吸气剂和二传手设计不佳吗？看到矛盾的建议 [英] Are getters and setters poor design? Contradictory advice seen

问题描述

我目前正在开发一个简单的Java游戏，有几种不同的模式。我扩展了一个主要的Game类，将主要逻辑放在其他类中。尽管如此，主要的游戏类仍然相当沉重。

I'm currently working on a simple game in Java with several different modes. I've extended a main Game class to put the main logic within the other classes. Despite this, the main game class is still pretty hefty.

在快速查看我的代码后，其中大部分是Getters and Setters（60％）与这是游戏逻辑真正需要的休息。

After taking a quick look at my code the majority of it was Getters and Setters (60%) compared to the rest that is truly needed for the logic of the game.

谷歌的一些搜索声称Getters and Setters是邪恶的，而其他人声称它们是必要的良好的OO实践和优秀的课程。

A couple of Google searches have claimed that Getters and Setters are evil, whilst others have claimed that they are necessary for good OO practice and great programs.

那我该怎么办？应该是哪个？我应该为我的私人变量更改我的Getters和Setter，还是应该坚持使用它们？

So what should I do? Which should it be? Should I be changing my Getters and Setters for my private variables, or should I stick with them?

推荐答案

还有一点大多数情况下，使用setter仍然可以通过允许您设置无意义的值来破坏封装。作为一个非常明显的例子，如果你在游戏上只有一个得分计数器，而不是

There is also the point of view that most of the time, using setters still breaks encapsulation by allowing you to set values that are meaningless. As a very obvious example, if you have a score counter on the game that only ever goes up, instead of

// Game
private int score;
public void setScore(int score) { this.score = score; }
public int getScore() { return score; }
// Usage
game.setScore(game.getScore() + ENEMY_DESTROYED_SCORE);

它应该是

// Game
private int score;
public int getScore() { return score; }
public void addScore(int delta) { score += delta; }
// Usage
game.addScore(ENEMY_DESTROYED_SCORE);

这可能是一个简单的例子。我想说的是，讨论getter / setter vs public fields经常会掩盖更大的问题，因为对象以一种亲密的方式操纵彼此的内部状态，因此过于紧密耦合。

This is perhaps a bit of a facile example. What I'm trying to say is that discussing getter/setters vs public fields often obscures bigger problems with objects manipulating each others' internal state in an intimate manner and hence being too closely coupled.

我们的想法是制定直接做你想做的事情的方法。一个例子是如何设置敌人的活着状态。您可能想要使用setAlive（boolean alive）方法。相反，你应该：

The idea is to make methods that directly do things you want to do. An example would be how to set enemies' "alive" status. You might be tempted to have a setAlive(boolean alive) method. Instead you should have:

private boolean alive = true;
public boolean isAlive() { return alive; }
public void kill() { alive = false; }

这样做的原因是，如果你更改了实现，那就不再有活着布尔值，而不是生命值，你可以在不破坏你之前写的两种方法的合同的情况下改变它：

The reason for this is that if you change the implementation that things no longer have an "alive" boolean but rather a "hit points" value, you can change that around without breaking the contract of the two methods you wrote earlier:

private int hp; // Set in constructor.
public boolean isAlive() { return hp > 0; } // Same method signature.
public void kill() { hp = 0; } // Same method signature.
public void damage(int damage) { hp -= damage; }

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