/*
 *  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.collections.map;

import java.util.Comparator;
import java.util.SortedMap;

import org.apache.commons.collections.Factory;
import org.apache.commons.collections.Transformer;

Decorates another SortedMap to create objects in the map on demand.
 When the LazyMap.get(Object) method is called with a key that does not exist in the map, the factory is used to create the object. The created object will be added to the map using the requested key. 

For instance:
Factory factory = new Factory() {
    public Object create() {
        return new Date();
    }
}
SortedMap lazy = Lazy.sortedMap(new HashMap(), factory);
Object obj = lazy.get("NOW");

After the above code is executed, obj will contain
a new Date instance. Furthermore, that Date
instance is mapped to the "NOW" key in the map.

Note that LazySortedMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using Collections.synchronizedSortedMap. This class may throw exceptions when accessed by concurrent threads without synchronization. 

This class is Serializable from Commons Collections 3.1.
Author:
Stephen Colebourne, Paul Jack
Since:
Commons Collections 3.0
Version:
$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $/**
 * Decorates another <code>SortedMap</code> to create objects in the map on demand.
 * <p>
 * When the {@link #get(Object)} method is called with a key that does not
 * exist in the map, the factory is used to create the object. The created
 * object will be added to the map using the requested key.
 * <p>
 * For instance:
 * <pre>
 * Factory factory = new Factory() {
 *     public Object create() {
 *         return new Date();
 *     }
 * }
 * SortedMap lazy = Lazy.sortedMap(new HashMap(), factory);
 * Object obj = lazy.get("NOW");
 * </pre>
 *
 * After the above code is executed, <code>obj</code> will contain
 * a new <code>Date</code> instance. Furthermore, that <code>Date</code>
 * instance is mapped to the "NOW" key in the map.
 * <p>
 * <strong>Note that LazySortedMap is not synchronized and is not thread-safe.</strong>
 * If you wish to use this map from multiple threads concurrently, you must use
 * appropriate synchronization. The simplest approach is to wrap this map
 * using {@link java.util.Collections#synchronizedSortedMap}. This class may throw 
 * exceptions when accessed by concurrent threads without synchronization.
 * <p>
 * This class is Serializable from Commons Collections 3.1.
 *
 * @since Commons Collections 3.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
 * 
 * @author Stephen Colebourne
 * @author Paul Jack
 */
public class LazySortedMap
        extends LazyMap
        implements SortedMap {

    
Serialization version /** Serialization version */
    private static final long serialVersionUID = 2715322183617658933L;

    
Factory method to create a lazily instantiated sorted map.
Params:
map –  the map to decorate, must not be null
factory –  the factory to use, must not be null
Throws:
IllegalArgumentException – if map or factory is null/**
     * Factory method to create a lazily instantiated sorted map.
     * 
     * @param map  the map to decorate, must not be null
     * @param factory  the factory to use, must not be null
     * @throws IllegalArgumentException if map or factory is null
     */
    public static SortedMap decorate(SortedMap map, Factory factory) {
        return new LazySortedMap(map, factory);
    }

    
Factory method to create a lazily instantiated sorted map.
Params:
map –  the map to decorate, must not be null
factory –  the factory to use, must not be null
Throws:
IllegalArgumentException – if map or factory is null/**
     * Factory method to create a lazily instantiated sorted map.
     * 
     * @param map  the map to decorate, must not be null
     * @param factory  the factory to use, must not be null
     * @throws IllegalArgumentException if map or factory is null
     */
    public static SortedMap decorate(SortedMap map, Transformer factory) {
        return new LazySortedMap(map, factory);
    }

    //-----------------------------------------------------------------------
    
Constructor that wraps (not copies).
Params:
map –  the map to decorate, must not be null
factory –  the factory to use, must not be null
Throws:
IllegalArgumentException – if map or factory is null/**
     * Constructor that wraps (not copies).
     * 
     * @param map  the map to decorate, must not be null
     * @param factory  the factory to use, must not be null
     * @throws IllegalArgumentException if map or factory is null
     */
    protected LazySortedMap(SortedMap map, Factory factory) {
        super(map, factory);
    }

    
Constructor that wraps (not copies).
Params:
map –  the map to decorate, must not be null
factory –  the factory to use, must not be null
Throws:
IllegalArgumentException – if map or factory is null/**
     * Constructor that wraps (not copies).
     * 
     * @param map  the map to decorate, must not be null
     * @param factory  the factory to use, must not be null
     * @throws IllegalArgumentException if map or factory is null
     */
    protected LazySortedMap(SortedMap map, Transformer factory) {
        super(map, factory);
    }

    //-----------------------------------------------------------------------
    
Gets the map being decorated.
Returns:
the decorated map/**
     * Gets the map being decorated.
     * 
     * @return the decorated map
     */
    protected SortedMap getSortedMap() {
        return (SortedMap) map;
    }

    //-----------------------------------------------------------------------
    public Object firstKey() {
        return getSortedMap().firstKey();
    }

    public Object lastKey() {
        return getSortedMap().lastKey();
    }

    public Comparator comparator() {
        return getSortedMap().comparator();
    }

    public SortedMap subMap(Object fromKey, Object toKey) {
        SortedMap map = getSortedMap().subMap(fromKey, toKey);
        return new LazySortedMap(map, factory);
    }

    public SortedMap headMap(Object toKey) {
        SortedMap map = getSortedMap().headMap(toKey);
        return new LazySortedMap(map, factory);
    }

    public SortedMap tailMap(Object fromKey) {
        SortedMap map = getSortedMap().tailMap(fromKey);
        return new LazySortedMap(map, factory);
    }

}