Are getters and setters poor design? Contradictory advice seen
This question already has an answer here:
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);
it should be
// Game
private int score;
public int getScore() { return score; }
public void addScore(int delta) { score += delta; }
// Usage
game.addScore(ENEMY_DESTROYED_SCORE);
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.
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; }
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; }
It really depends on the situation though - sometimes you really do just want a dumb data object.
You've already had a lot of good answers on this, so I'll just give my two cents. Getters and setters are very, very evil. They essentially let you pretend to hide your object's internals when most of the time all you've done is tossed in redundant code that does nothing to hide internal state. For a simple POJO, there's no reason why getName() and setName() can't be replaced with obj.name = "Tom".
If the method call merely replaces assignment, then all you've gained by preferring the method call is code bloat. Unfortunately, the language has enshrined the use of getters and setters in the JavaBeans specification, so Java programmers are forced to use them, even when doing so makes no sense whatsoever.
Fortunately, Eclipse (and probably other IDEs as well) lets you automatically generate them. And for a fun project, I once built a code-generator for them in XSLT. But if there's one thing I'd get rid of in Java, its the over-dependence on getters and setters.
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