1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.collections4.properties;
19
20 import java.util.AbstractMap;
21 import java.util.AbstractMap.SimpleEntry;
22 import java.util.Enumeration;
23 import java.util.LinkedHashSet;
24 import java.util.Map;
25 import java.util.Properties;
26 import java.util.Set;
27 import java.util.stream.Collectors;
28 import java.util.stream.Stream;
29
30 import org.apache.commons.collections4.iterators.IteratorEnumeration;
31
32 /**
33 * A drop-in replacement for {@link Properties} for sorting keys.
34 * <p>
35 * Overrides {@link Properties#keys()} to sort keys. Allows other methods on the superclass to work with sorted keys.
36 * </p>
37 *
38 * @see SortedPropertiesFactory#INSTANCE
39 * @since 4.2
40 */
41 public class SortedProperties extends Properties {
42
43 private static final long serialVersionUID = 1L;
44
45 @Override
46 public Set<Map.Entry<Object, Object>> entrySet() {
47 final Stream<SimpleEntry<Object, Object>> stream = sortedKeys().map(k -> new AbstractMap.SimpleEntry<>(k, getProperty(k)));
48 return stream.collect(Collectors.toCollection(LinkedHashSet::new));
49 }
50
51 @Override
52 public synchronized Enumeration<Object> keys() {
53 return new IteratorEnumeration<>(sortedKeys().collect(Collectors.toList()).iterator());
54 }
55
56 private Stream<String> sortedKeys() {
57 return keySet().stream().map(Object::toString).sorted();
58 }
59 }