toytest2.java

JAVA编程思想第四版英文原版习题答案. pdf原版的

//typeinfo/toys/ToyTest2.java
// TIJ4 Chapter Typeinfo, Exercise 2, page 561
// Incorporate a new kind of interface into ToyTest.java and 
// verify that it is detected and displayed properly.
package typeinfo.toys;
import static net.mindview.util.Print.*;

interface HasBatteries {}
interface Waterproof {}
interface Shoots {}
interface Flies {}

class Toy {
	// Comment out the following default constructor
	// to see NoSuchMethodError from (*1*)
	Toy() {}
	Toy(int i) {}
}

class FancyToy extends Toy 
	implements HasBatteries, Waterproof, Shoots, Flies {
		FancyToy() { super(1); }
}

public class ToyTest2 {
	static void printInfo(Class cc) {
		print("Class name: " + cc.getName() +
			" is interface? [" + cc.isInterface() + "]");
		print("Simple name: " + cc.getSimpleName());
		print("Canonical name: " + cc.getCanonicalName());
	}
	public static void main(String[] args) {
		Class c = null;
		try {
			c = Class.forName("typeinfo.toys.FancyToy");
		} catch(ClassNotFoundException e) {
			print("Can't find FancyToy");
			System.exit(1);
		}
		printInfo(c);
		for(Class face : c.getInterfaces())
			printInfo(face);
		Class up = c.getSuperclass();
		Object obj = null;
		try {
			// Requires default constructor:
			obj = up.newInstance();
		} catch(InstantiationException e) {
			print("Cannot instantiate");
			System.exit(1);
		} catch(IllegalAccessException i) {
			print("Cannot access");
			System.exit(1);
		}	
		printInfo(obj.getClass());
	}
}