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.ArrayList; 21 import java.util.Collections; 22 import java.util.Enumeration; 23 import java.util.List; 24 import java.util.Properties; 25 import java.util.Set; 26 27 import org.apache.commons.collections4.iterators.IteratorEnumeration; 28 29 /** 30 * A drop-in replacement for {@link Properties} for sorting keys. 31 * <p> 32 * Overrides {@link Properties#keys()} to sort keys. Allows other methods on the superclass to work with sorted keys. 33 * </p> 34 * 35 * @since 4.2 36 */ 37 public class SortedProperties extends Properties { 38 39 private static final long serialVersionUID = 1L; 40 41 @Override 42 public synchronized Enumeration<Object> keys() { 43 final Set<Object> keySet = keySet(); 44 final List<String> keys = new ArrayList<>(keySet.size()); 45 for (final Object key : keySet) { 46 keys.add(key.toString()); 47 } 48 Collections.sort(keys); 49 return new IteratorEnumeration<>(keys.iterator()); 50 } 51 }