Using the Standard Controller save method with an Extension Controller

When using an Extension Controller it can be useful to wrap the save method of the Standard Controller with a custom save method. This allows for things like:

• custom validation
• custom field assignment
• altering the resuling PageReference redirection

public with sharing class CustomExtensionController {
    
    Opportunity opp;
    ApexPages.StandardController sController;
    
    public CustomExtensionController (ApexPages.StandardController controller) {
        sController = controller;
        opp = (Opportunity)controller.getRecord();
    }
    
    public PageReference saveCustom() {
        
        // Custom Save code here...
        
        PageReference pr = sController.save();
        return pr;
        
        // Alternatively, could return a PR to the view page.
        //pageReference pv = sController.view();

    }
}