/*
* JBoss, Home of Professional Open Source
*
* Copyright 2009 Red Hat, Inc. and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.xnio;
import java.nio.channels.
Channel;
import java.util.
EventListener;
import org.jboss.logging.
Logger;
import static org.xnio._private.
Messages.
listenerMsg;
/**
* A listener for channel events. Possible channel events include: channel readable, channel writable, channel
* opened, channel closed, channel bound, channel unbound.
*
* @param <T> the channel type
*
* @since 2.0
*/
public interface
ChannelListener<T extends
Channel> extends
EventListener {
/**
* Handle the event on this channel.
*
* @param channel the channel event
*/
void
handleEvent(T
channel);
/**
* A setter for a channel listener. The indirection is necessary
* because while covariance is supported on return types, contravariance is not supported on parameters.
*
* @param <T> the channel type
*
* @since 2.0
*/
interface
Setter<T extends
Channel> {
/**
* Set the listener, or {@code null} to ignore the associated event type.
*
* @param listener the new listener
*/
void
set(
ChannelListener<? super T>
listener);
}
/**
* A simple implementation of {@link Setter}.
*
* @param <T> the channel type
*
* @since 3.0
*/
class
SimpleSetter<T extends
Channel> implements
Setter<T> {
private
ChannelListener<? super T>
channelListener;
/** {@inheritDoc} */
public void
set(final
ChannelListener<? super T>
listener) {
listenerMsg.
logf(
SimpleSetter.class.
getName(),
Logger.
Level.
TRACE, null, "Setting channel listener to %s",
listener);
channelListener =
listener;
}
/**
* Get the channel listener set on this setter.
*
* @return the channel listener
*/
public
ChannelListener<? super T>
get() {
return
channelListener;
}
public
String toString() {
return "Simple channel listener setter (currently=" +
channelListener + ")";
}
}
}