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/**
* Logback: the reliable, generic, fast and flexible logging framework.
* Copyright (C) 1999-2015, QOS.ch. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 2.1
* as published by the Free Software Foundation.
*/
package ch.qos.logback.core.net.server;
import java.io.Closeable;
import java.io.IOException;
/**
* A listener that accepts {@link Client} connections on behalf of a
* {@link ServerRunner}.
*
* This interface exists primarily to abstract away the details of the
* listener's underlying {@code ServerSocket} and the concurrency associated
* with handling multiple clients. Such realities make it difficult to create
* effective unit tests for the {@link ServerRunner} that are easy to
* understand and maintain.
*
* This interface captures the only those details about the listener that the
* {@code ServerRunner} cares about; namely, that it is something that has
* an underlying resource (or resources) that need to be closed before the
* listener is discarded.
*
*/
public interface ServerListener extends Closeable {
/**
* Accepts the next client that appears on this listener.
*
* An implementation of this method is expected to block the calling thread
* and not return until either a client appears or an exception occurs.
*
* @return client object
* @throws IOException
* @throws InterruptedException
*/
T acceptClient() throws IOException, InterruptedException;
/**
* Closes any underlying {@link Closeable} resources associated with this
* listener.
*
* Note that (as described in Doug Lea's discussion about interrupting I/O
* operations in "Concurrent Programming in Java" (Addison-Wesley
* Professional, 2nd edition, 1999) this method is used to interrupt
* any blocked I/O operation in the client when the server is shutting
* down. The client implementation must anticipate this potential,
* and gracefully exit when the blocked I/O operation throws the
* relevant {@link IOException} subclass.
*
* Note also, that unlike {@link Closeable#close()} this method is not
* permitted to propagate any {@link IOException} that occurs when closing
* the underlying resource(s).
*/
void close();
}