Getter-Setter和私有变量 [英] Getter-Setter and private variables

问题描述

如果我可以通过getter返回的引用更改私有变量的值，那么它是否绕过setter方法？它是否会破坏getter-setter和私有变量的目的

If I can change the value of private variable through getter-returned reference then isn't it bypassing the setter method? Doesn't it defeat the purpose of getter-setter and private variables

public class Test{

private Dimension cannotBeChanged;

public Test(int height, int width)
{
    if(height!=3)
       cannotBeChanged.height = height;
    if(width!=3)
       cannotBeChanged.width  = width;
}

public Dimension getDimension()
{
    return cannotBeChanged;
}


public void setDimension(int height, int width)
{
    if(height!=3)
       cannotBeChanged.height = height;
    if(width!=3)
       cannotBeChanged.width  = width;    
} 

 public static void main(String [] args)
{
    Test testOne = new Test(5,5);
    Dimension testSecond = testOne.getDimension();
    testSecond.height = 3; //Changed height and width to unwanted values
    testSecond.width= 3;
}

推荐答案

是的，确实如此。我在清洁代码一书的getter和setter中得出以下结论;如果你真的接受它就可以使用它。

Yes, It does. I have the following conclusion in getters and setters from the Clean Code book; you can use it if you really accept it.

1. 非常邪恶：公共领域。


2. 有点邪恶：吸气剂和二传手不需要它们。


3. 好：只有在真正需要的地方才有吸气剂和制定者 - 使
   类型暴露更大的行为恰好使用其状态
   而不仅仅是将类型视为由其他类型操纵的
   状态的存储库。

1. Very evil: public fields.
2. Somewhat evil: Getters and setters where they're not required.
3. Good: Getters and setters only where they're really required - make the type expose "larger" behaviour which happens to use its state, rather than just treating the type as a repository of state to be manipulated by other types.

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