Presentation On Enterprise Java Beans
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Enterprise Java Beans Presentation Transcript:
1.EJB (Enterprise Java Beans)
2.Agenda
What is an EJB ?
EJB Component.
EJB Benefit
EJB Security
Java Beans v/s EJB
Some EJB Server
References
3.What is an EJB ?
Development and deployment of Java applications that are:
Portable, Multi-tier, Scaleable, Secure, Distributed, Transactional
Server-side component encapsulating application functionality
Business logic
DB access
Integrate with other legacy systems
Serve multiple clients
Browser
Desktop apps
Other EJBs
Web app components (e.g., Servlets)
Web Service clients
4.What is an EJB ?
EJB container provides services to bean and manages its life cycle.
A component architecture
A component model
For developing object-oriented
distributed enterprise-level applications
5.EJB Component
6.EJB Session Beans
Session beans perform work for a client application
For example, a session bean could charge a credit card for a specific transaction
Two types of session beans
Stateful
Stateless
7.Session Beans - Stateful
Stateful – A stateful bean maintains a conversational state with a client. The client perceives that it is only talking to one bean, and that bean maintains information between calls
8.Session Beans - Stateless
Stateless – A stateless bean maintains no client information between method calls – the container can substitute beans as necessary between method calls
9.Stateless vs. Stateful
Stateless
No internal state, nothing maintained across client calls
Does not need to be passivated
Can be pooled to service multiple
Stateful
Possess internal state
Needs to handle passivation and activation
One per client
10.EJB - Entity Beans
Entity beans are classes that map to individual entities – typically, an Entity bean references a row in a database table, providing an object representation of that database object.
For example, an entity bean could represent a customer, and changing the values in that entity bean would cause updates to that database row
Entity beans provide an abstraction layer so that working with the entity is not specific to the storage mechanism for that entity.
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Enterprise Java Beans Presentation Transcript:
1.EJB (Enterprise Java Beans)
2.Agenda
What is an EJB ?
EJB Component.
EJB Benefit
EJB Security
Java Beans v/s EJB
Some EJB Server
References
3.What is an EJB ?
Development and deployment of Java applications that are:
Portable, Multi-tier, Scaleable, Secure, Distributed, Transactional
Server-side component encapsulating application functionality
Business logic
DB access
Integrate with other legacy systems
Serve multiple clients
Browser
Desktop apps
Other EJBs
Web app components (e.g., Servlets)
Web Service clients
4.What is an EJB ?
EJB container provides services to bean and manages its life cycle.
A component architecture
A component model
For developing object-oriented
distributed enterprise-level applications
5.EJB Component
6.EJB Session Beans
Session beans perform work for a client application
For example, a session bean could charge a credit card for a specific transaction
Two types of session beans
Stateful
Stateless
7.Session Beans - Stateful
Stateful – A stateful bean maintains a conversational state with a client. The client perceives that it is only talking to one bean, and that bean maintains information between calls
8.Session Beans - Stateless
Stateless – A stateless bean maintains no client information between method calls – the container can substitute beans as necessary between method calls
9.Stateless vs. Stateful
Stateless
No internal state, nothing maintained across client calls
Does not need to be passivated
Can be pooled to service multiple
Stateful
Possess internal state
Needs to handle passivation and activation
One per client
10.EJB - Entity Beans
Entity beans are classes that map to individual entities – typically, an Entity bean references a row in a database table, providing an object representation of that database object.
For example, an entity bean could represent a customer, and changing the values in that entity bean would cause updates to that database row
Entity beans provide an abstraction layer so that working with the entity is not specific to the storage mechanism for that entity.
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