What is apex extension?

What is apex extension?

A controller extension is an Apex class that extends the functionality of a standard or custom controller. Use controller extensions when: You want to leverage the built-in functionality of a standard controller but override one or more actions, such as edit, view, save, or delete.

How do you extend an apex class?

You can extend a class to provide more specialized behavior. A class that extends another class inherits all the methods and properties of the extended class. In addition, the extending class can override the existing virtual methods by using the override keyword in the method definition.

What is use of extension in Salesforce?

Controller extension in Salesforce is an Apex class containing a constructor that is used to add or extend the functionalities of a Standard Controller or custom controller in Salesforce. Extension controller is also used to leverage the functionality of another controller using our own custom logic.

Can you use an extension with a custom controller?

We can add number of extensions to visualforce page. See below syntax to define extension. We can use Stnadard controller/ Custom Controller and extensions at a time. But we cannot use Standard controller & Custom controller at a time.

What is Apex Param?

tag is used to pass values from JavaScript to an Apex controller,it can only be used with the folloing parent tags.

What is Apex controller?

The Apex Controller is by far one of the most advanced dedicated aquarium controllers on the market today. The Apex Controller has two different methods of control, through Fusion, the cloud-based software, and through the dashboard.

How do I inherit an apex class?

Inheritance in Apex

1. Syntax Apex inheritance. public virtual class Parent{ public void display(){ System.debug(‘This is Parent’);
2. Syntax of Sub class. public class Child extends Parent{ public void display show(){ System.debug(‘This is form Child’);
3. Create an object and call method. Child c = new Child(); c.show();
4. Output :

What is extended class?

The extends keyword extends a class (indicates that a class is inherited from another class). In Java, it is possible to inherit attributes and methods from one class to another. We group the “inheritance concept” into two categories: subclass (child) – the class that inherits from another class.

When should you use controller extensions?

Use controller extensions when:

1. You want to leverage the built-in functionality of a standard controller but override one or more actions, such as edit, view, save, or delete.
2. You want to add new actions.
3. You want to build a Visualforce page that respects user permissions.

What is StandardSetController why we use it?

StandardSetController objects allow you to create list controllers similar to, or as extensions of, the pre-built Visualforce list controllers provided by Salesforce.

How do I use Apex repeat?

apex:repeat is an iteration component that allows you to output the contents of a collection according to a structure that you specify. The collection can include up to 1,000 items….Using apex:repeat in Visualforce Page

What is Apex component?

A custom Visualforce component. All custom component definitions must be wrapped inside a single tag. This component supports HTML pass-through attributes using the “html-” prefix.

What happens when you extend a class in apex?

A class that extends another class inherits all the methods and properties of the extended class. In addition, the extending class can override the existing virtual methods by using the override keyword in the method definition. Overriding a virtual method allows you to provide a different implementation for an existing method.

Which is an example of a controller extension?

A controller extension is any Apex class containing a constructor that takes a single argument of type ApexPages.StandardController or CustomControllerName, where CustomControllerName is the name of a custom controller you want to extend. The following class is a simple example of a controller extension:

When do you use synchronous bn in apex?

apex.parallel.SyncBatchNorm extends torch.nn.modules.batchnorm._BatchNorm to support synchronized BN. It allreduces stats across processes during multiprocess (DistributedDataParallel) training. Synchronous BN has been used in cases where only a small local minibatch can fit on each GPU.

Which is an example of extending a class?

This is referred to as polymorphism. A class extends another class using the extends keyword in the class definition. A class can only extend one other class, but it can implement more than one interface. This example shows how the YellowMarker class extends the Marker class.