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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 one class, and by a specified process (class instantiation), while a factory can create objects by instantiating various classes, or by using other ...
Create a new direct instance of type T. [c] Execute the creation procedure make to the newly created instance. Attach the newly initialized object to the entity x. In the first snippet below, class POINT is defined. The procedure make is coded after the keyword feature.
This implied that the methods all classes have were the same, in particular the method to create new objects, i.e., new. To allow classes to have their own methods and their own instance variables (called class instance variables and should not be confused with class variables), Smalltalk-80 introduced for each class C their own metaclass C class.
According to Design Patterns: Elements of Reusable Object-Oriented Software: "Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory method lets a class defer instantiation to subclasses." [2] Creating an object often requires complex processes not appropriate to include within a composing object.
Fields may also be known as members, attributes, or properties. Objects are typically stored as contiguous regions of memory. Objects are accessed somewhat like variables with complex internal structures, and in many languages are effectively pointers, serving as actual references to a single instance of said object in memory within a heap or ...
Software reuse is also a major benefit of using Object classes. Classes facilitate re-use via inheritance and interfaces. When a new behavior is required it can often be achieved by creating a new class and having that class inherit the default behaviors and data of its superclass and then tailoring some aspect of the behavior or data accordingly.
(In the JavaScript language, one can do this by using a null prototype, i.e. Object.create(null).) Cloning refers to a process whereby a new object is constructed by copying the behavior of an existing object (its prototype). The new object then carries all the qualities of the original. From this point on, the new object can be modified.
With new-style classes, objects and types were unified, allowing the subclassing of types. Even entirely new types can be defined, complete with custom behavior for infix operators. This allows for many radical things to be done syntactically within Python. A new method resolution order for multiple inheritance was also adopted with Python 2.3 ...