656 lines
19 KiB
Java
656 lines
19 KiB
Java
/* InetAddress.java -- Class to model an Internet address
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Copyright (C) 1998, 1999, 2002, 2004, 2005, 2006
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Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.net;
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import java.io.IOException;
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import java.io.ObjectStreamException;
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import java.io.Serializable;
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/**
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* This class models an Internet address. It does not have a public
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* constructor. Instead, new instances of this objects are created
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* using the static methods getLocalHost(), getByName(), and
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* getAllByName().
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*
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* <p>This class fulfills the function of the C style functions gethostname(),
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* gethostbyname(), and gethostbyaddr(). It resolves Internet DNS names
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* into their corresponding numeric addresses and vice versa.</p>
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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* @author Per Bothner
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* @author Gary Benson (gbenson@redhat.com)
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*
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* @specnote This class is not final since JDK 1.4
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*/
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public class InetAddress implements Serializable
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{
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private static final long serialVersionUID = 3286316764910316507L;
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/**
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* Dummy InetAddress, used to bind socket to any (all) network interfaces.
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*/
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static InetAddress ANY_IF;
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static
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{
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byte[] addr;
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try
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{
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addr = VMInetAddress.lookupInaddrAny();
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}
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catch (UnknownHostException e)
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{
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// Make one up and hope it works.
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addr = new byte[] {0, 0, 0, 0};
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}
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try
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{
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ANY_IF = getByAddress(addr);
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}
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catch (UnknownHostException e)
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{
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throw (InternalError) new InternalError().initCause(e);
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}
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ANY_IF.hostName = ANY_IF.getHostName();
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}
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/**
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* Stores static localhost address object.
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*/
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static InetAddress LOCALHOST;
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static
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{
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try
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{
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LOCALHOST = getByAddress("localhost", new byte[] {127, 0, 0, 1});
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}
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catch (UnknownHostException e)
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{
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throw (InternalError) new InternalError().initCause(e);
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}
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}
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/**
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* The Serialized Form specifies that an int 'address' is saved/restored.
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* This class uses a byte array internally so we'll just do the conversion
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* at serialization time and leave the rest of the algorithm as is.
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*/
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private int address;
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/**
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* An array of octets representing an IP address.
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*/
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transient byte[] addr;
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/**
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* The name of the host for this address.
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*/
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String hostName;
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/**
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* Needed for serialization.
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*/
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private int family;
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/**
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* Constructor. Prior to the introduction of IPv6 support in 1.4,
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* methods such as InetAddress.getByName() would return InetAddress
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* objects. From 1.4 such methods returned either Inet4Address or
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* Inet6Address objects, but for compatibility Inet4Address objects
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* are serialized as InetAddresses. As such, there are only two
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* places where it is appropriate to invoke this constructor: within
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* subclasses constructors and within Inet4Address.writeReplace().
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*
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* @param ipaddr The IP number of this address as an array of bytes
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* @param hostname The hostname of this IP address.
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* @param family The address family of this IP address.
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*/
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InetAddress(byte[] ipaddr, String hostname, int family)
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{
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addr = (null == ipaddr) ? null : (byte[]) ipaddr.clone();
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hostName = hostname;
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this.family = family;
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}
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/**
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* Returns true if this address is a multicast address, false otherwise.
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* An address is multicast if the high four bits are "1110". These are
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* also known as "Class D" addresses.
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @return true if mulitcast, false if not
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*
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* @since 1.1
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*/
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public boolean isMulticastAddress()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if the InetAddress in a wildcard address
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isAnyLocalAddress()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if the InetAddress is a loopback address
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isLoopbackAddress()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if InetAddress is a link local address
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isLinkLocalAddress()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if InetAddress is a site local address
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isSiteLocalAddress()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if InetAddress is a global multicast address
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isMCGlobal()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if InetAddress is a node local multicast address.
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isMCNodeLocal()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if InetAddress is a link local multicast address.
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isMCLinkLocal()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if InetAddress is a site local multicast address.
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isMCSiteLocal()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Utility routine to check if InetAddress is a organization local
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* multicast address.
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @since 1.4
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*/
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public boolean isMCOrgLocal()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Returns the hostname for this address. This will return the IP address
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* as a String if there is no hostname available for this address
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*
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* @return The hostname for this address
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*/
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public String getHostName()
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{
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if (hostName == null)
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hostName = getCanonicalHostName();
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return hostName;
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}
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/**
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* Returns the canonical hostname represented by this InetAddress
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*/
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String internalGetCanonicalHostName()
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{
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try
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{
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return ResolverCache.getHostByAddr(addr);
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}
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catch (UnknownHostException e)
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{
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return getHostAddress();
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}
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}
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/**
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* Returns the canonical hostname represented by this InetAddress
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*
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* @since 1.4
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*/
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public String getCanonicalHostName()
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{
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String hostname = internalGetCanonicalHostName();
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SecurityManager sm = System.getSecurityManager();
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if (sm != null)
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{
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try
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{
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sm.checkConnect(hostname, -1);
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}
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catch (SecurityException e)
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{
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return getHostAddress();
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}
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}
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return hostname;
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}
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/**
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* Returns the IP address of this object as a byte array.
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*
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* @return IP address
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*/
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public byte[] getAddress()
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{
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// An experiment shows that JDK1.2 returns a different byte array each
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// time. This makes sense, in terms of security.
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return (byte[]) addr.clone();
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}
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/**
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* Returns the IP address of this object as a String.
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*
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* <p>This method cannot be abstract for backward compatibility reasons. By
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* default it always throws {@link UnsupportedOperationException} unless
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* overridden.</p>
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*
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* @return The IP address of this object in String form
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*
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* @since 1.0.2
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*/
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public String getHostAddress()
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Returns a hash value for this address. Useful for creating hash
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* tables. Overrides Object.hashCode()
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*
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* @return A hash value for this address.
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*/
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public int hashCode()
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{
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// There hashing algorithm is not specified, but a simple experiment
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// shows that it is equal to the address, as a 32-bit big-endian integer.
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int hash = 0;
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int len = addr.length;
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int i = len > 4 ? len - 4 : 0;
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for (; i < len; i++)
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hash = (hash << 8) | (addr[i] & 0xff);
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return hash;
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}
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/**
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* Tests this address for equality against another InetAddress. The two
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* addresses are considered equal if they contain the exact same octets.
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* This implementation overrides Object.equals()
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*
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* @param obj The address to test for equality
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*
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* @return true if the passed in object's address is equal to this one's,
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* false otherwise
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*/
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public boolean equals(Object obj)
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{
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if (! (obj instanceof InetAddress))
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return false;
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// "The Java Class Libraries" 2nd edition says "If a machine has
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// multiple names instances of InetAddress for different name of
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// that same machine are not equal. This is because they have
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// different host names." This violates the description in the
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// JDK 1.2 API documentation. A little experimentation
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// shows that the latter is correct.
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byte[] addr2 = ((InetAddress) obj).addr;
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if (addr.length != addr2.length)
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return false;
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for (int i = 0; i < addr.length; i++)
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if (addr[i] != addr2[i])
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return false;
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return true;
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}
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/**
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* Converts this address to a String. This string contains the IP in
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* dotted decimal form. For example: "127.0.0.1" This method is equivalent
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* to getHostAddress() and overrides Object.toString()
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*
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* @return This address in String form
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*/
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public String toString()
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{
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String addr = getHostAddress();
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String host = (hostName != null) ? hostName : "";
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return host + "/" + addr;
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}
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/**
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* Returns an InetAddress object given the raw IP address.
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*
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* The argument is in network byte order: the highest order byte of the
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* address is in getAddress()[0].
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*
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* @param addr The IP address to create the InetAddress object from
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*
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* @exception UnknownHostException If IP address has illegal length
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*
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* @since 1.4
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*/
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public static InetAddress getByAddress(byte[] addr)
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throws UnknownHostException
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{
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return getByAddress(null, addr);
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}
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/**
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* Creates an InetAddress based on the provided host name and IP address.
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* No name service is checked for the validity of the address.
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*
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* @param host The hostname of the InetAddress object to create
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* @param addr The IP address to create the InetAddress object from
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*
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* @exception UnknownHostException If IP address is of illegal length
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*
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* @since 1.4
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*/
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public static InetAddress getByAddress(String host, byte[] addr)
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throws UnknownHostException
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{
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if (addr.length == 4)
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return new Inet4Address(addr, host);
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if (addr.length == 16)
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{
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for (int i = 0; i < 12; i++)
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{
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if (addr[i] != (i < 10 ? 0 : (byte) 0xFF))
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return new Inet6Address(addr, host);
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}
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byte[] ip4addr = new byte[4];
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ip4addr[0] = addr[12];
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ip4addr[1] = addr[13];
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ip4addr[2] = addr[14];
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ip4addr[3] = addr[15];
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return new Inet4Address(ip4addr, host);
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}
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throw new UnknownHostException("IP address has illegal length");
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}
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/**
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* Returns an InetAddress object representing the IP address of
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* the given literal IP address in dotted decimal format such as
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* "127.0.0.1". This is used by SocketPermission.setHostPort()
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* to parse literal IP addresses without performing a DNS lookup.
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*
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* @param literal The literal IP address to create the InetAddress
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* object from
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*
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* @return The address of the host as an InetAddress object, or
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* null if the IP address is invalid.
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*/
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static InetAddress getByLiteral(String literal)
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{
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byte[] address = VMInetAddress.aton(literal);
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if (address == null)
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return null;
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try
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{
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return getByAddress(address);
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}
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catch (UnknownHostException e)
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{
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throw (InternalError) new InternalError().initCause(e);
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}
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}
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/**
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* Returns an InetAddress object representing the IP address of the given
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* hostname. This name can be either a hostname such as "www.urbanophile.com"
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* or an IP address in dotted decimal format such as "127.0.0.1". If the
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* hostname is null or "", the hostname of the local machine is supplied by
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* default. This method is equivalent to returning the first element in
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* the InetAddress array returned from GetAllByName.
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*
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* @param hostname The name of the desired host, or null for the local
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* loopback address.
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*
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* @return The address of the host as an InetAddress object.
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*
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* @exception UnknownHostException If no IP address for the host could
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* be found
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* @exception SecurityException If a security manager exists and its
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* checkConnect method doesn't allow the operation
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*/
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public static InetAddress getByName(String hostname)
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throws UnknownHostException
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{
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InetAddress[] addresses = getAllByName(hostname);
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return addresses[0];
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}
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/**
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* Returns an array of InetAddress objects representing all the host/ip
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* addresses of a given host, given the host's name. This name can be
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* either a hostname such as "www.urbanophile.com" or an IP address in
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* dotted decimal format such as "127.0.0.1". If the value is null, the
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* hostname of the local machine is supplied by default.
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*
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* @param hostname The name of the desired host, or null for the
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* local loopback address.
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*
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* @return All addresses of the host as an array of InetAddress objects.
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*
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* @exception UnknownHostException If no IP address for the host could
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* be found
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* @exception SecurityException If a security manager exists and its
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* checkConnect method doesn't allow the operation
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*/
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public static InetAddress[] getAllByName(String hostname)
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throws UnknownHostException
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{
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// If null or the empty string is supplied, the loopback address
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|
// is returned.
|
|
if (hostname == null || hostname.length() == 0)
|
|
return new InetAddress[] {LOCALHOST};
|
|
|
|
// Check if hostname is an IP address
|
|
InetAddress address = getByLiteral(hostname);
|
|
if (address != null)
|
|
return new InetAddress[] {address};
|
|
|
|
// Perform security check before resolving
|
|
SecurityManager sm = System.getSecurityManager();
|
|
if (sm != null)
|
|
sm.checkConnect(hostname, -1);
|
|
|
|
// Resolve the hostname
|
|
byte[][] iplist = ResolverCache.getHostByName(hostname);
|
|
if (iplist.length == 0)
|
|
throw new UnknownHostException(hostname);
|
|
|
|
InetAddress[] addresses = new InetAddress[iplist.length];
|
|
for (int i = 0; i < iplist.length; i++)
|
|
addresses[i] = getByAddress(hostname, iplist[i]);
|
|
|
|
return addresses;
|
|
}
|
|
|
|
/**
|
|
* Returns an InetAddress object representing the address of the current
|
|
* host.
|
|
*
|
|
* @return The local host's address
|
|
*
|
|
* @exception UnknownHostException If no IP address for the host could
|
|
* be found
|
|
*/
|
|
public static InetAddress getLocalHost() throws UnknownHostException
|
|
{
|
|
String hostname = VMInetAddress.getLocalHostname();
|
|
try
|
|
{
|
|
return getByName(hostname);
|
|
}
|
|
catch (SecurityException e)
|
|
{
|
|
return LOCALHOST;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Inet4Address objects are serialized as InetAddress objects.
|
|
* This deserializes them back into Inet4Address objects.
|
|
*/
|
|
private Object readResolve() throws ObjectStreamException
|
|
{
|
|
return new Inet4Address(addr, hostName);
|
|
}
|
|
|
|
private void readObject(ObjectInputStream ois)
|
|
throws IOException, ClassNotFoundException
|
|
{
|
|
ois.defaultReadObject();
|
|
addr = new byte[4];
|
|
addr[3] = (byte) address;
|
|
|
|
for (int i = 2; i >= 0; --i)
|
|
addr[i] = (byte) (address >>= 8);
|
|
}
|
|
|
|
private void writeObject(ObjectOutputStream oos) throws IOException
|
|
{
|
|
// Build a 32 bit address from the last 4 bytes of a 4 byte IPv4 address
|
|
// or a 16 byte IPv6 address.
|
|
int len = addr.length;
|
|
int i = len - 4;
|
|
|
|
for (; i < len; i++)
|
|
address = address << 8 | (addr[i] & 0xff);
|
|
|
|
oos.defaultWriteObject();
|
|
}
|
|
}
|