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In object oriented programming, the factory method pattern is a design pattern that uses factory methods to deal with the problem of creating objects without having to specify their exact class. Rather than by calling a constructor, this is done by calling a factory method to create an object. Factory methods can either be specified in an ...
In programming language theory, lazy evaluation, or call-by-need, [ 1 ] is an evaluation strategy which delays the evaluation of an expression until its value is needed ( non-strict evaluation) and which also avoids repeated evaluations (by the use of sharing ). [ 2 ][ 3 ] The benefits of lazy evaluation include: The ability to define control ...
In Simula, classes are defined in a block in which attributes, methods and class initialization are all defined together; thus all the methods that can be invoked on a class are defined together, and the definition of the class is complete. In Flavors, a mixin is a class from which another class can inherit slot definitions and methods. The ...
In class-based programming, a factory is an abstraction of a constructor of a class, while in prototype-based programming a factory is an abstraction of a prototype object. A constructor is concrete in that it creates objects as instances of a single class, and by a specified process (class instantiation), while a factory can create objects by instantiating various classes, or by using other ...
In computer programming, lazy initialization is the tactic of delaying the creation of an object, the calculation of a value, or some other expensive process until the first time it is needed. It is a kind of lazy evaluation that refers specifically to the instantiation of objects or other resources. This is typically accomplished by augmenting ...
For example, . is a very general pattern, [a-z] (match all lower case letters from 'a' to 'z') is less general and b is a precise pattern (matches just 'b'). The metacharacter syntax is designed specifically to represent prescribed targets in a concise and flexible way to direct the automation of text processing of a variety of input data, in a ...
The state pattern is a behavioral software design pattern that allows an object to alter its behavior when its internal state changes. This pattern is close to the concept of finite-state machines. The state pattern can be interpreted as a strategy pattern, which is able to switch a strategy through invocations of methods defined in the pattern ...
Observer pattern. In software design and engineering, the observer pattern is a software design pattern in which an object, named the subject, maintains a list of its dependents, called observers, and notifies them automatically of any state changes, usually by calling one of their methods . It is often used for implementing distributed event ...