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

Commons Collections example source code file (MapUtils.java)

This example Commons Collections source code file (MapUtils.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

boolean, byte, double, float, integer, io, map, map, number, number, object, object, short, string, string, text, util

The Commons Collections MapUtils.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;

import java.io.PrintStream;
import java.text.NumberFormat;
import java.text.ParseException;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.ResourceBundle;
import java.util.SortedMap;
import java.util.TreeMap;

import org.apache.commons.collections.map.FixedSizeMap;
import org.apache.commons.collections.map.FixedSizeSortedMap;
import org.apache.commons.collections.map.LazyMap;
import org.apache.commons.collections.map.LazySortedMap;
import org.apache.commons.collections.map.ListOrderedMap;
import org.apache.commons.collections.map.MultiValueMap;
import org.apache.commons.collections.map.PredicatedMap;
import org.apache.commons.collections.map.PredicatedSortedMap;
import org.apache.commons.collections.map.TransformedMap;
import org.apache.commons.collections.map.TransformedSortedMap;
import org.apache.commons.collections.map.TypedMap;
import org.apache.commons.collections.map.TypedSortedMap;
import org.apache.commons.collections.map.UnmodifiableMap;
import org.apache.commons.collections.map.UnmodifiableSortedMap;

/** 
 * Provides utility methods and decorators for
 * {@link Map} and {@link SortedMap} instances.
 * <p>
 * It contains various type safe methods
 * as well as other useful features like deep copying.
 * <p>
 * It also provides the following decorators:
 *
 *  <ul>
 *  <li>{@link #fixedSizeMap(Map)}
 *  <li>{@link #fixedSizeSortedMap(SortedMap)}
 *  <li>{@link #lazyMap(Map,Factory)}
 *  <li>{@link #lazyMap(Map,Transformer)}
 *  <li>{@link #lazySortedMap(SortedMap,Factory)}
 *  <li>{@link #lazySortedMap(SortedMap,Transformer)}
 *  <li>{@link #predicatedMap(Map,Predicate,Predicate)}
 *  <li>{@link #predicatedSortedMap(SortedMap,Predicate,Predicate)}
 *  <li>{@link #transformedMap(Map, Transformer, Transformer)}
 *  <li>{@link #transformedSortedMap(SortedMap, Transformer, Transformer)}
 *  <li>{@link #typedMap(Map, Class, Class)}
 *  <li>{@link #typedSortedMap(SortedMap, Class, Class)}
 *  <li>{@link #multiValueMap( Map )}
 *  <li>{@link #multiValueMap( Map, Class )}
 *  <li>{@link #multiValueMap( Map, Factory )}
 *  </ul>
 *
 * @since Commons Collections 1.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
 * 
 * @author <a href="mailto:jstrachan@apache.org">James Strachan
 * @author <a href="mailto:nissim@nksystems.com">Nissim Karpenstein
 * @author <a href="mailto:knielsen@apache.org">Kasper Nielsen
 * @author Paul Jack
 * @author Stephen Colebourne
 * @author Matthew Hawthorne
 * @author Arun Mammen Thomas
 * @author Janek Bogucki
 * @author Max Rydahl Andersen
 * @author <a href="mailto:equinus100@hotmail.com">Ashwin S
 * @author <a href="mailto:jcarman@apache.org">James Carman
 * @author Neil O'Toole
 */
public class MapUtils {
    
    /**
     * An empty unmodifiable map.
     * This was not provided in JDK1.2.
     */
    public static final Map EMPTY_MAP = UnmodifiableMap.decorate(new HashMap(1));
    /**
     * An empty unmodifiable sorted map.
     * This is not provided in the JDK.
     */
    public static final SortedMap EMPTY_SORTED_MAP = UnmodifiableSortedMap.decorate(new TreeMap());
    /**
     * String used to indent the verbose and debug Map prints.
     */
    private static final String INDENT_STRING = "    ";

    /**
     * <code>MapUtils should not normally be instantiated.
     */
    public MapUtils() {
    }    
    
    // Type safe getters
    //-------------------------------------------------------------------------
    /**
     * Gets from a Map in a null-safe manner.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map, <code>null if null map input
     */
    public static Object getObject(final Map map, final Object key) {
        if (map != null) {
            return map.get(key);
        }
        return null;
    }

    /**
     * Gets a String from a Map in a null-safe manner.
     * <p>
     * The String is obtained via <code>toString.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a String, <code>null if null map input
     */
    public static String getString(final Map map, final Object key) {
        if (map != null) {
            Object answer = map.get(key);
            if (answer != null) {
                return answer.toString();
            }
        }
        return null;
    }

    /**
     * Gets a Boolean from a Map in a null-safe manner.
     * <p>
     * If the value is a <code>Boolean it is returned directly.
     * If the value is a <code>String and it equals 'true' ignoring case
     * then <code>true is returned, otherwise false.
     * If the value is a <code>Number an integer zero value returns
     * <code>false and non-zero returns true.
     * Otherwise, <code>null is returned.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Boolean, <code>null if null map input
     */
    public static Boolean getBoolean(final Map map, final Object key) {
        if (map != null) {
            Object answer = map.get(key);
            if (answer != null) {
                if (answer instanceof Boolean) {
                    return (Boolean) answer;
                    
                } else if (answer instanceof String) {
                    return new Boolean((String) answer);
                    
                } else if (answer instanceof Number) {
                    Number n = (Number) answer;
                    return (n.intValue() != 0) ? Boolean.TRUE : Boolean.FALSE;
                }
            }
        }
        return null;
    }

    /**
     * Gets a Number from a Map in a null-safe manner.
     * <p>
     * If the value is a <code>Number it is returned directly.
     * If the value is a <code>String it is converted using
     * {@link NumberFormat#parse(String)} on the system default formatter
     * returning <code>null if the conversion fails.
     * Otherwise, <code>null is returned.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Number, <code>null if null map input
     */
    public static Number getNumber(final Map map, final Object key) {
        if (map != null) {
            Object answer = map.get(key);
            if (answer != null) {
                if (answer instanceof Number) {
                    return (Number) answer;
                    
                } else if (answer instanceof String) {
                    try {
                        String text = (String) answer;
                        return NumberFormat.getInstance().parse(text);
                        
                    } catch (ParseException e) {
                        logInfo(e);
                    }
                }
            }
        }
        return null;
    }

    /**
     * Gets a Byte from a Map in a null-safe manner.
     * <p>
     * The Byte is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Byte, <code>null if null map input
     */
    public static Byte getByte(final Map map, final Object key) {
        Number answer = getNumber(map, key);
        if (answer == null) {
            return null;
        } else if (answer instanceof Byte) {
            return (Byte) answer;
        }
        return new Byte(answer.byteValue());
    }

    /**
     * Gets a Short from a Map in a null-safe manner.
     * <p>
     * The Short is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Short, <code>null if null map input
     */
    public static Short getShort(final Map map, final Object key) {
        Number answer = getNumber(map, key);
        if (answer == null) {
            return null;
        } else if (answer instanceof Short) {
            return (Short) answer;
        }
        return new Short(answer.shortValue());
    }

    /**
     * Gets a Integer from a Map in a null-safe manner.
     * <p>
     * The Integer is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Integer, <code>null if null map input
     */
    public static Integer getInteger(final Map map, final Object key) {
        Number answer = getNumber(map, key);
        if (answer == null) {
            return null;
        } else if (answer instanceof Integer) {
            return (Integer) answer;
        }
        return new Integer(answer.intValue());
    }

    /**
     * Gets a Long from a Map in a null-safe manner.
     * <p>
     * The Long is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Long, <code>null if null map input
     */
    public static Long getLong(final Map map, final Object key) {
        Number answer = getNumber(map, key);
        if (answer == null) {
            return null;
        } else if (answer instanceof Long) {
            return (Long) answer;
        }
        return new Long(answer.longValue());
    }

    /**
     * Gets a Float from a Map in a null-safe manner.
     * <p>
     * The Float is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Float, <code>null if null map input
     */
    public static Float getFloat(final Map map, final Object key) {
        Number answer = getNumber(map, key);
        if (answer == null) {
            return null;
        } else if (answer instanceof Float) {
            return (Float) answer;
        }
        return new Float(answer.floatValue());
    }

    /**
     * Gets a Double from a Map in a null-safe manner.
     * <p>
     * The Double is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Double, <code>null if null map input
     */
    public static Double getDouble(final Map map, final Object key) {
        Number answer = getNumber(map, key);
        if (answer == null) {
            return null;
        } else if (answer instanceof Double) {
            return (Double) answer;
        }
        return new Double(answer.doubleValue());
    }

    /**
     * Gets a Map from a Map in a null-safe manner.
     * <p>
     * If the value returned from the specified map is not a Map then
     * <code>null is returned.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Map, <code>null if null map input
     */
    public static Map getMap(final Map map, final Object key) {
        if (map != null) {
            Object answer = map.get(key);
            if (answer != null && answer instanceof Map) {
                return (Map) answer;
            }
        }
        return null;
    }

    // Type safe getters with default values
    //-------------------------------------------------------------------------
    /**
     *  Looks up the given key in the given map, converting null into the
     *  given default value.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null
     *  @return  the value in the map, or defaultValue if the original value
     *    is null or the map is null
     */
    public static Object getObject( Map map, Object key, Object defaultValue ) {
        if ( map != null ) {
            Object answer = map.get( key );
            if ( answer != null ) {
                return answer;
            }
        }
        return defaultValue;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a string, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a string, or defaultValue if the 
     *    original value is null, the map is null or the string conversion
     *    fails
     */
    public static String getString( Map map, Object key, String defaultValue ) {
        String answer = getString( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a boolean, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a boolean, or defaultValue if the 
     *    original value is null, the map is null or the boolean conversion
     *    fails
     */
    public static Boolean getBoolean( Map map, Object key, Boolean defaultValue ) {
        Boolean answer = getBoolean( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a number, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a number, or defaultValue if the 
     *    original value is null, the map is null or the number conversion
     *    fails
     */
    public static Number getNumber( Map map, Object key, Number defaultValue ) {
        Number answer = getNumber( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a byte, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a number, or defaultValue if the 
     *    original value is null, the map is null or the number conversion
     *    fails
     */
    public static Byte getByte( Map map, Object key, Byte defaultValue ) {
        Byte answer = getByte( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a short, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a number, or defaultValue if the 
     *    original value is null, the map is null or the number conversion
     *    fails
     */
    public static Short getShort( Map map, Object key, Short defaultValue ) {
        Short answer = getShort( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  an integer, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a number, or defaultValue if the 
     *    original value is null, the map is null or the number conversion
     *    fails
     */
    public static Integer getInteger( Map map, Object key, Integer defaultValue ) {
        Integer answer = getInteger( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a long, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a number, or defaultValue if the 
     *    original value is null, the map is null or the number conversion
     *    fails
     */
    public static Long getLong( Map map, Object key, Long defaultValue ) {
        Long answer = getLong( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a float, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a number, or defaultValue if the 
     *    original value is null, the map is null or the number conversion
     *    fails
     */
    public static Float getFloat( Map map, Object key, Float defaultValue ) {
        Float answer = getFloat( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a double, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a number, or defaultValue if the 
     *    original value is null, the map is null or the number conversion
     *    fails
     */
    public static Double getDouble( Map map, Object key, Double defaultValue ) {
        Double answer = getDouble( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }

    /**
     *  Looks up the given key in the given map, converting the result into
     *  a map, using the default value if the the conversion fails.
     *
     *  @param map  the map whose value to look up
     *  @param key  the key of the value to look up in that map
     *  @param defaultValue  what to return if the value is null or if the
     *     conversion fails
     *  @return  the value in the map as a number, or defaultValue if the 
     *    original value is null, the map is null or the map conversion
     *    fails
     */
    public static Map getMap( Map map, Object key, Map defaultValue ) {
        Map answer = getMap( map, key );
        if ( answer == null ) {
            answer = defaultValue;
        }
        return answer;
    }
    

    // Type safe primitive getters
    //-------------------------------------------------------------------------
    /**
     * Gets a boolean from a Map in a null-safe manner.
     * <p>
     * If the value is a <code>Boolean its value is returned.
     * If the value is a <code>String and it equals 'true' ignoring case
     * then <code>true is returned, otherwise false.
     * If the value is a <code>Number an integer zero value returns
     * <code>false and non-zero returns true.
     * Otherwise, <code>false is returned.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a Boolean, <code>false if null map input
     */
    public static boolean getBooleanValue(final Map map, final Object key) {
        Boolean booleanObject = getBoolean(map, key);
        if (booleanObject == null) {
            return false;
        }
        return booleanObject.booleanValue();
    }

    /**
     * Gets a byte from a Map in a null-safe manner.
     * <p>
     * The byte is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a byte, <code>0 if null map input
     */
    public static byte getByteValue(final Map map, final Object key) {
        Byte byteObject = getByte(map, key);
        if (byteObject == null) {
            return 0;
        }
        return byteObject.byteValue();
    }

    /**
     * Gets a short from a Map in a null-safe manner.
     * <p>
     * The short is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a short, <code>0 if null map input
     */
    public static short getShortValue(final Map map, final Object key) {
        Short shortObject = getShort(map, key);
        if (shortObject == null) {
            return 0;
        }
        return shortObject.shortValue();
    }

    /**
     * Gets an int from a Map in a null-safe manner.
     * <p>
     * The int is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as an int, <code>0 if null map input
     */
    public static int getIntValue(final Map map, final Object key) {
        Integer integerObject = getInteger(map, key);
        if (integerObject == null) {
            return 0;
        }
        return integerObject.intValue();
    }

    /**
     * Gets a long from a Map in a null-safe manner.
     * <p>
     * The long is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a long, <code>0L if null map input
     */
    public static long getLongValue(final Map map, final Object key) {
        Long longObject = getLong(map, key);
        if (longObject == null) {
            return 0L;
        }
        return longObject.longValue();
    }

    /**
     * Gets a float from a Map in a null-safe manner.
     * <p>
     * The float is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a float, <code>0.0F if null map input
     */
    public static float getFloatValue(final Map map, final Object key) {
        Float floatObject = getFloat(map, key);
        if (floatObject == null) {
            return 0f;
        }
        return floatObject.floatValue();
    }

    /**
     * Gets a double from a Map in a null-safe manner.
     * <p>
     * The double is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @return the value in the Map as a double, <code>0.0 if null map input
     */
    public static double getDoubleValue(final Map map, final Object key) {
        Double doubleObject = getDouble(map, key);
        if (doubleObject == null) {
            return 0d;
        }
        return doubleObject.doubleValue();
    }

    // Type safe primitive getters with default values
    //-------------------------------------------------------------------------
    /**
     * Gets a boolean from a Map in a null-safe manner,
     * using the default value if the the conversion fails.
     * <p>
     * If the value is a <code>Boolean its value is returned.
     * If the value is a <code>String and it equals 'true' ignoring case
     * then <code>true is returned, otherwise false.
     * If the value is a <code>Number an integer zero value returns
     * <code>false and non-zero returns true.
     * Otherwise, <code>defaultValue is returned.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a Boolean, <code>defaultValue if null map input
     */
    public static boolean getBooleanValue(final Map map, final Object key, boolean defaultValue) {
        Boolean booleanObject = getBoolean(map, key);
        if (booleanObject == null) {
            return defaultValue;
        }
        return booleanObject.booleanValue();
    }

    /**
     * Gets a byte from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The byte is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a byte, <code>defaultValue if null map input
     */
    public static byte getByteValue(final Map map, final Object key, byte defaultValue) {
        Byte byteObject = getByte(map, key);
        if (byteObject == null) {
            return defaultValue;
        }
        return byteObject.byteValue();
    }

    /**
     * Gets a short from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The short is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a short, <code>defaultValue if null map input
     */
    public static short getShortValue(final Map map, final Object key, short defaultValue) {
        Short shortObject = getShort(map, key);
        if (shortObject == null) {
            return defaultValue;
        }
        return shortObject.shortValue();
    }

    /**
     * Gets an int from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The int is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as an int, <code>defaultValue if null map input
     */
    public static int getIntValue(final Map map, final Object key, int defaultValue) {
        Integer integerObject = getInteger(map, key);
        if (integerObject == null) {
            return defaultValue;
        }
        return integerObject.intValue();
    }

    /**
     * Gets a long from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The long is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a long, <code>defaultValue if null map input
     */
    public static long getLongValue(final Map map, final Object key, long defaultValue) {
        Long longObject = getLong(map, key);
        if (longObject == null) {
            return defaultValue;
        }
        return longObject.longValue();
    }

    /**
     * Gets a float from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The float is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a float, <code>defaultValue if null map input
     */
    public static float getFloatValue(final Map map, final Object key, float defaultValue) {
        Float floatObject = getFloat(map, key);
        if (floatObject == null) {
            return defaultValue;
        }
        return floatObject.floatValue();
    }

    /**
     * Gets a double from a Map in a null-safe manner,
     * using the default value if the the conversion fails.     
     * <p>
     * The double is obtained from the results of {@link #getNumber(Map,Object)}.
     *
     * @param map  the map to use
     * @param key  the key to look up
     * @param defaultValue  return if the value is null or if the
     *     conversion fails
     * @return the value in the Map as a double, <code>defaultValue if null map input
     */
    public static double getDoubleValue(final Map map, final Object key, double defaultValue) {
        Double doubleObject = getDouble(map, key);
        if (doubleObject == null) {
            return defaultValue;
        }
        return doubleObject.doubleValue();
    }

    // Conversion methods
    //-------------------------------------------------------------------------
    /**
     * Gets a new Properties object initialised with the values from a Map.
     * A null input will return an empty properties object.
     * 
     * @param map  the map to convert to a Properties object, may not be null
     * @return the properties object
     */
    public static Properties toProperties(final Map map) {
        Properties answer = new Properties();
        if (map != null) {
            for (Iterator iter = map.entrySet().iterator(); iter.hasNext();) {
                Map.Entry entry = (Map.Entry) iter.next();
                Object key = entry.getKey();
                Object value = entry.getValue();
                answer.put(key, value);
            }
        }
        return answer;
    }

    /**
     * Creates a new HashMap using data copied from a ResourceBundle.
     * 
     * @param resourceBundle  the resource bundle to convert, may not be null
     * @return the hashmap containing the data
     * @throws NullPointerException if the bundle is null
     */
    public static Map toMap(final ResourceBundle resourceBundle) {
        Enumeration enumeration = resourceBundle.getKeys();
        Map map = new HashMap();

        while (enumeration.hasMoreElements()) {
            String key = (String) enumeration.nextElement();
            Object value = resourceBundle.getObject(key);
            map.put(key, value);
        }
        
        return map;
    }
 
    // Printing methods
    //-------------------------------------------------------------------------
    /**
     * Prints the given map with nice line breaks.
     * <p>
     * This method prints a nicely formatted String describing the Map.
     * Each map entry will be printed with key and value.
     * When the value is a Map, recursive behaviour occurs.
     * <p>
     * This method is NOT thread-safe in any special way. You must manually
     * synchronize on either this class or the stream as required.
     *
     * @param out  the stream to print to, must not be null
     * @param label  The label to be used, may be <code>null.
     *  If <code>null, the label is not output.
     *  It typically represents the name of the property in a bean or similar.
     * @param map  The map to print, may be <code>null.
     *  If <code>null, the text 'null' is output.
     * @throws NullPointerException if the stream is <code>null
     */
    public static void verbosePrint(
        final PrintStream out,
        final Object label,
        final Map map) {

        verbosePrintInternal(out, label, map, new ArrayStack(), false);
    }

    /**
     * Prints the given map with nice line breaks.
     * <p>
     * This method prints a nicely formatted String describing the Map.
     * Each map entry will be printed with key, value and value classname.
     * When the value is a Map, recursive behaviour occurs.
     * <p>
     * This method is NOT thread-safe in any special way. You must manually
     * synchronize on either this class or the stream as required.
     *
     * @param out  the stream to print to, must not be null
     * @param label  The label to be used, may be <code>null.
     *  If <code>null, the label is not output.
     *  It typically represents the name of the property in a bean or similar.
     * @param map  The map to print, may be <code>null.
     *  If <code>null, the text 'null' is output.
     * @throws NullPointerException if the stream is <code>null
     */
    public static void debugPrint(
        final PrintStream out,
        final Object label,
        final Map map) {

        verbosePrintInternal(out, label, map, new ArrayStack(), true);
    }

    // Implementation methods
    //-------------------------------------------------------------------------
    /**
     * Logs the given exception to <code>System.out.
     * <p>
     * This method exists as Jakarta Collections does not depend on logging.
     *
     * @param ex  the exception to log
     */
    protected static void logInfo(final Exception ex) {
        System.out.println("INFO: Exception: " + ex);
    }

    /**
     * Implementation providing functionality for {@link #debugPrint} and for 
     * {@link #verbosePrint}.  This prints the given map with nice line breaks.
     * If the debug flag is true, it additionally prints the type of the object 
     * value.  If the contents of a map include the map itself, then the text 
     * <em>(this Map) is printed out.  If the contents include a 
     * parent container of the map, the the text <em>(ancestor[i] Map) is 
     * printed, where i actually indicates the number of levels which must be 
     * traversed in the sequential list of ancestors (e.g. father, grandfather, 
     * great-grandfather, etc).  
     *
     * @param out  the stream to print to
     * @param label  the label to be used, may be <code>null.
     *  If <code>null, the label is not output.
     *  It typically represents the name of the property in a bean or similar.
     * @param map  the map to print, may be <code>null.
     *  If <code>null, the text 'null' is output
     * @param lineage  a stack consisting of any maps in which the previous 
     *  argument is contained. This is checked to avoid infinite recursion when
     *  printing the output
     * @param debug  flag indicating whether type names should be output.
     * @throws NullPointerException if the stream is <code>null
     */
    private static void verbosePrintInternal(
        final PrintStream out,
        final Object label,
        final Map map,
        final ArrayStack lineage,
        final boolean debug) {
        
        printIndent(out, lineage.size());

        if (map == null) {
            if (label != null) {
                out.print(label);
                out.print(" = ");
            }
            out.println("null");
            return;
        }
        if (label != null) {
            out.print(label);
            out.println(" = ");
        }

        printIndent(out, lineage.size());
        out.println("{");

        lineage.push(map);

        for (Iterator it = map.entrySet().iterator(); it.hasNext();) {
            Map.Entry entry = (Map.Entry) it.next();
            Object childKey = entry.getKey();
            Object childValue = entry.getValue();
            if (childValue instanceof Map && !lineage.contains(childValue)) {
                verbosePrintInternal(
                    out,
                    (childKey == null ? "null" : childKey),
                    (Map) childValue,
                    lineage,
                    debug);
            } else {
                printIndent(out, lineage.size());
                out.print(childKey);
                out.print(" = ");
                
                final int lineageIndex = lineage.indexOf(childValue);
                if (lineageIndex == -1) {
                    out.print(childValue);
                } else if (lineage.size() - 1 == lineageIndex) {
                    out.print("(this Map)");    
                } else {
                    out.print(
                        "(ancestor["
                            + (lineage.size() - 1 - lineageIndex - 1)
                            + "] Map)");
                }
                
                if (debug && childValue != null) {
                    out.print(' ');
                    out.println(childValue.getClass().getName());
                } else {
                    out.println();
                }
            }
        }
        
        lineage.pop();

        printIndent(out, lineage.size());
        out.println(debug ? "} " + map.getClass().getName() : "}");
    }

    /**
     * Writes indentation to the given stream.
     *
     * @param out  the stream to indent
     */
    private static void printIndent(final PrintStream out, final int indent) {
        for (int i = 0; i < indent; i++) {
            out.print(INDENT_STRING);
        }
    }
    
    // Misc
    //-----------------------------------------------------------------------
    /**
     * Inverts the supplied map returning a new HashMap such that the keys of
     * the input are swapped with the values.
     * <p>
     * This operation assumes that the inverse mapping is well defined.
     * If the input map had multiple entries with the same value mapped to
     * different keys, the returned map will map one of those keys to the 
     * value, but the exact key which will be mapped is undefined.
     *
     * @param map  the map to invert, may not be null
     * @return a new HashMap containing the inverted data
     * @throws NullPointerException if the map is null
     */
    public static Map invertMap(Map map) {
        Map out = new HashMap(map.size());
        for (Iterator it = map.entrySet().iterator(); it.hasNext();) {
            Map.Entry entry = (Map.Entry) it.next();
            out.put(entry.getValue(), entry.getKey());
        }
        return out;
    }
     
    //-----------------------------------------------------------------------
    /**
     * Protects against adding null values to a map.
     * <p>
     * This method checks the value being added to the map, and if it is null
     * it is replaced by an empty string.
     * <p>
     * This could be useful if the map does not accept null values, or for
     * receiving data from a source that may provide null or empty string
     * which should be held in the same way in the map.
     * <p>
     * Keys are not validated.
     * 
     * @param map  the map to add to, may not be null
     * @param key  the key
     * @param value  the value, null converted to ""
     * @throws NullPointerException if the map is null
     */
    public static void safeAddToMap(Map map, Object key, Object value) throws NullPointerException {
        if (value == null) {
            map.put(key, "");
        } else {
            map.put(key, value);
        }
    }

    //-----------------------------------------------------------------------
    /**
     * Puts all the keys and values from the specified array into the map.
     * <p>
     * This method is an alternative to the {@link java.util.Map#putAll(java.util.Map)}
     * method and constructors. It allows you to build a map from an object array
     * of various possible styles.
     * <p>
     * If the first entry in the object array implements {@link java.util.Map.Entry}
     * or {@link KeyValue} then the key and value are added from that object.
     * If the first entry in the object array is an object array itself, then
     * it is assumed that index 0 in the sub-array is the key and index 1 is the value.
     * Otherwise, the array is treated as keys and values in alternate indices.
     * <p>
     * For example, to create a color map:
     * <pre>
     * Map colorMap = MapUtils.putAll(new HashMap(), new String[][] {
     *     {"RED", "#FF0000"},
     *     {"GREEN", "#00FF00"},
     *     {"BLUE", "#0000FF"}
     * });
     * </pre>
     * or:
     * <pre>
     * Map colorMap = MapUtils.putAll(new HashMap(), new String[] {
     *     "RED", "#FF0000",
     *     "GREEN", "#00FF00",
     *     "BLUE", "#0000FF"
     * });
     * </pre>
     * or:
     * <pre>
     * Map colorMap = MapUtils.putAll(new HashMap(), new Map.Entry[] {
     *     new DefaultMapEntry("RED", "#FF0000"),
     *     new DefaultMapEntry("GREEN", "#00FF00"),
     *     new DefaultMapEntry("BLUE", "#0000FF")
     * });
     * </pre>
     *
     * @param map  the map to populate, must not be null
     * @param array  an array to populate from, null ignored
     * @return the input map
     * @throws NullPointerException  if map is null
     * @throws IllegalArgumentException  if sub-array or entry matching used and an
     *  entry is invalid
     * @throws ClassCastException if the array contents is mixed
     * @since Commons Collections 3.2
     */
    public static Map putAll(Map map, Object[] array) {
        map.size();  // force NPE
        if (array == null || array.length == 0) {
            return map;
        }
        Object obj = array[0];
        if (obj instanceof Map.Entry) {
            for (int i = 0; i < array.length; i++) {
                Map.Entry entry = (Map.Entry) array[i];
                map.put(entry.getKey(), entry.getValue());
            }
        } else if (obj instanceof KeyValue) {
            for (int i = 0; i < array.length; i++) {
                KeyValue keyval = (KeyValue) array[i];
                map.put(keyval.getKey(), keyval.getValue());
            }
        } else if (obj instanceof Object[]) {
            for (int i = 0; i < array.length; i++) {
                Object[] sub = (Object[]) array[i];
                if (sub == null || sub.length < 2) {
                    throw new IllegalArgumentException("Invalid array element: " + i);
                }
                map.put(sub[0], sub[1]);
            }
        } else {
            for (int i = 0; i < array.length - 1;) {
                map.put(array[i++], array[i++]);
            }
        }
        return map;
    }

    //-----------------------------------------------------------------------
    /**
     * Null-safe check if the specified map is empty.
     * <p>
     * Null returns true.
     * 
     * @param map  the map to check, may be null
     * @return true if empty or null
     * @since Commons Collections 3.2
     */
    public static boolean isEmpty(Map map) {
        return (map == null || map.isEmpty());
    }

    /**
     * Null-safe check if the specified map is not empty.
     * <p>
     * Null returns false.
     * 
     * @param map  the map to check, may be null
     * @return true if non-null and non-empty
     * @since Commons Collections 3.2
     */
    public static boolean isNotEmpty(Map map) {
        return !MapUtils.isEmpty(map);
    }

    // Map decorators
    //-----------------------------------------------------------------------
    /**
     * Returns a synchronized map backed by the given map.
     * <p>
     * You must manually synchronize on the returned buffer's iterator to 
     * avoid non-deterministic behavior:
     *  
     * <pre>
     * Map m = MapUtils.synchronizedMap(myMap);
     * Set s = m.keySet();  // outside synchronized block
     * synchronized (m) {  // synchronized on MAP!
     *     Iterator i = s.iterator();
     *     while (i.hasNext()) {
     *         process (i.next());
     *     }
     * }
     * </pre>
     * 
     * This method uses the implementation in {@link java.util.Collections Collections}.
     * 
     * @param map  the map to synchronize, must not be null
     * @return a synchronized map backed by the given map
     * @throws IllegalArgumentException  if the map is null
     */
    public static Map synchronizedMap(Map map) {
        return Collections.synchronizedMap(map);
    }

    /**
     * Returns an unmodifiable map backed by the given map.
     * <p>
     * This method uses the implementation in the decorators subpackage.
     *
     * @param map  the map to make unmodifiable, must not be null
     * @return an unmodifiable map backed by the given map
     * @throws IllegalArgumentException  if the map is null
     */
    public static Map unmodifiableMap(Map map) {
        return UnmodifiableMap.decorate(map);
    }

    /**
     * Returns a predicated (validating) map backed by the given map.
     * <p>
     * Only objects that pass the tests in the given predicates can be added to the map.
     * Trying to add an invalid object results in an IllegalArgumentException.
     * Keys must pass the key predicate, values must pass the value predicate.
     * It is important not to use the original map after invoking this method,
     * as it is a backdoor for adding invalid objects.
     *
     * @param map  the map to predicate, must not be null
     * @param keyPred  the predicate for keys, null means no check
     * @param valuePred  the predicate for values, null means no check
     * @return a predicated map backed by the given map
     * @throws IllegalArgumentException  if the Map is null
     */
    public static Map predicatedMap(Map map, Predicate keyPred, Predicate valuePred) {
        return PredicatedMap.decorate(map, keyPred, valuePred);
    }

    /**
     * Returns a typed map backed by the given map.
     * <p>
     * Only keys and values of the specified types can be added to the map.
     * 
     * @param map  the map to limit to a specific type, must not be null
     * @param keyType  the type of keys which may be added to the map, must not be null
     * @param valueType  the type of values which may be added to the map, must not be null
     * @return a typed map backed by the specified map
     * @throws IllegalArgumentException  if the Map or Class is null
     */
    public static Map typedMap(Map map, Class keyType, Class valueType) {
        return TypedMap.decorate(map, keyType, valueType);
    }
    
    /**
     * Returns a transformed map backed by the given map.
     * <p>
     * This method returns a new map (decorating the specified map) that
     * will transform any new entries added to it.
     * Existing entries in the specified map will not be transformed.
     * If you want that behaviour, see {@link TransformedMap#decorateTransform}.
     * <p>
     * Each object is passed through the transformers as it is added to the
     * Map. It is important not to use the original map after invoking this 
     * method, as it is a backdoor for adding untransformed objects.
     * <p>
     * If there are any elements already in the map being decorated, they
     * are NOT transformed.
     *
     * @param map  the map to transform, must not be null, typically empty
     * @param keyTransformer  the transformer for the map keys, null means no transformation
     * @param valueTransformer  the transformer for the map values, null means no transformation
     * @return a transformed map backed by the given map
     * @throws IllegalArgumentException  if the Map is null
     */
    public static Map transformedMap(Map map, Transformer keyTransformer, Transformer valueTransformer) {
        return TransformedMap.decorate(map, keyTransformer, valueTransformer);
    }
    
    /**
     * Returns a fixed-sized map backed by the given map.
     * Elements may not be added or removed from the returned map, but 
     * existing elements can be changed (for instance, via the 
     * {@link Map#put(Object,Object)} method).
     *
     * @param map  the map whose size to fix, must not be null
     * @return a fixed-size map backed by that map
     * @throws IllegalArgumentException  if the Map is null
     */
    public static Map fixedSizeMap(Map map) {
        return FixedSizeMap.decorate(map);
    }

    /**
     * Returns a "lazy" map whose values will be created on demand.
     * <p>
     * When the key passed to the returned map's {@link Map#get(Object)}
     * method is not present in the map, then the factory will be used
     * to create a new object and that object will become the value
     * associated with that key.
     * <p>
     * For instance:
     * <pre>
     * Factory factory = new Factory() {
     *     public Object create() {
     *         return new Date();
     *     }
     * }
     * Map lazyMap = MapUtils.lazyMap(new HashMap(), factory);
     * Object obj = lazyMap.get("test");
     * </pre>
     *
     * After the above code is executed, <code>obj will contain
     * a new <code>Date instance.  Furthermore, that Date
     * instance is the value for the <code>"test" key in the map.
     *
     * @param map  the map to make lazy, must not be null
     * @param factory  the factory for creating new objects, must not be null
     * @return a lazy map backed by the given map
     * @throws IllegalArgumentException  if the Map or Factory is null
     */
    public static Map lazyMap(Map map, Factory factory) {
        return LazyMap.decorate(map, factory);
    }

    /**
     * Returns a "lazy" map whose values will be created on demand.
     * <p>
     * When the key passed to the returned map's {@link Map#get(Object)}
     * method is not present in the map, then the factory will be used
     * to create a new object and that object will become the value
     * associated with that key. The factory is a {@link Transformer}
     * that will be passed the key which it must transform into the value.
     * <p>
     * For instance:
     * <pre>
     * Transformer factory = new Transformer() {
     *     public Object transform(Object mapKey) {
     *         return new File(mapKey);
     *     }
     * }
     * Map lazyMap = MapUtils.lazyMap(new HashMap(), factory);
     * Object obj = lazyMap.get("C:/dev");
     * </pre>
     *
     * After the above code is executed, <code>obj will contain
     * a new <code>File instance for the C drive dev directory.
     * Furthermore, that <code>File instance is the value for the
     * <code>"C:/dev" key in the map.
     * <p>
     * If a lazy map is wrapped by a synchronized map, the result is a simple
     * synchronized cache. When an object is not is the cache, the cache itself
     * calls back to the factory Transformer to populate itself, all within the
     * same synchronized block.
     *
     * @param map  the map to make lazy, must not be null
     * @param transformerFactory  the factory for creating new objects, must not be null
     * @return a lazy map backed by the given map
     * @throws IllegalArgumentException  if the Map or Transformer is null
     */
    public static Map lazyMap(Map map, Transformer transformerFactory) {
        return LazyMap.decorate(map, transformerFactory);
    }

    /**
     * Returns a map that maintains the order of keys that are added
     * backed by the given map.
     * <p>
     * If a key is added twice, the order is determined by the first add.
     * The order is observed through the keySet, values and entrySet.
     *
     * @param map  the map to order, must not be null
     * @return an ordered map backed by the given map
     * @throws IllegalArgumentException  if the Map is null
     */
    public static Map orderedMap(Map map) {
        return ListOrderedMap.decorate(map);
    }

    /**
     * Creates a mult-value map backed by the given map which returns
     * collections of type ArrayList.
     *
     * @param map  the map to decorate
     * @return a multi-value map backed by the given map which returns ArrayLists of values.
     * @see MultiValueMap
     * @since Commons Collections 3.2
     */
    public static Map multiValueMap(Map map) {
        return MultiValueMap.decorate(map);
    }

    /**
     * Creates a multi-value map backed by the given map which returns
     * collections of the specified type.
     *
     * @param map  the map to decorate
     * @param collectionClass  the type of collections to return from the map (must contain public no-arg constructor
     *  and extend Collection).
     * @return a multi-value map backed by the given map which returns collections of the specified type
     * @see MultiValueMap
     * @since Commons Collections 3.2
     */
    public static Map multiValueMap(Map map, Class collectionClass) {
        return MultiValueMap.decorate(map, collectionClass);
    }

    /**
     * Creates a multi-value map backed by the given map which returns
     * collections created by the specified collection factory.
     *
     * @param map  the map to decorate
     * @param collectionFactory  a factor which creates collection objects
     * @return a multi-value map backed by the given map which returns collections
     * created by the specified collection factory
     * @see MultiValueMap
     * @since Commons Collections 3.2
     */
    public static Map multiValueMap(Map map, Factory collectionFactory) {
        return MultiValueMap.decorate(map, collectionFactory);
    }

    // SortedMap decorators
    //-----------------------------------------------------------------------
    /**
     * Returns a synchronized sorted map backed by the given sorted map.
     * <p>
     * You must manually synchronize on the returned buffer's iterator to 
     * avoid non-deterministic behavior:
     *  
     * <pre>
     * Map m = MapUtils.synchronizedSortedMap(myMap);
     * Set s = m.keySet();  // outside synchronized block
     * synchronized (m) {  // synchronized on MAP!
     *     Iterator i = s.iterator();
     *     while (i.hasNext()) {
     *         process (i.next());
     *     }
     * }
     * </pre>
     * 
     * This method uses the implementation in {@link java.util.Collections Collections}.
     * 
     * @param map  the map to synchronize, must not be null
     * @return a synchronized map backed by the given map
     * @throws IllegalArgumentException  if the map is null
     */
    public static Map synchronizedSortedMap(SortedMap map) {
        return Collections.synchronizedSortedMap(map);
    }

    /**
     * Returns an unmodifiable sorted map backed by the given sorted map.
     * <p>
     * This method uses the implementation in the decorators subpackage.
     *
     * @param map  the sorted map to make unmodifiable, must not be null
     * @return an unmodifiable map backed by the given map
     * @throws IllegalArgumentException  if the map is null
     */
    public static Map unmodifiableSortedMap(SortedMap map) {
        return UnmodifiableSortedMap.decorate(map);
    }

    /**
     * Returns a predicated (validating) sorted map backed by the given map.
     * <p>
     * Only objects that pass the tests in the given predicates can be added to the map.
     * Trying to add an invalid object results in an IllegalArgumentException.
     * Keys must pass the key predicate, values must pass the value predicate.
     * It is important not to use the original map after invoking this method,
     * as it is a backdoor for adding invalid objects.
     *
     * @param map  the map to predicate, must not be null
     * @param keyPred  the predicate for keys, null means no check
     * @param valuePred  the predicate for values, null means no check
     * @return a predicated map backed by the given map
     * @throws IllegalArgumentException  if the SortedMap is null
     */
    public static SortedMap predicatedSortedMap(SortedMap map, Predicate keyPred, Predicate valuePred) {
        return PredicatedSortedMap.decorate(map, keyPred, valuePred);
    }

    /**
     * Returns a typed sorted map backed by the given map.
     * <p>
     * Only keys and values of the specified types can be added to the map.
     * 
     * @param map  the map to limit to a specific type, must not be null
     * @param keyType  the type of keys which may be added to the map, must not be null
     * @param valueType  the type of values which may be added to the map, must not be null
     * @return a typed map backed by the specified map
     */
    public static SortedMap typedSortedMap(SortedMap map, Class keyType, Class valueType) {
        return TypedSortedMap.decorate(map, keyType, valueType);
    }
    
    /**
     * Returns a transformed sorted map backed by the given map.
     * <p>
     * This method returns a new sorted map (decorating the specified map) that
     * will transform any new entries added to it.
     * Existing entries in the specified map will not be transformed.
     * If you want that behaviour, see {@link TransformedSortedMap#decorateTransform}.
     * <p>
     * Each object is passed through the transformers as it is added to the
     * Map. It is important not to use the original map after invoking this 
     * method, as it is a backdoor for adding untransformed objects.
     * <p>
     * If there are any elements already in the map being decorated, they
     * are NOT transformed.
     *
     * @param map  the map to transform, must not be null, typically empty
     * @param keyTransformer  the transformer for the map keys, null means no transformation
     * @param valueTransformer  the transformer for the map values, null means no transformation
     * @return a transformed map backed by the given map
     * @throws IllegalArgumentException  if the SortedMap is null
     */
    public static SortedMap transformedSortedMap(SortedMap map, Transformer keyTransformer, Transformer valueTransformer) {
        return TransformedSortedMap.decorate(map, keyTransformer, valueTransformer);
    }
    
    /**
     * Returns a fixed-sized sorted map backed by the given sorted map.
     * Elements may not be added or removed from the returned map, but 
     * existing elements can be changed (for instance, via the 
     * {@link Map#put(Object,Object)} method).
     *
     * @param map  the map whose size to fix, must not be null
     * @return a fixed-size map backed by that map
     * @throws IllegalArgumentException  if the SortedMap is null
     */
    public static SortedMap fixedSizeSortedMap(SortedMap map) {
        return FixedSizeSortedMap.decorate(map);
    }

    /**
     * Returns a "lazy" sorted map whose values will be created on demand.
     * <p>
     * When the key passed to the returned map's {@link Map#get(Object)}
     * method is not present in the map, then the factory will be used
     * to create a new object and that object will become the value
     * associated with that key.
     * <p>
     * For instance:
     *
     * <pre>
     * Factory factory = new Factory() {
     *     public Object create() {
     *         return new Date();
     *     }
     * }
     * SortedMap lazy = MapUtils.lazySortedMap(new TreeMap(), factory);
     * Object obj = lazy.get("test");
     * </pre>
     *
     * After the above code is executed, <code>obj will contain
     * a new <code>Date instance.  Furthermore, that Date
     * instance is the value for the <code>"test" key.
     *
     * @param map  the map to make lazy, must not be null
     * @param factory  the factory for creating new objects, must not be null
     * @return a lazy map backed by the given map
     * @throws IllegalArgumentException  if the SortedMap or Factory is null
     */
    public static SortedMap lazySortedMap(SortedMap map, Factory factory) {
        return LazySortedMap.decorate(map, factory);
    }
    
    /**
     * Returns a "lazy" sorted map whose values will be created on demand.
     * <p>
     * When the key passed to the returned map's {@link Map#get(Object)}
     * method is not present in the map, then the factory will be used
     * to create a new object and that object will become the value
     * associated with that key. The factory is a {@link Transformer}
     * that will be passed the key which it must transform into the value.
     * <p>
     * For instance:
     * <pre>
     * Transformer factory = new Transformer() {
     *     public Object transform(Object mapKey) {
     *         return new File(mapKey);
     *     }
     * }
     * SortedMap lazy = MapUtils.lazySortedMap(new TreeMap(), factory);
     * Object obj = lazy.get("C:/dev");
     * </pre>
     *
     * After the above code is executed, <code>obj will contain
     * a new <code>File instance for the C drive dev directory.
     * Furthermore, that <code>File instance is the value for the
     * <code>"C:/dev" key in the map.
     * <p>
     * If a lazy map is wrapped by a synchronized map, the result is a simple
     * synchronized cache. When an object is not is the cache, the cache itself
     * calls back to the factory Transformer to populate itself, all within the
     * same synchronized block.
     *
     * @param map  the map to make lazy, must not be null
     * @param transformerFactory  the factory for creating new objects, must not be null
     * @return a lazy map backed by the given map
     * @throws IllegalArgumentException  if the Map or Transformer is null
     */
    public static SortedMap lazySortedMap(SortedMap map, Transformer transformerFactory) {
        return LazySortedMap.decorate(map, transformerFactory);
    }

}

Other Commons Collections examples (source code examples)

Here is a short list of links related to this Commons Collections MapUtils.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.