package com.ack.learning;
public interface AnInterface {
// can define constants in interfaces
public static final int MAX_VALUE = 300;
// but really use interfaces for declaring methods
public void aMethod();
public int anotherMethod( String hey ) throws Exception;
public void yetAnotherMethod() throws Exception, ArithmeticException;
}
class ImplementInterfaceClass implements AnInterface {
public void aMethod() {
}
// note that methods are matched on formal parameter types and
// method name.
public int anotherMethod( String yep ) throws Exception {
// note that when you implement an interface, its constants
// are brought into the defining class's scope
if( true ) {
return MAX_VALUE;
}
else {
// however, best to always prefix constants with the defining
// class or interface for readability purposes
return AnInterface.MAX_VALUE;
}
}
/**
* this causes a duplication definition of anotherMethod because
* the method signature only differs by the return type. In Java,
* if two method differ only by the return type they are the same method
* from an inheritance perspective
*
public String anotherMethod(String yep) throws Exception
{
return null;
}
*/
// finally, you can selectively choose which exception to declare
// on the throws clause of the implementing method, here we choose to omit
// Exception
public void yetAnotherMethod() throws ArithmeticException {
}
}