| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.catalina.tribes.group; |
| |
| import java.io.Serializable; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import java.util.List; |
| |
| import org.apache.catalina.tribes.Member; |
| |
| /** |
| * <p>Title: Membership - Absolute Order</p> |
| * |
| * <p>Description: A simple, yet agreeable and efficient way of ordering members</p> |
| * <p> |
| * Ordering members can serve as a basis for electing a leader or coordinating efforts.<br> |
| * This is stinky simple, it works on the basis of the <code>Member</code> interface |
| * and orders members in the following format: |
| * </p> |
| * <ol> |
| * <li>IP comparison - byte by byte, lower byte higher rank</li> |
| * <li>IPv4 addresses rank higher than IPv6, ie the lesser number of bytes, the higher rank</li> |
| * <li>Port comparison - lower port, higher rank</li> |
| * <li>UniqueId comparison- byte by byte, lower byte higher rank</li> |
| * </ol> |
| * |
| * |
| * @version 1.0 |
| * @see org.apache.catalina.tribes.Member |
| */ |
| public class AbsoluteOrder { |
| public static final AbsoluteComparator comp = new AbsoluteComparator(); |
| |
| protected AbsoluteOrder() { |
| super(); |
| } |
| |
| |
| public static void absoluteOrder(Member[] members) { |
| if ( members == null || members.length <= 1 ) return; |
| Arrays.sort(members,comp); |
| } |
| |
| public static void absoluteOrder(List<Member> members) { |
| if ( members == null || members.size() <= 1 ) return; |
| java.util.Collections.sort(members, comp); |
| } |
| |
| public static class AbsoluteComparator implements Comparator<Member>, |
| Serializable { |
| |
| private static final long serialVersionUID = 1L; |
| |
| @Override |
| public int compare(Member m1, Member m2) { |
| int result = compareIps(m1,m2); |
| if ( result == 0 ) result = comparePorts(m1,m2); |
| if ( result == 0 ) result = compareIds(m1,m2); |
| return result; |
| } |
| |
| public int compareIps(Member m1, Member m2) { |
| return compareBytes(m1.getHost(),m2.getHost()); |
| } |
| |
| public int comparePorts(Member m1, Member m2) { |
| return compareInts(m1.getPort(),m2.getPort()); |
| } |
| |
| public int compareIds(Member m1, Member m2) { |
| return compareBytes(m1.getUniqueId(),m2.getUniqueId()); |
| } |
| |
| protected int compareBytes(byte[] d1, byte[] d2) { |
| int result = 0; |
| if ( d1.length == d2.length ) { |
| for (int i=0; (result==0) && (i<d1.length); i++) { |
| result = compareBytes(d1[i],d2[i]); |
| } |
| } else if ( d1.length < d2.length) { |
| result = -1; |
| } else { |
| result = 1; |
| } |
| return result; |
| } |
| |
| protected int compareBytes(byte b1, byte b2) { |
| return compareInts(b1,b2); |
| } |
| |
| protected int compareInts(int b1, int b2) { |
| int result = 0; |
| if ( b1 == b2 ) { |
| |
| } else if ( b1 < b2) { |
| result = -1; |
| } else { |
| result = 1; |
| } |
| return result; |
| } |
| } |
| |
| } |