(完整版)毕设外文翻译-详细解析Java中抽象类和接口的区别

Parsing Java Abstraction of the Difference Between Classes and

Interfaces

In Java language, abstract scale-up and with support class abstraction definition of two mechanisms. Because of these two kinds of mechanism of existence, just gives Java powerful object-oriented skills. Abstract scale-up and with between classes abstraction definition for support has great similarities, even interchangeable, so many developers into line non-abstract class definition for abstract scale-up and it is becoming more casual with choice. In fact, both between still has the very big difference, for their choice even reflected in problem domain essence of understanding, to design the intentions of the understanding correctly and reasonable. This paper will for the difference analysis, trying to give a developer with a choice between them are based.

Understand class abstraction

Abstract class and interface in Java language is used for abstract classes (in this article non-abstract class not from abstract scale-up translation, it represents an abstract body, and abstract scale-up for Java language used to define class abstraction in one way, please readers distinguish) defined, then what are the abstract classes, use abstract classes for us any good?

In object-oriented concept, we know all objects is through class to describe, but in turn not such. Not all classes are used to describe object, if a class does not contain enough information to portray a concrete object, this class is abstract classes. Abstract classes are often used to characterization of problem field in our analysis, design that the abstract concepts, is to the series will look different, but essentially the same exact conception of abstraction. For example: if we carry out a graphical editing software development, will find problem domain exists round, triangle so some specific concept, they are different, but they all belong to shape such a concept, shape this concept in problem domain is not exist, it is an abstract concept. Precisely because the abstract concepts in problem field no corresponding specific concept, so to characterization abstract concepts non-abstract class cannot be instantiated.

In an object-oriented field, mainly used for class abstraction types hidden. We can

construct a fixed a group of behavior of abstract description, but this group of behavior but can have any a possible concrete implementation. This abstract describe is abstract classes, and this an arbitrary a possible concrete realization is behaved for all possible derived class. Modules can be operating an abstract body. Due to the module dependent on a fixed abstraction body, so it can are not allowed to modify, Meanwhile, through the abstract derived from the body, also can expand the behavior of this module function. Familiar with OCP readers must know, object-oriented design to be able to achieve a core principle OCP (Open - Closed flying), class abstraction is one of the key.

From the perspectives of grammar definition abstract class and interface

In grammatical perspective, Java language for abstract scale-up and with gives different definitions below to define a way, called produce professional Demo abstract class as an example to illustrate the difference.

In the abstract scale-up manner, produce professional Demo can have their own data members, also can have the members of the abstract method, and with the realization of the way, produce professional Demo can have only static cannot be modified data members, all the members of the methods is abstract. In a sense, with a special kind of abstract class.

From programming, from the perspective of abstract scale-up and with can be used to achieve "cancel" thoughts make themselves. But in the specific use top still have some difference.

First, abstract class in Java language suggests is a kind of inheriting relationship, a class can be used only once inheritance relationship (because Java do not support more inheritance ZhuanZhu). - However, a class but can implement multiple with. Maybe it is Java language designers in considering Java for multiple inheritance support of a compromise to consider it.

Secondly, in the definition of abstract scale-up, we may give methods of default behavior. But in with the definition of method cannot have the default behavior, to bypass this limits, must use entrust, but it will add some complexity, sometimes can cause a lot of trouble.

In class abstraction cannot define the default behavior is there another serious problem that may cause on the maintenance of trouble. Because if later want to modify the