001/*
002 * JGrapes Event Driven Framework
003 * Copyright (C) 2016-2018 Michael N. Lipp
004 * 
005 * This program is free software; you can redistribute it and/or modify it 
006 * under the terms of the GNU Affero General Public License as published by 
007 * the Free Software Foundation; either version 3 of the License, or 
008 * (at your option) any later version.
009 * 
010 * This program is distributed in the hope that it will be useful, but 
011 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
012 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License 
013 * for more details.
014 * 
015 * You should have received a copy of the GNU Affero General Public License along 
016 * with this program; if not, see <http://www.gnu.org/licenses/>.
017 */
018
019package org.jgrapes.io.events;
020
021import java.io.IOException;
022import java.util.Optional;
023
024import org.jgrapes.core.Event;
025
026/**
027 * This event signals that an I/O subchannel will no longer be used.
028 * Components that have allocated resources for that channel should
029 * release them in response to receiving this event.
030 */
031public class Closed extends Event<Void> {
032
033    private Throwable error;
034
035    /**
036     * Creates a new event that signals a close in response to
037     * an error (usually an {@link IOException}.
038     */
039    public Closed(Throwable error) {
040        this.error = error;
041    }
042
043    /**
044     * Creates a new event that signals a regular close.
045     */
046    public Closed() {
047        this(null);
048    }
049
050    /**
051     * Returns the cause of the {@link Closed} event in case of error.
052     *
053     * @return the optional failure
054     */
055    public Optional<Throwable> error() {
056        return Optional.ofNullable(error);
057    }
058}