Introduction to Apex

Apex is a potent programming language designed by Salesforce that is used to create unique features and apps on the Salesforce network. Its seamless integration with the Salesforce ecosystem enables developers to automate procedures, interface with third-party systems, and apply intricate business logic. Developers acquainted with Java or C# may easily transition to Apex, an object-oriented, strongly-typed language with a syntax like those of those languages.

Key Features of Apex

Apex is a potent programming language made especially for creating Salesforce platform apps. Many characteristics that make it easier to create applications that are reliable, scalable, and maintainable are offered by it. Here, we go in-depth on a few of Apex's most important features.

1. Strongly-Typed Language

Apex is a strongly-typed language, meaning that every variable must be declared with a specific data type. This characteristic helps identify errors at compile time, ensuring higher code reliability and fewer runtime issues.

Integer count = 5;
String name = 'Salesforce';
Boolean isActive = true;

In this example, count is an integer, name is a string, and isActive is a boolean, each declared with a specific data type.

1. Object-Oriented Programming (OOP)

Apex supports the principles of object-oriented programming, including inheritance, polymorphism, encapsulation, and abstraction. These principles allow developers to create reusable and modular code.

public class Animal {
    public void speak() {
        System.debug('Animal speaks');
    }
}

public class Dog extends Animal {
    public override void speak() {
        System.debug('Dog barks');
    }
}

In this example, the Dog class inherits from the Animal class and overrides the speak method to provide its own implementation.

1. Built-in Support for Salesforce Operations

Apex has built-in support for Data Manipulation Language (DML) operations, such as insert, update, delete, and undelete. This makes it easy to interact with Salesforce data directly from Apex code.

Account acc = new Account(Name = 'Acme Corporation');
insert acc;

acc.Name = 'Acme Corp';
update acc;

delete acc;

In this example, an Account record is inserted, updated, and then deleted using DML operations.

1. Governor Limits

To ensure efficient use of resources in a multi-tenant environment, Salesforce imposes governor limits on various operations, such as the number of DML statements, SOQL queries, and execution time. Developers must write optimized code to stay within these limits, promoting efficient and performant applications.

public class GovernorLimitExample {
    public void checkLimits() {
        Integer limits = Limits.getDmlStatements();
        System.debug('DML Statements Limit: ' + limits);
    }
}

In this example, the Limits class is used to check the current DML statement limit.

1. Integration Capabilities

Apex can make HTTP callouts to external web services, allowing seamless integration with third-party systems. It also supports platform events and custom RESTful services for building event-driven architectures and custom APIs.

public class CalloutExample {
    @future(callout=true)
    public static void makeCallout() {
        HttpRequest req = new HttpRequest();
        req.setEndpoint('https://api.example.com/data');
        req.setMethod('GET');

        Http http = new Http();
        HttpResponse res = http.send(req);

        System.debug(res.getBody());
    }
}

In this example, the makeCallout method makes an HTTP GET request to an external API and logs the response.

1. Asynchronous Processing

Apex supports asynchronous processing through future methods, Queueable Apex, batch Apex, and scheduled Apex. These features enable developers to handle long-running processes and improve performance by offloading time-consuming tasks.

public class AsyncExample {
    @future
    public static void processRecords() {
        List<Account> accounts = [SELECT Id, Name FROM Account];
        for (Account acc : accounts) {
            acc.Name = acc.Name + ' - Processed';
        }
        update accounts;
    }
}

In this example, the processRecords method is marked as @future, allowing it to run asynchronously.

1. Testing and Debugging

Salesforce requires 75% code coverage for deploying Apex code to production. Apex provides robust testing and debugging tools, including unit tests, the Test class, and the debug log.

@IsTest
private class AccountTest {
    @IsTest
    static void testAccountUpdate() {
        Account acc = new Account(Name = 'Test Account');
        insert acc;

        acc.Name = 'Updated Account';
        update acc;

        Account updatedAcc = [SELECT Name FROM Account WHERE Id = :acc.Id];
        System.assertEquals('Updated Account', updatedAcc.Name);
    }
}

In this example, a test class verifies that an account's name is updated correctly, ensuring code functionality and meeting code coverage requirements.

1. Custom Metadata Types

Custom metadata types allow developers to define application metadata that can be packaged, deployed, and upgraded alongside their application. This feature is powerful for managing configuration data without hardcoding values.

public class MetadataHelper {
    public static List<CustomMetadata__mdt> getActiveMetadata() {
        return [SELECT DeveloperName, Value__c FROM CustomMetadata__mdt WHERE Active__c = true];
    }
}

In this example, CustomMetadata_mdt is a custom metadata type with fields DeveloperName, Valuec, and Active_c. This query retrieves all active custom metadata records, which can be used to drive application logic dynamically.

1. Platform Events

Platform Events provide a scalable way to deliver secure, customizable event notifications within Salesforce or from external sources. They are essential for building event-driven architectures.

public class OrderEventTrigger {
    public static void handleOrderCreated(OrderEvent__e event) {
        // Custom logic to handle order creation event
        System.debug('Order created: ' + event.OrderNumber__c);
    }
}

In this snippet, OrderEvent__e is a platform event representing an order creation event. The trigger processes the event and logs the order number, demonstrating how to respond to platform events with custom logic.

1. Apex Scheduler

Apex Scheduler enables developers to schedule Apex classes to run at specific times. This is particularly useful for batch processing and periodic tasks.

global class DataSyncScheduler implements Schedulable {
    global void execute(SchedulableContext sc) {
        // Perform data synchronization tasks
        System.debug('Data synchronization started.');
    }
}

// Schedule the class to run daily at midnight
String cronExpression = '0 0 0 * * ?';
System.schedule('Daily Data Sync', cronExpression, new DataSyncScheduler());

The DataSyncScheduler class implements the Schedulable interface, allowing it to be scheduled with a cron expression to run daily at midnight.

Future Methods and Queueable Apex in Salesforce

Future methods and Queueable Apex are advanced features in Salesforce Apex that enable developers to execute code asynchronously, improving application performance and responsiveness. This section explores these features, their benefits, and how to leverage them effectively.

1. Future Methods

Future methods allow developers to run Apex code asynchronously in the background. They are particularly useful for executing long-running operations or making callouts to external systems without blocking the user interface.

public class AsyncOperations {
    @future
    public static void processRecords(Set<Id> recordIds) {
        List<Account> accountsToUpdate = [SELECT Id, Name FROM Account WHERE Id IN :recordIds];
        for (Account acc : accountsToUpdate) {
            acc.Name = acc.Name + ' - Processed';
        }
        update accountsToUpdate;
    }
}

In this example, the processRecords method is annotated with @future, indicating that it will be executed asynchronously. It updates account names based on the provided set of record IDs.

Key Points:

Asynchronous Execution: Future methods run asynchronously, allowing them to perform tasks without delaying the main transaction.

Governor Limits: Future methods are subject to Salesforce governor limits, including limits on CPU time, heap size, and DML operations.

No Return Value: Future methods cannot return a value to the calling code, making them suitable for fire-and-forget scenarios.

1. Queueable Apex

Queueable Apex provides more flexibility than future methods by allowing chaining of job execution, implementing complex job dependencies, and supporting synchronous operations after asynchronous jobs complete.

public class AsyncProcessing implements Queueable {
    public void execute(QueueableContext context) {
        List<Contact> contactsToUpdate = [SELECT Id, Email FROM Contact WHERE Email LIKE 'test%'];
        for (Contact con : contactsToUpdate) {
            con.Email = con.Email.replace('test', 'updated');
        }
        update contactsToUpdate;
    }
}

In this example, the AsyncProcessing class implements the Queueable interface and performs asynchronous updates to contact email addresses that match a specific pattern.

Key Points:

Chaining Jobs: Queueable Apex jobs can be chained together to execute sequentially, allowing for complex job orchestration.

Synchronous Execution: Queueable Apex supports synchronous operations in the execute method after asynchronous processing completes.

Enhanced Flexibility: Unlike future methods, Queueable Apex jobs can implement Database.AllowsCallouts and Database.Stateful interfaces, supporting callouts and maintaining state between transactions.

Comparing Future Methods and Queueable Apex

FeatureFuture MethodsQueueable ApexExecution ContextAsynchronousAsynchronousLimitsGovernor limits applyGovernor limits applyReturn ValueNo return valueNo return valueChainingNot supportedSupportedSynchronous MethodsNot supportedSupported (execute method)InterfacesLimited (e.g., @future(callout=true))More flexible (Queueable, Database.AllowsCallouts, Database.Stateful)Use CasesFire-and-forget operations, simple async tasksComplex job chaining, async operations with state

Best Practices for Asynchronous Apex

Governor Limits: Ensure code adheres to Salesforce governor limits, especially when processing large datasets or making callouts.

Error Handling: Implement robust error handling to manage exceptions and ensure transactional integrity.

Testing: Write unit tests to validate asynchronous code behavior and ensure code coverage requirements are met.

Monitoring: Monitor asynchronous job execution using Salesforce debug logs and monitoring tools to diagnose and optimize performance.

Conclusion

Future methods and Queueable Apex are essential tools for building scalable and responsive applications on the Salesforce platform. By leveraging these features, developers can perform long-running operations asynchronously, integrate with external systems, and orchestrate complex job dependencies effectively. Understanding the differences between future methods and Queueable Apex helps in choosing the right tool for specific use cases and optimizing application performance.

For more detailed information, refer to the official Salesforce documentation on Future Methods and Queueable Apex.