001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      https://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 */
017
018package org.apache.commons.collections4.properties;
019
020import java.util.AbstractMap;
021import java.util.Collections;
022import java.util.Enumeration;
023import java.util.LinkedHashSet;
024import java.util.Map;
025import java.util.Properties;
026import java.util.Set;
027import java.util.TreeSet;
028import java.util.function.BiConsumer;
029import java.util.stream.Collectors;
030import java.util.stream.Stream;
031
032/**
033 * A drop-in replacement for {@link Properties} for sorting keys.
034 * <p>
035 * Overrides {@link Properties#keys()} to sort keys. Allows other methods on the superclass to work with sorted keys.
036 * </p>
037 *
038 * @see SortedPropertiesFactory#INSTANCE
039 * @since 4.2
040 */
041public class SortedProperties extends Properties {
042
043    private static final long serialVersionUID = 1L;
044
045    /**
046     * Constructs a new instance.
047     */
048    public SortedProperties() {
049        // empty
050    }
051
052    @Override
053    public Set<Map.Entry<Object, Object>> entrySet() {
054        return keyStream().map(k -> new AbstractMap.SimpleEntry<>(k, get(k))).collect(Collectors.toCollection(LinkedHashSet::new));
055    }
056
057    /**
058     * Enumerates all key/value pairs in the specified TreeSet and omits the property if the key or value is not a string.
059     *
060     * @param result The result set to populate.
061     * @return The given set.
062     */
063    private synchronized TreeSet<String> enumerateStringProperties(final TreeSet<String> result) {
064        if (defaults != null) {
065            result.addAll(defaults.stringPropertyNames());
066        }
067        for (final Enumeration<?> e = keys(); e.hasMoreElements();) {
068            final Object k = e.nextElement();
069            final Object v = get(k);
070            if (k instanceof String && v instanceof String) {
071                result.add((String) k);
072            }
073        }
074        return result;
075    }
076
077    @Override
078    public synchronized void forEach(final BiConsumer<? super Object, ? super Object> action) {
079        keyStream().forEach(k -> action.accept(k, get(k)));
080    }
081
082    @Override
083    public synchronized Enumeration<Object> keys() {
084        return Collections.enumeration(keySet());
085    }
086
087    @Override
088    public Set<Object> keySet() {
089        return new TreeSet<>(super.keySet());
090    }
091
092    private Stream<Object> keyStream() {
093        return keySet().stream();
094    }
095
096    @Override
097    public Enumeration<?> propertyNames() {
098        return Collections.enumeration(stringPropertyNames());
099    }
100
101    @Override
102    public Set<String> stringPropertyNames() {
103        return enumerateStringProperties(new TreeSet<>());
104    }
105}