1 package org.apache.maven.plugins.shade.resource.properties;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import java.util.ArrayList;
23 import java.util.Collections;
24 import java.util.Comparator;
25 import java.util.Enumeration;
26 import java.util.Iterator;
27 import java.util.LinkedHashSet;
28 import java.util.LinkedList;
29 import java.util.List;
30 import java.util.Map;
31 import java.util.Properties;
32 import java.util.Set;
33
34 /**
35 * Internal Properties instance sorting its keys on iterations for store() usages.
36 * It ensures properties persistence is deterministic.
37 *
38 * IMPORTANT: this only overrides methods used across JVM in store() so ordering is not guaranteed for other cases.
39 */
40 public class SortedProperties extends Properties
41 {
42 @Override
43 public Set<Map.Entry<Object, Object>> entrySet()
44 {
45 final List<Map.Entry<Object, Object>> entries = new ArrayList<>( super.entrySet() );
46 Collections.sort( entries, new Comparator<Map.Entry<Object, Object>>()
47 {
48 @Override
49 public int compare( Map.Entry<Object, Object> o1, Map.Entry<Object, Object> o2 )
50 {
51 return String.valueOf( o1.getKey() ).compareTo( String.valueOf( o2.getKey() ) );
52 }
53 } );
54 return new LinkedHashSet<>( entries );
55 }
56
57 @Override
58 public synchronized Enumeration<Object> keys() // ensure it is sorted to be deterministic
59 {
60 final List<String> keys = new LinkedList<>();
61 for ( Object k : super.keySet() )
62 {
63 keys.add( (String) k );
64 }
65 Collections.sort( keys );
66 final Iterator<String> it = keys.iterator();
67 return new Enumeration<Object>()
68 {
69 @Override
70 public boolean hasMoreElements()
71 {
72 return it.hasNext();
73 }
74
75 @Override
76 public Object nextElement()
77 {
78 return it.next();
79 }
80 };
81 }
82 }