home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Commons Collections example source code file (TransformedSortedMap.java)

This example Commons Collections source code file (TransformedSortedMap.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Collections tags/keywords

comparator, map, object, object, sortedmap, sortedmap, transformedmap, transformedsortedmap, transformedsortedmap, transformer, transformer, util

The Commons Collections TransformedSortedMap.java source code

/*
 *  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.Map;
import java.util.SortedMap;

import org.apache.commons.collections.Transformer;

/**
 * Decorates another <code>SortedMap  to transform objects that are added.
 * <p>
 * The Map put methods and Map.Entry setValue method are affected by this class.
 * Thus objects must be removed or searched for using their transformed form.
 * For example, if the transformation converts Strings to Integers, you must
 * use the Integer form to remove objects.
 * <p>
 * <strong>Note that TransformedSortedMap 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 {@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 13:33:15 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author Stephen Colebourne
 */
public class TransformedSortedMap
        extends TransformedMap
        implements SortedMap {

    /** Serialization version */
    private static final long serialVersionUID = -8751771676410385778L;
    
    /**
     * Factory method to create a transforming sorted map.
     * <p>
     * If there are any elements already in the map being decorated, they
     * are NOT transformed.
     * Constrast this with {@link #decorateTransform}.
     * 
     * @param map  the map to decorate, must not be null
     * @param keyTransformer  the predicate to validate the keys, null means no transformation
     * @param valueTransformer  the predicate to validate to values, null means no transformation
     * @throws IllegalArgumentException if the map is null
     */
    public static SortedMap decorate(SortedMap map, Transformer keyTransformer, Transformer valueTransformer) {
        return new TransformedSortedMap(map, keyTransformer, valueTransformer);
    }

    /**
     * Factory method to create a transforming sorted map that will transform
     * existing contents of the specified map.
     * <p>
     * If there are any elements already in the map being decorated, they
     * will be transformed by this method.
     * Constrast this with {@link #decorate}.
     * 
     * @param map  the map to decorate, must not be null
     * @param keyTransformer  the transformer to use for key conversion, null means no transformation
     * @param valueTransformer  the transformer to use for value conversion, null means no transformation
     * @throws IllegalArgumentException if map is null
     * @since Commons Collections 3.2
     */
    public static SortedMap decorateTransform(SortedMap map, Transformer keyTransformer, Transformer valueTransformer) {
        TransformedSortedMap decorated = new TransformedSortedMap(map, keyTransformer, valueTransformer);
        if (map.size() > 0) {
            Map transformed = decorated.transformMap(map);
            decorated.clear();
            decorated.getMap().putAll(transformed);  // avoids double transformation
        }
        return decorated;
    }

    //-----------------------------------------------------------------------
    /**
     * Constructor that wraps (not copies).
     * <p>
     * If there are any elements already in the collection being decorated, they
     * are NOT transformed.</p>
     * 
     * @param map  the map to decorate, must not be null
     * @param keyTransformer  the predicate to validate the keys, null means no transformation
     * @param valueTransformer  the predicate to validate to values, null means no transformation
     * @throws IllegalArgumentException if the map is null
     */
    protected TransformedSortedMap(SortedMap map, Transformer keyTransformer, Transformer valueTransformer) {
        super(map, keyTransformer, valueTransformer);
    }

    //-----------------------------------------------------------------------
    /**
     * 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 TransformedSortedMap(map, keyTransformer, valueTransformer);
    }

    public SortedMap headMap(Object toKey) {
        SortedMap map = getSortedMap().headMap(toKey);
        return new TransformedSortedMap(map, keyTransformer, valueTransformer);
    }

    public SortedMap tailMap(Object fromKey) {
        SortedMap map = getSortedMap().tailMap(fromKey);
        return new TransformedSortedMap(map, keyTransformer, valueTransformer);
    }

}

Other Commons Collections examples (source code examples)

Here is a short list of links related to this Commons Collections TransformedSortedMap.java source code file:

new blog posts

 

Copyright 1998-2016 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.