Enterprise Bean (EJB) programming tutorials

Enterprise Beans Tutorial

Home| Forums | Join Google Group | Join Yahoo Group | Jobs

Earn Money
Trading Forex Online
  Paramount Airways
  Free Data Recovery
Cargo
Job Portal
  HSBC Investment
Management
Cheap Web Hosting
  Make Trip
  Cheap Air Travel
Leisure Hotel
  Free Air Travel
  Mutual Fund Informations
Cheapest Cellular Plan
Free Sexy Indians
  Call Center Software
  Hot Indian

Enterprise Beans Tutorial

12 ejbFindByPrimaryKey method accepts as an argument the primary key, which it uses to locate an entity
bean. The ejbFindByPrimaryKey method may look strange to you, because it uses a primaryKey for both the method argument and return value. However, remember that the client does not call
ejbFindByPrimaryKey directly. It is the EJB container that calls the ejbFindByPrimaryKey method.
The client invokes the findByPrimaryKey method, which is defined in the home interface. The following list summarizes the rules for the finder methods that you implement in an entity bean class with bean-managed persistence: The ejbFindByPrimaryKey method must be implemented.
A finder method name must start with the prefix ejbFind.
The access control modifier must be public.
The method modifier cannot be final or static.
The arguments and return type must be legal types for Java RMI.
The return type must be the primary key or a collection of primary keys.
The throws clause may include the javax.ejb.FinderException, and other exceptions that are specific to your application. If a finder method returns a single primary key, it should throw the javax.ejb.ObjectNotFoundException if the requested entity does not exist. The
ObjectNotFoundException is a subclass of FinderException. If a finder method returns a collection of primary keys, it should throw a FinderException. The Business Methods The business methods contain the business logic that you want to encapsulate within the entity bean.
Usually, the business methods do not access the database, allowing you to separate business logic from the database access code. The requirements for the signature of a business method are the same for both session and entity beans: The method name must not conflict with a method name defined by the EJB architecture. For example, you cannot call a business method ejbCreate or ejbActivate. The access control modifier must be public.
The method modifier cannot be final or static.
The arguments and return types must be legal types for Java RMI.
The throws clause may include the the exceptions that you define for your application. The debit method, for example, throws the InsufficientBalanceException. To indicate a system-level
problem, a business method should throw the javax.ejb.EJBException. Database Calls SQL Statement in AccountEJB Method Resulting SQL Statement ejbCreate insert ejbFindByPrimaryKey select ejbFindByLastName select ejbFindInRange select ejbLoad select ejbRemove delete ejbStore update Home Interface The create methods in the home interface must conform to these requirements: It has the same number and types of arguments as its matching ejbCreate method in the enterprise bean class. It returns the remote interface type of the enterprise bean.