CoR object structure Request handlers are extensions of a base class that maintains a reference to the next handler in the chain. This handler is known as the successor. The code of the base class implementing handleRequest() method is shown as:

public abstract class BaseHandler {
...
public void
handleRequest(SomeRequestObject sro) {
if(successor != null)
successor.handleRequest(sro);
}
}

Thus, handlers pass the request to the next handler in the chain by default. A concrete class of BaseHandler might be implemented like this:

public class SpamFilter extends BaseHandler {
public void
handleRequest(SomeRequestObject mailMessage) { if(isSpam(mailMessage))
{
// If the message is spam
// take spam-related action. Do not forward message.
}
else {
// Message is not spam. super.handleRequest(mailMessage);
// Pass message to next filter in the chain.
}
}
}