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In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral (null) behavior.The null object design pattern, which describes the uses of such objects and their behavior (or lack thereof), was first published as "Void Value" [1] and later in the Pattern Languages of Program Design book series as "Null Object".
Multiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class. It is distinct from single inheritance, where an object or class may only inherit from one particular object or class.
This means that it is no longer a problem to define Circle.stretchX, and the inheritance reflects the mathematical relationship between circles and ellipses. A disadvantage is that changing the value of an instance then requires an assignment, which is inconvenient and prone to programming errors, e.g., Orbit(planet[i]) := Orbit(planet[i]).stretchX
Reportedly, Java inventor James Gosling has spoken against implementation inheritance, stating that he would not include it if he were to redesign Java. [19] Language designs that decouple inheritance from subtyping (interface inheritance) appeared as early as 1990; [ 21 ] a modern example of this is the Go programming language.
In Java, several factories are used in the javax.xml.parsers package, such as javax.xml.parsers.DocumentBuilderFactory or javax.xml.parsers.SAXParserFactory. In the HTML5 DOM API , the Document interface contains a createElement() factory method for creating specific elements of the HTMLElement interface.
In software engineering, the Twin pattern is a software design pattern that allows developers to model multiple inheritance in programming languages that do not support multiple inheritance. This pattern avoids many of the problems with multiple inheritance. [1]
The relationships are specified in the science of object-oriented design and object interface standards defined by popular use, language designers (Java, C++, Smalltalk, Visual Prolog) and standards committees for software design like the Object Management Group. The class hierarchy can be as deep as needed.
Composition over inheritance (or composite reuse principle) in object-oriented programming (OOP) is the principle that classes should favor polymorphic behavior and code reuse by their composition (by containing instances of other classes that implement the desired functionality) over inheritance from a base or parent class. [2]