Apex is Salesforce's programming language that allows developers to execute flow and transaction control statements on the Salesforce Platform's server side. To build efficient, scalable, and maintainable applications using Apex, it's important to follow best practices to avoid pitfalls such as governor limits, poor performance, and security vulnerabilities. Below are some key best practices for writing Apex code:
Salesforce imposes governor limits to ensure that shared resources are not overwhelmed by individual transactions. Being aware of and designing for these limits is crucial to prevent runtime errors.
Limit Queries: Perform the least number of SOQL queries possible in a transaction. For instance, try to use relationship queries (e.g., SELECT Id, Name FROM Account WHERE Id IN :accountIds).
Bulkify Code: Always bulkify your code to handle large data sets, especially when working with triggers, batch classes, or scheduled jobs.
Use SELECT with only required fields: Minimize the number of fields retrieved to reduce query consumption.
Efficient Loops: Avoid SOQL or DML operations inside loops. Instead, accumulate data and perform operations in bulk after the loop.
One of the most critical best practices in Apex is to ensure that your code can handle multiple records at once. Salesforce may trigger code for one record or hundreds of records, and your Apex code should handle both cases.
Use Collections: Store data in collections (like Lists, Sets, or Maps) and perform SOQL queries, DML operations, or other logic on the entire collection instead of processing one record at a time.
DML in Bulk: Perform DML (insert, update, delete) statements outside loops. For example, instead of calling insert inside a loop, aggregate records and then perform the insert statement once after the loop.
Never hardcode IDs or values directly into Apex code. Salesforce environments, such as sandboxes and production, often have different IDs (e.g., for custom objects or record types).
Use Custom Settings or Custom Metadata Types: Store values like record type IDs, picklist values, and configuration settings in custom settings or metadata types, so they can be easily updated without changing the code.
Use Labels: For user-facing text or messages, use custom labels to make your application easily translatable and configurable.
Apex queries are resource-intensive, and it’s important to optimize your SOQL queries.
Use Indexing: Use indexed fields (such as Id, Name, CreatedDate, etc.) in your WHERE clause to speed up queries.
Avoid SELECT * Statements: Always select only the fields you need to improve performance and reduce resource consumption.
Limit Results: Use the LIMIT keyword or add conditions to avoid retrieving more records than necessary.
Proper exception handling is vital to ensure your application behaves gracefully in case of errors.
Use try-catch Blocks: Always use try-catch blocks to handle exceptions, especially in scenarios where the failure could impact the user experience.
Log Errors: Log errors to custom objects or use debug logging to track issues in your Apex code.
Handle DML Exceptions: When performing DML operations, check for errors and handle them with meaningful messages. For example, Database.insert(records, false) returns a list of results where you can check for failures.
Salesforce requires that you write test methods to cover at least 75% of your code before it can be deployed to production. But testing goes beyond that:
Write Test Methods for All Scenarios: Write tests for both positive and negative cases. Ensure you test bulk operations and edge cases (e.g., empty inputs, invalid data).
Use @isTest Annotation: Mark test classes with @isTest to ensure they are not counted toward your organization's code limit.
Use Test.startTest() and Test.stopTest(): These methods allow you to separate test setup from actual tests, ensuring that any governor limits (like CPU time) are accurately measured during the test.
Avoid Hardcoding Test Data: Use the Test.loadData() method to load test data, or dynamically create the necessary records in your test method.
Salesforce is built around the concept of security, and Apex code must adhere to strict security protocols.
Field-Level Security: Always check for field-level security before accessing or modifying a field’s value. Use Schema.sObjectType.Account.fields.Name.isAccessible() to check field-level security.
Object-Level Security: Use Schema.sObjectType.Account.isAccessible() to check whether the current user has permission to read or modify a record of a given object type.
Enforce Sharing Rules: Always ensure that sharing rules are respected when querying for records. Use with sharing for classes and without sharing only when necessary.
Avoid SOQL Injection: Be cautious when dynamically constructing SOQL queries. Use bind variables rather than concatenating strings to avoid SOQL injection vulnerabilities.
For long-running operations, use asynchronous processing to avoid blocking user actions and hitting governor limits.
Queueable Apex: A more flexible, modern alternative to future methods. It allows for chaining jobs and provides more control over the execution context.
Batch Apex: Use Batch Apex when processing large volumes of data. It divides the data into manageable chunks and processes them asynchronously, ensuring your code doesn't hit governor limits.
Scheduled Apex: Schedule jobs to run at specific intervals, useful for periodic data maintenance tasks.
Collections like Lists, Sets, and Maps are essential in handling data in Apex efficiently. Proper use of these collections can improve code readability and performance.
Use Maps for Lookups: Use Maps when you need to perform lookups by key to avoid looping through Lists or Arrays.
Use Sets for Uniqueness: Use Sets to automatically handle uniqueness for items, as Sets don’t allow duplicate entries.
Iterate Over Collections: When processing a list of records, avoid nested loops over multiple collections—try to flatten the process using maps or sets.
Well-organized code is easier to maintain and less prone to errors.
Separation of Concerns: Organize your Apex classes to separate concerns (e.g., business logic, data access) into different classes or methods.
Use Comments and Documentation: Ensure your code is well-commented. Document the purpose of complex logic and describe the functionality of methods, classes, and trigger actions.
Adopt Naming Conventions: Follow standard naming conventions for classes, methods, variables, and triggers to improve code readability.
By adhering to these Apex best practices, you can write efficient, maintainable, and scalable code that works well within the Salesforce ecosystem. Always consider governor limits, optimize your queries and DML operations, and ensure your code is secure and testable. Following these practices not only helps to improve performance but also ensures that your code is flexible and adaptable as Salesforce evolves.