| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.collections4; |
| |
| /** |
| * Defines a map that maintains order and allows both forward and backward |
| * iteration through that order. |
| * |
| * @param <K> the type of the keys in the map |
| * @param <V> the type of the values in the map |
| * |
| * @since 3.0 |
| * @version $Id$ |
| */ |
| public interface OrderedMap<K, V> extends IterableMap<K, V> { |
| |
| /** |
| * Obtains an <code>OrderedMapIterator</code> over the map. |
| * <p> |
| * A ordered map iterator is an efficient way of iterating over maps |
| * in both directions. |
| * |
| * @return a map iterator |
| */ |
| @Override |
| OrderedMapIterator<K, V> mapIterator(); |
| |
| /** |
| * Gets the first key currently in this map. |
| * |
| * @return the first key currently in this map |
| * @throws java.util.NoSuchElementException if this map is empty |
| */ |
| K firstKey(); |
| |
| /** |
| * Gets the last key currently in this map. |
| * |
| * @return the last key currently in this map |
| * @throws java.util.NoSuchElementException if this map is empty |
| */ |
| K lastKey(); |
| |
| /** |
| * Gets the next key after the one specified. |
| * |
| * @param key the key to search for next from |
| * @return the next key, null if no match or at end |
| */ |
| K nextKey(K key); |
| |
| /** |
| * Gets the previous key before the one specified. |
| * |
| * @param key the key to search for previous from |
| * @return the previous key, null if no match or at start |
| */ |
| K previousKey(K key); |
| |
| } |