Java - 包含变量的抽象类？ [英] Java - Abstract class to contain variables?

问题描述

是否是抽象类定义实例变量的好习惯？

Is it good practice to let abstract classes define instance variables?

public abstract class ExternalScript extends Script {

    String source;

    public abstract void setSource(String file);

    public abstract String getSource();
}

然后，子类ExternalJavaScript.class会自动获取源变量，如果所有的子类本身定义了源代码，而不是继承，我觉得阅读代码更容易。

The sub class, ExternalJavaScript.class, would then automatically get the source variable but I feel it's easier to read the code if all the sub classes themselves define the source, instead of from inheritance.

您的建议是什么？

/ Adam

推荐答案

我会认为这样的东西会好得多，因为你添加一个变量，所以为什么不限制访问，使它更清洁？

I would have thought that something like this would be much better, since you're adding a variable, so why not restrict access and make it cleaner? Your getter/setters should do what they say on the tin.

public abstract class ExternalScript extends Script {

private String source;

public void setSource(String file) {
    source = file;
}

public String getSource() {
    return source;
}

把这个问题带回来， / setter代码是什么时候读的？如果他们都做得到和设置，那么你不需要担心在读代码时该函数'做什么。
还有一些其他原因需要考虑：

Bringing this back to the question, do you ever bother looking at where the getter/setter code is when reading it? If they all do getting and setting then you don't need to worry about what the function 'does' when reading the code. There are a few other reasons to think about too:

• 如果源被保护（可以通过子类访问）凌乱：谁在改变变量？


• 如果你的getter / setter方法没有获取和设置，那么描述一个对象，当你需要重构时，它变得很难，而方法会使这个步骤更容易。

总是认为你的类是不是真的不同的东西，这应该有助于决定你是否需要什么更多

Always think whether your class is really a different thing or not, and that should help decide whether you need anything more.

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