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/* license: https://mit-license.org
*
* UDP: User Datagram Protocol
*
* Written in 2021 by Moky
*
* ==============================================================================
* The MIT License (MIT)
*
* Copyright (c) 2021 Albert Moky
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
* ==============================================================================
*/
package chat.dim.udp;
import java.io.IOException;
import java.net.SocketAddress;
import java.nio.channels.DatagramChannel;
import java.util.Set;
import chat.dim.net.Channel;
import chat.dim.net.Connection;
import chat.dim.socket.BaseHub;
import chat.dim.type.AddressPairMap;
class ChannelPool extends AddressPairMap {
@Override
public Channel get(SocketAddress remote, SocketAddress local) {
assert remote != null || local != null : "both addresses are empty";
// -- Step 1 --
// (remote, local)
// this step will get the channel connected to the remote address
// and bound to the local address at the same time;
// (null, local)
// this step will get a channel bound to the local address, and
// surely not connected;
// (remote, null)
// this step will get a channel connected to the remote address,
// no matter which local address to be bound;
Channel channel = super.get(remote, local);
if (channel != null) {
return channel;
} else if (remote == null) {
// failed to get a channel bound to the local address
return null;
}
// -- Step 2 --
// (remote, local)
// try to get a channel which bound to the local address, but
// not connected to any remote address;
// (null, local)
// this situation has already done at step 1;
if (local != null) {
// ignore the remote address
channel = super.get(null, local);
if (channel != null && channel.getRemoteAddress() == null) {
// got a channel not connected yet
return channel;
}
}
// -- Step 3 --
// (remote, null)
// try to get a channel that bound to any local address, but
// not connected yet;
Set all = allValues();
for (Channel item : all) {
if (item.getRemoteAddress() == null) {
return item;
}
}
// not found
return null;
}
@Override
public void set(SocketAddress remote, SocketAddress local, Channel value) {
Channel old = get(remote, local);
if (old != null && old != value) {
remove(remote, local, old);
}
super.set(remote, local, value);
}
@Override
public Channel remove(SocketAddress remote, SocketAddress local, Channel value) {
Channel cached = super.remove(remote, local, value);
if (cached != null && cached.isOpen()) {
try {
cached.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return cached;
}
}
public abstract class PacketHub extends BaseHub {
private final AddressPairMap channelPool;
protected PacketHub(Connection.Delegate delegate) {
super(delegate);
channelPool = createChannelPool();
}
protected AddressPairMap createChannelPool() {
return new ChannelPool();
}
public void bind(SocketAddress local) throws IOException {
Channel sock = getChannel(null, local);
if (sock == null) {
DatagramChannel udp = DatagramChannel.open();
udp.configureBlocking(true);
udp.socket().setReuseAddress(true);
udp.socket().bind(local);
udp.configureBlocking(false);
Channel channel = createChannel(null, local, udp);
setChannel(null, local, channel);
}
}
//
// Channel
//
/**
* Create channel with socket & address
*
* @param sock - socket
* @param remote - remote address
* @param local - local address
* @return null on socket error
*/
protected Channel createChannel(SocketAddress remote, SocketAddress local, DatagramChannel sock) {
return new PacketChannel(remote, local, sock);
}
@Override
protected Set allChannels() {
return channelPool.allValues();
}
protected Channel getChannel(SocketAddress remote, SocketAddress local) {
return channelPool.get(remote, local);
}
protected void setChannel(SocketAddress remote, SocketAddress local, Channel channel) {
channelPool.set(remote, local, channel);
}
@Override
protected void removeChannel(SocketAddress remote, SocketAddress local, Channel channel) {
channelPool.remove(remote, local, channel);
}
@Override
public Channel open(SocketAddress remote, SocketAddress local) {
assert remote != null || local != null : "both addresses are empty";
// get channel with direction (remote, local)
return getChannel(remote, local);
}
}
