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 * http://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.ArrayList; 021import java.util.Collections; 022import java.util.Enumeration; 023import java.util.List; 024import java.util.Properties; 025import java.util.Set; 026 027import org.apache.commons.collections4.iterators.IteratorEnumeration; 028 029/** 030 * A drop-in replacement for {@link Properties} for sorting keys. 031 * <p> 032 * Overrides {@link Properties#keys()} to sort keys. Allows other methods on the superclass to work with sorted keys. 033 * </p> 034 * 035 * @since 4.2 036 */ 037public class SortedProperties extends Properties { 038 039 private static final long serialVersionUID = 1L; 040 041 @Override 042 public synchronized Enumeration<Object> keys() { 043 final Set<Object> keySet = keySet(); 044 final List<String> keys = new ArrayList<>(keySet.size()); 045 for (final Object key : keySet) { 046 keys.add(key.toString()); 047 } 048 Collections.sort(keys); 049 return new IteratorEnumeration<Object>(keys.iterator()); 050 } 051}