4 * Copyright 2015 TJ <hacker@iam.tj>.
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 package uk.ac.ntu.n0521366.wsyd.libs;
26 import java.util.Comparator;
27 import java.io.Serializable;
30 * Order by Long values; usable to sort keys in Collections e.g. TreeMap<Long, WSYD_Member>.
32 * Implements serializable in order that the Collection using it doesn't cause
33 * deserialize Exceptions due to missing Comparator
35 * @author TJ <hacker@iam.tj>
37 public class WSYD_Member_Comparator_UserID implements Comparator<Long>, Serializable {
39 * Sorts numerically low to high
43 * @return -1 if user1 < user2, 0 if user1 == user2, 1 if user1 > user2
44 * @throws NullPointerException
47 public int compare(Long user1, Long user2) throws NullPointerException {
48 if (user1 == null || user2 == null)
49 throw new NullPointerException();
50 return Long.compare(user1, user2);