EventListener
interface declares handleEvent(Event evt)
method, and in the code below GeneratorListener
extends that interface. I am told this code is correct. BUT I don't see why Printer class does not have to implement handleEvent
method? Isn't it the case that all the methods in an interface must be implemented?
public interface GeneratorListener extends EventListener {
void objectGenerated(String object);
}
public class Printer implements GeneratorListener {
public void objectGenerated(String object) {
System.out.println(object);
}
}
Seems I know the answer. Method
public void handleEvent(Event evt);
is contained in org.w3c.dom.events.EventListener. But in your GeneratorListener interface you probably imported java.util.EventListener that looks like
package java.util;
/**
* A tagging interface that all event listener interfaces must extend.
* @since JDK1.1
*/
public interface EventListener {
}
So your Printer class implements the only abstract method that you have in Printer class hierarchy. That's why your code is correct.
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