- /*
- * Copyright 2001-2004 The Apache Software Foundation
- *
- * Licensed 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.collections;
-
- /**
- * Defines a map that maintains order and allows both forward and backward
- * iteration through that order.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.6 $ $Date: 2004/02/18 01:15:42 $
- *
- * @author Stephen Colebourne
- */
- public interface OrderedMap extends IterableMap {
-
- /**
- * Obtains an <code>OrderedMapIterator</code> over the map.
- * <p>
- * A ordered map iterator is an efficient way of iterating over maps
- * in both directions.
- * <pre>
- * BidiMap map = new TreeBidiMap();
- * MapIterator it = map.mapIterator();
- * while (it.hasNext()) {
- * Object key = it.next();
- * Object value = it.getValue();
- * it.setValue("newValue");
- * Object previousKey = it.previous();
- * }
- * </pre>
- *
- * @return a map iterator
- */
- OrderedMapIterator orderedMapIterator();
-
- /**
- * 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
- */
- public Object 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
- */
- public Object 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
- */
- public Object nextKey(Object 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
- */
- public Object previousKey(Object key);
-
- }