如果你了解面向对象的设计，你很快就会知道它封装您的数据是非常重要的。bet188足球封装的最简单的形式是使用访问器（获取和设置方法）或属性 - 如果你的语言支持它。（有些人甚至为此在类中 -SelfEncapsulation
您可以通过在当他们看到一个getter方法口的左侧的抽搐告诉他们，有迅速拉他们的战斧和满意的叫声作为另一次吸气时从类毫不留情地凿成其在感激的狂喜立刻昏睡 the manly Getter Eradicator's feet.
What do people mean when they say a method doesn't change the observable state of an object?
当你写对一个网页测试，您需要参考该网页中的元素，以点击链接，并确定钱包显示的。然而,如果你写操作HT的测试ML elements directly your tests will be brittle to changes in the UI.A page object wraps an HTML page, or fragment, with an application-specific API, allowing you to manipulate page elements without digging around in the HTML.
One of the most common ways to modularize an information-rich program is to separate it into three broad layers: presentation (UI), domain logic (aka business logic), and data access.So you often see web applications divided into a web layer that knows about handling HTTP requests and rendering HTML, a business logic layer that contains validations and calculations, and a data access layer that sorts out how to manage persistent data in a database or remote services.
Is it good OO design to have data in my classes with theprotectedAccessModifier?
When I first came across C# I liked the notion of properties right from the start.The getX and setX conventions of C++/Java always seems rather silly to me, it's much more natural to write
obj.X = other.X。Providing a property with get and set methods turns a common convention into a naturally supported feature of the language.
Published Interfaceis a term I used (first in188足球比分直播) to refer to a class interface that's used outside the code base that it's defined in.As such it means more than public in Java and indeed even more than a non-internal public in C#.In my column for IEEE Software I argued thatthe distinction between published and public is actually more important than that between public and private.
Sealing a method or a class prevents subclasses from overriding it.
Data encapsulation is a central tenet in object-oriented style.This says that the fields of an object should not be exposed publicly, instead all access from outside the object should be via accessor methods (getters and setters).There are languages that allow publicly accessible fields, but we usually caution programmers not to do this.Self-encapsulationgoes a step further, indicating that allinternalaccess to a data field should also go through accessor methods as well.Only the accessor methods should touch the data value itself.If the data field isn't exposed to the outside, this will mean adding additional private accessors.
Tell-Don't-Ask is a principle that helps people remember that object-orientation is about bundling data with the functions that operate on that data.It reminds us that rather than asking an object for data and acting on that data, we should instead tell an object what to do.This encourages to move behavior into an object to go with the data.
All services offered by a module should be available through a uniform notation, which does not betray whether they are implemented through storage or through computation.
-- Bertrand Meyer
Bertrand Meyer coined this principle in his highly-influential bookObject-Oriented Software Construction。
The essential point of the principle is that if you have a person object and you ask it for its age, you should use the same notation whether the age is a stored field of the object or a computed value.It effectively means that a client of the person should neither know nor care whether the age is stored or computed.