Apex Reference Guide

Apex Reference Guide
Release Notes
Apex DML Operations
ApexPages Namespace
AppLauncher Namespace
Approval Namespace
Auth Namespace
Cache Namespace
Canvas Namespace
ChatterAnswers Namespace
CommercePayments Namespace
ConnectApi Namespace
Database Namespace
Datacloud Namespace
DataSource Namespace
DataWeave Namespace
Dom Namespace
EventBus Namespace
ExternalService Namespace
Flow Namespace
Functions Namespace
Invocable Namespace
KbManagement Namespace
LxScheduler Namespace
Messaging Namespace
Metadata Namespace
Pref_center Namespace
Process Namespace
QuickAction Namespace
Reports Namespace
RichMessaging Namespace
Schema Namespace
Search Namespace
Sfc Namespace
Sfdc_Checkout Namespace
sfdc_surveys Namespace
Site Namespace
Support Namespace
System Namespace
AccessLevel Class
AccessType Enum
Address Class
Answers Class
ApexPages Class
Approval Class
Assert Class
AsyncInfo Class
AsyncOptions Class
Blob Class
Boolean Class
BusinessHours Class
Callable Interface
Cases Class
Collator Class
Comparable Interface
Comparator Interface
Continuation Class
Cookie Class
Crypto Class
Custom Metadata Type Methods
Custom Settings Methods
Database Class
Date Class
Datetime Class
Decimal Class
Domain Class
DomainCreator Class
DomainParser Class
DomainType Enum
Double Class
EmailMessages Class
EncodingUtil Class
Enum Methods
EventBus Class
Exception Class and Built-In Exceptions
FlexQueue Class
FeatureManagement Class
Formula Class
FormulaRecalcFieldError Class
FormulaRecalcResult Class
Http Class
HttpCalloutMock Interface
HttpRequest Class
HttpResponse Class
Id Class
Ideas Class
InstallHandler Interface
Integer Class
JSON Class
JSONGenerator Class
JSONParser Class
JSONToken Enum
Label Class
Limits Class
List Class
Location Class
LoggingLevel Enum
Long Class
Map Class
Matcher Class
Math Class
Messaging Class
MultiStaticResourceCalloutMock Class
Network Class
OrgLimit Class
OrgLimits Class
PageReference Class
Packaging Class
Pattern Class
Queueable Interface
QueueableContext Interface
QueueableDuplicateSignature Class
QuickAction Class
Quiddity Enum
RemoteObjectController
Request Class
ResetPasswordResult Class
RestContext Class
RestRequest Class
RestResponse Class
SandboxPostCopy Interface
Schedulable Interface
SchedulableContext Interface
Schema Class
Search Class
Security Class
SelectOption Class
Set Class
Site Class
SObject Class
SObjectAccessDecision Class
StaticResourceCalloutMock Class
String Class
StubProvider Interface
System Class
Test Class
Time Class
TimeZone Class
Trigger Class
TriggerOperation Enum
Type Class
Type Methods
UninstallHandler Interface
URL Class
UserInfo Class
UserManagement Class
Version Class
WebServiceCallout Class
WebServiceMock Interface
XmlStreamReader Class
XmlStreamWriter Class
TerritoryMgmt Namespace
TxnSecurity Namespace
UserProvisioning Namespace
VisualEditor Namespace
Wave Namespace
Appendices
PDF

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Type Class

Contains methods for getting the Apex type that corresponds to an Apex class and for instantiating new types.

Namespace

System

Usage

Use the forName methods to retrieve the type of an Apex class, which can be a built-in or a user-defined class. You can use these methods to retrieve the type of public and global classes, and not private classes even if the context user has access. Also, use the newInstance method if you want to instantiate a Type that implements an interface and call its methods while letting someone else, such as a subscriber of your package, provide the methods’ implementations.

A call to Type.forName() can cause the class to be compiled.

Note

Example: Instantiating a Type Based on Its Name

The following sample shows how to use the Type methods to instantiate a Type based on its name. A typical application of this scenario is when a package subscriber provides a custom implementation of an interface that is part of an installed package. The package can get the name of the class that implements the interface through a custom setting in the subscriber’s org. The package can then instantiate the type that corresponds to this class name and invoke the methods that the subscriber implemented.

In this sample, Vehicle represents the interface that the VehicleImpl class implements. The last class contains the code sample that invokes the methods implemented in VehicleImpl.

This is the Vehicle interface.
This is the implementation of the Vehicle interface.
The method in this class gets the name of the class that implements the Vehicle interface through a custom setting value. It then instantiates this class by getting the corresponding type and calling the newInstance method. Next, it invokes the methods implemented in VehicleImpl. This sample requires that you create a public list custom setting named CustomImplementation with a text field named className. Create one record for this custom setting with a data set name of Vehicle and a class name value of VehicleImpl.

Class Property

The class property returns the System.Type of the type it is called on. It’s exposed on all Apex built-in types including primitive data types and collections, sObject types, and user-defined classes. This property can be used instead of forName methods.

Call this property on the type name. For example:

You can use this property for the second argument of JSON.deserialize, deserializeStrict, JSONParser.readValueAs, and readValueAsStrict methods to get the type of the object to deserialize. For example:

Type Methods

The following are methods for Type.

equals(typeToCompare)

Returns true if the specified type is equal to the current type; otherwise, returns false.

Signature

public Boolean equals(Object typeToCompare)

Parameters

typeToCompare
Type: Object
The type to compare with the current type.

Return Value

Type: Boolean

Example

forName(fullyQualifiedName)

Returns the type that corresponds to the specified fully qualified class name.

Signature

public static System.Type forName(String fullyQualifiedName)

Parameters

fullyQualifiedName
Type: String
The fully qualified name of the class to get the type of. The fully qualified class name contains the namespace name, for example, MyNamespace.ClassName.

Return Value

Type: System.Type

Usage

  • This method returns null if called outside a managed package to get the type of a non-global class in a managed package. This is because the non-global class isn’t visible outside the managed package. For Apex saved using Salesforce API version 27.0 and earlier, this method does return the corresponding class type for the non-global managed package class.
  • When called from an installed managed package to get the name of a local type in an organization with no defined namespace, the forName(fullyQualifiedName) method returns null. Instead, use the forName(namespace, name) method and specify an empty string or null for the namespace argument.
  • A call to Type.forName() can cause the class to be compiled.

Note

forName(namespace, name)

Returns the type that corresponds to the specified namespace and class name.

Signature

public static System.Type forName(String namespace, String name)

Parameters

namespace
Type: String
The namespace of the class. If the class doesn't have a namespace, set the namespace argument to null or an empty string.
name
Type: String
The name of the class.

Return Value

Type: System.Type

Usage

  • This method returns null if called outside a managed package to get the type of a non-global class in a managed package. This is because the non-global class isn’t visible outside the managed package. For Apex saved using Salesforce API version 27.0 and earlier, this method does return the corresponding class type for the non-global managed package class.
  • Use this method instead of forName(fullyQualifiedName) if it’s called from a managed package installed in an organization with no defined namespace. To get the name of a local type, set the namespace argument to an empty string or null. For example, Type t = Type.forName('', 'ClassName');.
  • A call to Type.forName() can cause the class to be compiled.

Note

Example

This example shows how to get the type that corresponds to the ClassName class and the MyNamespace namespace.

getName()

Returns the name of the current type.

Signature

public String getName()

Return Value

Type: String

Example

This example shows how to get a Type’s name. It first obtains a Type by calling forName, then calls getName on the Type object.

hashCode()

Returns a hash code value for the current type.

Signature

public Integer hashCode()

Return Value

Type: Integer

Usage

The returned hash code value corresponds to the type name hash code that String.hashCode returns.

isAssignableFrom(sourceType)

Returns true if an object reference of the specified type can be assigned from the child type; otherwise, returns false.

Signature

public Boolean isAssignableFrom(Type sourceType)

Parameters

sourceType
The type of the object with which you are checking compatibility.

Return Value

Type: Boolean

The method returns true when the method is invoked as parentType.isAssignableFrom(childType). When invoked in any of the following ways, the method returns false:
  • childType.isAssignableFrom(parentType)
  • typeA.isAssignableFrom(TypeB) where TypeB is a sibling of TypeA
  • typeA.isAssignableFrom(TypeB) where TypeB and TypeA are unrelated

A childType is the child of a parentType when it implements an interface, extends a virtual or abstract class, or is the same System.Type as the parentType.

Note

Usage

Unlike the instanceof operator, this method allows you to check type compatibility without having to create a class instance. This method eliminates static compile-time dependencies that instanceof requires.

The following code demonstrates how a typical ISV customer can use isAssignableFrom() to check compatibility between a customer-defined type (customerProvidedPluginType) and a valid plugin type.

Example

The following code snippet first defines sibling classes A and B that both implement the Callable interface and an unrelated class C. Then, it explores several type comparisons using isAssignableFrom().

newInstance()

Creates an instance of the current type and returns this new instance.

Signature

public Object newInstance()

Return Value

Type: Object

Usage

Because newInstance returns the generic object type, you should cast the return value to the type of the variable that will hold this value.

This method enables you to instantiate a Type that implements an interface and call its methods while letting someone else provide the methods’ implementation. For example, a package developer can provide an interface that a subscriber who installs the package can implement. The code in the package calls the subscriber's implementation of the interface methods by instantiating the subscriber’s Type.

Example

This example shows how to create an instance of a Type. It first gets a Type by calling forName with the name of a class (ShapeImpl), then calls newInstance on this Type object. The newObj instance is declared with the interface type (Shape) that the ShapeImpl class implements. The return value of the newInstance method is cast to the Shape type.

toString()

Returns a string representation of the current type, which is the type name.

Signature

public String toString()

Return Value

Type: String

Usage

This method returns the same value as getName. String.valueOf and System.debug use this method to convert their Type argument into a String.

Example

This example calls toString on the Type corresponding to a list of Integers.