Book Image

EJB 3 Developer Guide

By : Michael Sikora
Book Image

EJB 3 Developer Guide

By: Michael Sikora

Overview of this book

Table of Contents (18 chapters)
EJB 3 Developer Guide
Credits
About the Author
About the Reviewers
Preface
Annotations and Their Corresponding Packages

Entity LifeCycle Callback Methods


We saw session bean callback methods in Chapter 2. Callback methods are also provided for events in an entity's lifecycle. The callback events are:

  • PostLoad

  • PrePersist

  • PostPersist

  • PreRemove

  • PostRemove

  • PreUpdate

  • PostUpdate

An entity can define a method corresponding to one or more of these events by prefixing the method with a corresponding annotation. So a PostLoad method would be prefixed by @PostLoad and so on.

The PostLoad callback method is invoked by the entity manager after an entity has been loaded by a query, or after a refresh operation. For example, in the Customer entity we could add a PostLoad method as follows:

@PostLoad
public void postLoad(){
System.out.println("customer.postLoad method invoked");
}

Note we do not have to name our method postLoad(). Any name is acceptable provided the method returns a void, has no arguments and does not throw a checked exception. This applies to any of the entity lifecycle callback methods.

The PrePersist...