Apex Developer Guide

Apex Developer Guide
Release Notes
Getting Started with Apex
Writing Apex
Data Types and Variables
Control Flow Statements
Classes, Objects, and Interfaces
Classes
Interfaces
Keywords
Annotations
AuraEnabled Annotation
BeforeClass Annotation (Developer Preview)
Deprecated Annotation
Future Annotation
IntegrationTest Annotation (Developer Preview)
InvocableMethod Annotation
InvocableVariable Annotation
IsTest Annotation
JsonAccess Annotation
NamespaceAccessible Annotation
ReadOnly Annotation
RemoteAction Annotation
SuppressWarnings Annotation
TestSetup Annotation
TearDown Annotation (Developer Preview)
TestVisible Annotation
Apex REST Annotations
Classes and Casting
Differences Between Apex Classes and Java Classes
Class Definition Creation
Namespace Prefix
Apex Code Versions
Lists of Custom Types and Sorting
Using Custom Types in Map Keys and Sets
Working with Data in Apex
Document Your Apex Code
Running Apex
Debugging, Testing, and Deploying Apex
Apex Reference
Appendices
PDF

Note: This release is in preview. Features described here don’t become generally available until the latest general availability date that Salesforce announces for this release. Before then, and where features are noted as beta, pilot, or developer preview, we can’t guarantee general availability within any particular time frame or at all. Make your purchase decisions only on the basis of generally available products and features.

ReadOnly Annotation

The @ReadOnly annotation allows you to perform less restrictive queries against the Lightning Platform database by increasing the limit of the number of returned rows for a request to 1,000,000. All other limits still apply. The annotation blocks the following operations within the request: DML operations, calls to System.schedule, and enqueued asynchronous Apex jobs.

The @ReadOnly annotation is available for REST and SOAP Web services and the Schedulable interface. To use the @ReadOnly annotation, the top-level request must be in the schedule execution or the Web service invocation. For example, if a Visualforce page calls a Web service that contains the @ReadOnly annotation, the request fails because Visualforce is the top-level request, not the Web service.

Visualforce pages can call controller methods with the @ReadOnly annotation, and those methods run with the same relaxed restrictions. To increase other Visualforce-specific limits, such as the size of a collection that can be used by an iteration component like <apex:pageBlockTable>, you can set the readonly attribute on the <apex:page> tag to true. For more information, see Working with Large Sets of Data in the Visualforce Developer's Guide.

Versioned Behavior Changes

Prior to API version 49.0, using @ReadOnly on Apex REST methods (@HttpDelete, @HttpGet, @HttpPatch, @HttpPost, or @HttpPut) also required annotating the method with @RemoteAction. In API version 49.0 and later, you can annotate Apex REST methods with just @ReadOnly.