Apex Tutorial

Introduction

Apex is a proprietary programming language developed by Salesforce that allows developers to execute flow and transaction control statements on the Salesforce platform. It enables developers to add business logic to system events, such as button clicks, related record updates, and Visualforce pages. This Apex tutorial will provide a complete overview of Apex.

Apex runs on the Lightning Platform, which is a cloud-based application development platform. With Apex, developers can build complete business applications that leverage the declarative power of the Lightning Platform.

This Apex tutorial will discuss in detail its history and background, key functionalities, how to set it up, create applications, and more. We've also included some examples of apex programming code to explain the concepts. Continue with this Apex tutorial to learn more about getting started with Apex programming!

Overview

Apex is an object-oriented programming language that allows developers to execute flow and transaction control statements on the Lightning platform.

Some key highlights of Apex:

• It is a proprietary language developed by Salesforce to extend standard CRM functionality.
• Enables adding business logic and complex validation rules to Salesforce objects
• Helps create dynamic applications on the Force.com platform
• Provides services like DML operations, exception handling, debugging, SObject, and Schema describe information
• Supports data manipulation language (DML) operations like INSERT, UPDATE, DELETE, and database query languages (SOQL/SOSL) through static and dynamic SOQL/SOSL queries.
• Seamlessly integrates with other Lightning Platform languages like Visualforce and Lightning Web Components
• Runs completely on the Lightning Platform. No software installation is required.

With Apex programming language, developers can build a variety of applications like:

• Custom business logic for objects
• Complex validation rules, formulas, and custom triggers
• Custom user interfaces like Visualforce pages and Lightning components
• Custom web services
• Complex reporting and analytics
• AI and predictive apps with Einstein Analytics

History and Background

Apex was first introduced by Salesforce in 2007 as part of its Lightning Platform release, aimed at enabling developers to extend applications hosted on the platform.

Here's a quick history of how Apex has evolved over the years:

• Spring '07 - The first version of Apex was released, allowing developers to write simple triggers and execute anonymous blocks of code.
• Summer '07 - Flow control constructs like if/else blocks were added along with the ability to query data using SOQL and SOSL.
• Winter '08 - Added support for custom objects, unit test coverage, and approval management.
• Spring '10 - Major update to enable the creation of Visualforce pages and development of custom user interfaces.
• Winter '13 - Milestone release with the addition of REST APIs, inline triggers, and queued asynchronous Apex.
• Spring '15 - Lightning Components introduced, providing a declarative UI framework.
• Winter '19 - Latest major release with Einstein Analytics, Lightning Web Components, and platform enhancements.

As you can see, Apex has come a long way from simple database triggers to a full-fledged development platform enabling advanced applications on Lightning.

What is Apex?

Apex is an object-oriented, case-insensitive programming language offered by Salesforce to allow developers to execute flow and transaction control statements on the Lightning Platform.

It is modeled after Java and acts as a proprietary alternative to Java for building apps on the Lightning platform. With Apex, you can add business logic to system events like button clicks, related record updates, and Visualforce pages.

Some key characteristics of Apex:

• Proprietary language from Salesforce - not based on other languages
• Case-insensitive
• Object-oriented like Java, with similar block and conditional statements
• Integrated with core Salesforce features like SOQL and SOSL
• Enables adding validation rules, business processes, and dynamic UI
• Runs completely on Lightning Platform (no software installation needed)
• Easy to test and deploy

Here is a basic example of Apex syntax:

public class HelloWorld {

  public static void main() {
    System.debug('Hello World!');  
  }

}

This implements a simple "Hello World" debug statement in Apex by defining a class with a main method.

As you can see, Apex provides a straightforward way to implement business logic and add robust functionality to Salesforce applications.

What is Apex Used For?

Apex enables developers to add business logic and backend functionality to Salesforce applications in a variety of ways.

Here are some common use cases and Apex programming examples:

• Custom triggers - To perform custom actions when records are inserted, updated, deleted, etc.
  For example:

  trigger ContactUpdate on Contact (after update) {
    //code to send email alert
  }

• Complex validation rules - Enforce intricate business rules beyond standard validation.
  For example:

AND(ISPICKVAL(Status__c , "Active"),(StartDate__c <= TODAY()), (EndDate__c >= TODAY())

• Custom interfaces - Build dynamic UIs like Visualforce pages and Lightning components.
  For example:

  <apex:page>
     <h1>Hello {$User.FirstName}!</h1>
  </apex:page>

• Integration extensions - Connect to external services, ERPs, databases, etc. via APIs.
  For example:

HttpResponse res = Http.send(req);
if (res.getStatusCode() == 200) {
  // success response handling
}

• Background jobs - Schedule asynchronous jobs for long-running processes.
  For example:

@future
public static void runAsyncJob() {
  // long running logic 
}

• AI apps - Incorporate Einstein AI into apps for predictive analytics.
  For example:

  PredictionService.predictSentiment(text);

• PredictionService.predictSentiment(text);As you can see, Apex allows developers to incorporate a wide range of business logic and advanced functionality into Salesforce applications above and beyond the standard features.Now let's look at some of the key functionalities provided by Apex.

Key Functionalities

Apex provides a robust set of functionalities and services, enabling developers to build a variety of applications and solutions on Salesforce.

Here are some of the major capabilities:

• DML operations - Supports all standard data manipulation language (DML) operations like INSERT, UPDATE, UPSERT, DELETE, and UNDELETE. Allows seamless CRUD access to all objects.
• SOQL and SOSL - Provides ability to query data using Salesforce Object Query Language (SOQL) and Salesforce Object Search Language (SOSL) with both static and dynamic queries.
• User interface - Options to build immersive UI like multi-page Visualforce web apps Lightning components with client-side controllers.
• Exception handling - Robust exception handling with built-in exceptions like DmlException, QueryException, and the ability to define custom exceptions.
• Testing framework - Apex provides an integrated unit test framework and the ability to achieve 100% code coverage for continuous integration.
• Debugging - Can debug code snippets interactively using the Developer Console and also view debug logs in real time.
• Data access - Seamlessly access data across standard and custom objects as well as external sources via APIs and callouts.
• Managing records - Approval management for records, ability to submit outbound messages, access record history, etc.
• Batch Apex - Schedule batch jobs to process large data volumes asynchronously
• Queueable Apex - Enqueue jobs for asynchronous execution to improve performance and avoid governor limits.

As you can see, Apex provides all the tools needed to incorporate advanced business logic and functionality for enterprise-grade application development on Salesforce.

Now let's look at how to set up Apex.

How to Set Up Apex?

Setting up Apex is straightforward since it runs completely on the Lightning Platform without needing any separate software installation.

Here are the steps to get set up:

1. Make sure you have a Salesforce account on developer.salesforce.com.
2. Enable Dev Hub in your Salesforce org from Setup. This activates Apex along with other Lightning Platform features.
3. Open the Developer Console from the toolbar to start writing Apex classes and triggers
4. Alternatively, use an IDE like Visual Studio Code with Salesforce extensions for developing with Apex
5. Start with sample Apex code snippets or Trailhead projects to learn the syntax.
6. Use the debugging and log features to troubleshoot errors and issues
7. Leverage version control tools like Git with repos like GitHub to manage code
8. Install apps like FinancialForce Apex Common to get reusable classes and helpers
9. Utilize forums like Salesforce Developer Forums to discuss best practices
   
   As you can see, getting started with Apex is quick and easy since everything runs on the Lightning cloud.

Now, let's look at how to build applications with Apex.

How to Create Applications in Apex?

Apex enables developers to build a wide range of applications and solutions on the Lightning Platform.

Here are the basic steps to create an app with Apex:

1. Identify use case - Determine what kind of app you want to build, like a customer portal, inventory management, etc.
2. Create objects - Design the data models and schema for your app using custom and standard objects
3. Develop interfaces - Build the UI with Visualforce, Lightning web components, communities, etc.
4. Write business logic - Add Apex classes, triggers, and validation rules for the backend functionality.
5. Integrate external services - Connect to external apps, databases, and services using Apex callouts and APIs.
6. Incorporate security - Implement proper user authentication, data security, and permissions.
7. Handle testing and deployment - Leverage tools like Jenkins and GitHub for CI/CD pipelines.
8. Ongoing maintenance - Monitor app health and user feedback for improvements and new features.
   
   Here is a sample Apex app with a Visualforce page and Apex controller.

// ContactFormController Apex class
public with sharing class ContactFormController {

  public Contact contact {get; set;}

  public ContactFormController() {
    contact = new Contact();
  }

  public void submit() {
    insert contact;
  }

}

This implements a basic contact form that takes first and last name input from a Visualforce page and saves it by calling the Apex controller submit method.

As you can see, Apex provides the ability to build sophisticated, enterprise-grade apps on the Lightning Platform.

Conclusion

Apex enables developers to build powerful applications and solutions on the Lightning Platform. With Apex, you can go beyond the declarative capabilities of Lightning and add complex business logic, integrate external systems, create dynamic UIs, and more.

Apex, combined with other Lightning Platform tools, provides a robust platform for building the next generation of apps on Salesforce.

To take the next steps with Apex, start with Trailhead trails and work through Apex programs for practice. The Salesforce community provides plenty of resources for Apex developers of all skill levels to learn and connect. Explore the many Apex code practices online and enrich your skills.

Frequently Asked Questions

1. What is the difference between Apex and Apex code?

Apex refers to the language itself, while Apex code refers to the programs/source code written using Apex. Apex code consists of Apex classes, triggers, and anonymous blocks.

2. What IDEs support Apex?

Popular IDEs like Visual Studio Code, IntelliJ, Eclipse, and Atom can be used for Apex development using relevant extensions and plugins. Salesforce Extensions for VS Code provide excellent support.

3. What is the relationship between Apex and Java?

Apex is based on Java language constructs like syntax, functions, and OOP concepts. So, knowledge of Java helps you learn Apex faster. Apex is proprietary to Salesforce, not just an extension of Java.

4. How to use Apex for mobile app development?

Apex provides integration with Salesforce Mobile SDK, which enables writing business logic and connecting to data for mobile apps. For example, REST APIs in Apex can be leveraged.

5. What is the difference between Apex and Visualforce?

Apex is a backend programming language, while Visualforce is a frontend framework for building user interfaces on the Lightning Platform. They are often used together in apps.

6. How do you debug Apex code?

Use Debug perspective in Developer Console to set breakpoints, step through code, and inspect variables in Apex. Also, view debug logs in the Logs tab for debugging.