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/* * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.nio.ch; import java.nio.channels.*;import java.net.InetAddress;import java.net.NetworkInterface;import java.util.*; /** * Simple registry of membership keys for a MulticastChannel. * * Instances of this object are not safe by multiple concurrent threads. */ class MembershipRegistry {     // map multicast group to keys    private Map<InetAddress,List<MembershipKeyImpl>> groups = null;     MembershipRegistry() {    }     /**     * Checks registry for membership of the group on the given     * network interface.     */    MembershipKey checkMembership(InetAddress group, NetworkInterface interf,                                  InetAddress source)    {        if (groups != null) {            List<MembershipKeyImpl> keys = groups.get(group);            if (keys != null) {                for (MembershipKeyImpl key: keys) {                    if (key.networkInterface().equals(interf)) {                        // already a member to receive all packets so return                        // existing key or detect conflict                        if (source == null) {                            if (key.sourceAddress() == null)                                return key;                            throw new IllegalStateException("Already a member to receive all packets");                        }                         // already have source-specific membership so return key                        // or detect conflict                        if (key.sourceAddress() == null)                            throw new IllegalStateException("Already have source-specific membership");                        if (source.equals(key.sourceAddress()))                            return key;                    }                }            }        }        return null;    }     /**     * Add membership to the registry, returning a new membership key.     */    void add(MembershipKeyImpl key) {        InetAddress group = key.group();        List<MembershipKeyImpl> keys;        if (groups == null) {            groups = new HashMap<InetAddress,List<MembershipKeyImpl>>();            keys = null;        } else {            keys = groups.get(group);        }        if (keys == null) {            keys = new LinkedList<MembershipKeyImpl>();            groups.put(group, keys);        }        keys.add(key);    }     /**     * Remove a key from the registry     */    void remove(MembershipKeyImpl key) {        InetAddress group = key.group();        List<MembershipKeyImpl> keys = groups.get(group);        if (keys != null) {            Iterator<MembershipKeyImpl> i = keys.iterator();            while (i.hasNext()) {                if (i.next() == key) {                    i.remove();                    break;                }            }            if (keys.isEmpty()) {                groups.remove(group);            }        }    }     /**     * Invalidate all keys in the registry     */    void invalidateAll() {        if (groups != null) {            for (InetAddress group: groups.keySet()) {                for (MembershipKeyImpl key: groups.get(group)) {                    key.invalidate();                }            }        }    }}