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Chain-of-responsibility Pattern
In object-oriented design, the chain-of-responsibility pattern is a behavioral design pattern consisting of a source of command objects and a series of processing objects. Each processing object contains logic that defines the types of command objects that it can handle; the rest are passed to the next processing object in the chain. A mechanism also exists for adding new processing objects to the end of this chain. In a variation of the standard chain-of-responsibility model, some handlers may act as dispatchers, capable of sending commands out in a variety of directions, forming a ''tree of responsibility''. In some cases, this can occur recursively, with processing objects calling higher-up processing objects with commands that attempt to solve some smaller part of the problem; in this case recursion continues until the command is processed, or the entire tree has been explored. An XML interpreter might work in this manner. This pattern promotes the idea of loose coupling. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object-oriented Design
Object-oriented analysis and design (OOAD) is a technical approach for analyzing and designing an application, system, or business by applying object-oriented programming, as well as using visual modeling throughout the software development process to guide stakeholder communication and product quality. OOAD in modern software engineering is typically conducted in an iterative and incremental way. The outputs of OOAD activities are analysis models (for OOA) and design models (for OOD) respectively. The intention is for these to be continuously refined and evolved, driven by key factors like risks and business value. History In the early days of object-oriented technology before the mid-1990s, there were many different competing methodologies for software development and object-oriented modeling, often tied to specific Computer Aided Software Engineering (CASE) tool vendors. No standard notations, consistent terms and process guides were the major concerns at the time, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unified Modeling Language
The Unified Modeling Language (UML) is a general-purpose visual modeling language that is intended to provide a standard way to visualize the design of a system. UML provides a standard notation for many types of diagrams which can be roughly divided into three main groups: behavior diagrams, interaction diagrams, and structure diagrams. The creation of UML was originally motivated by the desire to standardize the disparate notational systems and approaches to software design. It was developed at Rational Software in 1994–1995, with further development led by them through 1996. In 1997, UML was adopted as a standard by the Object Management Group (OMG) and has been managed by this organization ever since. In 2005, UML was also published by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) as the ISO/IEC 19501 standard. Since then the standard has been periodically revised to cover the latest revision of UML. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single Responsibility Principle
The single-responsibility principle (SRP) is a computer programming principle that states that "A module should be responsible to one, and only one, actor." The term actor refers to a group (consisting of one or more stakeholders or users) that requires a change in the module. Robert C. Martin, the originator of the term, expresses the principle as, "A class should have only one reason to change". Because of confusion around the word "reason", he later clarified his meaning in a blog post titled "The Single Responsibility Principle", in which he mentioned Separation of Concerns and stated that "Another wording for the Single Responsibility Principle is: Gather together the things that change for the same reasons. Separate those things that change for different reasons." In some of his talks, he also argues that the principle is, in particular, about roles or actors. For example, while they might be the same person, the role of an accountant is different from a database administr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Design Pattern
In software engineering, a software design pattern or design pattern is a general, reusable solution to a commonly occurring problem in many contexts in software design. A design pattern is not a rigid structure to be transplanted directly into source code. Rather, it is a description or a template for solving a particular type of problem that can be deployed in many different situations. Design patterns can be viewed as formalized best practices that the programmer may use to solve common problems when designing a software application or system. Object-oriented design patterns typically show relationships and interactions between classes or objects, without specifying the final application classes or objects that are involved. Patterns that imply mutable state may be unsuited for functional programming languages. Some patterns can be rendered unnecessary in languages that have built-in support for solving the problem they are trying to solve, and object-oriented patterns are no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS X
macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. Within the market of Desktop computer, desktop and laptop computers, it is the Usage share of operating systems#Desktop and laptop computers, second most widely used desktop OS, after Microsoft Windows and ahead of all Linux distributions, including ChromeOS and SteamOS. , the most recent release of macOS is MacOS Sequoia, macOS 15 Sequoia, the 21st major version of macOS. Mac OS X succeeded classic Mac OS, the primary Mac operating systems, Macintosh operating system from 1984 to 2001. Its underlying architecture came from NeXT's NeXTSTEP, as a result of NeXT#1997–2006: Acquisition by Apple, Apple's acquisition of NeXT, which also brought Steve Jobs back to Apple. The first desktop version, Mac OS X 10.0, was released on March 24, 2001. Mac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cocoa Touch
UIKit is an application development environment and graphical user interface toolkit from Apple Inc. used to build apps for the iOS, iPadOS, watchOS, tvOS, and visionOS operating systems. UIKit provides an abstraction layer of iOS, the operating system for the iPhone, iPod Touch, and iPad. UIKit is insipired by the AppKit found in the macOS Cocoa API toolset and, like it, is primarily written in the Objective-C language. UIKit allows the use of hardware and features that are not found in macOS computers and are thus unique to the iOS range of devices. Just like AppKit, UIKit follows a Model–View–Controller (MVC) software architecture. UIKit contains a different set of graphical control elements from AppKit. Tools for developing applications based on UIKit are included in the iOS SDK. UIKit in relation to other layers iOS, watchOS, and tvOS technologies can be seen as a set of layers, with UIKit at the highest level and the core operating system / kernel at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cocoa (API)
Cocoa is Apple's native object-oriented application programming interface (API) for its desktop operating system macOS. Cocoa consists of the Foundation Kit, Application Kit, and Core Data frameworks, as included by the Cocoa.h header file, and the libraries and frameworks included by those, such as the C standard library and the Objective-C runtime.Mac Technology Overview: OS X Frameworks Developer.apple.com. Retrieved on September 18, 2013. Cocoa applications are typically developed using the development tools provided by Apple, specifically Xcode (formerly [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Diagram
In software engineering, a sequence diagram shows process interactions arranged in time sequence. This diagram depicts the processes and objects involved and the sequence of messages exchanged as needed to carry out the functionality. Sequence diagrams are typically associated with use case realizations in the 4+1 architectural view model of the system under development. Sequence diagrams are sometimes called event diagrams or event scenarios. For a particular scenario of a use case, the diagrams show the events that external actors generate, their order, and possible inter-system events. The diagram emphasizes events that cross the system boundary from actors to systems. A system sequence diagram should be done for the main success scenario of the use case, and frequent or complex alternative scenarios. There are two kinds of sequence diagrams: * Sequence Diagram (SD): A regular version of sequence diagram describes how the system operates, and every object within a system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class Diagram
In software engineering, a class diagram in the Unified Modeling Language (UML) is a type of static structure diagram that describes the structure of a system by showing the system's classes, their attributes, operations (or methods), and the relationships among objects. The class diagram is the main building block of object-oriented modeling. It is used for general conceptual modeling of the structure of the application, and for detailed modeling, translating the models into programming code. Class diagrams can also be used for data modeling Data modeling in software engineering is the process of creating a data model for an information system by applying certain formal techniques. It may be applied as part of broader Model-driven engineering (MDE) concept. Overview Data modeli .... The classes in a class diagram represent both the main elements, interactions in the application, and the classes to be programmed. In the diagram, classes are represented with boxes that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Behavioral Pattern
In software engineering, behavioral design patterns are design patterns that identify common communication patterns among objects. By doing so, these patterns increase flexibility in carrying out communication. Design patterns Examples of this type of design pattern include: ; Blackboard design pattern : Provides a computational framework for the design and implementation of systems that integrate large and diverse specialized modules, and implement complex, non-deterministic control strategies ; Chain-of-responsibility pattern : Command objects are handled or passed on to other objects by logic-containing processing objects ;Command pattern : Command objects encapsulate an action and its parameters ;"Externalize the stack" : Turn a recursive function into an iterative function that uses a stack ; Interpreter pattern : Implement a specialized computer language to rapidly solve a specific set of problems ; Iterator pattern : Iterators are used to access the elements of an aggreg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Patterns
''Design Patterns: Elements of Reusable Object-Oriented Software'' (1994) is a software engineering book describing software design patterns. The book was written by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, with a foreword by Grady Booch. The book is divided into two parts, with the first two chapters exploring the capabilities and pitfalls of object-oriented programming, and the remaining chapters describing 23 classic software design patterns. The book includes examples in C++ and Smalltalk. It has been influential to the field of software engineering and is regarded as an important source for object-oriented design theory and practice. More than 500,000 copies have been sold in English and in 13 other languages. The authors are often referred to as the ''Gang of Four'' (GoF). Development and publication history The book started at a birds-of-a-feather session at the 1990 OOPSLA meeting, "Towards an Architecture Handbook", where Erich Gamma and Ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
