1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

package com.esotericsoftware.kryonet;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.net.SocketException;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;

import static com.esotericsoftware.minlog.Log.*;

/** @author Nathan Sweet <misc@n4te.com> */
class UdpConnection {
	InetSocketAddress connectedAddress;
	DatagramChannel datagramChannel;
	int keepAliveMillis = 19000;
	final ByteBuffer readBuffer, writeBuffer;
	private final Serialization serialization;
	private SelectionKey selectionKey;
	private final Object writeLock = new Object();
	private long lastCommunicationTime;

	public UdpConnection (Serialization serialization, int bufferSize) {
		this.serialization = serialization;
		readBuffer = ByteBuffer.allocate(bufferSize);
		writeBuffer = ByteBuffer.allocateDirect(bufferSize);
	}

	public void bind (Selector selector, InetSocketAddress localPort) throws IOException {
		close();
		readBuffer.clear();
		writeBuffer.clear();
		try {
			datagramChannel = selector.provider().openDatagramChannel();
			datagramChannel.socket().bind(localPort);
			datagramChannel.configureBlocking(false);
			selectionKey = datagramChannel.register(selector, SelectionKey.OP_READ);

			lastCommunicationTime = System.currentTimeMillis();
		} catch (IOException ex) {
			close();
			throw ex;
		}
	}

	public void connect (Selector selector, InetSocketAddress remoteAddress) throws IOException {
		close();
		readBuffer.clear();
		writeBuffer.clear();
		try {
			datagramChannel = selector.provider().openDatagramChannel();
			datagramChannel.socket().bind(null);
			datagramChannel.socket().connect(remoteAddress);
			datagramChannel.configureBlocking(false);

			selectionKey = datagramChannel.register(selector, SelectionKey.OP_READ);

			lastCommunicationTime = System.currentTimeMillis();

			connectedAddress = remoteAddress;
		} catch (IOException ex) {
			close();
			IOException ioEx = new IOException("Unable to connect to: " + remoteAddress);
			ioEx.initCause(ex);
			throw ioEx;
		}
	}

	public InetSocketAddress readFromAddress () throws IOException {
		DatagramChannel datagramChannel = this.datagramChannel;
		if (datagramChannel == null) throw new SocketException("Connection is closed.");
		lastCommunicationTime = System.currentTimeMillis();
		return (InetSocketAddress)datagramChannel.receive(readBuffer);
	}

	public Object readObject (Connection connection) {
		readBuffer.flip();
		try {
			try {
				Object object = serialization.read(connection, readBuffer);
				if (readBuffer.hasRemaining())
					throw new KryoNetException("Incorrect number of bytes (" + readBuffer.remaining()
						+ " remaining) used to deserialize object: " + object);
				return object;
			} catch (Exception ex) {
				throw new KryoNetException("Error during deserialization.", ex);
			}
		} finally {
			readBuffer.clear();
		}
	}

	/** This method is thread safe. */
	public int send (Connection connection, Object object, SocketAddress address) throws IOException {
		DatagramChannel datagramChannel = this.datagramChannel;
		if (datagramChannel == null) throw new SocketException("Connection is closed.");
		synchronized (writeLock) {
			try {
				try {
					serialization.write(connection, writeBuffer, object);
				} catch (Exception ex) {
					throw new KryoNetException("Error serializing object of type: " + object.getClass().getName(), ex);
				}
				writeBuffer.flip();
				int length = writeBuffer.limit();
				datagramChannel.send(writeBuffer, address);

				lastCommunicationTime = System.currentTimeMillis();

				boolean wasFullWrite = !writeBuffer.hasRemaining();
				return wasFullWrite ? length : -1;
			} finally {
				writeBuffer.clear();
			}
		}
	}

	public void close () {
		connectedAddress = null;
		try {
			if (datagramChannel != null) {
				datagramChannel.close();
				datagramChannel = null;
				if (selectionKey != null) selectionKey.selector().wakeup();
			}
		} catch (IOException ex) {
			if (DEBUG) debug("kryonet", "Unable to close UDP connection.", ex);
		}
	}

	public boolean needsKeepAlive (long time) {
		return connectedAddress != null && keepAliveMillis > 0 && time - lastCommunicationTime > keepAliveMillis;
	}
}