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Prototype Pattern
The prototype pattern is a creational design pattern (computer science), design pattern in software development. It is used when the type of object (computer science), objects to create is determined by a prototype, prototypical instance (computer science), instance, which is cloned to produce new objects. This pattern is used to avoid subclass (computer science), subclasses of an object creator in the client application, like the factory method pattern does and to avoid the inherent cost of creating a new object in the standard way (e.g., using the 'new (C++), new' keyword) when it is prohibitively expensive for a given application. To implement the pattern, the client declares an abstract base class that specifies a virtual method#Abstract classes and pure virtual functions, pure virtual ''clone()'' method. Any class that needs a "polymorphism (computer science), polymorphic constructor (computer science), constructor" capability derives itself from the abstract base class, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Pattern (computer Science)
In software engineering, a software design pattern is a general, reusable solution to a commonly occurring problem within a given context in software design. It is not a finished design that can be transformed directly into source or machine code. Rather, it is a description or template for how to solve a problem that can be used in many different situations. Design patterns are formalized best practices that the programmer can use to solve common problems when designing an 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 not necessarily suitable for non-object-oriented langua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Function Prototype
In computer programming, a function prototype or function interface is a declaration of a function that specifies the function’s name and type signature (arity, data types of parameters, and return type), but omits the function body. While a function definition specifies ''how'' the function does what it does (the "implementation"), a function prototype merely specifies its interface, i.e. ''what'' data types go in and come out of it. The term "function prototype" is particularly used in the context of the programming languages C and C++ where placing forward declarations of functions in header files allows for splitting a program into translation units, i.e. into parts that a compiler can separately translate into object files, to be combined by a linker into an executable or a library. In a prototype, parameter names are optional (and in C/C++ have function prototype scope, meaning their scope ends at the end of the prototype), however, the type is necessary along with all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decorator Pattern
In object-oriented programming, the decorator pattern is a design pattern that allows behavior to be added to an individual object, dynamically, without affecting the behavior of other objects from the same class. The decorator pattern is often useful for adhering to the Single Responsibility Principle, as it allows functionality to be divided between classes with unique areas of concern as well as to the Open-Closed Principle, by allowing the functionality of a class to be extended without being modified. Decorator use can be more efficient than subclassing, because an object's behavior can be augmented without defining an entirely new object. Overview The ''decorator'' design pattern is one of the twenty-three well-known ''design patterns''; these describe how to solve recurring design problems and design flexible and reusable object-oriented software—that is, objects which are easier to implement, change, test, and reuse. What problems can it solve? * Responsibilities sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composite Pattern
In software engineering, the composite pattern is a partitioning design pattern. The composite pattern describes a group of objects that are treated the same way as a single instance of the same type of object. The intent of a composite is to "compose" objects into tree structures to represent part-whole hierarchies. Implementing the composite pattern lets clients treat individual objects and compositions uniformly. Overview The Composite design pattern is one of the twenty-three well-known '' GoF design patterns'' that describe how to solve recurring design problems to design flexible and reusable object-oriented software, that is, objects that are easier to implement, change, test, and reuse. What problems can the Composite design pattern solve? * A part-whole hierarchy should be represented so that clients can treat part and whole objects uniformly. * A part-whole hierarchy should be represented as tree structure. When defining (1) Part objects and (2) Whole objects that ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delegation (programming)
In computing or computer programming, delegation refers generally to one entity passing something to another entity,Barry Wilkinson, ''Grid Computing: Techniques and Applications'' (2009), p. 164, . and narrowly to various specific forms of relationships. These include: * Delegation (object-oriented programming), evaluating a member of one object (the receiver) in the context of another, original object (the sender). ** Delegation pattern, a design pattern implementing this feature. ** Forwarding (object-oriented programming), an often-confused technique where a sending object uses the corresponding member of another object, without the receiving object having any knowledge of the original, sending object. ** Object aggregation or consultation, general term for one object using another. * Delegation (computer security), one user or process allowing another user or process to use their credentials or permissions. * Delegate (CLI), a form of type-safe function pointer used by the Com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inheritance (computer Science)
In object-oriented programming, inheritance is the mechanism of basing an object or class upon another object ( prototype-based inheritance) or class ( class-based inheritance), retaining similar implementation. Also defined as deriving new classes ( sub classes) from existing ones such as super class or base class and then forming them into a hierarchy of classes. In most class-based object-oriented languages, an object created through inheritance, a "child object", acquires all the properties and behaviors of the "parent object" , with the exception of: constructors, destructor, overloaded operators and friend functions of the base class. Inheritance allows programmers to create classes that are built upon existing classes, to specify a new implementation while maintaining the same behaviors ( realizing an interface), to reuse code and to independently extend original software via public classes and interfaces. The relationships of objects or classes through inheritance give ris ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Singleton Pattern
In software engineering, the singleton pattern is a software design pattern that restricts the instantiation of a class to a singular instance. One of the well-known "Gang of Four" design patterns, which describe how to solve recurring problems in object-oriented software, the pattern is useful when exactly one object is needed to coordinate actions across a system. More specifically, the singleton pattern allows objects to: * Ensure they only have one instance * Provide easy access to that instance * Control their instantiation (for example, hiding the constructors of a class) The term comes from the mathematical concept of a singleton. Common uses Singletons are often preferred to global variables because they do not pollute the global namespace (or their containing namespace). Additionally, they permit lazy allocation and initialization, whereas global variables in many languages will always consume resources. The singleton pattern can also be used as a basis for oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Builder Pattern
The builder pattern is a design pattern designed to provide a flexible solution to various object creation problems in object-oriented programming. The intent of the Builder design pattern is to separate the construction of a complex object from its representation. It is one of the Gang of Four design patterns. Overview The Builder design pattern is one of the ''Design Patterns'' that describe how to solve recurring design problems in object-oriented software. The Builder design pattern solves problems like: * How can a class (the same construction process) create different representations of a complex object? * How can a class that includes creating a complex object be simplified? Creating and assembling the parts of a complex object directly within a class is inflexible. It commits the class to creating a particular representation of the complex object and makes it impossible to change the representation later independently from (without having to change) the class. The Build ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abstract Factory Pattern
The abstract factory pattern provides a way to encapsulate a group of individual factories that have a common theme without specifying their concrete classes. In normal usage, the client software creates a concrete implementation of the abstract factory and then uses the generic interface of the factory to create the concrete objects that are part of the theme. The client does not know (or care) which concrete objects it gets from each of these internal factories, since it uses only the generic interfaces of their products. This pattern separates the details of implementation of a set of objects from their general usage and relies on object composition, as object creation is implemented in methods exposed in the factory interface. An example of this would be an abstract factory class DocumentCreator that provides interfaces to create a number of products (e.g., createLetter() and createResume()). The system would have any number of derived concrete versions of the DocumentCreator cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creational Pattern
In software engineering, creational design patterns are design patterns that deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. The basic form of object creation could result in design problems or in added complexity to the design. Creational design patterns solve this problem by somehow controlling this object creation. Overview Creational design patterns are composed of two dominant ideas. One is encapsulating knowledge about which concrete classes the system uses. Another is hiding how instances of these concrete classes are created and combined. Creational design patterns are further categorized into object-creational patterns and class-creational patterns, where object-creational patterns deal with object creation and class-creational patterns deal with class-instantiation. In greater details, object-creational patterns defer part of its object creation to another object, while class-creational patterns defer its object cre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prototype UML
A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and software programming. A prototype is generally used to evaluate a new design to enhance precision by system analysts and users. Prototyping serves to provide specifications for a real, working system rather than a theoretical one. In some design workflow models, creating a prototype (a process sometimes called materialization) is the step between the formalization and the evaluation of an idea. A prototype can also mean a typical example of something such as in the use of the derivation 'prototypical'. This is a useful term in identifying objects, behaviours and concepts which are considered the accepted norm and is analogous with terms such as stereotypes and archetypes. The word '' prototype'' derives from the Greek , "primitive form", neutral of , "original, primitive", from πρῶτ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
