Design Patterns Explained Java Code Examples
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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 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. -
Object-Oriented Analysis, Design and Implementation
Undergraduate Topics in Computer Science Brahma Dathan Sarnath Ramnath Object-Oriented Analysis, Design and Implementation An Integrated Approach Second Edition Undergraduate Topics in Computer Science Undergraduate Topics in Computer Science (UTiCS) delivers high-quality instruc- tional content for undergraduates studying in all areas of computing and information science. From core foundational and theoretical material to final-year topics and applications, UTiCS books take a fresh, concise, and modern approach and are ideal for self-study or for a one- or two-semester course. The texts are all authored by established experts in their fields, reviewed by an international advisory board, and contain numerous examples and problems. Many include fully worked solutions. More information about this series at http://www.springer.com/series/7592 Brahma Dathan • Sarnath Ramnath Object-Oriented Analysis, Design and Implementation An Integrated Approach Second Edition 123 Brahma Dathan Sarnath Ramnath Department of Information and Computer Department of Computer Science Science and Information Technology Metropolitan State University St. Cloud State University St. Paul, MN St. Cloud, MN USA USA Series editor Ian Mackie Advisory Board Samson Abramsky, University of Oxford, Oxford, UK Karin Breitman, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil Chris Hankin, Imperial College London, London, UK Dexter Kozen, Cornell University, Ithaca, USA Andrew Pitts, University of Cambridge, Cambridge, UK Hanne Riis Nielson, Technical University of Denmark, Kongens Lyngby, Denmark Steven Skiena, Stony Brook University, Stony Brook, USA Iain Stewart, University of Durham, Durham, UK A co-publication with the Universities Press (India) Private Ltd., licensed for sale in all countries outside of India, Pakistan, Bhutan, Bangladesh, Sri Lanka, Nepal, The Maldives, Middle East, Malaysia, Indonesia and Singapore. -
Designpatternsphp Documentation Release 1.0
DesignPatternsPHP Documentation Release 1.0 Dominik Liebler and contributors Jul 18, 2021 Contents 1 Patterns 3 1.1 Creational................................................3 1.1.1 Abstract Factory........................................3 1.1.2 Builder.............................................8 1.1.3 Factory Method......................................... 13 1.1.4 Pool............................................... 18 1.1.5 Prototype............................................ 21 1.1.6 Simple Factory......................................... 24 1.1.7 Singleton............................................ 26 1.1.8 Static Factory.......................................... 28 1.2 Structural................................................. 30 1.2.1 Adapter / Wrapper....................................... 31 1.2.2 Bridge.............................................. 35 1.2.3 Composite............................................ 39 1.2.4 Data Mapper.......................................... 42 1.2.5 Decorator............................................ 46 1.2.6 Dependency Injection...................................... 50 1.2.7 Facade.............................................. 53 1.2.8 Fluent Interface......................................... 56 1.2.9 Flyweight............................................ 59 1.2.10 Proxy.............................................. 62 1.2.11 Registry............................................. 66 1.3 Behavioral................................................ 69 1.3.1 Chain Of Responsibilities................................... -
Design Patterns in Ocaml
Design Patterns in OCaml Antonio Vicente [email protected] Earl Wagner [email protected] Abstract The GOF Design Patterns book is an important piece of any professional programmer's library. These patterns are generally considered to be an indication of good design and development practices. By giving an implementation of these patterns in OCaml we expected to better understand the importance of OCaml's advanced language features and provide other developers with an implementation of these familiar concepts in order to reduce the effort required to learn this language. As in the case of Smalltalk and Scheme+GLOS, OCaml's higher order features allows for simple elegant implementation of some of the patterns while others were much harder due to the OCaml's restrictive type system. 1 Contents 1 Background and Motivation 3 2 Results and Evaluation 3 3 Lessons Learned and Conclusions 4 4 Creational Patterns 5 4.1 Abstract Factory . 5 4.2 Builder . 6 4.3 Factory Method . 6 4.4 Prototype . 7 4.5 Singleton . 8 5 Structural Patterns 8 5.1 Adapter . 8 5.2 Bridge . 8 5.3 Composite . 8 5.4 Decorator . 9 5.5 Facade . 10 5.6 Flyweight . 10 5.7 Proxy . 10 6 Behavior Patterns 11 6.1 Chain of Responsibility . 11 6.2 Command . 12 6.3 Interpreter . 13 6.4 Iterator . 13 6.5 Mediator . 13 6.6 Memento . 13 6.7 Observer . 13 6.8 State . 14 6.9 Strategy . 15 6.10 Template Method . 15 6.11 Visitor . 15 7 References 18 2 1 Background and Motivation Throughout this course we have seen many examples of methodologies and tools that can be used to reduce the burden of working in a software project. -
The Use of Design Pattern on Informatics Engineering Students Thesis
Advances in Intelligent Systems Research (AISR), volume 157 Mathematics, Informatics, Science, and Education International Conference (MISEIC 2018) The Use of Design Pattern on Informatics Engineering Students Thesis Alifah Diantebes Aindra, Aim Abdulkarim Eki Nugraha Oktarica Pratiwi Suryoningtyas, Department of Civil Education Department of Computer Science and Aji Prasetya Wibawa Universitas Pendidikan Indonesia Universitas Pendidikan Indonesia Department of Vocational Education Bandung, Indonesia Bandung, Indonesia Universitas Negeri Malang [email protected] [email protected] Malang, Indonesia [email protected], [email protected], [email protected] Abstract— University students should write a thesis to get the process of software development to reduce the development their undergraduate (Bachelor) degree is. Most Informatics process so that students can complete their thesis quickly. By engineering students of the Electrical Engineering reducing the development time of a software, it can also reduce Department in Universitas Negeri Malang use research and the costs during the production process [1]. One of these development method for their thesis. There are many solutions is to use design patterns for the development. The use solutions or methods in software engineering which aim to of a design pattern can reduce the development time, facilitate develop a good quality software. One of these solutions is communication between the development team, written source using design patterns. Several benefits of using the design code becomes more flexible and easy to reuse [2]. patterns are; decreasing time of production, having a Unlike the above mentioned, to implement or adapt the reusable and flexible code, and making people easier to design pattern, a proper and good preparation from the understand. -
Java Design Patterns I
Java Design Patterns i Java Design Patterns Java Design Patterns ii Contents 1 Introduction to Design Patterns 1 1.1 Introduction......................................................1 1.2 What are Design Patterns...............................................1 1.3 Why use them.....................................................2 1.4 How to select and use one...............................................2 1.5 Categorization of patterns...............................................3 1.5.1 Creational patterns..............................................3 1.5.2 Structural patterns..............................................3 1.5.3 Behavior patterns...............................................3 2 Adapter Design Pattern 5 2.1 Adapter Pattern....................................................5 2.2 An Adapter to rescue.................................................6 2.3 Solution to the problem................................................7 2.4 Class Adapter..................................................... 11 2.5 When to use Adapter Pattern............................................. 12 2.6 Download the Source Code.............................................. 12 3 Facade Design Pattern 13 3.1 Introduction...................................................... 13 3.2 What is the Facade Pattern.............................................. 13 3.3 Solution to the problem................................................ 14 3.4 Use of the Facade Pattern............................................... 16 3.5 Download the Source Code............................................. -
Object-Oriented Desgin Flyweight Pattern George Blankenship 1
Object-Oriented Desgin Flyweight Pattern CSCI 253 Object Oriented Design: Flyweight Pattern George Blankenship Flyweight Pattern George Blankenship 1 Overview Creational Patterns Structural Patterns Behavioral Patterns Singleton Composite Chain of Respons. Abstract factory Façade Command Factory Method Proxy Interpreter Prototype Flyweight Iterator Builder Mediator Adapter Memento Bridge Observer Decorator State Strategy Template Method Flyweight Pattern George Blankenship Visitor 2 The Elements of a Design Pattern • A pattern name • The problem that the pattern solves – Including conditions for the pattern to be applicable • The solution to the problem brought by the pattern – The elements (classes-objects) involved, their roles, responsibilities, relationships and collaborations – Not a particular concrete design or implementation • The consequences of applying the pattern – Time and space trade off – Language and implementation issues – Effects on flexibility, extensibility, portability Flyweight Pattern George Blankenship 3 George Blankenship 1 Object-Oriented Desgin Flyweight Pattern The Flyweight Pattern: The Problem Some applications benefit from using objects in their design but a naïve implementation is prohibitively expensive because of the large number of objects Column • use an object for each character in a text document editor Character h a l l o • use a layout object for each widget in a GUI Row Flyweight Pattern George Blankenship 4 Page Objects Flyweight Pattern George Blankenship 5 Page Classes Flyweight -
Design Pattern Driven Development of Model Transformations
DESIGN PATTERN DRIVEN DEVELOPMENT OF MODEL TRANSFORMATIONS by HUSEYIN ERGIN JEFF GRAY, COMMITTEE CHAIR JEFFREY CARVER RALF LAEMMEL RANDY SMITH EUGENE SYRIANI SUSAN VRBSKY A DISSERTATION Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Computer Science in the Graduate School of The University of Alabama TUSCALOOSA, ALABAMA 2017 Copyright Huseyin Ergin 2017 ALL RIGHTS RESERVED ABSTRACT Model-Driven Engineering (MDE) is considered a well-established software development ap- proach that uses abstraction to bridge the gap between the problem space and the software implementation. These abstractions are represented by models that make the validation of the real system easier. In MDE, many problems are solved using model transformation, which is a paradigm that manipulates high-level models to translate, evolve, or simulate them. However, the development of a model transformation for a specific problem is still a hard task. The main reason is the lack of a development process where transformations must be designed before implemented. Design patterns provide experiential reuse to soft- ware engineers when faced with recurring problems. In the literature, design patterns have been used to generate partially reusable software designs in order to help developers. There are many design patterns focused development methodologies proposed. However, most of them specialize in object-oriented design patterns. Given the various contexts in which de- sign patterns have been applied, model transformations may also benefit from a patterns approach. Although several studies have proposed design patterns for model transforma- tion, there is still no accepted common language to express them or a methodology that places design patterns at the heart of the development of model transformations. -
Design Patterns Design Patterns
Design Patterns • More design patterns (GoF) – Structural: Adapter, Bridge, Façade – Creational: Abstract Factory, Singleton – Behavioral: Observer, Iterator, State, Visitor Design Patterns-10, CS431 F06, BG Ryder/A Rountev 1 Design Patterns • Design patterns have become very popular in the last decade or so • Major source: GoF book 1995 • “Design Patterns: Elements of Reusable Object- Oriented Software” • Gamma, Helm, Johnson, Vlissides (gang of 4) • Patterns describe well-known solutions to common design problems • Used in Java libraries, especially in the GUI libraries Design Patterns-10, CS431 F06, BG Ryder/A Rountev 2 1 Design Patterns (LAR Ch26; GoF) • Structural • Concerned with how classes and objects are composed to make larger structures (Adapter, Bridge, Composite, Façade) • Creational • Abstract the instantiation process to make a system independent of how its objects are created & represented (Abstract Factory, Singleton) • Behavioral • Describe patterns of communication and interaction between objects (algorithms and responsibility assignment) (Observer, State, Strategy, Mediator) Design Patterns-10, CS431 F06, BG Ryder/A Rountev 3 Adapter Pattern: Interface Matcher • Problem: incompatible interfaces • Solution: create a wrapper that maps one interface to another • Key point: neither interface has to change and they execute in decoupled manner – Think of how you use a power plug adaptor when you travel to Europe • Example: – Client written against some interface – Server with the right functionality but with the wrong interface -
Design Patterns Chapter 3
A Brief Introduction to Design Patterns Jerod Weinman Department of Computer Science Grinnell College [email protected] Contents 1 Introduction 2 2 Creational Design Patterns 4 2.1 Introduction ...................................... 4 2.2 Factory ........................................ 4 2.3 Abstract Factory .................................... 5 2.4 Singleton ....................................... 8 2.5 Builder ........................................ 8 3 Structural Design Patterns 10 3.1 Introduction ...................................... 10 3.2 Adapter Pattern .................................... 10 3.3 Façade ......................................... 11 3.4 Flyweight ....................................... 12 3.5 Proxy ......................................... 13 3.6 Decorator ....................................... 14 4 Behavioral Design Patterns 20 4.1 Introduction ...................................... 20 4.2 Chain of Responsibility ................................ 20 4.3 Observer ........................................ 20 4.4 Visitor ......................................... 22 4.5 State .......................................... 25 1 Chapter 1 Introduction As you have probably experienced by now, writing correct computer programs can sometimes be quite a challenge. Writing the programs is fairly easy, it can be the “correct” part that maybe is a bit hard. One of the prime culprits is the challenge in understanding a great number of complex interactions. We all have probably experienced the crash of some application program