我正在做一本书中的一些练习,以下练习有些问题。
package net.mindview.util;
public interface Generator<T> { T next(); } ///:~
package net.mindview.util;
public class BasicGenerator1<T> implements Generator<T> {
private Class<T> type;
public BasicGenerator1(Class<T> type){ this.type = type; }
public T next() {
try {
// Assumes type is a public class:
return type.newInstance();
} catch(Exception e) {
throw new RuntimeException(e);
}
}
// Produce a Default generator given a type token:
public static <T> Generator<T> create(Class<T> type) {
return new BasicGenerator1<T>(type);
}
} ///:~
package cont;
public class CountedObject {
private static long counter = 0;
private final long id = counter++;
public long id() { return id; }
public String toString() { return "CountedObject " + id;}
} ///:~
package cont;
import net.mindview.util.*;
public class BasicGeneratorDemo {
public static void main(String[] args) {
//this line works
//Generator<CountedObject> gen = BasicGenerator1.create(CountedObject.class);
//am stuck here
Generator<CountedObject> gen = new BasicGenerator1<CountedObject>;
for(int i = 0; i < 5; i++)
System.out.println(gen.next());
}
}
我必须更改BasicGeneratorDemo.java,以便它使用显式构造函数而不是通用的create()方法。我该如何实现?
谢谢
最佳答案
好的,您需要传递一个参数:
Generator<CountedObject> gen = new BasicGenerator1<CountedObject>(CountedObject.class);
关于java - 使用构造函数基于参数化的父类(super class)创建Generator,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/9581545/