Design Patterns Creational Patterns Structural Patterns Behavioural Patterns Concurrency Patterns Questions
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Learning Functional Programming in Scala Alvin Alexander
Learning Functional Programming in Scala Alvin Alexander A logical, step by step approach to learning functional programming Copyright Learning Functional Programming in Scala Copyright 2017 Alvin J. Alexander All rights reserved. No part of this book may be reproduced without prior written permission from the author. Disclaimer: This book is presented solely for educational purposes, and it’s also a work in progress. While best efforts have been used in prepar- ing this book, the author makes no representations or warranties of any kind and assume no liabilities of any kind with respect to the accuracy or completeness of the contents, and specifically disclaim any implied war- ranties of merchantability or fitness of use for a particular purpose. The author shall not be held liable or responsible to any person or entity with respect to any loss or incidental or consequential damages caused, or al- leged to have been caused, directly or indirectly, by the information or programs contained herein. Any use of this information is at your own risk. The advice and strategies contained herein may not be suitable for your situation. Version 0.1.1, published May 15, 2017 (The cover photo was taken on the Dalton Highway in Alaska, some- where between Fairbanks and Prudhoe Bay.) Contents 1 Changelog 1 2 Preface 3 3 Introduction (or, Why I Wrote This Book) 5 4 WhoThisBookisFor 11 5 Goals 15 6 Question Everything 23 7 Rules for Programming in this Book 33 8 One Rule for Reading this Book 39 9 What is “Functional Programming”? 41 10 What is This Lambda -
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. -
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. -
Five Considerations for Software Developers
FiveFive ConsiderationsConsiderations forfor SoftwareSoftware DevelopersDevelopers Kevlin Henney [email protected] Presented at Jfokus, Stockholm, 30th January 2008. Kevlin Henney [email protected] [email protected] Curbralan Ltd http://www.curbralan.com Voice: +44 117 942 2990 Fax: +44 870 052 2289 Agenda • Introduction • Consideration 1: Economy • Consideration 2: Visibility • Consideration 3: Spacing • Consideration 4: Symmetry • Consideration 5: Emergence • Outroduction 2 What general qualities in a software architecture help to promote its success? We can of course focus on fitness for purpose, cost of change, organisational acceptance, and so on, but are there broad considerations that can be kept in mind when looking at the structural and developmental side of an architecture? Those involved in software have a lot to keep in mind as they negotiate the worlds inside and outside of their code and the relationship between them. For those interested in improving the state of their art there are many (many) sources of specific recommendations they can use to sharpen their practice. This talk takes a step back from the busy, overpopulated and often overwhelming world of such recommendations to focus on five general considerations that can inform more detailed recommendations and specific decisions. Introduction StructuralSoftwareStructural engineering engineering engineering is is theis the the science science science an and dand art art art of of designingof designing designing and and and making, making, making, with with with economyeconomy and and elegance, elegance, buildings,applications, buildings, bridges, bridges, bridges, frameworks, frameworks, frameworks, and and and other other other similar similar similar structuresstructures so so that that they they can can safely safely resist resist the the forces forces to to which which they they may may be be subjected. -
Dissertation a Meta-Modeling Approach to Specifying
DISSERTATION A META-MODELING APPROACH TO SPECIFYING PATTERNS Submitted by Dae-Kyoo Kim Department of Computer Science In partial fulfillment of the requirements for the Degree of Doctor of Philosophy Colorado State University Fort Collins, Colorado Summer 2004 COLORADO STATE UNIVERSITY June 21, 2004 WE HEREBY RECOMMEND THAT THE DISSERTATION PREPARED UNDER OUR SUPERVISION BY DAE-KYOO KIM ENTITLED A META- MODELING APPROACH TO SPECIFYING PATTERNS BE ACCEPTED AS FULFILLING IN PART REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY. Committee on Graduate Work Committee Member: Dr. James M. Bieman Committee Member: Dr. Sudipto Ghosh Committee Member: Dr. Daniel E. Turk Adviser: Dr. Robert B. France Department Head: Dr. L. Darrell Whitley ii ABSTRACT OF DISSERTATION A META-MODELING APPROACH TO SPECIFYING PATTERNS A major goal in software development is to produce quality products in less time and with less cost. Systematic reuse of software artifacts that encapsulate high-quality development experience can help one achieve the goal. Design patterns are a common form of reusable design experience that can help developers reduce development time. Prevalent design patterns are, however, described informally (e.g., [35]). This prevents systematic use of patterns. The research documented in this dissertation is aimed at developing a practical pattern specification technique that supports the systematic use of patterns during design modeling. A pattern specification language called the Role-Based Metamod- eling Language (RBML) was developed as part of this research. The RBML specifies a pattern as a specialization of the UML metamodel. The RBML uses the Unified Modeling Language (UML) as a syntactic base to enable the use of UML modeling tools for creating and evolving pattern specifications. -
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................................... -
Lecture 26: Creational Patterns
Creational Patterns CSCI 4448/5448: Object-Oriented Analysis & Design Lecture 26 — 11/29/2012 © Kenneth M. Anderson, 2012 1 Goals of the Lecture • Cover material from Chapters 20-22 of the Textbook • Lessons from Design Patterns: Factories • Singleton Pattern • Object Pool Pattern • Also discuss • Builder Pattern • Lazy Instantiation © Kenneth M. Anderson, 2012 2 Pattern Classification • The Gang of Four classified patterns in three ways • The behavioral patterns are used to manage variation in behaviors (think Strategy pattern) • The structural patterns are useful to integrate existing code into new object-oriented designs (think Bridge) • The creational patterns are used to create objects • Abstract Factory, Builder, Factory Method, Prototype & Singleton © Kenneth M. Anderson, 2012 3 Factories & Their Role in OO Design • It is important to manage the creation of objects • Code that mixes object creation with the use of objects can become quickly non-cohesive • A system may have to deal with a variety of different contexts • with each context requiring a different set of objects • In design patterns, the context determines which concrete implementations need to be present © Kenneth M. Anderson, 2012 4 Factories & Their Role in OO Design • The code to determine the current context, and thus which objects to instantiate, can become complex • with many different conditional statements • If you mix this type of code with the use of the instantiated objects, your code becomes cluttered • often the use scenarios can happen in a few lines of code • if combined with creational code, the operational code gets buried behind the creational code © Kenneth M. Anderson, 2012 5 Factories provide Cohesion • The use of factories can address these issues • The conditional code can be hidden within them • pass in the parameters associated with the current context • and get back the objects you need for the situation • Then use those objects to get your work done • Factories concern themselves just with creation, letting your code focus on other things © Kenneth M. -
Declare Property Class Accept Null C
Declare Property Class Accept Null C Woesome and nontechnical Joshuah planned inveterately and pull-outs his frontiers sourly and daftly. Unquiet Bernard fly-by very instructively while Rick remains ectotrophic and chastened. Sometimes stereoscopic Addie unnaturalizes her acorns proportionally, but unlidded Cat invert heinously or orientalizes rancorously. Even experts are accepted types and positional parameters and references, and assigns to. Use HasValue property to check has value is assigned to nullable type sometimes not Static Nullable class is a. Thank you declare more freely, declare property class accept null c is useful to provide only one dispiriting aspect of. Here we're defining a suggest that extracts all non-nullable property keys from plant type. By disabling cookies to accept all? The car variable inside counter Person class shouldn't be declared type grass and. Use JSDoc type. Any class property name, null safe code token stream of properties and corresponds to accept a class! Why death concept of properties came into C The decline because not two reasons If the members of a class are private then select another class in C. JavaScript Properties of variables with null or undefined. Type cup type as should pickle the null value variable the pastry of the variable to which null. CS31 Intro to C Structs and Pointers. Using the New Null Conditional Operator in C 6 InformIT. Your extra bet is to get themselves the good group of initializing all variables when you disabled them. This class that null values can declare variables declared inside an exception handling is nullable context switches a varargs in. -
Prof. Catalin Boja, Phd [email protected] Source Code Quality
Design patterns Prof. Catalin Boja, PhD [email protected] http://acs.ase.ro/software-quality-testing Source code quality Principles for writing the code: • Easy to read / understand - clear • Easy to modify - structured • Easy to reuse • Simple (complexity) • Easy to test • Implement patterns for the standard problem Left: Simply Explained: Code Reuse 2009-12- acs.ase.ro [email protected] 03.By Oliver Widder, Webcomics Geek Aad Poke.2 Source code quality Forces that influence it: • Available time (delivery terms) • Costs • The experience of the programmer • Programmer competences • Specifications clarity • Solution complexity • Change rates for specifications, requirements, team, etc http://khristianmcfadyen.com/ acs.ase.ro [email protected] 3 Anti-Pattern: Big ball of mud “A Big Ball of Mud is a haphazardly structured, sprawling, sloppy, duct-tape- and-baling-wire, spaghetti- code jungle.” Brian Foote and Joseph Yoder, Big Ball of Mud, September 1997 acs.ase.ro [email protected] 4 Anti-Pattern: Big ball of mud Where from ? Why ? • Throwaway code - Temporary (Prototyping) solutions to be replaced / rewritten • Cut and Paste code • Adapting code by commenting / deleting other solutions • Very short or unrealistic deadlines • Lack of experience • Lack of standards / procedures acs.ase.ro [email protected] 5 Anti-Pattern: Big ball of mud How do you avoid it? • Rewriting the code (Refactoring) to an acceptable maturity level • Use Clean Code Principles • Design Patterns Implementation acs.ase.ro [email protected] 6 Design-pattern • A pattern is a reusable solution for a standard problem in a given context • Facilitates the reuse of architectures and software design • They are not data structures acs.ase.ro [email protected] 7 Design-pattern “A pattern involves a general “.. -
8 Lecture 1 Introduction to the Class Diagram
ECE 573 1st Edition Exam # 1 Study Guide Lectures: 1 - 8 Lecture 1 Introduction to the Class diagram, Inheritance and Association Class Diagram The final code was supplemented with a diagram describing the relationships between classes. The intermediate classes of the code are related by objects. This is what is represented in a class diagram. The Class diagram basically consists of “a Class name”, “attributes” and “operation”. Given this basic graphical notation, it is possible to show the following kinds of relationships between classes: Inheritance Association Encapsulation Inheritance It is denoted using open triangle between Superclass and its Subclass. The triangle “points" to the superclass, and extends to the subclass (es). Inheritance fulfills the IS-A definitions. A derived class can be treated like a base class object under all circumstances. Association General binary relationships between classes. It is commonly represented as direct or indirect references between classes. Associations are shown by a line in the class diagram, with optional role names and multiplicities. Multiplicities can be i) I..u closed ii) I singleton range iii) 0..* entire nonnegative integer. An association may also be specialized by a particular class. This Association class may provide more attributes to describe the association. Encapsulations Encapsulation is a special kind of association, which is denoted using a diamond and extending line. There are two kinds of encapsulation i.e. Aggregation and Composition. Aggregation is a special form of association representing has-a and part-whole relationship. Distinguishes the whole (aggregate class) from its parts (component class). No relationship in the lifetime of the aggregate and the components (can exist separately). -
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.