Factory Method Design Pattern Real World Example
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(GOF) Java Design Patterns Mock Exams
Gang of Four (GOF) Java Design Patterns Mock Exams http://www.JavaChamp.com Open Certification Plattform Authors: N. Ibrahim, Y. Ibrahim Copyright (c) 2009-2010 Introducing JavaChamp.com Website JavaChamp.com is an Open Certification Platform. What does this mean? JavaChamp is the best place to learn, share, and certify your professional skills. We help you develop yourself in the field of computer science and programming Here are the most significant features offered by JavaChamp: Online Exams Start Online Certification Exams in SCJP, SCEA, EJB, JMS, JPA and more... Top quality mock exams for SCJP, SCEA, EJB, JMS, JPA. Start Express or topic-wise customized exam. * We offer you unlimited free mock exams * Exams cover subjects like SCJP, SCEA, EJB, JMS, JPA,.. * You can take as many exams as you want and at any time and for no charges * Each exam contains 20 multiple choice questions * You can save the exams taken in your exams history * Your exams history saves the exams you took, the scores you got, time took you to finish the exam, date of examination and also saves your answers to the questions for later revision * You can re-take the same exam to monitor your progress * Your exams history helps the system to offer you variant new questions every time you take a new exam, therefore we encourage you to register and maintain an exams history Network Find guidance through the maze, meet Study-Mates, Coaches or Trainees... Studying together is fun, productive and helps you in building your professional network and collecting leads Bookshelf JavaChamp Bookshelf full of PDF eBooks.. -
Usage of Factory Design Pattern
What is a Creational Pattern? Creational Patterns are concerned with object creation problems faced during software design. Object creation often results in design problems, creational patterns solve this problem by controlling the object creation. Factory pattern A Factory Pattern or Factory Method Pattern says that just define an interface or abstract class for creating an object but let the subclasses decide which class to instantiate. In other words, subclasses are responsible to create the instance of the class. The Factory Method Pattern is also known as Virtual Constructor. A Factory returns an instance of an object based on the data supplied to it. The instance returned can be one of many classes that extend a common parent class or interface. ("Animal" as a parent class, then "Dog", "Cat", "Zebra" as child classes.) Create objects without exposing their instantiation logic. Consequences: The requestor is independent of the concrete object that is created (how that object is created, and which class is actually created). Advantage of Factory Design Pattern Factory Method Pattern allows the sub-classes to choose the type of objects to create. It promotes the loose-coupling by eliminating the need to bind application-specific classes into the code. That means the code interacts solely with the resultant interface or abstract class, so that it will work with any classes that implement that interface or that extends that abstract class. Usage of Factory Design Pattern When a class doesn't know what sub-classes will be required to create When a class wants that its sub-classes specify the objects to be created. -
Acceptor-Connector an Object Creational Pattern for Connecting and Initializing Communication Services
Acceptor-Connector An Object Creational Pattern for Connecting and Initializing Communication Services Douglas C. Schmidt [email protected] Department of Computer Science Washington University St. Louis, MO 63130, USA An earlier version of this paper appeared in a chapter in TRACKING the book Pattern Languages of Program Design 3, edited SATELLITES STATION by Robert Martin, Frank Buschmann, and Dirke Riehle pub- PEERS lished by Addison-Wesley, 1997. 1Intent STATUS INFO The Acceptor-Connector design pattern decouples connec- WIDE AREA NETWORK tion establishment and service initialization in a distributed COMMANDS BULK DATA system from the processing performed once a service is ini- TRANSFER tialized. This decoupling is achieved with three compo- nents: acceptors, connectors,andservice handlers. A con- GATEWAY nector actively establishes a connection with a remote ac- ceptor component and initializes a service handler to pro- cess data exchanged on the connection. Likewise, an ac- LOCAL AREA NETWORK ceptor passively waits for connection requests from remote GROUND connectors, establishing a connection upon arrival of such a STATION PEERS request, and initializing a service handler to process data ex- changed on the connection. The initialized service handlers Figure 1: The Physical Architecture of a Connection- then perform application-specific processing and communi- oriented Application-level Gateway cate via the connection established by the connector and ac- ceptor components. The Gateway transmits data between its Peers using the connection-oriented TCP/IP protocol [1]. In our exam- 2 Example ple network configuration, each service is bound to a con- nection endpoint designated by an IP host address and a TCP To illustrate the Acceptor-Connector pattern, consider the port number. -
The Future of Embedded Software
The Future of Embedded Software Edward A. Lee Professor, Chair of EE, and Associate Chair of EECS UC Berkeley ARTEMIS 2006 Annual Conference Graz, Austria May 22-24, 2006 Why Embedded Software? Why Now? “Information technology (IT) is on the verge of another revolution. Driven by the increasing capabilities and ever declining costs of computing and communications devices, IT is being embedded into a growing range of physical devices linked together through networks and will become ever more pervasive as the component technologies become smaller, faster, and cheaper... These networked systems of embedded computers ... have the potential to change radically the way people interact with their environment by linking together a range of devices and sensors that will allow information to be collected, shared, and processed in unprecedented ways. ... The use of [these embedded computers] throughout society could well dwarf previous milestones in the information revolution.” National Research Council Report Embedded Everywhere Lee, Berkeley 2 The Key Obstacle to Progress: Gap Between Systems and Computing | Traditional dynamic systems theory needs to adapt to better account for the behavior of software and networks. | Traditional computer science needs to adapt to embrace time, concurrency, and the continuum of physical processes. Lee, Berkeley 3 The Next Systems Theory: Simultaneously Physical and Computational The standard model: Embedded software is software on small computers. The technical problem is one of optimization (coping with limited resources). The Berkeley model: Embedded software is software integrated with physical processes. The technical problem is managing time and concurrency in computational systems. Lee, Berkeley 4 Obstacles in Today’s Technology: Consider Real Time Electronics Technology Delivers Timeliness… … and the overlaying software abstractions discard it. -
Automatic Verification of Java Design Patterns
Automatic Verification of Java Design Patterns Alex Blewitt, Alan Bundy, Ian Stark Division of Informatics, University of Edinburgh 80 South Bridge, Edinburgh EH1 1HN, UK [email protected] [email protected] [email protected] Abstract 2. Design patterns There are a number of books which catalogue and de- Design patterns are widely used by object oriented de- scribe design patterns [4, 1, 6] including an informal de- signers and developers for building complex systems in ob- scription of the key features and examples of their use. ject oriented programming languages such as Java. How- However, at the moment there are no books which attempt ever, systems evolve over time, increasing the chance that to formalise these descriptions, possibly for the following the pattern in its original form will be broken. reasons: We attempt to show that many patterns (implemented in Java) can be verified automatically. Patterns are defined 1. The implementation (and description) of the pattern is in terms of variants, mini-patterns, and constraints in a language-specific. pattern description language called SPINE. These specifi- 2. There are often several ways to implement a pattern cations are then processed by HEDGEHOG, an automated within the same language. proof tool that attempts to prove that Java source code 3. Formal language descriptions are not common within meets these specifications. the object oriented development community. Instead, each pattern is presented as a brief description, and an example of its implementation and use. Designers and developers are then expected to learn the ‘feel’ of a pat- 1. -
Design Patterns Promote Reuse
Design Patterns Promote Reuse “A pattern describes a problem that occurs often, along with a tried solution to the problem” - Christopher Alexander, 1977 • Christopher Alexander’s 253 (civil) architectural patterns range from the creation of cities (2. distribution of towns) to particular building problems (232. roof cap) • A pattern language is an organized way of tackling an architectural problem using patterns Kinds of Patterns in Software • Architectural (“macroscale”) patterns • Model-view-controller • Pipe & Filter (e.g. compiler, Unix pipeline) • Event-based (e.g. interactive game) • Layering (e.g. SaaS technology stack) • Computation patterns • Fast Fourier transform • Structured & unstructured grids • Dense linear algebra • Sparse linear algebra • GoF (Gang of Four) Patterns: structural, creational, behavior The Gang of Four (GoF) • 23 structural design patterns • description of communicating objects & classes • captures common (and successful) solution to a category of related problem instances • can be customized to solve a specific (new) problem in that category • Pattern ≠ • individual classes or libraries (list, hash, ...) • full design—more like a blueprint for a design The GoF Pattern Zoo 1. Factory 13. Observer 14. Mediator 2. Abstract factory 15. Chain of responsibility 3. Builder Creation 16. Command 4. Prototype 17. Interpreter 18. Iterator 5. Singleton/Null obj 19. Memento (memoization) 6. Adapter Behavioral 20. State 21. Strategy 7. Composite 22. Template 8. Proxy 23. Visitor Structural 9. Bridge 10. Flyweight 11. -
Design Pattern Interview Questions
DDEESSIIGGNN PPAATTTTEERRNN -- IINNTTEERRVVIIEEWW QQUUEESSTTIIOONNSS http://www.tutorialspoint.com/design_pattern/design_pattern_interview_questions.htm Copyright © tutorialspoint.com Dear readers, these Design Pattern Interview Questions have been designed specially to get you acquainted with the nature of questions you may encounter during your interview for the subject of Design Pattern. As per my experience good interviewers hardly plan to ask any particular question during your interview, normally questions start with some basic concept of the subject and later they continue based on further discussion and what you answer: What are Design Patterns? Design patterns represent the best practices used by experienced object-oriented software developers. Design patterns are solutions to general problems that software developers faced during software development. These solutions were obtained by trial and error by numerous software developers over quite a substantial period of time. What is Gang of Four GOF? In 1994, four authors Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides published a book titled Design Patterns - Elements of Reusable Object-Oriented Software which initiated the concept of Design Pattern in Software development. These authors are collectively known as Gang of Four GOF. Name types of Design Patterns? Design patterns can be classified in three categories: Creational, Structural and Behavioral patterns. Creational Patterns - These design patterns provide a way to create objects while hiding the creation logic, rather than instantiating objects directly using new opreator. This gives program more flexibility in deciding which objects need to be created for a given use case. Structural Patterns - These design patterns concern class and object composition. Concept of inheritance is used to compose interfaces and define ways to compose objects to obtain new functionalities. -
Addison Wesley, 2000, Pp
------==Proudly Presented by MODELER==------ preface.fm Page xv Wednesday, June 6, 2001 4:18 PM Preface Design patterns and object-oriented programming. They hold such promise to make your life as a software designer and developer eas- ier. Their terminology is bandied about every day in the technical and even the popular press. But it can be hard to learn them, to become proficient with them, to understand what is really going on. Perhaps you have been using an object-oriented or object-based language for years. Have you learned that the true power of objects is not inheritance but is in “encapsulating behaviors”? Perhaps you are curious about design patterns and have found the literature a bit too esoteric and high-falutin. If so, this book is for you. It is based on years of teaching this material to software developers, both experienced and new to object orientation. It is based upon the belief—and our experience—that once you understand the basic principles and motivations that underlie these concepts, why they are doing what they do, your learning curve will be incredibly shorter. And in our discussion of design patterns, you will under- stand the true mindset of object orientation, which is a necessity before you can become proficient. As you read this book, you will gain a solid understanding of the ten most essential design patterns. You will learn that design pat- terns do not exist on their own, but are supposed to work in con- cert with other design patterns to help you create more robust applications. -
Principles of Design
Principles of Design Balance Proportion/Scale Emphasis Rhythm Introduction The principles of design are essential to the development and production of clothing used by individuals and families around the world. Each principle has a specific role in creating an aesthetically pleasing garment or ensemble. The principles of design consist of: balance, proportion (also referred to as scale), emphasis, and rhythm. When a garment or ensemble uses the elements and principles of design to create a visual unity, harmony is achieved. Garments often integrate more than one principle, while drawing from the elements of design to create a cohesive look. The following discussion will present background information on each of the principles of design and applications to clothing design and construction. Balance According to Wolfe (2011) balance implies that there is an equilibrium or uniformity among the parts of a design (p. 205). To achieve balance, a garment or ensemble should have equal visual weight throughout the design. The use of structural features, added embellishments, or decorations to a garment contribute to the appearance of a garment or ensemble being balanced or not. A clothing designer can utilize surface designs on fabric to construct a garment creating visual balance. Further, color, line, and texture can impact the balance of a design. For example, cool and light colors have less visual weight than dark, warm colors. If an individual is wearing a small amount of a dark, warm color it can be balanced out with a larger amount of cool, light colors. Balance used in clothing design can be categorized into two groups: Formal and Informal Balance. -
Srm University Faculty of Engineering and Technology
SRM UNIVERSITY FACULTY OF ENGINEERING AND TECHNOLOGY SCHOOL OF COMPUTING DEPARTMENT OF SWE COURSE PLAN Course Code : CS0373 Course Title : DESIGN PATTERNS Semester : VII Course Time : July – December 2014 C Day Hour Timing Day 1 6 2.20 to 3.10 Day 3 5 1.30 to 2.20 Day 5 3,5 10.35 to 11.25 and 1.30 to 2.20 Location : S.R.M.E.C – University Building (12 th Floor) Faculty Details Sec. Name Office Office hour Mail id Ms. Cinza Susan University Monday to Friday [email protected] Abraham Building Required Text Books: TEXT BOOK 1Alan Shalloway, James Trott, “Design Patterns Explained: A New Perspective on Object- Oriented Design”,Addison-Wesley, 2005 2. Joshua Kerievsky, “Refactoring to Patterns”, Addison-Wesley, 2004 REFERENCE BOOKS 1. Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides, “Design Patterns : Elements of Reusable Object-Oriented Software”, Addison-Wesley, 1995. 2. Eric Freeman, Elisabeth Freeman, Kathy Sierra, Bert Bates, “Head First Design Patterns”, O'Reilly Media, Inc., 2004. 3. Martin Fowler, Kent Beck, John Brant, William Opdyke, Don Roberts.“Refactoring: Improving the Design of Existing Code”, Addison-Wesley, 1999. Prerequisite : Software Engineering Principles Software Architecture Software Design Objectives This course introduces the students to 1. Understand and be able to apply incremental/iterative development 2. Understand common design patterns 3. Be able to identify appropriate design patterns for various problems 4. Be able to refactor poorly designed program by using appropriate design patterns. Assessment Details Cycle Test 1 : 10 Marks Cyle Test II : 10 Marks Model Exam : 20 Marks Surprise Test : 5 Marks Attendance : 5 Marks Test Schedule S.No. -
Design Patterns. Introduction
DESIGN PATTERNS COURSE 1 OGANIZATION q Course q Each week 2 hours, Room 050A q Laboratory q Each odd/even school week, Room 050A q Presence q Course: minimum 50% q Laboratory: minimum 50% q Grade q Written exam 50% q Course activity 1%+ laboratory activity 24% q Presentation of a pattern 10% q Project 15% ORGANIZATION q Course & laboratories q available at http://staff.fmi.uvt.ro/~flavia.micota/ q Contact q e-mail: [email protected] q cab. 046B q Classroom q 1rcgcs COURSE CONTENT q Design patterns q Creational q Structural q Behavioral q Refactoring q Anti-patterns q Students presentations of a pattern WAY YOU CHOSE THIS COURSE? WAY YOU CHOSE THIS COURSE? q Some reasons from http://www.ida.liu.se/~chrke55/courses/SWE/bunus/DP01_1sli de.pdf q I could get some easy points. q Everybody is talking about so it must to be cool. q If I master this I can added it to my CV. q Increase my salary at the company. q Applying patterns is easier than thinking q A great place to pick up ideas to plagiarize. DESIGN CHALLENGES q Designing software with good modularity is hard! q Designs often emerge from a lot of trial and error q Are there solutions to common recurring problems? q A Design Pattern is a Tried and True Solution To a Common Problem q Basically, people, who have done this a lot, are making a suggestion! SOURCE CODE QUALITY q What characteristics should be respected in order to deliver a quality sorce code for a project? SOURCE CODE QUALITY q What characteristics should be respected in order to deliver a quality sorce code for a project? q Easy to read/understood – clear q Easy to modify – structured q Easy to reuse q Simple (complexity) q Easy to test q Implements patterns for standard problems SOURCE CODE QUALITY q What influence source code quality? q Development time q Costs q Programmer experience q Programmer abilities q Specifications clarity q Solution complexity q Requirements change rate, team, … PATTERNS q A pattern is a recurring solution to a standard problem, in a context. -
Dependency Injection in Unity3d
Dependency Injection in Unity3D Niko Parviainen Bachelor’s thesis March 2017 Technology, communication and transport Degree Programme in Software Engineering Description Author(s) Type of publication Date Parviainen, Niko Bachelor’s thesis March 2017 Language of publication: English Number of pages Permission for web publi- 57 cation: x Title of publication Dependency Injection in Unity3D Degree programme Degree Programme in Software Engineering Supervisor(s) Rantala, Ari Hämäläinen, Raija Assigned by Psyon Games Oy Abstract The objective was to find out how software design patterns and principles are applied to game development to achieve modular design. The tasks of the research were to identify the dependency management problem of a modular design, find out what the solutions offered by Unity3D are, find out what the dependency injection pattern is and how it is used in Unity3D environment. Dependency management in Unity3D and the dependency injection pattern were studied. Problems created by Unity3D’s solutions were introduced with examples. Dependency in- jection pattern was introduced with examples and demonstrated by implementing an ex- ample game using one of the available third-party frameworks. The aim of the example game was to clarify if the use of dependency injection brings modularity in Unity3D envi- ronment and what the cost of using it is. The principles of SOLID were introduced with generic examples and used to assist depend- ency injection to further increase the modularity by bringing the focus on class design. Dependency injection with the help of SOLID principles increased the modularity by loosely coupling classes even though slightly increasing the overall complexity of the architecture.