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 package org.apache.commons.collections; 018 019 import java.util.Comparator; 020 021 /** 022 * Defines a type of <code>Bag</code> that maintains a sorted order among 023 * its unique representative members. 024 * 025 * @since Commons Collections 2.0 026 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 027 * 028 * @author Chuck Burdick 029 */ 030 public interface SortedBag extends Bag { 031 032 /** 033 * Returns the comparator associated with this sorted set, or null 034 * if it uses its elements' natural ordering. 035 * 036 * @return the comparator in use, or null if natural ordering 037 */ 038 public Comparator comparator(); 039 040 /** 041 * Returns the first (lowest) member. 042 * 043 * @return the first element in the sorted bag 044 */ 045 public Object first(); 046 047 /** 048 * Returns the last (highest) member. 049 * 050 * @return the last element in the sorted bag 051 */ 052 public Object last(); 053 054 }