方法的重点职责

Question

我读过几本 OOP 书籍，其中强调了定义类的规则，这些规则集中了一组职责。在我工作过的许多应用程序中，大多数时候都遵守了这一点。然而，我看到很多情况下，很多逻辑被转储到一个方法中，使得难以理解/单元测试。定义方法时需要遵循哪些最佳实践？

Answer 1

普遍的共识是，决定方法应该做什么的最佳方法是遵循 Do One Thing 哲学。

Each method should do one thing and one thing only.

Answer 2

作为示例，让我们看一下以下方法：

public static void printDetails() {
    System.out.println("Current time: " + LocalTime.now());
    System.out.println("Current date: " + LocalDate.now());

    System.out.println("Available processors: " + Runtime.getRuntime().availableProcessors());
    System.out.println("Max memory: " + Runtime.getRuntime().maxMemory());
    System.out.println("Free memory: " + Runtime.getRuntime().freeMemory());
}

经过一些重构后，我们有了更具可读性和可维护性的版本：

public static void printDetails() {
    printDateTimeDetails();
    printProcessorDetails();
    printMemoryDetails();
}

更容易阅读。更重要的是 - 它更容易测试。当您阅读此方法的主体时，您会清楚地了解它的用途。如果您需要更多详细信息，只需更深入地查看代码并查看每个方法的作用。

public static void printProcessorDetails() {
    System.out.println("Available processors: " + getAvailableProcessors());
}

public static int getAvailableProcessors() {
    return Runtime.getRuntime().availableProcessors();
}

public static void printMemoryDetails() {
    System.out.println("Max memory: " + getMaxMemory());
    System.out.println("Free memory: " + getFreeMemory());
}

public static long getFreeMemory() {
    return Runtime.getRuntime().freeMemory();
}

public static long getMaxMemory() {
    return Runtime.getRuntime().maxMemory();
}

private static void printDateTimeDetails() {
    System.out.println("Current time: " + LocalTime.now());
    System.out.println("Current date: " + LocalDate.now());
}

而且这样的代码是可重用的。

The Boy Scouts have a rule: "Always leave the campground cleaner than you found it." Actually the original form of that rule, written by Robert Stephenson Smyth Baden-Powell, the father of scouting, was "Try and leave this world a little better than you found it."

当然，这一切都是我的看法。

方法的重点职责

Focussed Responsibility of a Method

java

methods

refactoring

solid-principles