as its input modules that have been unit tested, groups them in larger aggregates, applies tests defined in an integration test plan to those aggregates, and delivers as its output the integrated system ready for system testing

The challenge with writing true unit tests in Apex can also leave those wishing to follow practices like TDD struggling due to the lack of dependency injection and mocking support in the Apex runtime. We start to desire mocking support such as what we find for example in Java’s Mockito (the inspiration behind ApexMocks).

The lines between unit vs integration testing and which we should use and when can get blurred since Force.com does need Apex tests to invoke Apex Triggers for coverage (requiring actual test integration with the database) and if your using Workflows a lot you may want the behaviour of these reflected in your tests. So one cannot completely move away from writing integration tests of course. But is there a better way for us to regain some of the benefits other platforms enjoy in this area for the times we feel it would benefit us?

Problems writing Unit Tests for complex code bases…

Integration TestingThe problem is a true unit tests aim to test a small unit of the code, typically a specific method. However if this method ends up querying the database we need to have inserted those records prior to calling the method and then assert the records afterwards. If your familiar with Apex Enterprise Patterns, you’ll recognise the following separation of concerns in this diagram which shows clearly what code might be executed in a controller test for example.

For complex applications this approach per test can be come quite an overhead before you even get to call your controller method and assert the results! Lets face it, as we have to wait longer and longer for such tests, this inhibits our desire to write further more complex tests that may more thoroughly test the code with different data combinations and use cases.

 

 

 

What if we could emulate the database layer somehow?

Well those of you familiar with Apex Enterprise Patterns will know its big on separation of concerns. Thus aspects such as querying the database and updating it are encapsulated away in so called Selectors and the Unit Of Work. Just prior to Dreamforce 2014, the patterns introduced the Application class, this provides a single application wide means to access the Service, Domain, Selector and Unit Of Work implementations as apposed to directly instantiating them.

If you’ve been reading my book, you’ll know that this also provides access to new Object Orientated Programming possibilities, such as polymorphism between the Service layer and Domain layer, allowing for a functional frameworks and greater reuse to be constructed within the code base.

In this two part blog series, we are focusing on the role of the Application class and its setMock methods. These methods, modelled after the platforms Test.setMock method (for mocking HTTP comms), provide a means to mock the core architectural layers of an application which is based on the Apex Enterprise Patterns. By allowing mocking in these areas, we can see that we can write unit tests that focus only on the behaviour of the controller, service or domain class we are testing.

Unit Testing

Preparing your Service, Domain and Selector classes for mocking

As described in my Dreamforce 2014 presentation, Apex Interfaces are key to implementing mocking. You must define these in order to allow the mocking framework to substitute dynamically different implementations. The patterns library also provides base interfaces that reflect the base class methods for the Selector and Domain layers. The sample application contains a full example of these interfaces and how they are applied.


// Service layer interface

public interface IOpportunitiesService
{
	void applyDiscounts(Set<ID> opportunityIds, Decimal discountPercentage);

	Set<Id> createInvoices(Set<ID> opportunityIds, Decimal discountPercentage);

	Id submitInvoicingJob();
}

// Domain layer interface

public interface IOpportunities extends fflib_ISObjectDomain
{
	void applyDiscount(Decimal discountPercentage, fflib_ISObjectUnitOfWork uow);
}

// Selector layer interface

public interface IOpportunitiesSelector extends fflib_ISObjectSelector
{
	List<Opportunity> selectByIdWithProducts(Set<ID> idSet);
}

First up apply the Domain class interfaces as follows…


// Implementing Domain layer interface

public class Opportunities extends fflib_SObjectDomain
	implements IOpportunities {

	// Rest of the class
}

Next is the Service class, since the service layer remains stateless and global, i prefer to retain the static method style. Since you cannot apply interfaces to static methods, i use the following convention, though I’ve seen others with inner classes. First create a new class something like OpportunitiesServiceImpl, copy the implementation of the existing service into it and remove the static modifier from the method signatures before apply the interface. The original service class then becomes a stub for the service entry point.


// Implementing Service layer interface

public class OpportunitiesServiceImpl
	implements IOpportunitiesService
{
	public void applyDiscounts(Set<ID> opportunityIds, Decimal discountPercentage)
	{
		// Rest of the method...
	}

	public Set<Id> createInvoices(Set<ID> opportunityIds, Decimal discountPercentage)
	{
		// Rest of the method...
	}

	public Id submitInvoicingJob()
	{
		// Rest of the method...
	}
}

// Service layer stub

global with sharing class OpportunitiesService
{
	global static void applyDiscounts(Set<ID> opportunityIds, Decimal discountPercentage)
	{
		service().applyDiscounts(opportunityIds, discountPercentage);
	}

	global static Set<Id> createInvoices(Set<ID> opportunityIds, Decimal discountPercentage)
	{
		return service().createInvoices(opportunityIds, discountPercentage);
	}

	global static Id submitInvoicingJob()
	{
		return service().submitInvoicingJob();
	}	

	private static IOpportunitiesService service()
	{
		return new OpportunitiesServiceImpl();
	}
}

Finally the Selector class, like the Domain class is a simple matter of applying the interface.

public class OpportunitiesSelector extends fflib_SObjectSelector
	implements IOpportunitiesSelector
{
	// Rest of the class
}

Implementing Application.cls

Once you have defined and implemented your interfaces you need to ensure there is a means to switch at runtime the different implementations of them, between the real implementation and a the mock implementation as required within a test context. To do this a factory pattern is applied for calling logic to obtain the appropriate instance. Define the Application class as follows, using the factory classes provided in the library. Also note that the Unit Of Work is defined here in a single maintainable place.

public class Application
{
	// Configure and create the UnitOfWorkFactory for this Application
	public static final fflib_Application.UnitOfWorkFactory UnitOfWork =
		new fflib_Application.UnitOfWorkFactory(
				new List<SObjectType> {
					Invoice__c.SObjectType,
					InvoiceLine__c.SObjectType,
					Opportunity.SObjectType,
					Product2.SObjectType,
					PricebookEntry.SObjectType,
					OpportunityLineItem.SObjectType });	

	// Configure and create the ServiceFactory for this Application
	public static final fflib_Application.ServiceFactory Service =
		new fflib_Application.ServiceFactory(
			new Map<Type, Type> {
					IOpportunitiesService.class => OpportunitiesServiceImpl.class,
					IInvoicingService.class => InvoicingServiceImpl.class });

	// Configure and create the SelectorFactory for this Application
	public static final fflib_Application.SelectorFactory Selector =
		new fflib_Application.SelectorFactory(
			new Map<SObjectType, Type> {
					Opportunity.SObjectType => OpportunitiesSelector.class,
					OpportunityLineItem.SObjectType => OpportunityLineItemsSelector.class,
					PricebookEntry.SObjectType => PricebookEntriesSelector.class,
					Pricebook2.SObjectType => PricebooksSelector.class,
					Product2.SObjectType => ProductsSelector.class,
					User.sObjectType => UsersSelector.class });

	// Configure and create the DomainFactory for this Application
	public static final fflib_Application.DomainFactory Domain =
		new fflib_Application.DomainFactory(
			Application.Selector,
			new Map<SObjectType, Type> {
					Opportunity.SObjectType => Opportunities.Constructor.class,
					OpportunityLineItem.SObjectType => OpportunityLineItems.Constructor.class,
					Account.SObjectType => Accounts.Constructor.class,
					DeveloperWorkItem__c.SObjectType => DeveloperWorkItems.class });
}

Using Application.cls

If your adapting an existing code base, be sure to leverage the Application class factory methods in your application code, seek out code which is explicitly instantiating the classes of your Domain, Selector and Unit Of Work usage. Note you don’t need to worry about Service class references, since this is now just a stub entry point.

The following code shows how to wrap the Application factory methods using convenience methods that can help avoid repeated casting to the interfaces, it’s up to you if you adopt these or not, the effect is the same regardless. Though the modification the service method shown above is required.


// Service class Application factory usage

global with sharing class OpportunitiesService
{
	private static IOpportunitiesService service()
	{
		return (IOpportunitiesService) Application.Service.newInstance(IOpportunitiesService.class);
	}
}

// Domain class Application factory helper

public class Opportunities extends fflib_SObjectDomain
	implements IOpportunities
{
	public static IOpportunities newInstance(List<Opportunity> sObjectList)
	{
		return (IOpportunities) Application.Domain.newInstance(sObjectList);
	}
}

// Selector class Application factory helper

public with sharing class OpportunitiesSelector extends fflib_SObjectSelector
	implements IOpportunitiesSelector
{
	public static IOpportunitiesSelector newInstance()
	{
		return (IOpportunitiesSelector) Application.Selector.newInstance(Opportunity.SObjectType);
	}
}

With these methods in place reference them and those on the Application class as shown in the following example.

public class OpportunitiesServiceImpl
	implements IOpportunitiesService
{
	public void applyDiscounts(Set<ID> opportunityIds, Decimal discountPercentage)
	{
		// Create unit of work to capture work and commit it under one transaction
		fflib_ISObjectUnitOfWork uow = Application.UnitOfWork.newInstance();

		// Query Opportunities
		List<Opportunity> oppRecords =
			OpportunitiesSelector.newInstance().selectByIdWithProducts(opportunityIds);

		// Apply discount via Opportunties domain class behaviour
		IOpportunities opps = Opportunities.newInstance(oppRecords);
		opps.applyDiscount(discountPercentage, uow);

		// Commit updates to opportunities
		uow.commitWork();
	}
}

The Selector factory does carry some useful generic helpers, these will internally utilise the Selector classes as defined on the Application class definition above.


List<Opportunity> opps =
   (List<Opportunity>) Application.Selector.selectById(myOppIds);

List<Account> accts =
   (List<Account>) Application.Selector.selectByRelationship(opps, Account.OpportunityId);

Summary and Part Two

In this blog we’ve looked at how to defined and apply interfaces between your service, domain, selector and unit of work dependencies. Using a factory pattern through the indirection of the Application class we have implemented an injection framework within the definition of these enterprise application separation of concerns.

I’ve seen dependency injection done via constructor injection, my personal preference is to use the approach shown in this blog. My motivation for this lies with the fact that these pattern layers are well enough known throughout the application code base and the Application class supports other facilities such as polymorphic instantiation of domain classes and helper methods as shown above on the Selector factory.

In the second part of this series we will look at how to write true unit tests for your controller, service and domain classes, leveraging the amazing ApexMocks library! If in the meantime you wan to get a glimpse of what this might look like take a wonder through the Apex Enterprise Patterns sample application tests here and here.


// Provide a mock instance of a Unit of Work
Application.UnitOfWork.setMock(uowMock);

// Provide a mock instance of a Domain class
Application.Domain.setMock(domainMock);

// Provide a mock instance of a Selector class
Application.Selector.setMock(selectorMock);

// Provide a mock instance of a Service class
Application.Service.setMock(IOpportunitiesService.class, mockService);


18 Comments

Creating, Assigning and Checking Custom Permissions

I have been wanting to explore Custom Permissions for a little while now, since they are now GA in Winter’15 i thought its about time i got stuck in. Profiles, Permission Sets have until recently, been focusing on granting permissions to entities only known to the platform, such as objects, fields, Apex classes and Visualforce pages. In most cases these platform entities map to a specific feature in your application you want to provide permission to access.

However there are cases where this is not always that simple. For example consider a Visualforce page you that controls a given process in your application, it has three buttons on it Run, Clear History and Reset. You can control access to the page itself, but how do you control access to the three buttons? What you need is to be able to teach Permission Sets and Profiles about your application functionality, enter Custom Permissions!

CustomPermissions
CustomPermission

NOTE: That you can also define dependencies between your Custom Permissions, for example Clear History and Reset permissions might be dependent on a Manage Important Process  custom permission in your package.

Once these have been created, you can reference them in your packaged Permission Sets and since they are packaged themselves, they can also be referenced by admins managing your application in a subscriber org.

SetCustomPermissions

The next step is to make your code react to these custom permissions being assigned or not.

New Global Variable $Permission

You can use the $Permission from a Visualforce page or as SFDCWizard points out here from Validation Rules! Here is the Visualforce page example given by Salesforce in their documentation.

<apex:pageBlock rendered="{!$Permission.canSeeExecutiveData}">
   <!-- Executive Data Here -->
</apex:pageBlock>

Referencing Custom Permissions from Apex

IMPORTANT UPDATE: Since API 41 (Winter’18) there is now a native way to read Custom Permissions. The following may still be useful if you have requirements not met by the native method. FeatureManagement.checkPermission.

In the case of object and field level permissions, the Apex Describe API can be used to determine if an object or field is available and for what purpose, read or edit for example. This is not going help us here, as custom permissions are not related to any specific object or field. The solution is to leverage the Permission Set Object API to query the SetupEntityAccess and CustomPermission records for Permission Sets or Profiles that are assigned to the current user.

The following SOQL snippets are from the CustomPermissionsReader class i created to help with reading Custom Permissions in Apex (more on this later). As you can see you need to run two SOQL statements to get what you need. The first to get the Id’s the second to query if the user actually has been assigned a Permission Set with them in.


List<CustomPermission> customPermissions =
    [SELECT Id, DeveloperName
       FROM CustomPermission
       WHERE NamespacePrefix = :namespacePrefix];

List<SetupEntityAccess> setupEntities =
    [SELECT SetupEntityId
       FROM SetupEntityAccess
       WHERE SetupEntityId in :customPermissionNamesById.keySet() AND
             ParentId IN (SELECT PermissionSetId
                FROM PermissionSetAssignment
                WHERE AssigneeId = :UserInfo.getUserId())];

Now personally i don’t find this approach that appealing for general use, firstly the Permission Set object relationships are quite hard to get your head around and secondly we get charged by the platform to determine security through the SOQL governor. As a good member of the Salesforce community I of course turned my dislike into an Idea “Native Apex support for Custom Permissions” and posted it here to recommend Salesforce include a native class for reading these, similar to Custom Labels for example.

Introducing CustomPermissionReader

In the meantime I have set about creating an Apex class to help make querying and using Custom Permissions easier. Such a class might one day be replaced if my Idea becomes a reality or maybe its internal implementation just gets improved. One things for sure, i’d much rather use it for now than seed implicit SOQL’s throughout a code base!

Its pretty straight forward to use, construct it in one of two ways, depending if you want all non-namespaced Custom Permissions or if your developing a AppExchange package, give it any one of your packaged Custom Objects and it will ensure that it only ever reads the Custom Permissions associated with your package.

You can download the code and test for CustomPermissionsReader here.


// Default constructor scope is all Custom Permissions in the default namespace
CustomPermissionsReader cpr = new CustomPermissionsReader();
Boolean hasPermissionForReset = cpr.hasPermission('Reset');

// Alternative constructor scope is Custom Permissions that share the
//   same namespace as the custom object
CustomPermissionsReader cpr = new CustomPermissionsReader(MyPackagedObject.SObjectType);
Boolean hasPermissionForReset = cpr.hasPermission('Reset');

Like any use of SOQL we must think in a bulkified way, indeed its likely that for average to complex peaces of functionality you may want to check at least two or more custom permissions once you get started with them. As such its not really good practice to make single queries in each case.

For this reason the CustomPermissionsReader was written to load all applicable Custom Permissions and act as kind of cache. In the next example you’ll see how i’ve leveraged the Application class concept from the Apex Enterprise Patterns conventions to make it a singleton for the duration of the Apex execution context.

Here is an example of an Apex test that creates a PermissionSet, adds the Custom Permission and assigns it to the running user to confirm the Custom Permission was granted.

	@IsTest
	private static void testCustomPermissionAssigned() {

		// Create PermissionSet with Custom Permission and assign to test user
		PermissionSet ps = new PermissionSet();
		ps.Name = 'Test';
		ps.Label = 'Test';
		insert ps;
		SetupEntityAccess sea = new SetupEntityAccess();
		sea.ParentId = ps.Id;
		sea.SetupEntityId = [select Id from CustomPermission where DeveloperName = 'Reset'][0].Id;
		insert sea;
		PermissionSetAssignment psa = new PermissionSetAssignment();
		psa.AssigneeId = UserInfo.getUserId();
		psa.PermissionSetId = ps.Id;
		insert psa;

		// Create reader
		CustomPermissionsReader cpr = new CustomPermissionsReader();

		// Assert the CustomPermissionsReader confirms custom permission assigned
		System.assertEquals(true, cpr.hasPermission('Reset'));
	}

Seperation of Concerns and Custom Permissions

Those of you familiar with using Apex Enterprise Patterns might be wondering where checking Custom Permission fits in terms of separation of concerns and the layers the patterns promote.

The answer is at the very least in or below the Service Layer, enforcing any kind of security is the responsibility of the Service layer and callers of it are within their rights to assume it is checked. Especially if you have chosen to expose your Service layer as your application API.

This doesn’t mean however you cannot improve your user experience by using it from within Apex Controllers,  Visualforce pages or @RemoteAction methods to control the visibility of related UI components, no point in teasing the end user!

Integrating CustomerPermissionsReader into your Application class

The following code uses the Application class concept i introduced last year and at Dreamforce 2014, which is a single place to access your application scope concepts, such as factories for selectors, domain and service class implementations (it also has a big role to play when mocking).

public class Application {

	/**
	 * Expoeses typed representation of the Applications Custom Permissions
	 **/
	public static final PermissionsFactory Permissions = new PermissionsFactory();

	/**
	 * Class provides a typed representation of an Applications Custom Permissions
	 **/
	public class PermissionsFactory extends CustomPermissionsReader
	{
		public Boolean Reset { get { return hasPermission('Reset'); } }
	}
}

This approach ensures their is only one instance of the CustomPermissionsReader per Apex Execution context and also through the properties it exposes gives a compiler checked way of referencing the Custom Permissions, making it easier for application developers code to access them.

if(Application.Permissions.Reset)
{
  // Do something to do with Reset...
}

Finally, as a future possibility, this approach gives a nice injection point for mocking the status of Custom Permissions in your Apex Unit tests, rather than having to go through the trouble of setting up a Permission Set and assigning it in your test code every time as shown above.

Call to Action: Ideas to Upvote

While writing this blog I created one Idea and came across a two others, i’d like to call you the reader to action on! Please take a look and of course only if you agree its a good one, give it the benefit of your much needed up vote!

 


6 Comments

Preview of Advanced Apex Enterprise Patterns Session

At this years Dreamforce i will be presenting not one, but two sessions on Apex Enterprise Patterns this year. The first will be re-run of last years session, Apex Enterprise Patterns : Building Strong Foundations. The second will be a follow on session dealing with more advanced topics around the patterns. Imaginatively entitled Advanced Apex Enterprise Patterns. The current abstract for this session is as follows…

Complex code can easily get out of hand without good design, so in this deep dive you will better understand how to apply the advanced design patterns used by highly experienced Salesforce developers. Starting with Interface & Base Class examples of OO design we quickly move on to new design features including: Application Factory, Field Level Security Support, Selector FieldSet support and Dependency Injection, Mock Testing of Services, Domain and Selector layers.​ By the end you will have a better understanding of how and when to apply these advanced Apex patterns.

If you attended the FinancialForce.com DevTalk in June this year, you will have got a sneak peak of some of the improvements being made to the supporting library for the patterns available in this repo. If you didn’t you’ll have to wait till Dreamforce! Oh go on then, i’ll give you a teaser here…

  • Introduction
  • Selector Enhancements, FieldSet and QueryFactory Support
  • Application Factory Introduction
  • Using Apex Interfaces to implement Common Service Layer Functionality
  • Introducing ApexMocks
  • Using ApexMocks with Service, Selector and Domain Layers
  • Field Level Security Experiment
  • Q&A 

I’m quite excited about all this content, but perhaps if pushed, i’d have to highlight the new Application Factory concept along with the integration with the exciting new ApexMocks library (also from FinancialForce.com R&D). This brings with it easier support for implementing polymorphic use cases in your application and the ability to mock layers of the patterns, such as Unit Of Work, Domain, Selector and Service layers. Allowing to develop true unit tests that are fast to execute by the platform and plentiful in terms of the variation of tests you’ll be able to develop without fear of extending the time your sat waiting for tests to execute!

Its is against my nature to publish a blog without a code sample in it, so i’ll leave you to ponder the following….

	public void applyDiscounts(Set<ID> opportunityIds, Decimal discountPercentage)
	{
		// Create unit of work to capture work and commit it under one transaction
	    fflib_ISObjectUnitOfWork uow = Application.UnitOfWork.newInstance();

		// Query Opportunities
		List<Opportunity> oppRecords =
			OpportunitiesSelector.newInstance().selectByIdWithProducts(opportunityIds);

		// Apply discount via Opportunties domain class behaviour
		IOpportunities opps = Opportunities.newInstance(oppRecords);
		opps.applyDiscount(discountPercentage, uow);

		// Commit updates to opportunities
		uow.commitWork();
	}

Here is a more generic service layer example, leveraging polymorphic Domain classes!

	public void generate(Set<Id> sourceRecordIds)
	{
		// Create unit of work to capture work and commit it under one transaction
		fflib_ISObjectUnitOfWork uow = Application.UnitOfWork.newInstance();

		// Invoicing Factory helps domain classes produce invoices
		InvoicingService.InvoiceFactory invoiceFactory = new InvoicingService.InvoiceFactory(uow);

		// Construct domain class capabile of performing invoicing
		fflib_ISObjectDomain domain =
			Application.Domain.newInstance(
				Application.Selector.selectById(sourceRecordIds));
		if(domain instanceof InvoicingService.ISupportInvoicing)
		{
			// Ask the domain object to generate its invoices
			InvoicingService.ISupportInvoicing invoicing = (InvoicingService.ISupportInvoicing) domain;
			invoicing.generate(invoiceFactory);
			// Commit generated invoices to the database
			uow.commitWork();
			return;
		}

		// Related Domain object does not support the ability to generate invoices
		throw new fflib_Application.ApplicationException('Invalid source object for generating invoices.');
	}

This last example shows how ApexMocks has been integrated into Application Factory concept via the setMock methods. The following is true test of only the service layer logic, by mocking the unit of work, domain and selector layers.

	@IsTest
	private static void callingServiceShouldCallSelectorApplyDiscountInDomainAndCommit()
	{
		// Create mocks
		fflib_ApexMocks mocks = new fflib_ApexMocks();
		fflib_ISObjectUnitOfWork uowMock = new fflib_SObjectMocks.SObjectUnitOfWork(mocks);
		IOpportunities domainMock = new Mocks.Opportunities(mocks);
		IOpportunitiesSelector selectorMock = new Mocks.OpportunitiesSelector(mocks);

		// Given
		mocks.startStubbing();
		List<Opportunity> testOppsList = new List<Opportunity> {
			new Opportunity(
				Id = fflib_IDGenerator.generate(Opportunity.SObjectType),
				Name = 'Test Opportunity',
				StageName = 'Open',
				Amount = 1000,
				CloseDate = System.today()) };
		Set<Id> testOppsSet = new Map<Id, Opportunity>(testOppsList).keySet();
		mocks.when(domainMock.sObjectType()).thenReturn(Opportunity.SObjectType);
		mocks.when(selectorMock.sObjectType()).thenReturn(Opportunity.SObjectType);
		mocks.when(selectorMock.selectByIdWithProducts(testOppsSet)).thenReturn(testOppsList);
		mocks.stopStubbing();
		Decimal discountPercent = 10;
		Application.UnitOfWork.setMock(uowMock);
		Application.Domain.setMock(domainMock);
		Application.Selector.setMock(selectorMock);

		// When
		OpportunitiesService.applyDiscounts(testOppsSet, discountPercent);

		// Then
		((IOpportunitiesSelector)
			mocks.verify(selectorMock)).selectByIdWithProducts(testOppsSet);
		((IOpportunities)
			mocks.verify(domainMock)).applyDiscount(discountPercent, uowMock);
		((fflib_ISObjectUnitOfWork)
			mocks.verify(uowMock, 1)).commitWork();
	}

All these examples will be available in the sample application repo once i’ve completed the prep for the session in a few weeks time.

Sadly the FinancialForce.com session on ApexMocks was not selected for Dreamforce 2014, however not to worry! FinancialForce.com will be hosting a DevTalk event during Dreamforce week where Jesse Altman will be standing in for the library author Paul Hardaker (get well soon Paul!), book your place now!

Finally, if you have been using the patterns for a while and have a question you want to ask in this session, please feel free to drop your idea into the comments box below this blog post!