/interpreter/tags/at2dist041108/src/edu/vub/at/actors/net/comm/Address.java

  1/**
  2 * AmbientTalk/2 Project
  3 * Address.java created on 2-apr-2007 at 10:52:36
  4 * (c) Programming Technology Lab, 2006 - 2007
  5 * Authors: Tom Van Cutsem & Stijn Mostinckx
  6 * 
  7 * Permission is hereby granted, free of charge, to any person
  8 * obtaining a copy of this software and associated documentation
  9 * files (the "Software"), to deal in the Software without
 10 * restriction, including without limitation the rights to use,
 11 * copy, modify, merge, publish, distribute, sublicense, and/or
 12 * sell copies of the Software, and to permit persons to whom the
 13 * Software is furnished to do so, subject to the following
 14 * conditions:
 15 *
 16 * The above copyright notice and this permission notice shall be
 17 * included in all copies or substantial portions of the Software.
 18 *
 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 20 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 21 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 22 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 23 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 24 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 26 * OTHER DEALINGS IN THE SOFTWARE.
 27 */
 28package edu.vub.at.actors.net.comm;
 29
 30import edu.vub.at.util.logging.Logging;
 31
 32import java.io.ByteArrayInputStream;
 33import java.io.ByteArrayOutputStream;
 34import java.io.DataInputStream;
 35import java.io.DataOutputStream;
 36import java.io.IOException;
 37import java.io.Serializable;
 38import java.net.InetAddress;
 39import java.net.ServerSocket;
 40
 41/**
 42 * Instances of this class represent low-level network addresses of AmbientTalk
 43 * virtual machines.
 44 * 
 45 * An <tt>Address</tt> is frequently multicast across the network via UDP, serving
 46 * as the contents of a VM's <i>heartbeat</i>.
 47 * 
 48 * Implementation-wise, an <tt>Address</tt> encapsulates an IP address and a port number,
 49 * which is the address on which the {@link ServerSocket} of the {@link MasterConnectionThread}
 50 * is listening for incoming connections.
 51 * 
 52 * @author tvcutsem
 53 */
 54public class Address implements Serializable, Comparable {
 55
 56	/** the maximum size of a serialized address to be transported over UDP */
 57	public static final int MAX_ADDRESS_BYTE_SIZE = 256;
 58	
 59	public final InetAddress ipAddress_;
 60	public final int port_;
 61	
 62	/** the name of the overlay network to which this AmbientTalk VM belongs */
 63	public final String ambientTalkNetworkName_;
 64	
 65	/** an address is serialized at construction time and cached because it is constant */
 66	public final byte[] serializedForm_;
 67	
 68	/** the string form is cached because it is frequently used in the compareTo method */
 69	private final String stringForm_;
 70	
 71	/**
 72	 * @throws RuntimeException if the network name is so long that the serialized form
 73	 * of this <tt>Address</tt> would exceed {@link Address#MAX_ADDRESS_BYTE_SIZE}.
 74	 */
 75	public Address(InetAddress ipAddress, int port, String ambientTalkNetworkName) {
 76		ipAddress_ = ipAddress;
 77		port_ = port;
 78		ambientTalkNetworkName_ = ambientTalkNetworkName;
 79		serializedForm_ = toBytes();
 80		stringForm_ = ipAddress.toString() + port;
 81		
 82		// check for overflow
 83		if (serializedForm_.length > MAX_ADDRESS_BYTE_SIZE) {
 84			throw new RuntimeException("Address too long: " + this.toString());
 85		}
 86	}
 87	
 88	/**
 89	 * Deserialize a network address manually from a byte stream.
 90	 */
 91	public static Address fromBytes(byte[] serializedForm) throws IOException {
 92		ByteArrayInputStream bin = new ByteArrayInputStream(serializedForm);
 93		DataInputStream din = new DataInputStream(bin);
 94		String address = din.readUTF();
 95		InetAddress ipAddress = InetAddress.getByName(address);
 96		int port = din.readInt();
 97		String groupName = din.readUTF();
 98		din.close();
 99		return new Address(ipAddress, port, groupName);
100	}
101
102	/**
103	 * @return whether the receiver address and the parameter denote VMs that are
104	 * connected to the same AmbientTalk overlay network.
105	 */
106	public boolean inSameNetwork(Address other) {
107		return ambientTalkNetworkName_.equals(other.ambientTalkNetworkName_);
108	}
109	
110	/**
111	 * Compares two addresses based on their internal representation. There is no
112	 * logical ordering defined on addresses. However, it is guaranteed that
113	 * if <code>adr1.compareTo(adr2) > 0</code> then <code>adr2.compareTo(adr1) < 0</code>.
114	 */
115	public int compareTo(Object otherAddress) {
116		return stringForm_.compareTo(((Address) otherAddress).stringForm_);
117	}
118
119	public boolean equals(Object other) {
120		if (other instanceof Address) {
121			Address otherAddress = (Address) other;
122			return (ipAddress_.equals(otherAddress.ipAddress_) && port_ == otherAddress.port_)
123			         && (ambientTalkNetworkName_.equals(otherAddress.ambientTalkNetworkName_));
124		} else {
125			return false;
126		}
127	}
128	
129	/**
130	 * It is guaranteed that if two addresses are equal, then they map to the same hash code.
131	 */
132	public int hashCode() {
133		return ipAddress_.hashCode() | port_;
134	}
135	
136	public String toString() {
137		return ipAddress_.toString() + ":" + port_ + "[" + ambientTalkNetworkName_ + "]";
138	}
139	
140	private byte[] toBytes() {
141		try {
142			ByteArrayOutputStream bout = new ByteArrayOutputStream();
143			DataOutputStream dout = new DataOutputStream(bout);
144			dout.writeUTF(ipAddress_.getHostAddress());
145			dout.writeInt(port_);
146			dout.writeUTF(ambientTalkNetworkName_);
147			dout.close();
148			return bout.toByteArray();
149		} catch (IOException e) {
150			Logging.VirtualMachine_LOG.fatal("Could not construct serialized address:", e);
151			return null;
152		}
153	}
154	
155}