强制子类使用超类的@Override 方法。超类中的方法必须有主体

Question

我想从 SuperClass.

强制 SubClasses 到 @Override 方法

SuperClass 中的方法不能 abstract，因为我想提供一些基本实现。

这是我的代码示例：

public abstract class GenericModel<T extends GenericModel> {
    long id, counter;

    public String methodToBeOverridenInSubClass(String name) {
        // some basic implementation
        // rest details will be provided by subclass
        return name;
    }

}
public class SubClass extends GenericModel<SubClass> {
    @Override
    public String methodToBeOverridenInSubClass(String name) {
        switch (name) {
            case "name": return "Real name";
            default: super.methodToBeOverridenInSubClass(name);
        }
    }
}

这个post很有趣： MustOverrideException and MethodNotOverridenException

请帮帮我

Answer 1

您可以使用两种方法：

public abstract String methodToBeOverridenInSubClass(String name);


protected String commonMethodToUseInSubClasses(String name) {
    // some basic implementation
    return name;
}

这样子类必须重写 methodToBeOverridenInSubClass 但您仍然可以对 commonMethodToUseInSubClasses.

中的所有子类使用通用代码

Answer 2

也许Template method pattern解决了您正在寻找的问题。您在其中创建了一个父级 class 并实现了一种方法，该方法描述了调用其他方法（步骤）的过程。这些步骤是抽象的，因此它们由子 class.

实现

来自维基百科的示例：

/**
* An abstract class that is common to several games in
* which players play against the others, but only one is
* playing at a given time.
*/

abstract class Game {

protected int playersCount;
abstract void initializeGame();
abstract void makePlay(int player);
abstract boolean endOfGame();
abstract void printWinner();

/* A template method : */
public final void playOneGame(int playersCount) {
    this.playersCount = playersCount;
    initializeGame();
    int j = 0;
    while (!endOfGame()) {
        makePlay(j);
        j = (j + 1) % playersCount;
    }
    printWinner();
}
}

//Now we can extend this class in order 
//to implement actual games:

class Monopoly extends Game {

/* Implementation of necessary concrete methods */
void initializeGame() {
    // Initialize players
    // Initialize money
}
void makePlay(int player) {
    // Process one turn of player
}
boolean endOfGame() {
    // Return true if game is over 
    // according to Monopoly rules
}
void printWinner() {
    // Display who won
}
/* Specific declarations for the Monopoly game. */

// ...
}

class Chess extends Game {

/* Implementation of necessary concrete methods */
void initializeGame() {
    // Initialize players
    // Put the pieces on the board
}
void makePlay(int player) {
    // Process a turn for the player
}
boolean endOfGame() {
    // Return true if in Checkmate or 
    // Stalemate has been reached
}
void printWinner() {
    // Display the winning player
}
/* Specific declarations for the chess game. */

// ...
}

强制子类使用超类的@Override 方法。超类中的方法必须有主体

Force SubClasses to @Override method from SuperClass. Method in SuperClass must have body

java

methods

inheritance

overriding

abstract