J2ee and Web Services

J2ee and Web Services : 

J2ee and Web Services JAVA PLATFORMS J2SE – Java 2 Standard Edition  Java for the desktop / workstation J2ME – Java 2 Micro Edition  Java for the consumer device J2EE - Java 2 Enterprise Edition  Java for the server

J2ee and Web Services : 

J2ee and Web Services J2ee J2se J2me

J2ee and Web Services : 

J2ee and Web Services J2EE Supports Extensible Markup Language Web Applications Web Services Support / WSDL Standard Format UDDI and ebXML Standard Formats HTTP-SOAP Transport Protocol

J2ee and Web Services : 

J2ee and Web Services J2EE comes with a built in application server J2EE defines Java API for XML Processing (JAXP) API for processing XML Uses SAX and DOM standards

J2ee and Web Services : 

J2ee and Web Services J2EE does not specify the nature and structure of the runtime. J2EE Container – capability of the runtime to manage application components. J2EE APIs specifies the contract between the applications and the container.

J2EE Architecture : 

J2EE Application Server HTML/ XML Applet Client Applica-tion JDBC JavaMail RMI IIOP JNDI JMS RDBMS Mail Server CORBA Directory Services Client Application Logic Data J2EE Architecture

J2ee and Web Services : 

The Component technologies – to hold the business logic. (JSP, Servlets and EJB) The Service technologies – to provide supported services to application components (JDBC, JTA, JNDI) The Communication technologies – transparent to appln programmer, provide the mechanism for communication among different parts of the appln. (JMS, JavaMail, RMI-IIOP) They are re-usable software units containing business logic. An EJB is just a collection of Java classes and an XML file, bundled into a single unit. J2ee and Web Services

Enterprise Java Beans : 

They are re-usable software units containing business logic. An EJB is just a collection of Java classes and an XML file, bundled into a single unit. Java classes must follow certain rules and provide certain callback methods. Enterprise Java Beans

Different kinds of EJB : 

Session Beans Entity Beans Message-driven Beans Different kinds of EJB

Session Beans : 

Intended for the use of a single client. Lifespan is limited to that of its client. When the client leaves the web site or the application is shut down, the session bean disappears. Session Beans

StateFul Session Beans : 

Can keep information on behalf of its client across method calls. For example, Full information of the client is stored in every transactions example , credit card StateFul Session Beans

Stateless Session Beans : 

Stateless Session Beans This bean implements a particular business logic, though its created for a particular client, it doesn’t have to remember anything about the client. Can be considered as a remote procedure that gets executed on behalf of the client, taking some parameters and returns the result (of calculation in a particular business rule context).

Entity Beans : 

Persistence is its basic property. It stays around even after the program is terminated until it is deleted. When the program is restarted, it can gain access to this bean again. It can be used by any program on the network. It is executed remotely. It is identified by a primary key. Its nothing but the object representation of records in RDBMS tables. Entity Beans

J2ee and Web Services : 

Advantages J2EE provides a complete architecture for developing - Distributed systems including object persistence, session tracking, transaction management, … Separation of technical and application-specific code - Deployment descriptors - Container Managed Persistence J2ee and Web Services

J2ee and Web Services : 

Disadvantages Very complex technology Even simple examples require many interfaces, bean classes, deployment descriptors. Many errors occur only at runtime (several steps required until the application is running) - Compilation - Packaging - Deployment - Running the application J2ee and Web Services

Web application framework : 

A Web Application Framework (WAF) is a reusable, skeletal, semi-complete modular platform that can be specialized to produce custom web applications , which commonly serve the web browsers via the Http's protocol. WAF usually implements the Model-View-Controller (MVC) design pattern, typically in the Model 2 architecture to develop request-response web-based applications on the Java EE and .NET models. Web application framework

Model View Controller : 

Model View Controller

Web Aplication Framework : 

Web Aplication Framework Request-based Framework : Struts WebWork Beehive , Stripes Component-based Framework Jave Server Faces (JSF) Tapestry Wicket Hybrid – Meta Framework RIFE Spring Framework RIA-based Framework DWR Echo2 JSON-RPC-Java