1 / 45

CHAPTER 10

CHAPTER 10. Distributed Object-Based Systems. [ Team 1: Jessica Reece & Venkat Purimetla ]. INTRODUCTION. In distributed object-based systems, the notion of an object plays a key role in establishing distribution transparency.

violet-best
Download Presentation

CHAPTER 10

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHAPTER 10 Distributed Object-Based Systems [ Team 1: Jessica Reece & Venkat Purimetla ]

  2. INTRODUCTION • In distributed object-based systems, the notion of an object plays a key role in establishing distribution transparency. • In principle, everything is treated as an object and clients are offered services and resources in the form of objects that they can invoke. • Objects are versatile and are tremendous help with building systems. • Why are distributed objects important? • It’s relatively easy to hide distribution aspects behind an object’s interface. • This chapter looks at how principles of distributed systems are applied to a number of well-known object-based systems. [ Team 1: Jessica Reece & Venkat Purimetla ]

  3. 10.1 ARCHITECTURE • Object Orientation • It has the natural ability to build software into well-defined and more or less independent components. • Modularity means that developers can concentrate on a specific functionality, independent of what the other developers are doing • With independent objects hosted by a remote server, this created a high degree of distribution transparency – which then formed a solid basis for developing a new generation of distributed systems. [ Team 1: Jessica Reece & Venkat Purimetla ]

  4. RUOK 1 • Why is an object important in/to distributed systems • It establishes transparency • It helps with building up systems • Both • Neither [ Team 1: Jessica Reece & Venkat Purimetla ]

  5. RUOK 2 • Why is Object Orientation (OO) important? • It has the natural ability to build software into well defined and more-or-less independent components. • Developers can concentrate on specific functionality • Both • Neither [ Team 1: Jessica Reece & Venkat Purimetla ]

  6. Architecture [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  7. Distributed Objects • Object that encapsulates data is called the state, and the operations on those data is called methods. • Methods are made available through an interface. • There is no "legal" way a process can access or manipulate the state of an object other than by invoking methods made available to it via an object's interface. [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  8. Organization of a remote object • When a client binds to a distributed object. an implementation of the object’s interface, called a proxy, is then loaded into the client's address space [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  9. Continued… • A proxy is analogous to a client stub in RPC systems. • The only thing it does is marshal method invocations into messages and unmarshal reply messages to return the result of the method invocation to the client • Incoming invocation requests are first passed to a server stub, which unmarshals them to make method invocations at the object's interface at the server [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  10. Continued… • The server stub is also responsible for marshaling replies and forwarding reply messages to the client side proxy. • The server-side stub is often referred to as a skeleton as it provides the bare means for letting the server middleware access the user-defined objects. [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  11. R U O K 3? • What are the legal ways a process can access the state of an object? a. Calling method directly b. Invoking methods made available via an object’s interface c. Invoking methods by passing a reference d. All of the above [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  12. R U O K 4? 2. What is true for a proxy in organization of a remote object? a. Marshal method invocations into messages and unmarshal reply messages to return the result of the method invocation to the client. b. Unmarshals incoming invocation requests to make method invocations at the object's interface at the server. [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  13. Distributed System State • A characteristic, but somewhat counterintuitive feature of most distributed objects is that their state is not distributed: it resides at a single machine. • Only the interfaces implemented by the object are made available on other machines. • In a general distributed object, the state itself may be physically distributed across multiple machines, but this distribution is also hidden from clients behind the object's interfaces. [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  14. R U O K 5? 3. Which among the following is a feature of distributed object? • Distributed object’s state is distributed. • All the interfaces are available on other machines . • Distributed object’s state is not distributed. • All of the above. [Team 2: Nirzari Iyer(1001117633) Sharan Raghu (1001117995)]

  15. Team 3 Mrinmoy Prasad 1001103732 Revanth Pobala 1001086526

  16. Compile Time vs. Run Time • A class is a description of an abstract type in terms of a module with data elements and operations on that data • An object can be fully defined by means of its class and the interfaces that the class implements. • The most obvious form of objects , compile-time objects, are directly related to language-level objects supported by Java and C++ and they are easier to build distributed systems. • With run-time objects, the implementation is left “open” and this approach to object-based distributed systems allows an application to be constructed from objects written in multiple languages. • This scheme may use object adapters that act as wrappers that give implementations an object appearance

  17. R U O K 6) Object 7) Class 8) Run Time 9) Compile Time A) description of an abstract type in terms of a module with data elements and operations on that data B) object can be fully defined by means of its class and the interfaces that the class implements C) operations performed by a compiler, programming language requirements that must be met by source code for it to be successfully compiled. D) the process of performing instructions one by one during the run time phase

  18. Persistent And Transient Objects Quiz 29 due at 5 PM Thursday, 31 October 2014 Team 4: Gopi Chand Tadikonda Sashidhar Reddy Kalluri

  19. Persistent And Transient Objects Persistent Objects • Present even if it is currently not contained in the ad- dress space of any server process. • Independent of its current server. • Server manages this object's state on secondary storage. Transient Objects • Exists as long as the server that is hosting the object. • Most object-based distributed systems simply support both types.

  20. R U O K 10? 1. Persistent Object is all About : ? • Independent of its current server. b. Server manages this object's state on secondary storage c. All of the above d. None of the above.

  21. R U O K 11? 2. Object based Distributed system support: • Persistent Objects. b. Transient Objects c. None of the above d. All of the above.

  22. Enterprise Java Beans Quiz 28 due at 5 PM Monday, 3 November 2014 Team-5 Vinod Vemasani Vaishnavi K

  23. EJB • Characteristics of EJB • An EJB is essentially a Java object that is hosted by a special server. • Various ways for remote clients to invoke the object 3 . Server provides the support to separate application functionality from systems-oriented functionality. 4. Includes functions for looking up objects, storing objects, letting objects be part of a transaction [Team5:Vinod V Vaishnavi K]

  24. R U O K 12? • Which of the following describe EJB? • EJB is a java object • Hosted by special server to invoke the object • Server supports separate application functionality. • All of the above. [Team5:Vinod V Vaishnavi K]

  25. Architecture of EJB • EJB is embedded inside a container which efficiently provides interfaces to underlying services that are implemented by the application server. • Container can more or less automatically bind the EJB to these services, meaning that the correct references are readily available to a programmer.Alice uses Bob’s public key to encrypt her identity and a challenge. • Services include those for remote method invocation (RMI),database access (JDBC), naming (JNDI), and messaging (JMS) [Team5:Vinod V Vaishnavi K]

  26. R U O K ? Match the following terms with their definitions below. 13. Container __ 14. RMI __ 15.JDBC __ 16.JNDI __ 17. JMS __ a. Database Access. b. Bind the EJB to these services. c. Messaging d. Naming. e. Method Invocation [Team5:Vinod V Vaishnavi K]

  27. Types of EJB’s • Stateless Session Bean-Transient object that is invoked once. Example-Implementing a service like searching the top ranked books and discarding this session after finishing. • Stateful Session Bean-Maintaining client related state. Example-Shopping cart which maintains the items in the clients cart even if the session finishes. • Entity Bean- It is also called “long lived” persistent object. It is stored in database and will have the features of a distributed transaction. It stores the information for client access next time. • Message-Driven Beans-Programs objects that react to incoming messages. They cannot be invoked by the client directly. It is called by the server which it has be previously prescribed. • The beans contains code handling which server discards it so that it can be seen as stateless. [Team5:Vinod V Vaishnavi K]

  28. R U O K ? 18 Stateless Session Bean- __ 19 Stateful Session Bean- __ 20 Entity Bean- __ 21 Message-Driven Bean- __ • Is also called “long lived” persistent object. • Shopping cart which maintains the items in the clients cart even if the session finishes. • Cannot be invoked by the client directly. • Transient object that is invoked once. [Team5:Vinod V Vaishnavi K]

  29. CSE 5306 Chapter 10Lab 25 Team 6Globe Distributed Shared Objects PAGE 448 [BHARGAVI 1001050437RUHAVI 1001017760]

  30. Globe • System where scalability plays a central role. • Deal with constructing a large scale wide area system that can support huge numbers of users and objects. • The difference between other object based systems is that objects determines how its state will be distributed over its replicas. • Like other object-based systems ,objects in Globe are expected to encapsulate state and operations on that state. [BHARGAVI 1001050437RUHAVI 1001017760]

  31. R U O K 22? 1. Which of the following are true about globe distributed shared objects? • Globe is a completely different type of distributed system. • Globe is a system in which scalability plays a central role. • All aspects that deal with constructing a large-scale wide-area system that can support huge numbers of users and objects drive the design of Globe. • All of the above. • None of the above. [BHARGAVI 1001050437RUHAVI 1001017760]

  32. Objects in Globe Objects decides : • How, when and where its state should be migrated. • If its state is to be replicated, if so, how replication should take place. • Its security policy and implementation. [BHARGAVI 1001050437RUHAVI 1001017760]

  33. R U O K 23? 2. What are objects in globe expected to do? • Encapsulate state • Encapsulate operations • Both of the above • None of the above [BHARGAVI 1001050437RUHAVI 1001017760]

  34. R U O K 24? 3. Is the statement, “objects in globe are put in charge as much as possible” true or false? • True • False • Cannot be determined [BHARGAVI 1001050437RUHAVI 1001017760]

  35. R U O K 25? • 5. What’s the difference between other object based systems? • Objects determines how its state will be distributed over its replicas. • Objects also controls its own policies in other areas as well. • Both of the above • None of the above [BHARGAVI 1001050437RUHAVI 1001017760]

  36. R U O K 26? 6. What does objects in globe decide? • How, when and where its state should be migrated. • If its state is to be replicated, if so, how replication should take place. • Its security policy and implementation. • All of the above • None of the above [BHARGAVI 1001050437RUHAVI 1001017760]

  37. Distributed Object-based Systems Object-Model By Sriram Devarapu Avdhut Mankavale

  38. Globe Object Model • Doesn’t adopt remote object model. • Objects physically distributed. • State of object distributed and replicated across multiple process.

  39. Distributed Shared Object

  40. RUOK 27 • Following are properties of Globe Object Model: a. Doesn’t adopt remote object model. b. Objects physically distributed. c. State of object distributed and replicated across multiple process. d. All of above. e. None of above.

  41. Distributed Shared Object • Distributed shared objects offers a process, bound to it, local implementation of interfaces called local representative or local object. • Interfaces hide object implementation details leaving its methods visible.

  42. Globe Local Object’s Flavors • Primitive Local Oject: • Doesn’t contain any other local objects. • Composite Local Object: • Composed of multiple local objects • Used to create objects for implementation of distributed shared objects.

  43. Composite Local Object

  44. RUOK 28 2. Following is true about a distributed shared object. a. It offers local implementation of interfaces to processes bound to it. b. Interfaces hide object implementation details leaving its methods visible. c. All of above. d. None of above.

  45. RUOK 29 3. Flavors of Globe local objects • Primitive local object. • Composite local object. • Both of above. • None of above.

More Related