You can use ApexPages.Action to create an action method that you can use in a Visualforce custom controller or controller extension.
Usage
For example, you could create a saveOver method on a controller extension
that performs a custom save.
Instantiation
The following code snippet
illustrates how to instantiate a new
ApexPages.Action object that uses the save action:
ApexPages.Action saveAction = new ApexPages.Action('{!save}');