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      1 /**
      2  *
      3  */
      4 package javax.jmdns.impl;
      5 
      6 import java.lang.reflect.Method;
      7 import java.net.InetAddress;
      8 import java.net.NetworkInterface;
      9 import java.net.SocketException;
     10 import java.util.Enumeration;
     11 import java.util.HashSet;
     12 import java.util.Set;
     13 import java.util.logging.Level;
     14 import java.util.logging.Logger;
     15 
     16 import javax.jmdns.NetworkTopologyDiscovery;
     17 
     18 /**
     19  * This class implements NetworkTopologyDiscovery.
     20  *
     21  * @author Pierre Frisch
     22  */
     23 public class NetworkTopologyDiscoveryImpl implements NetworkTopologyDiscovery {
     24     private final static Logger logger = Logger.getLogger(NetworkTopologyDiscoveryImpl.class.getName());
     25 
     26     private final Method        _isUp;
     27 
     28     private final Method        _supportsMulticast;
     29 
     30     /**
     31      *
     32      */
     33     public NetworkTopologyDiscoveryImpl() {
     34         super();
     35         Method isUp;
     36         try {
     37             isUp = NetworkInterface.class.getMethod("isUp", (Class<?>[]) null);
     38         } catch (Exception exception) {
     39             // We do not want to throw anything if the method does not exist.
     40             isUp = null;
     41         }
     42         _isUp = isUp;
     43         Method supportsMulticast;
     44         try {
     45             supportsMulticast = NetworkInterface.class.getMethod("supportsMulticast", (Class<?>[]) null);
     46         } catch (Exception exception) {
     47             // We do not want to throw anything if the method does not exist.
     48             supportsMulticast = null;
     49         }
     50         _supportsMulticast = supportsMulticast;
     51     }
     52 
     53     /*
     54      * (non-Javadoc)
     55      * @see javax.jmdns.JmmDNS.NetworkTopologyDiscovery#getInetAddresses()
     56      */
     57     @Override
     58     public InetAddress[] getInetAddresses() {
     59         Set<InetAddress> result = new HashSet<InetAddress>();
     60         try {
     61 
     62             for (Enumeration<NetworkInterface> nifs = NetworkInterface.getNetworkInterfaces(); nifs.hasMoreElements();) {
     63                 NetworkInterface nif = nifs.nextElement();
     64                 for (Enumeration<InetAddress> iaenum = nif.getInetAddresses(); iaenum.hasMoreElements();) {
     65                     InetAddress interfaceAddress = iaenum.nextElement();
     66                     if (logger.isLoggable(Level.FINEST)) {
     67                         logger.finest("Found NetworkInterface/InetAddress: " + nif + " -- " + interfaceAddress);
     68                     }
     69                     if (this.useInetAddress(nif, interfaceAddress)) {
     70                         result.add(interfaceAddress);
     71                     }
     72                 }
     73             }
     74         } catch (SocketException se) {
     75             logger.warning("Error while fetching network interfaces addresses: " + se);
     76         }
     77         return result.toArray(new InetAddress[result.size()]);
     78     }
     79 
     80     /*
     81      * (non-Javadoc)
     82      * @see javax.jmdns.JmmDNS.NetworkTopologyDiscovery#useInetAddress(java.net.NetworkInterface, java.net.InetAddress)
     83      */
     84     @Override
     85     public boolean useInetAddress(NetworkInterface networkInterface, InetAddress interfaceAddress) {
     86         try {
     87             if (_isUp != null) {
     88                 try {
     89                     if (!((Boolean) _isUp.invoke(networkInterface, (Object[]) null)).booleanValue()) {
     90                         return false;
     91                     }
     92                 } catch (Exception exception) {
     93                     // We should hide that exception.
     94                 }
     95             }
     96             if (_supportsMulticast != null) {
     97                 try {
     98                     if (!((Boolean) _supportsMulticast.invoke(networkInterface, (Object[]) null)).booleanValue()) {
     99                         return false;
    100                     }
    101                 } catch (Exception exception) {
    102                     // We should hide that exception.
    103                 }
    104             }
    105             if (interfaceAddress.isLoopbackAddress()) {
    106                 return false;
    107             }
    108             return true;
    109         } catch (Exception exception) {
    110             return false;
    111         }
    112     }
    113 
    114     /*
    115      * (non-Javadoc)
    116      * @see javax.jmdns.NetworkTopologyDiscovery#lockInetAddress(java.net.InetAddress)
    117      */
    118     @Override
    119     public void lockInetAddress(InetAddress interfaceAddress) {
    120         // Default implementation does nothing.
    121     }
    122 
    123     /*
    124      * (non-Javadoc)
    125      * @see javax.jmdns.NetworkTopologyDiscovery#unlockInetAddress(java.net.InetAddress)
    126      */
    127     @Override
    128     public void unlockInetAddress(InetAddress interfaceAddress) {
    129         // Default implementation does nothing.
    130     }
    131 
    132 }
    133