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 * version 2 for more details (a copy is included in the LICENSE file that
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package sun.nio.ch;

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.nio.channels.MembershipKey;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

Simple registry of membership keys for a MulticastChannel. Instances of this object are not safe by multiple concurrent threads.
/** * 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 list of keys private Map<InetAddress, List<MembershipKeyImpl>> groups; MembershipRegistry() { }
Checks registry for membership of the group on the given network interface.
/** * 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.
/** * 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<>(); keys = null; } else { keys = groups.get(group); } if (keys == null) { keys = new LinkedList<>(); groups.put(group, keys); } keys.add(key); }
Remove a key from the registry
/** * 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); } } } @FunctionalInterface interface ThrowingConsumer<T, X extends Throwable> { void accept(T action) throws X; }
Invoke an action for each key in the registry
/** * Invoke an action for each key in the registry */
<X extends Throwable> void forEach(ThrowingConsumer<MembershipKeyImpl, X> action) throws X { if (groups != null) { for (List<MembershipKeyImpl> keys : groups.values()) { for (MembershipKeyImpl key : keys) { action.accept(key); } } } }
Invalidate all keys in the registry
/** * Invalidate all keys in the registry */
void invalidateAll() { forEach(MembershipKeyImpl::invalidate); } }