我想在abstract static method
中创建abstract class
。我很清楚this question这在Java中是不可能的。什么是默认的解决方法/替代思考问题的方法/是否有一个选项可以为看似有效的示例(如下所示)做这个?
动物类和子类:
我有一个带有各种子类的基类Animal
。我想强制所有子类能够从xml字符串创建一个对象。对于这个,除了静态之外什么都没有意义呢? E.g:
public void myMainFunction() {
ArrayList<Animal> animals = new ArrayList<Animal>();
animals.add(Bird.createFromXML(birdXML));
animals.add(Dog.createFromXML(dogXML));
}
public abstract class Animal {
/**
* Every animal subclass must be able to be created from XML when required
* (E.g. if there is a tag <bird></bird>, bird would call its 'createFromXML' method
*/
public abstract static Animal createFromXML(String XML);
}
public class Bird extends Animal {
@Override
public static Bird createFromXML(String XML) {
// Implementation of how a bird is created with XML
}
}
public class Dog extends Animal {
@Override
public static Dog createFromXML(String XML) {
// Implementation of how a dog is created with XML
}
}
因此,在需要静态方法的情况下,我需要一种强制所有子类实现此静态方法的方法,有没有办法可以做到这一点?
答案 0 :(得分:2)
您可以创建一个工厂来生产动物对象。下面是一个示例,为您提供一个开始:
public void myMainFunction() {
ArrayList<Animal> animals = new ArrayList<Animal>();
animals.add(AnimalFactory.createAnimal(Bird.class,birdXML));
animals.add(AnimalFactory.createAnimal(Dog.class,dogXML));
}
public abstract class Animal {
/**
* Every animal subclass must be able to be created from XML when required
* (E.g. if there is a tag <bird></bird>, bird would call its 'createFromXML' method
*/
public abstract Animal createFromXML(String XML);
}
public class Bird extends Animal {
@Override
public Bird createFromXML(String XML) {
// Implementation of how a bird is created with XML
}
}
public class Dog extends Animal {
@Override
public Dog createFromXML(String XML) {
// Implementation of how a dog is created with XML
}
}
public class AnimalFactory{
public static <T extends Animal> Animal createAnimal(Class<T> animalClass, String xml) {
// Here check class and create instance appropriately and call createFromXml
// and return the cat or dog
}
}