001/**
002 *
003 * Copyright 2013-2017 Florian Schmaus
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.jivesoftware.smack.util.dns;
018
019import java.net.InetAddress;
020import java.util.List;
021
022import org.jivesoftware.smack.util.StringUtils;
023
024/**
025 * A DNS SRV RR.
026 *
027 * @see <a href="http://tools.ietf.org/html/rfc2782">RFC 2782: A DNS RR for specifying the location of services (DNS
028 * SRV)</a>
029 * @author Florian Schmaus
030 * 
031 */
032public class SRVRecord extends HostAddress implements Comparable<SRVRecord> {
033
034    private int weight;
035    private int priority;
036
037    /**
038     * SRV Record constructor.
039     * 
040     * @param fqdn Fully qualified domain name
041     * @param port The connection port
042     * @param priority Priority of the target host
043     * @param weight Relative weight for records with same priority
044     * @param inetAddresses list of addresses.
045     * @throws IllegalArgumentException fqdn is null or any other field is not in valid range (0-65535).
046     */
047    public SRVRecord(String fqdn, int port, int priority, int weight, List<InetAddress> inetAddresses) {
048        super(fqdn, port, inetAddresses);
049        StringUtils.requireNotNullOrEmpty(fqdn, "The FQDN must not be null");
050        if (weight < 0 || weight > 65535)
051            throw new IllegalArgumentException(
052                    "DNS SRV records weight must be a 16-bit unsigned integer (i.e. between 0-65535. Weight was: "
053                            + weight);
054
055        if (priority < 0 || priority > 65535)
056            throw new IllegalArgumentException(
057                    "DNS SRV records priority must be a 16-bit unsigned integer (i.e. between 0-65535. Priority was: "
058                            + priority);
059
060        this.priority = priority;
061        this.weight = weight;
062
063    }
064
065    public int getPriority() {
066        return priority;
067    }
068
069    public int getWeight() {
070        return weight;
071    }
072
073    @Override
074    public int compareTo(SRVRecord other) {
075        // According to RFC2782,
076        // "[a] client MUST attempt to contact the target host with the lowest-numbered priority it can reach".
077        // This means that a SRV record with a higher priority is 'less' then one with a lower.
078        int res = other.priority - this.priority;
079        if (res == 0) {
080            res = this.weight - other.weight;
081        }
082        return res;
083    }
084
085    @Override
086    public String toString() {
087        return super.toString() + " prio:" + priority + ":w:" + weight;
088    }
089}