org.jnode.net.ipv4.resolver.ResolverImpl.java Source code

Introduction

Here is the source code for org.jnode.net.ipv4.resolver.ResolverImpl.java

Source

/*
 * $Id: ResolverImpl.java 4215 2008-06-08 05:47:07Z crawley $
 *
 * JNode.org
 * Copyright (C) 2003-2006 JNode.org
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; If not, write to the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
/*
 * 2008 - 2010 (c) Waterford Institute of Technology
 *         TSSG, EU ICT 4WARD
 *
 * 2010 (c) Pouzin Society
 *   - Forked from EU ICT 4WARD Open Source Distribution.
 *   - Organisation Strings updated to reflect fork.
 *
 *
 * Author        : pphelan(at)tssg.org
 *
 * Modifications : Changes to port JNode code base to OSGi platform.
 *                 - Rewrite of Resolver to be simple Host file implementation.
 *
 */
package org.jnode.net.ipv4.resolver;

import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.*;
import org.jnode.driver.net.NetworkException;
import org.jnode.net.ProtocolAddress;
import org.jnode.net.Resolver;
import org.jnode.net.ipv4.IPv4Address;

/**
 * @author Martin Hartvig
 */
public class ResolverImpl implements Resolver {
    private Map<String, ProtocolAddress[]> hosts = new HashMap<String, ProtocolAddress[]>();
    private Map<String, String[]> rhosts = new HashMap<String, String[]>();
    @SuppressWarnings("unused")
    private static Log log = LogFactory.getLog(ResolverImpl.class);

    ResolverImpl() {
        synchronized (hosts) {
            hosts.put("localhost", new ProtocolAddress[] { new IPv4Address("127.0.0.1") });
            rhosts.put("127.0.0.1", new String[] { "localhost" });
        }
    }

    public void addEntry(String hostName, ProtocolAddress[] protocolAddresses) throws NetworkException {
        synchronized (hosts) {
            hosts.put(hostName, protocolAddresses);

            for (ProtocolAddress ad : protocolAddresses) {
                String pAddr = ad.toString();
                String[] currentArray = rhosts.get(pAddr);
                if (currentArray == null) {
                    rhosts.put(pAddr, new String[] { hostName });
                } else {
                    String[] newArray = new String[currentArray.length + 1];
                    newArray = currentArray.clone();
                    newArray[currentArray.length] = hostName;
                    rhosts.put(pAddr, newArray);
                }
            }
        }
        /**
        StringBuffer buf = new StringBuffer();
        for (String ipAddr : rhosts.keySet()) {
           buf.append("Entry: " + ipAddr + " - (");
           for (String hostname : rhosts.get(ipAddr)){
        buf.append(hostname + ",");
           }
           buf.append(")");
        }
        log.info(buf.toString());
        */
    }

    /**
     * Get from hosts file.
     * 
     * @param _hostname
     * @return
     */
    private ProtocolAddress[] getFromHostsFile(String hostname) {
        ProtocolAddress[] lookup;
        synchronized (hosts) {
            lookup = hosts.get(hostname);
        }
        return lookup;
    }

    /**
     * Gets the address(es) of the given hostname.
     * 
     * @param hostname
     * @return All addresses of the given hostname. The returned array is at
     *         least 1 address long.
     * @throws java.net.UnknownHostException
     */
    public ProtocolAddress[] getByName(final String hostname) throws UnknownHostException {
        if (hostname == null) {
            throw new UnknownHostException("null");
        }
        if (hostname.equals("*")) {
            // FIXME ... why is this a special case? Comment please or fix it.
            throw new UnknownHostException("*");
        }
        ProtocolAddress[] protocolAddresses = getFromHostsFile(hostname);
        if (protocolAddresses != null) {
            return protocolAddresses;
        }
        throw new UnknownHostException(hostname);
    }

    /**
     * Gets the hostname of the given address.
     * 
     * @param address
     * @return All hostnames of the given hostname. The returned array is at
     *         least 1 hostname long.
     * @throws java.net.UnknownHostException
     */

    public String[] getByAddress(ProtocolAddress address) throws UnknownHostException {
        String[] lookup;
        synchronized (hosts) {
            lookup = rhosts.get(address.toString());
        }
        if (lookup != null)
            return lookup;

        throw new UnknownHostException(address.toString());
    }

}