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Technical training at SCIENTECH TECHNOLOGIES By Deeksha Chauhan, VII sem (CSE) http://powerpointpresentationon.blogspot.com • Scientech Technologies was found in 1983 • an ISO 9001:2000 certified company • Scientech Technologies is a leading name in the field of Test and Measuring Instruments and Technical Training Equipment. • Head office is at Indore and Branch offices at Mumbai, Pune, New Delhi, Chennai, Hyderabad, Kolkata, Jaipur, Lucknow, Chandigarh and Bangalore. • Scientech has won the prestigious EFY readers choice award in the Educational Trainers/kits category in 2004, 2005, 2006 and again in 2008. • Scientech is an active member of Worlddidac, Switzerland • Are emerging Global Leader of Innovative, Competitive and Eco friendly Electronic Equipments, Software Products and Turn-key Solutions for Industry and Technology Training. • To achieve this they are enhancing Customer Satisfaction based on Research, Modern manufacturing techniques and continuous improvement in Quality of the products and the Services. • key drivers to growth focus on Employees and Customers, Use of latest Technology, Intense Marketing, Service Support and High Ethical Practices. • Fuel Cell Trainer NV6007 Fuel Cell Trainer is a modular experimental system designed to study the working of Solar-Hydrogen cycle. The Reversible Fuel Cell is unique, as it acts as both, an Electrolyzer and a Fuel Cell. • Video Processing Platform The ST111 Video Processing Solution provides an ideal vehicle for study and implementation of Video/ Image Processing Algorithm. ST111 provides a complete, readyto-teach platform that can be used in courses on Video Processing. The ST111 board suits a wide range of exercises from simple tasks and illustrating fundamental concepts, to challenging designs requiring detailed knowledge. • Robotic Arm NV3301 Robotic Arm is versatile training equipment for all robotics enthusiasts to understand the very basic concept of robotics. Robotic arm can be controlled from software or control panel. Control panel has LCD, switches, home sensor LED, connector for external interface with DIP switches and USB interface. From software user can control each DOF individually through mouse click or key board. • JAVA • J2EE EJB(Enterprise JavaBeans) Why java? 1.It’s almost entirely object-oriented 2.It has a vast library of predefined objects and operations 3.It’s more platform independent 4.It’s more secure 5.It isn’t C++ • An applet is designed to be embedded in a Web page, • • • and run by a browser Applets run in a sandbox with numerous restrictions; for example, they can’t read files and then use the network A servlet is designed to be run by a web server An application is a conventional program • The .class files generated by the compiler are not • • executable binaries o so Java combines compilation and interpretation Instead, they contain “byte-codes” to be executed by the Java Virtual Machine o other languages have done this, e.g. UCSD Pascal This approach provides platform independence, and greater security • Comments are almost like C++ • Primitive data types are like C • Declarations look like C • Expressions are like C(Assignment statements , Arithmetic operators, Boolean operators, Comparisons operators JAVA does not have pointers or pointer arithmetic Control statements are like C but conditions must be boolean • • • In C, almost everything is in functions • In Java, almost everything is in classes • There is often only one class per file • There must be only one public class per file • The file name must be the same as the name of that public class, but with a .java extension • Java is case-sensitive; maxval, maxVal, and MaxVal are • • • • • three different names Class names begin with a capital letter All other names begin with a lowercase letter Subsequent words are capitalized: theBigOne Underscores are not used in names These are very strong conventions! • Classes are arranged in a hierarchy • The root, or topmost, class is Object • Every class but Object has at least one superclass • A class may have subclasses • Each class inherits all the fields and methods of its (possibly numerous) superclasses • Stands for “Java 2, Enterprise Edition” • It is a collection of standards o JDBC, JNDI, JMX, JMS • It is a component technology o Enterprise JavaBeans • It is an “application server” o Following in the footsteps of Component Transaction Monitors • Distributed Objects o CORBA, DCOM, etc. o Three-tier scenario: presentation, business logic, and backend databases Hard to “get right” without the proper infrastructure • Server-Side Components o Focuses on encapsulating “business rules” into objects in the middle tier • Component Transaction Monitors o Descendant of CORBA’s Object Request Broker provides discovery, persistence, event notification, transactions, etc. for three-tier or n-tier applications • A specification o Version 1.4 o Response to JSR-151 o Umbrella which freezes other technologies Each has its own spec / rev + reference implementation • A Download o Interfaces o Reference implementation Rollup of individual technologies’ reference implementations E.g. Tomcat 4.X for Servlet 2.0 o Compatibility Test Suite o BluePrints • High Availability • Security • Reliability • Scalability …of Enterprise Information Services (EISs), …Usually in a multitier environment. • Applets (Just like conventional Applet) • Application Clients o Just like conventional J2SE application o Except may require J2EE APIs • JSP / Servlet o Anything that talks HTTP o Requires container; Apache/Tomcat is RefImpl • EJB o Transactional component o Requires container + server o Download gives you RefImpl Enterprise JavaBeans is a standard server-side component model for component transaction monitors It’s a standard for building server-side components and deploying them in component transaction monitors ClientSide invoke s Stub Clien t Networ k connect to remote object Middle Tier Skeleton invok e Server-Side Component return return return result result result s s s “thinks” its making Stub and Skeleton are auto-generated; client a local call, most networking details are hidden from client; the main The Cast…In Order of Appearance 1. EJB Server Provider 2. EJB Container Provider 3. Enterprise Bean Provider 4. Deployer Combined for our purposes... 5. Application [EJB Client] Assembler 6. System Administrator EJB Spec lists roles in a different order EnterpriseBean-centric vice chronological • Implement majority of EJB spec • Provide backbone of EJB System o Mediator among other players: EJB Clients EnterpriseBean At least one “backend” database • Various implementations o BEA/Weblogic, IBM/Websphere, 8 others • EJB 2.X should clear up Container bounds • Reusable software component • Built / bought to meet a business need • Deployed to an EJB Server implementation • Serves multiple users across enterprise • Application that uses EnterpriseBean o GUI or non-GUI (e.g. Servlets) o Java or CORBA o Remote or local (EB Intranet; NNS; other EnterpriseBean) • Client view is remote interfaces • Considered less trustworthy than server side o Client flaw should not affect EJB Server create( ) Clientfind() EJB Server Containe r XHome EnterpriseBe an X (Wire Tier 1……………………Tier ) 2………………………..Tier N Existing Databas (Wire e ) Doesn’t Exist pooled ejbCreate () ejbLoad( ) ejbPassivate () ejbActivate () ready ejbFind( ) ejbRemov e() ejbStore businessMetho() d() • Two Types of Enterprise JavaBeans o Entity Beans Used to model business concepts such as customer, cruise ship, inventory item, etc. o Session Beans A server-side “representative” of the client; session beans are responsible for managing processes or tasks; for instance in an airline reservation scenario, the session bean would be responsible for reserving a seat on a particular flight and verifying payment EnterpriseBean that is long lived • Maps to backend data store o Bean-managed persistence o Container-managed persistence • Has unique key (“primary key” or XPK) • Implements EntityBean interface Examples: EmployeeBean with SSN as PK EnterpriseBean that is short lived • Duration no longer than user login • State not stored to any database • Examples: o ShoppingCartBean o TableModelBean • Implements EnterpriseBean interface Client Using only Entity Beans Client Using Session Beans EJB Server • 6 classes o All are of type Exception • 12 interfaces o 6 are seen by EJB Client o other 6 are only seen by EJB Server/Container o Often implement java.io.Serializable or java.io.Remote • Any enterprise bean must define two interfaces and one or two classes o Remote interface defines a bean’s external interface must extend javax.ejb.EJBObject (which in turn extends java.rmi.Remote) o Home interface The home interface defines a bean’s “life cycle” methods, eg. create bean, remove bean, find bean, etc. must extend javax.ejb.EJBHome which also extends java.rmi.Remote • Bean Class o The java class that actually implements the bean’s external interface, e.g. the bean class provides implementations for the bean’s “business methods” o An entity bean must implement the javax.ejb.EntityBean interface, while a session bean must implement the (you guessed it) javax.ejb.SessionBean. Both of these interfaces extend javax.ejb.EnterpriseBean • Primary Key o The primary key is a very simple class that provides a pointer into a database; Only entity beans need a primary key. This class must implment java.io.Serializable (so the entity bean can • Clients never interact directly with a bean class, they use • • stubs (which connect to skeletons, which connect to “containers” which call the bean class…whew!) Why? This allows the application server to replicate bean instances (for performance reasons), manage transactions, etc. A bean also interacts with its server via a container interface: the container calls the bean’s life cycle methods, manages the bean’s persistence, etc. Client EJB Server Home Interface Hom e Stub EJB Container Remote Interface EJB Stu b Home Interface EJB Hom e Remote Interface EJB Object Bean Class • Entity beans are distinct from Session But no distinction between Bean Managed & Container Managed Persistence Void ejbActivate(); Invoked by container to associate with EJBObject void ejbLoad(); “Do a database lookup” (bean-managed persistence only) void ejbPassivate(); Invoked by container; about to get dissociated with EJBObject void ejbRemove(); void ejbStore(); - “Persist yourself to database” (bean-managed persistence only) void setEntityContext(EntityContext ctx); • SessionBeans are distinct from Entity Void ejbActivate(); void ejbPassivate(); void ejbRemove(); void setSessionContext(SessionContext); • Resource Management o Instance Pooling and Swapping Server can invoke multiple instances of a bean to handle multiple incoming requests (pooling) An instance of a bean class can handle requests from multiple skeletons (swapping) o Activation if a bean is “stateful”, application servers automate the process of saving and restoring bean state • Primary Services o Concurrency Beans are automatically thread safe; application servers handle concurrent access to a bean; They also handle reentrance o Transactions Bean operations can belong to a transaction and the application server handles “rolling back” an application’s state if a partially completed transaction fails o Persistence Application servers can map beans into database entries (and back again) o Naming (bean discovery) and Security (encrypted communication and access control)