Apex Development

Apex Development Style Guide

Core Principles

CRITICAL: Follow the NimbleUser Apex Style Guide (fork of Google Java Style Guide adapted for Salesforce Apex). Write clean, maintainable, and consistent Apex code that adheres to industry best practices.

Source File Structure

File Organization

Required Order:

1. Top-level ApexDoc comments
2. Class declaration
3. Class members in logical order

Key Rules:

• Exactly ONE top-level class per file
• File name MUST match class name with .cls extension
• UTF-8 encoding
• NO tab characters (use 4 spaces for indentation)
• ASCII horizontal spaces only

Example:

/**
 * @description Handles account-related business logic
 */
public with sharing class AccountService {
    // Fields
    private static final Integer MAX_RECORDS = 200;
    private AccountRepository repository;

    // Constructors
    public AccountService() {
        this.repository = new AccountRepository();
    }

    // Public methods
    public List<Account> getActiveAccounts() {
        return repository.findActiveAccounts();
    }

    // Private methods
    private void validateAccount(Account acc) {
        // validation logic
    }
}

Formatting Standards

Braces (K&R Style)

Always Required for if, else, for, do, while - even for single-line bodies.

Rules:

• Opening brace on SAME line as statement
• Line break AFTER opening brace
• Line break BEFORE closing brace
• Closing brace on its own line

CORRECT:

// ✅ CORRECT
if (isValid) {
    processRecord();
}

if (count > 0) {
    updateRecords();
} else {
    createRecords();
}

for (Account acc : accounts) {
    acc.Status__c = 'Active';
}

// Empty block (allowed)
public void emptyMethod() {}

WRONG:

// ❌ WRONG - Missing braces
if (isValid)
    processRecord();

// ❌ WRONG - Opening brace on new line
if (isValid)
{
    processRecord();
}

// ❌ WRONG - No braces for single line
for (Account acc : accounts)
    acc.Status__c = 'Active';

Indentation

• Each block level: +4 spaces
• Continuation lines: minimum +4 spaces
• NO tabs allowed

public void complexMethod() {
    if (condition) {
        for (Integer i = 0; i < limit; i++) {
            system.debug('Level 3 indent = 12 spaces');
        }
    }
}

Line Length and Wrapping

Column Limit: 120 characters

Breaking Rules:

• Break at HIGHER syntactic levels
• Non-assignment operators: break BEFORE the symbol
• Assignment operators: break AFTER the symbol (or before, both acceptable)
• Method names stay ATTACHED to opening parenthesis
• Commas stay ATTACHED to preceding token
• Continuation lines: minimum +4 spaces indent

CORRECT:

// ✅ Method call wrapping
Account newAccount = AccountFactory.createAccount(
    accountName,
    industryType,
    annualRevenue
);

// ✅ Long condition wrapping
if (account.AnnualRevenue > THRESHOLD
    && account.Industry == 'Technology'
    && account.Rating == 'Hot') {
    processHighValueAccount(account);
}

// ✅ Assignment wrapping
String longMessage =
    'This is a very long message that exceeds the line limit';

SOQL/SOSL Formatting

Special Rules for SOQL:

• Line breaks are OPTIONAL
• Break BEFORE reserved words
• Standard +4 space indentation from containing block
• Reserved words in ALL UPPERCASE

CORRECT:

// ✅ CORRECT - Multi-line SOQL
List<Account> accounts = [
    SELECT Id, Name, Industry, AnnualRevenue,
        (SELECT Id, FirstName, LastName FROM Contacts)
    FROM Account
    WHERE Industry = :targetIndustry
        AND AnnualRevenue > :minRevenue
    ORDER BY Name
    LIMIT 200
];

// ✅ CORRECT - Simple single-line SOQL
List<Account> accounts = [SELECT Id, Name FROM Account WHERE Industry = 'Technology'];

// ✅ CORRECT - Dynamic SOQL
String query =
    'SELECT Id, Name FROM Account ' +
    'WHERE Industry = :industry ' +
    'ORDER BY Name';

Whitespace

Vertical Whitespace (Blank Lines):

• Single blank line BETWEEN class members (fields, constructors, methods, nested classes)
• Optional between consecutive fields for logical grouping
• Between statements for logical subsections

Horizontal Whitespace:

// ✅ CORRECT spacing
if (isValid) {           // Space after 'if', before '{'
    x = a + b;           // Space around operators
    y = c * d;           // Space around operators
}

// Comment spacing       // Space after '//'
String name = 'Test';   // Space before comment

// ❌ WRONG spacing
if(isValid){             // No space after 'if'
    x=a+b;               // No space around operators
}

Horizontal Alignment:

• NOT required
• Permitted but NOT enforced
• Warning: "Creates problems for future maintenance"

// Optional (not required)
private Integer  x      = 1;
private String   name   = 'Test';
private Boolean  active = true;

Naming Conventions

Class Names

UpperCamelCase - Nouns or noun phrases

CORRECT:

public class AccountService {}
public class OpportunityTriggerHandler {}
public class HttpClient {}
public class XmlParser {}          // XML acronym

Test Classes:

public class AccountServiceTest {}
public class OpportunityTriggerHandlerTest {}

Method Names

lowerCamelCase - Verbs or verb phrases

CORRECT:

public void processRecords() {}
public Account getAccountById(Id accountId) {}
public Boolean isValidEmail(String email) {}
public void sendEmail() {}

Test Methods:

// Pattern: <methodName>_<condition>_<expectation>
@isTest
static void getAccountById_withValidId_returnsAccount() {}

@isTest
static void processRecords_withEmptyList_throwsException() {}

Constant Names

CONSTANT_CASE - All uppercase with underscores

CORRECT:

private static final Integer MAX_RETRY_COUNT = 3;
private static final String DEFAULT_COUNTRY = 'USA';
public static final String API_VERSION = '60.0';

Must be:

• static final fields
• Deeply immutable contents
• NOT just "intending to never mutate"

Field Names

lowerCamelCase - Nouns or noun phrases

CORRECT:

private AccountRepository accountRepository;
private Integer retryCount;
private String errorMessage;

Properties - UpperCamelCase:

public String AccountName { get; set; }
public Integer RecordCount { get; private set; }
public Boolean IsActive { get; }

Parameter and Local Variable Names

lowerCamelCase - Descriptive names

CORRECT:

public void updateAccount(Account accountToUpdate, String newStatus) {
    String previousStatus = accountToUpdate.Status__c;
    Integer recordCount = 0;
}

AVOID:

• Single-character names (except loop counters)
• Non-descriptive names

Camel Case Rules

1. Convert phrase to ASCII, remove apostrophes
2. Split on spaces and punctuation
3. Lowercase everything, uppercase first character(s)
4. Join into single identifier

Examples:

• "XML HTTP request" → XmlHttpRequest
• "new customer ID" → newCustomerId
• "supports IPv6 on iOS" → supportsIpv6OnIos

Code Organization

Class Member Ordering

Use logical order that maintainers can explain:

1. Constants
2. Static fields
3. Instance fields
4. Constructors
5. Public methods
6. Private methods
7. Inner classes

Overloaded Methods:

• Appear SEQUENTIALLY
• NO intervening code

public class OrderService {
    // Constants
    private static final Integer MAX_ORDERS = 100;

    // Static fields
    private static OrderRepository repository = new OrderRepository();

    // Instance fields
    private String userId;

    // Constructors
    public OrderService() {
        this(UserInfo.getUserId());
    }

    public OrderService(String userId) {
        this.userId = userId;
    }

    // Public methods
    public List<Order> getOrders() {
        return getOrders(MAX_ORDERS);
    }

    public List<Order> getOrders(Integer limitCount) {
        return repository.findByUserId(userId, limitCount);
    }

    // Private methods
    private void validateOrder(Order ord) {
        // validation
    }
}

Variable Declarations

• ONE variable per declaration
• Declare CLOSE to first use (not at block start)
• Local variables are NOT constants (don't use CONSTANT_CASE)

CORRECT:

public void processAccounts(List<Account> accounts) {
    for (Account acc : accounts) {
        String industry = acc.Industry;  // Declared close to use
        Integer revenue = acc.AnnualRevenue;

        if (revenue > THRESHOLD) {
            String message = 'High value account';  // Declared when needed
            sendNotification(message);
        }
    }
}

Modifiers Order

Standard Order:

private protected public global virtual abstract with sharing without sharing

Examples:

public with sharing class AccountService {}
private abstract class BaseHandler {}
public virtual class TriggerHandler {}
global without sharing class IntegrationService {}

ApexDoc Standards

When Required

MUST document:

• ALL global and public classes
• ALL global, public, or protected members of public classes

MAY skip:

• Self-explanatory methods (simple getters/setters)
• Overriding methods (can reference parent)
• Private classes and members (use as needed)

Format

At-clauses Order:

1. @description
2. @param
3. @return
4. @throws

Multi-line continuations: +4 spaces from @

CORRECT:

/**
 * @description Retrieves active accounts for the specified industry
 * @param industry The industry to filter accounts
 * @param minRevenue The minimum annual revenue threshold
 * @return List of active accounts matching criteria, or empty list
 *     if no matches found
 * @throws QueryException if database query fails
 */
public List<Account> getActiveAccounts(String industry, Decimal minRevenue) {
    // implementation
}

/**
 * @description Handles account creation with validation and
 *     duplicate checking
 */
public class AccountCreationService {
    // implementation
}

Summary Fragment

• Brief noun phrase or verb phrase
• NOT complete sentence
• Capitalized and punctuated as sentence
• DO NOT start with "A {@code Foo} is a..." or "This method returns..."

CORRECT:

/** Processes pending orders and sends notifications */
/** Service for managing account lifecycle */
/** Validates email format and domain */

WRONG:

/** This method processes pending orders */  // ❌ Don't start with "This method"
/** A service that manages accounts */        // ❌ Don't start with "A"

Testing Best Practices

Test Class Declaration

@isTest
private class AccountServiceTest {
    // All test classes are PRIVATE
    // Marked with @isTest annotation
}

Test Method Pattern

@isTest
static void getAccountById_withValidId_returnsAccount() {
    // Pattern: <methodName>_<condition>_<expectation>

    // Setup
    Account testAccount = TestDataFactory.createAccount('Test Corp');
    insert testAccount;

    // Execute
    Test.startTest();
    Account result = AccountService.getAccountById(testAccount.Id);
    Test.stopTest();

    // Verify
    System.assertNotEquals(null, result, 'Account should be found');
    System.assertEquals('Test Corp', result.Name, 'Account name should match');
}

Test.startTest() and Test.stopTest()

ALWAYS use to isolate operation under test:

• Resets governor limits
• Separates setup from execution
• Forces async operations to complete

@isTest
static void processLargeDataSet_withManyRecords_completesSuccessfully() {
    // Setup - can use full governor limits
    List<Account> accounts = TestDataFactory.createAccounts(200);
    insert accounts;

    // Execute - fresh governor limits
    Test.startTest();
    AccountService.processAccounts(accounts);
    Test.stopTest();

    // Verify
    List<Account> results = [SELECT Id, Status__c FROM Account];
    System.assertEquals(200, results.size());
}

SeeAllData

AVOID @isTest(SeeAllData=true) unless absolutely necessary:

• Real data can change anytime
• Causes unpredictable test failures
• Use test data factories instead

Only acceptable for:

• Testing with standard objects that can't be created in tests
• Specific integration scenarios

Mocking

Use mocking libraries (e.g., fflib-apex-mocks):

@isTest
static void getAccounts_withRepositoryError_throwsException() {
    // Mock the dependency
    AccountRepository mockRepo = (AccountRepository)
        Mock.newInstance(AccountRepository.class);

    Mock.when(mockRepo.findActiveAccounts())
        .thenThrow(new QueryException('Database error'));

    AccountService service = new AccountService(mockRepo);

    Test.startTest();
    try {
        service.getActiveAccounts();
        System.assert(false, 'Should have thrown exception');
    } catch (QueryException e) {
        System.assertEquals('Database error', e.getMessage());
    }
    Test.stopTest();
}

Mocking Requirements:

• Public or global zero-argument constructor
• OR @testVisible protected constructor

Exception Handling

NEVER ignore exceptions:

// ❌ WRONG - Silent failure
try {
    processRecords();
} catch (Exception e) {
    // Empty catch block!
}

// ✅ CORRECT - Log and handle
try {
    processRecords();
} catch (DmlException e) {
    System.debug(LoggingLevel.ERROR, 'Failed to process records: ' + e.getMessage());
    throw new ProcessingException('Unable to complete processing', e);
} catch (Exception e) {
    System.debug(LoggingLevel.ERROR, 'Unexpected error: ' + e.getMessage());
    notifyAdministrator(e);
}

Apex-Specific Best Practices

Properties

// Read-only property
public Integer RecordCount { get; }

// Read-write property
public String AccountName { get; set; }

// Write-only property
public String Password { set; }

// Custom getter/setter
private String internalValue;
public String CustomProperty {
    get {
        return internalValue?.toUpperCase();
    }
    set {
        internalValue = value?.trim();
    }
}

Bulkification

ALWAYS write bulk-safe code:

// ✅ CORRECT - Bulk safe
public void updateAccountRatings(List<Account> accounts) {
    List<Account> toUpdate = new List<Account>();

    for (Account acc : accounts) {
        if (acc.AnnualRevenue > 1000000) {
            acc.Rating = 'Hot';
            toUpdate.add(acc);
        }
    }

    if (!toUpdate.isEmpty()) {
        update toUpdate;  // Single DML
    }
}

// ❌ WRONG - Not bulk safe
public void updateAccountRating(Account acc) {
    if (acc.AnnualRevenue > 1000000) {
        acc.Rating = 'Hot';
        update acc;  // DML in loop = governor limit hit
    }
}

Governor Limits

Key Limits to Monitor:

• SOQL queries: 100 (synchronous), 200 (async)
• DML statements: 150
• Records per DML: 10,000
• Heap size: 6 MB (synchronous), 12 MB (async)
• CPU time: 10,000 ms (synchronous), 60,000 ms (async)

Best Practices:

• Bulkify all operations
• Use collections for DML
• Query outside loops
• Use SOQL for loops for large datasets

// ✅ CORRECT - Query outside loop
Map<Id, Account> accountMap = new Map<Id, Account>(
    [SELECT Id, Name FROM Account WHERE Id IN :accountIds]
);

for (Contact con : contacts) {
    Account acc = accountMap.get(con.AccountId);
    // process
}

// ❌ WRONG - Query in loop
for (Contact con : contacts) {
    Account acc = [SELECT Id, Name FROM Account WHERE Id = :con.AccountId];
    // Hits SOQL limit with 101 contacts!
}

Quick Reference

Common Patterns

Service Class:

public with sharing class AccountService {
    private AccountRepository repository;

    public AccountService() {
        this.repository = new AccountRepository();
    }

    public List<Account> getActiveAccounts() {
        return repository.findActiveAccounts();
    }
}

Repository Pattern:

public class AccountRepository {
    public List<Account> findActiveAccounts() {
        return [
            SELECT Id, Name, Industry
            FROM Account
            WHERE IsActive__c = true
            ORDER BY Name
        ];
    }
}

Trigger Handler:

public class AccountTriggerHandler extends TriggerHandler {
    public override void beforeInsert() {
        for (Account acc : (List<Account>) Trigger.new) {
            validateAccount(acc);
        }
    }

    private void validateAccount(Account acc) {
        // validation logic
    }
}

Key Reminders

1. Follow K&R brace style - Opening brace on same line
2. 120 character line limit - Break at higher syntactic levels
3. 4 spaces for indentation - NO tabs
4. One variable per declaration - Declare close to first use
5. UpperCamelCase for classes - Nouns or noun phrases
6. lowerCamelCase for methods - Verbs or verb phrases
7. CONSTANT_CASE for constants - Static final deeply immutable
8. Document all public APIs - Use ApexDoc with at-clauses
9. Write bulk-safe code - Handle collections, not single records
10. Test everything - Use descriptive test names, Test.startTest/stopTest
11. Never ignore exceptions - Log and handle appropriately
12. SOQL reserved words uppercase - SELECT, FROM, WHERE, etc.

References

This skill is based on:

• NimbleUser Apex Style Guide (https://nimbleuser.github.io/apex-style-guide/)
• Google Java Style Guide (adapted for Apex)
• Salesforce Apex Developer Guide
• Apex Best Practices

Created for: Claude Code Purpose: Ensure consistent, maintainable Apex development following industry standards Style Guide: NimbleUser Apex Style Guide