chat.dim.udp.PacketChannelReader Maven / Gradle / Ivy
/* license: https://mit-license.org
*
* UDP: User Datagram Protocol
*
* Written in 2022 by Moky
*
* ==============================================================================
* The MIT License (MIT)
*
* Copyright (c) 2022 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.ByteBuffer;
import java.nio.channels.DatagramChannel;
import chat.dim.socket.BaseChannel;
import chat.dim.socket.ChannelReader;
public class PacketChannelReader extends ChannelReader {
protected PacketChannelReader(BaseChannel channel) {
super(channel);
}
//
// Receive
//
protected SocketAddress tryReceive(ByteBuffer dst, DatagramChannel sock) throws IOException {
try {
return sock.receive(dst);
} catch (IOException e) {
e = checkError(e, sock);
if (e != null) {
// connection lost?
throw e;
}
// received nothing
return null;
}
}
protected SocketAddress receiveFrom(ByteBuffer dst, DatagramChannel sock) throws IOException {
SocketAddress remote = tryReceive(dst, sock);
int cnt = dst.position();
// check data
IOException error = checkData(dst, cnt, sock);
if (error != null) {
// connection lost!
throw error;
}
// OK
return remote;
}
@Override
public SocketAddress receive(ByteBuffer dst) throws IOException {
DatagramChannel sock = getSocket();
assert sock != null : "socket lost, cannot receive data.";
if (sock.isConnected()) {
// connected (TCP/UDP)
return read(dst) > 0 ? getRemoteAddress() : null;
} else {
// not connect (UDP)
return receiveFrom(dst, sock);
}
}
}