Mutable Class Design Pattern Nikolay Malitsky Nova Southeastern University, [email protected]
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1 Design Pattern for Open Class (DRAFT) 2 Abstract Factory
1 Design Pattern for Open Class (DRAFT) Tanaka Akira <[email protected]> A design pattern describes a software architecture which is reusable and exten- sible. [GoF] is the book containing 23 design patterns for OOP languages like C++ and Java. [GoF] describes several trade offs of the patterns. In C++ and Java, a class is defined by only one module. However, there are languages which can define a class by two or more modules: Cecil, MultiJava, AspectJ, MixJuice, CLOS, Ruby, etc. Such class is called "open class" because it is extensible by modules implemented later [Chambers]. For languages with open class, more extensible and/or simpler design patterns exists. We studied design patterns with open class for each GoF design patterns. In this paper, we describe two patterns: the Abstract Factory pattern and the Visitor pattern. 2 Abstract Factory The Abstract Factory pattern is a design pattern for separating class names from the code which generates the object group of related classes for making them configurable. Following figure is the class diagram of the Abstract Factory pattern. Since the example described in [GoF] uses only one concrete factory for each binaries, the required concrete factory is selected statically. The example builds two binaries for Motif and Presentation Manager from a single source code. Two concrete factories are exist for Motif and Presentation Manager. When a binary is built, it is selected which concrete factory is linked. Such static selection can be implemented with the fewer number of classes by open class as following modules. • The module which defines Window and ScrollBar class and their methods which is independent to window systems. -
Design Case Study: Java Swing
Principles of Software Construction: Objects, Design, and Concurrency Part 2: Design case studies Design case study: Java Swing Charlie Garrod Chris Timperley 17-214 1 Administrivia • Reading due today: UML and Patterns 26.1 and 26.4 • Homework 4b due Thursday, October 17th https://commons.wikimedia.org/wiki/File:1_carcassonne_aerial_2016.jpg 17-214 2 Key concepts from Thursday • Observer design pattern • Introduction to concurrency – Not enough synchronization: safety failure – Too much synchronization: liveness failure • Event-based programming • Introduction to GUIs 17-214 3 GUI programming is inherently multi-threaded • Swing event dispatch thread (EDT) handles all GUI events – Mouse events, keyboard events, timer events, etc. • No other time-consuming activity allowed on the EDT – Violating this rule can cause liveness failures 17-214 4 Swing has many event listener interfaces • ActionListener • MouseListener • AdjustmentListener • TreeExpansionListener • FocusListener • TextListener • ItemListener • WindowListener • KeyListener • … class ActionEvent { int when; String actionCommand; int modifiers; Object source(); int id; … interface ActionListener { } void actionPerformed(ActionEvent e); } 17-214 5 Aside: lambdas vs. explicit class declarations? //static public void main… JFrame window = … JPanel panel = new JPanel(); window.setContentPane(panel); panel to hold the button JButton button = new JButton(“Click me”); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { System.out.println(“Button -
Tree Visitors in Clojure Update the Java Visitor Pattern with Functional Zippers
Tree visitors in Clojure Update the Java Visitor pattern with functional zippers Skill Level: Intermediate Alex Miller ([email protected]) Senior Engineer Revelytix 20 Sep 2011 JVM language explorer Alex Miller has recently discovered the benefits of implementing the Visitor pattern using Clojure, a functional Lisp variant for the Java Virtual Machine. In this article, he revisits the Visitor pattern, first demonstrating its use in traversing tree data in Java programs, then rewriting it with the addition of Clojure's functional zippers. I’ve used trees of domain objects in my Java applications for many years. More recently, I’ve been using them in Clojure. In each case, I've found that the Visitor pattern is a reliable tool for manipulating trees of data. But there are differences in how the pattern works in a functional versus object-oriented language, and in the results it yields. About Clojure Clojure is a dynamic and functional programming language variant of Lisp, written specifically for the JVM. Learn more about Clojure on developerWorks: •"The Clojure programming language" •"Clojure and concurrency" •"Solving the Expression Problem with Clojure 1.2" •"Using CouchDB with Clojure" In this article, I revisit domain trees and the Visitor pattern for the Java language, Tree visitors in Clojure Trademarks © Copyright IBM Corporation 2011 Page 1 of 27 developerWorks® ibm.com/developerWorks then walk through several visitor implementations using Clojure. Being a functional language, Clojure brings new tricks to data query and manipulation. In particular, I've found that integrating functional zippers into the Visitor pattern yields efficiency benefits, which I explore. -
A Survey of Architectural Styles.V4
Survey of Architectural Styles Alexander Bird, Bianca Esguerra, Jack Li Liu, Vergil Marana, Jack Kha Nguyen, Neil Oluwagbeminiyi Okikiolu, Navid Pourmantaz Department of Software Engineering University of Calgary Calgary, Canada Abstract— In software engineering, an architectural style is a and implementation; the capabilities and experience of highest-level description of an accepted solution to a common developers; and the infrastructure and organizational software problem. This paper describes and compares a selection constraints [30]. These styles are not presented as out-of-the- of nine accepted architectural styles selected by the authors and box solutions, but rather a framework within which a specific applicable in various domains. Each pattern is presented in a software design may be made. If one were to say “that cannot general sense and with a domain example, and then evaluated in be called a layered architecture because the such and such a terms of benefits and drawbacks. Then, the styles are compared layer must communicate with an object other than the layer in a condensed table of advantages and disadvantages which is above and below it” then one would have missed the point of useful both as a summary of the architectural styles as well as a architectural styles and design patterns. They are not intended tool for selecting a style to apply to a particular project. The to be definitive and final, but rather suggestive and a starting paper is written to accomplish the following purposes: (1) to give readers a general sense of several architectural styles and when point, not to be used as a rule book but rather a source of and when not to apply them, (2) to facilitate software system inspiration. -
Diplomarbeit Im Fachbereich Elektrotechnik & Informatik an Der
Bachelor Thesis Prannoy Mulmi Design and Implementation of an Archive Microservice solution for the Multi-Agent Research and Simulation Distributed System Fakultät Technik und Informatik Faculty of Engineering and Computer Science Department Informations- und Department of Information and Elektrotechnik Electrical Engineering Prannoy Mulmi Design and Implementation of an Archive Microservice solution for the Multi-Agent Research and Simulation Distributed System Bachelor Thesis based on the study regulations for the Bachelor of Engineering degree programme Information Engineering at the Department of Information and Electrical Engineering of the Faculty of Engineering and Computer Science of the Hamburg University of Applied Sciences Supervising examiner : Prof. Dr. rer. nat. Henning Dierks Second Examiner : Prof. Dr. rer. nat. Thomas Clemen Day of delivery 23. Juli 2018 Prannoy Mulmi Title of the Bachelor Thesis Design and Implementation of an Archive Microservice solution for the Multi-Agent Research and Simulation Distributed System Keywords Distributed System, Microservice, Two-Phase commit protocol, Archive, Decentrali- zed data, Multi-Agent Research and Simulation (MARS) Abstract This thesis introduces the design and implementation of an Archive Microservice in the Multi-Agent Research and Simulation (MARS) framework. Due to the distributed architecture of the system, the process of the archive and restore is complex to imple- ment and maintain as there multiple possibilities of failure. This thesis uses different strategies to -
Object-Oriented Desgin Visitor Pattern George Blankenship 1
Object-Oriented Desgin Visitor Pattern CSCI 253 Object Oriented Design: Visitor Pattern George Blankenship Visitor 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 Visitor 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 Visitor Pattern George Blankenship 3 George Blankenship 1 Object-Oriented Desgin Visitor Pattern The Visitor Pattern: The Problem Represents an operation to be performed on the elements of an object structure. Visitor lets you define a new operation without changing the classes of the elements on which it operates • many distinct and unrelated operations need to be performed on objects in an object structure an you want to avoid “polluting” their classes with these operations • the classes defining the object structure rarely change but you often want to define new operations over the structure Visitor Pattern George Blankenship 4 Visitor Example • The root of the structure accepts a visitor: root.accept( visitor ) • The root and every child object in the structure have a an accept method: void accept( visitor ) { visitor.visit( this ); for each child of mine child.accept( visitor ) next } • In short order our visitor gets a visit() call from each object in the collection. -
Methods & Tools
METHODS & TOOLS Practical knowledge for the software developer, tester and project manager ISSN 1661-402X Spring 2011 (Volume 19 - number 1) www.methodsandtools.com The Salesmen/Developers Ratio at Software Vendors Many of us might think that software is a technological industry. Maybe. But maybe not. If you consider Oracle or Microsoft, I suppose that few of us would consider them as technology leaders, but we will all recognize their financial strength and marketing power. Long lasting organizations in the software industry might have more financial strength than technological capabilities. The recent conflict between Oracle and the creator of Hudson, an open source continuous integration server, is just another episode in the opposition between developers- and salesmen-driven software companies. On one side you have Oracle, for which Hudson is just small project inherited from the Sun buyout and that owns the "Hudson" brand. On the other side, you find Kohsuke Kawaguchi, who created Hudson and wants keep some control on its development. Hudson has been "forked", the open source code being used to start another project. You now have a Jenkins CI project that includes most of the active Hudson contributors and a Hudson CI project backed by Oracle and Sonatype, the commercial company behind the Maven project. Everything is however not black and white. Kohsuke Kawaguchi has joined Cloudbees, a company that has some management and financing coming from ex-JBoss managers, people that know how to make money with open source software. These people are not working hard for the only sake of technology evolution. You can judge the main orientation of a company looking at its salesmen/developers ratios. -
Lecture 1 for Chapter 8, Object Design: Reusing Pattern Solutions
Object-Oriented Software Engineering Using UML, Patterns, and Java Chapter 8, Object Design: 8, Object Chapter Reuse and Patterns I and Patterns Reuse Object Design Object design is the process of adding details to the requirements analysis and making implementation decisions The object designer must choose among different ways to implement the analysis model with the goal to minimize execution time, memory and other measures of cost Requirements Analysis: Use cases, functional and dynamic model deliver operations for object model Object Design: Iterates on the models, in particular the object model and refine the models Object Design serves as the basis of implementation System Development as a Set of Activities System Problem Application objects Analysis Solution objects Design Custom objects - Object Design Off-the-Shelf Components - System Design Existing Machine Examples of Object Design Activities Identification of existing components Full definition of associations Full definition of classes (System Design => Service, Object Design => Subsystem interfaces/API) Choosing algorithms and data structures Identifying possibilities of reuse Detection of solution-domain classes Optimization Increase of inheritance Decision on control …… A More Detailed View of Object Design Activities Select Subsystem Specification Reuse Identifying missing Identifying components attributes & operations Specifying visibility Adjusting components Specifying types & signatures Identifying patterns Specifying constraints Specifying exceptions -
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................................... -
Permissions, Visitor Pattern
Selected Topics in Object Oriented Programming Lecture 3: More OOP principles Leonid Barenboim Permissions Permissions define the areas within a program from which a feature (field/ method) can be accessed: private – only within the same class. protected - only within the class and its subclasses. public – from everywhere. Permission in java Java use somewhat different rules: private – only within the same class. package – only within the same package. protected – within the same package and within the subclasses outside the package. public – from everywhere. Selecting the right permission The principle of encapsulation suggests the following rules: All non-static fields should be private Service methods should be public Helper methods should be private/protected Permission rules in specific languages Smalltalk – all fields are private all methods are public Scripting languages (e.g., python) - No permissions! - Everything is public! The Visitor Pattern Reminder: Polymorphism Reminder: Polymorphism Animal animal; animal = new Dog; Animal * animal.say(); \\ “Woof” animal = new Cat; + say() * animal.say(); \\ “Miau” Cat Dog + say() + say() System.out.println(“Miau”) System.out.println(“Woof”) What happens if a method accepts an argument? boolean b; Animal * Animal cat = new Cat(); Animal mouse = new + say() * Mouse(); + eats(mouse: Mouse) : bool * b = cat.eats(mouse); + eats(cat: Cat) : bool * //compilation error Cat Mouse + say() + say() +eats(mouse : Mouse) : bool +eats(mouse : Mouse) : bool +eats(cat : Cat) : bool +eats(cat : Cat) : bool No support for polymorphism of arguments • Java (and many other languages) supports only polymorphism of the receiver (the variable on which the method is invoked). • Polymorphism of the receiver is performed using single dispatch. • Polymorphism of arguments is performed using multiple-level dispatch, which is resource consuming. -
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. -
Design Pattern Implementation in Java and Aspectj
Design Pattern Implementation in Java and AspectJ Jan Hannemann Gregor Kiczales University of British Columbia University of British Columbia 201-2366 Main Mall 201-2366 Main Mall Vancouver B.C. V6T 1Z4 Vancouver B.C. V6T 1Z4 jan [at] cs.ubc.ca gregor [at] cs.ubc.ca ABSTRACT successor in the chain. The event handling mechanism crosscuts the Handlers. AspectJ implementations of the GoF design patterns show modularity improvements in 17 of 23 cases. These improvements When the GoF patterns were first identified, the sample are manifested in terms of better code locality, reusability, implementations were geared to the current state of the art in composability, and (un)pluggability. object-oriented languages. Other work [19, 22] has shown that implementation language affects pattern implementation, so it seems The degree of improvement in implementation modularity varies, natural to explore the effect of aspect-oriented programming with the greatest improvement coming when the pattern solution techniques [11] on the implementation of the GoF patterns. structure involves crosscutting of some form, including one object As an initial experiment we chose to develop and compare Java playing multiple roles, many objects playing one role, or an object [27] and AspectJ [25] implementations of the 23 GoF patterns. playing roles in multiple pattern instances. AspectJ is a seamless aspect-oriented extension to Java, which means that programming in AspectJ is effectively programming in Categories and Subject Descriptors Java plus aspects. D.2.11 [Software Engineering]: Software Architectures – By focusing on the GoF patterns, we are keeping the purpose, patterns, information hiding, and languages; D.3.3 intent, and applicability of 23 well-known patterns, and only allowing [Programming Languages]: Language Constructs and Features – the solution structure and solution implementation to change.