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在JAVA中是println方法访问器还是mutator？

[英]Is println method accessor or mutator in JAVA?

原文 2014-02-06 21:30:10 2 3 java/ println

In System.out.println , println is a accessor or mutator method in JAVA ? 在System.out.println ， println是JAVA中的访问器还是mutator方法？

Thank you.... 谢谢....

3 个解决方案

I would say it's neither. 我会说它不是。 It only exists for its side effects ; 它只存在副作用 ; it is not obliged to do anything at all to the internal state of System.out (which is what accessors and mutators are about). 它没有义务对System.out的内部状态做任何事情（这是访问者和变更者的意思）。

It's not an accessor, because it doesn't return a value (it's void ). 它不是访问器，因为它不返回值（它是void ）。 One could argue that it's a mutator, because it modifies the state of the underlying I/O system (it has side effects), but it's not a clear-cut distinction, because is not modifying the state of the System class or any of its instances. 有人可能认为它是一个mutator，因为它修改了底层I / O系统的状态（它有副作用），但它不是一个明确的区别，因为它不是修改System类或其任何一个的状态实例。

The accessor/mutator distinction generally applies to methods that return a value obtained from an object's attributes (accessors) or methods that modify those attributes (mutators), but this is not the case for println() , the state being modified (an output stream) lies outside of the class. accessor / mutator的区别通常适用于返回从对象的属性（访问器）或修改这些属性（mutators）的方法获得的值的方法，但println()的情况不是这样，正在修改的状态（输出流））在课堂之外。

No. Accessors are "getXXX", mutators are "setXXX". 没有。访问者是“getXXX”，mutators是“setXXX”。 println is neither. println既不是。