Review of Ios Architectural Pattern for Testability, Modifiability, and Performance Quality
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Component Design Recall: Problem with Subclassing
the gamedesigninitiative at cornell university Lecture 8 Component Design Recall: Problem with Subclassing Games have lots of classes Each game entity is different NPC Needs its own functionality (e.g. object methods) Human Orc Want to avoid redundancies Makes code hard to change Common source of bugs Human Human Orc Orc Warrior Archer Warrior Archer Might be tempted to subclass Common behavior in parents Redundant Behavior Specific behavior in children the gamedesigninitiative 2 Architecture Patterns at cornell university Recall: Problem with Subclassing Games have lots of classes Each game entity is different NPC Needs its own functionality (e.g. object methods) Warrior Archer Want to avoid redundancies Makes code hard to change Common source of bugs Human Orc Human Orc Warrior Warrior Archer Archer Might be tempted to subclass Common behavior in parents Redundant Behavior Specific behavior in children the gamedesigninitiative 3 Architecture Patterns at cornell university Alternative: Decorator Pattern New Functionality OriginalReference to Original Request Decorator Object Functionalitybase object Object the gamedesigninitiative 4 Architecture Patterns at cornell university Alternate: Delegation Pattern Original Reference to Request Delegate Object delegate Object Forward Request Inversion of the Decorator Pattern the gamedesigninitiative 5 Architecture Patterns at cornell university Issues with Static Typing Method in original class Original object class obj.request(arg1,…, argn) Original Reference to Request Delegate -
Game Architecture Revisited Recall: the Game Loop
the gamedesigninitiative at cornell university Lecture 8 Game Architecture Revisited Recall: The Game Loop Receive player input Process player actions Update 60 times/s Process NPC actions Interactions (e.g. physics) = 16.7 ms Cull non-visible objects Transform visible objects Draw Draw to backing buffer Display backing buffer the gamedesigninitiative 2 Architecture Revisited at cornell university The Game Loop Receive player input Process player actions Update Process NPC actions Interactions (e.g. physics) Almost everything is in loop Draw Except asynchronous actions Is enough for simple games How do we organize this loop? Do not want spaghetti code Distribute over programmers the gamedesigninitiative 3 Architecture Revisited at cornell university Model-View-Controller Pattern Controller Calls the • Updates model in methods of response to events • Updates view with model changes Model View • Defines/manages • Displays model the program data to the user/player • Responds to the • Provides interface controller requests for the controller the gamedesigninitiative 4 Architecture Revisited at cornell university The Game Loop and MVC Model: The game state Value of game resources Location of game objects Update View: The draw phase Rendering commands only Major computation in update Draw Controller: The update phase Alters the game state Vast majority of your code the gamedesigninitiative 5 Architecture Revisited at cornell university Application Structure Root Controller Ownership Subcontroller Subcontroller View Model Model -
Design Specification for Delegation and Incentives in Cardano
Engineering Design Specification for Delegation and Incentives in Cardano–Shelley AN IOHK TECHNICAL REPORT Philipp Kant Lars Brunjes¨ Duncan Coutts [email protected] [email protected] [email protected] [email protected] April 11, 2019 Abstract This document describes the requirements and design for a delegation and incentives mechanism to be used in the Shelley release of Cardano. List of Contributors Lars Brunjes,¨ Jared Corduan, Duncan Coutts, Philipp Kant, Dimitris Karakostas, Aggelos Kiayias, Elias Koutsoupias, Mario Larangeira, Damian Nadales, Aikaterini-Panagiota Stouka. Contents 1 Purpose 4 2 Requirements 5 2.1 Functional Requirements . .5 2.1.1 Proof of Eligibility . .5 2.1.2 Visibility of Delegation on the Blockchain . .5 2.1.3 Restricting Chain Delegation . .5 2.1.4 Cheap Re-Delegation . .5 2.1.5 Neutral Addresses . .5 2.2 Security Requirements . .6 2.2.1 Sybil Attack Protection at Stake Pool Level . .6 2.2.2 Address Non-malleability . .6 2.2.3 Public Spending Keys Should not be Disclosed Prematurely . .6 2.2.4 Mitigate Key Exposure . .6 2.2.5 Handle Inactive Stake Pools . .6 2.2.6 Avoid Hard Transition . .6 2.2.7 Change Delegation Without Spending Key . .7 2.3 Non-functional Requirements . .7 2.3.1 Asymptotic space and time complexity . .7 2.3.2 Minimise economic attacks . .7 2.4 Requirements to Preserve Existing Features . .7 2.4.1 Master Recovery Key . .7 1 2.4.2 Address Recognition . .7 2.4.3 Wallet should be Runnable on Independent Devices . .7 2.4.4 Maintain Privacy . -
Chapter 1. Origins of Mac OS X
1 Chapter 1. Origins of Mac OS X "Most ideas come from previous ideas." Alan Curtis Kay The Mac OS X operating system represents a rather successful coming together of paradigms, ideologies, and technologies that have often resisted each other in the past. A good example is the cordial relationship that exists between the command-line and graphical interfaces in Mac OS X. The system is a result of the trials and tribulations of Apple and NeXT, as well as their user and developer communities. Mac OS X exemplifies how a capable system can result from the direct or indirect efforts of corporations, academic and research communities, the Open Source and Free Software movements, and, of course, individuals. Apple has been around since 1976, and many accounts of its history have been told. If the story of Apple as a company is fascinating, so is the technical history of Apple's operating systems. In this chapter,[1] we will trace the history of Mac OS X, discussing several technologies whose confluence eventually led to the modern-day Apple operating system. [1] This book's accompanying web site (www.osxbook.com) provides a more detailed technical history of all of Apple's operating systems. 1 2 2 1 1.1. Apple's Quest for the[2] Operating System [2] Whereas the word "the" is used here to designate prominence and desirability, it is an interesting coincidence that "THE" was the name of a multiprogramming system described by Edsger W. Dijkstra in a 1968 paper. It was March 1988. The Macintosh had been around for four years. -
Rights Reserved. Permission to Make Digital Or Hard Copies of All Or Part Of
Copyright © 1994, by the author(s). All rights reserved. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. MICROSOFT WINDOWS NT AND THE COMPETITION FOR DESKTOP COMPUTING by Brad Peters, William R. Bush, and A. Richard Newton Memorandum No. UCB/ERL M94/3 31 January 1994 MICROSOFT WINDOWS NT AND THE COMPETITION FOR DESKTOP COMPUTING by Brad Peters, William R. Bush, and A. Richard Newton Memorandum No. UCB/ERL M94/3 31 January 1994 MICROSOFT WINDOWS NT AND THE COMPETITION FOR DESKTOP COMPUTING by Brad Peters, William R. Bush, and A. Richard Newton Memorandum No. UCB/ERL M94/3 31 January 1994 ELECTRONICS RESEARCH LABORATORY College ofEngineering University ofCalifornia, Berkeley 94720 MICROSOFT WINDOWS NT AND THE COMPETITION FOR DESKTOP COMPUTING by Brad Peters, William R. Bush, and A. Richard Newton Memorandum No. UCB/ERL M94/3 31 January 1994 ELECTRONICS RESEARCH LABORATORY College ofEngineering University ofCalifornia, Berkeley 94720 Microsoft Windows NT And The Competition for Desktop Computing January 1994 Department ofElectrical Engineering and Computer Sciences University ofCalifornia Berkeley, California 94720 Abstract This report contains two papers, An Introduction to Microsoft Windows NT And Its Competitors, and The Status ofWindows NT and Its Competitors At The End of1993. The first paper, written in April 1993,presents an overview of the technology of Windows NT, and analyzes the competitors and competitive factors in the desktop operating system race. -
Title: Foundation Patterns Authors: Dwight Deugo E-Mail: Deugo@Scs
Title: Foundation Patterns Authors: Dwight Deugo E-mail: [email protected] Address: School of Computer Science Carleton University 1125 Colonel By Drive Ottawa, Ontario, Canada, K1S 5B6 Telephone: (613) 520-2600 ext. 8438 (613) 520-4333 Fax: (613) 520-4334 Abstract: Many patterns depended on one important distinction: the distinction between an object's class and its type. For example, many patterns rely on interface inheritance, although, on examining their structures, most are described using implementation inheritance. The making of this implicit distinction gives evidence that there are patterns, fundamental to many, that live within other patterns and are at the foundation of good object-oriented principles. I give these patterns the name foundation patterns. I discuss two such foundation patterns: delegation and substitution, separating the two into their rightful positions, making clear what each patterns' role is in object-oriented design. Foundation Patterns Dwight Deugo [email protected] School of Computer Science Carleton University Introduction Although not mentioned, many patterns depend on one important distinction. This is the distinction between an object's class and its type. Stated another way, these patterns rely on interface inheritance rather than on implementation inheritance. Nevertheless, on examining their structures, most pattern descriptions use implementation inheritance. This is not surprising, since languages like Smalltalk and C++ do not explicitly support the notion of a type or a subtype within the language. Java is the exception to this, directly supporting interfaces and their inheritance, bringing attention to these well deserving topics. The making of this implicit distinction gives evidence that there are other patterns, fundamental to many, if not all patterns, which are either assumed and undocumented or still waiting to be discovered. -
Automatic Graph Drawing Lecture 15 Early HCI @Apple/Xerox
Inf-GraphDraw: Automatic Graph Drawing Lecture 15 Early HCI @Apple/Xerox Reinhard von Hanxleden [email protected] 1 [Wikipedia] • One of the first highly successful mass- produced microcomputer products • 5–6 millions produced from 1977 to 1993 • Designed to look like a home appliance • It’s success caused IBM to build the PC • Influenced by Breakout • Visicalc, earliest spreadsheet, first ran on Apple IIe 1981: Xerox Star • Officially named Xerox 8010 Information System • First commercial system to incorporate various technologies that have since become standard in personal computers: • Bitmapped display, window-based graphical user interface • Icons, folders, mouse (two-button) • Ethernet networking, file servers, print servers, and e- mail. • Sold with software based on Lisp (early functional/AI language) and Smalltalk (early OO language) [Wikipedia, Fair Use] Xerox Star Evolution of “Document” Icon Shape [Wikipedia, CC BY-SA 3.0] 1983: Apple Lisa [Wikipedia, CC BY-SA 2.0 fr] Apple Lisa • One of the first personal computers with a graphical user interface (GUI) • In 1982, Steve Jobs (Cofounder of Apple, with Steve Wozniak) was forced out of Lisa project, moved on into existing Macintosh project, and redefined Mac as cheaper, more usable version of Lisa • Lisa was challenged by relatively high price, insufficient SW library, unreliable floppy disks, and immediate release of Macintosh • Sold just about 10,000 units in two years • Introduced several advanced features that would not reappear on Mac or PC for many years Lisa Office -
This Is a Fairy Tale •.• NOT! a Primer on Moving SAS® Applications
This is a Fairy Tale•.• NOT! A Primer on Moving SAS® Applications Across Graphical Operating Systems James Hefner, Entergy Corporation, Beaumont, TX lineup. The PowerPC's PowerOpen operating system should be ABSTRACT able to run Windows, Windows NT, OS/2, Macintosh, and UNIX applications unmodified (using SoftPC to run Windows & OS/2 Currently, most SAS Software application developers have on~ apps). Current plans are to offer these new machines at prices one or two graphical operating systems (such as Microsoft that are highly competitive with the current top-of-the-!ine WindowsTN, or OSFlMoti~ to support. However, the pending offerings by IBM PC manufacturerS and Apple, nol 10 mention release of the SAS System for the Apple® Macintosh®I and the UNIX workstations. This could mean a change in the platform you introduction of new hardware and software such as the PowerPC are currently using, as well as the ability (or need) to be able to and Wabi, means that application developers may have to use and write applications using any of the five operating support two or more graphical operating systems. systems. This paper is intended to assist application developers, both in New Graphical Operating Systems the teaching of the fundamentals of graphical operating systems, and in Ihe moving of SAS/Af® and SAS/EIS® applicalions from In addition to the platforms mentioned above, Apple and IBM are one operating system to another. currently working on the Taligent operating system, which will have an object-oriented, graphical front end. IBM is also INTRODUCTION discussing porling its object·orienled 0512 2.x Workplace Shell 10 a new ver.sion of PC DOS® and AIX®, IBM's version of UNIX (to If you are a SAS' application developer, you may currently be be called Workplace OS). -
Enabling White-Box Reuse in a Pure Composition Language
Enabling White-Box Reuse in a Pure Composition Language Diplomarbeit der Philosophisch-naturwissenschaftlichen Fakultat¨ der Universitat¨ Bern vorgelegt von Andreas Schlapbach Dezember 2002 Leiter der Arbeit: Prof. Dr. O. Nierstrasz Nathanael Scharli¨ Institut fur¨ Informatik und angewandte Mathematik i Abstract Inheritance is a key concept of object-oriented programming languages, features such as conceptual modeling and reusability are largely accredited to it. While many useful com- ponents have been, and will be, developed in this paradigm, the form of white-box reuse offered by inheritance has a fundamental flaw: reusing components by inheritance requires an understanding of the internals of the components. We can not treat components of object-oriented languages as black-box entities, inheritance breaks encapsulation and in- troduces subtle dependencies between base and extending classes. Component-oriented programming addresses this problem by shifting away from program- ming towards software composition. We build applications by scripting components. In- stead of overriding the internals of a component, we focus on composing its interfaces only. This form of black-box reuse leads to a flexible and extendible architecture with reusable components. In this master's thesis we propose a migration strategy from class inheritance { a white- box form of reuse { to component composition as a black-box form of reuse. We present a language extension that gives us the power of inheritance combined with the ease of scripting. It enables us to reuse Java components using inheritance in JPiccola { a small, pure and general composition language implemented on the Java platform { at a high level of abstraction. Using the services provided by the language extension we can seamlessly generate interfaces and subclasses from JPiccola. -
Volume 15, 1~L~Mber 2 April 1994
ISSN 1035-7521 AUUG Inc. Newsletter Volume 15, 1~l~mber 2 April 1994 Registered by Australia Post, Publication Number NBG6524 The AUUG incorporated Newsletter Volume 15 Number 2 April 1994 CONTENTS AUUG General Information ...................... 3 Editorial ............................ 5 AUUG President’s Page ....................... 6 AUUG Corporate Sponsors - A New Level of Participation ............ 7 AUUG Institutional Members ..... : ............... 8 Letters to the Editor ........................ 11 Announcements AUUG Appoints New Business Manager ................ 15 AUUG Freephone Number .................... 16 McKusick does Oz T-shirt .................... 17 Call for Articles for the Australian .................. 18 AUUG & Zircon Systems Reach Agreement ............... 19 AUUG & the Express Book Store Reach Agreement ............ 20 AUUG Local Chapters AUUG Regional Contacts .................... 21 AUUG Inc. - Victorian Chapter ................... 22 Update on AU-tJG Inc. - Victorian Chapter Activities Stephen Prince . 23 From the Western Front Janet Jackson .... 24 WAUG - Meeting Reviews Adrian Booth .... 25 1994 Perth AUUG Summer Conference Overview Adrian Booth .... 26 Impressions of the 1994 Perth AUUG Summer Conference Janet Jackson .... 28 AUUG NSW Chapter Julian Dryden .... 30 AARNet Mail Affiliation., ...................... 31 Book Reviews .......................... 35 Prentice Hall Book Order Form ................... 41 WOodsLane Information ..................... 42 Open System Publications ...................... 43 !AUUGN -
Michael J. Harper Standalone Code
Michael J. Harper Standalone Code LLC 57195 Beaver Drive, PO Box 3846 (541) 362-1840 Sunriver OR 97707 [email protected] @doktahahpah, @standalonecode, www.github.com/mharper, www.standalonecode.com Summary I have been a software developer since 1982 and an independent contractor/consultant since 1992. For the past several years, I have focused on two areas of development: mobile development with iOS and Android and web development with Ruby on Rails. I conceived and implemented the TRX FORCE app — the 12-week conditioning program designed for the US Military — on both iOS and Android — which appeared in the Apple "Strength" commercial. In addition, I have collaborated on the Norton Online Backup iOS app and I built an app named “Circle 8” that helps tourists find their way around Sunriver, OR and its 33+ miles of bike paths. Another project was a trifecta of Rails, iOS, and Android development showcasing how to “Live Like a Local” when visiting the Hotel Monaco DC. I have also implemented Android versions of Circle 8, Analog Analytics, and PEAR Sports (Bluetooth LE heart-rate based real-time coaching). For Star Wars Celebration in Anaheim, CA in April 2015, I implemented an iBeacon-based "Scanner" app that displays "trading cards" for each character scanned. I have been working with iBeacon/AltBeacon technology on iOS, Android, and Linux for Radius Networks for the past year. I discovered Ruby on Rails via the Java Posse podcast when I was doing Java EE development for Symantec circa 2006. I have collaborated on numerous Rails apps since then including Norton Online Backup for Symantec and Hubbub Health for Regence. -
Workflow Patterns in Bindflow
Workflow Patterns implemented in BindFlow™ Jason Kleban BindFlow LLC Portions of the software described in this document are covered by U.S. Patent No. 8,051,427. Abstract We present an operating environment, called BindFlow™, and a companion program structure well suited for workflow programs which automate portions of real-world business processes. The flowchart logic of most business processes can be authored concisely using traditional programming techniques; however, the extended delays, overlapped execution, and hardware constraints in practical workflow scenarios severely complicate programs. We examine workflow programs as a mix of nondeterministic operations and deterministic transformations. Isolating a process’s deterministic transformations from its nondeterministic operations allows us to record every input into the process. Instances can be safely unloaded from memory, destroying state, because the record of the inputs is all that is required to rebuild the logical state of a process instance on demand. We introduce the BindFlow model and explore its ability to express the workflow patterns that have been recognized in the research by van der Aalst, Russell, ter Hofstede, et al., documented at http://www.workflowpatterns.com. 2 Pattern Implementation Quick Reference Control-Flow 20 Cancellation and Force Completion 53 Cancel Task 53 Basic 20 Cancel Case 54 Sequence 20 Cancel Region 55 Parallel Split 21 Cancel Multiple Instance Activity 56 Synchronization 22 Complete Multiple Instance Activity 57 Exclusive Choice 23 Iteration