    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *     http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.configuration2;
    019
    020import java.util.Iterator;
    021import java.util.List;
    022import java.util.Map;
    023import java.util.Properties;
    024
    025import org.apache.commons.configuration2.convert.ListDelimiterHandler;
    026import org.apache.commons.lang3.StringUtils;
    027
    028/**
    029 * Configuration converter. Helper class to convert between Configuration,
    030 * ExtendedProperties and standard Properties.
    031 *
    032 * @author <a href="mailto:mpoeschl@marmot.at">Martin Poeschl</a>
    033 */
    034public final class ConfigurationConverter
    035{
    036    /** Constant for the default separator for properties with multiple values. */
    037    private static final char DEFAULT_SEPARATOR = ',';
    038
    039    /**
    040     * Private constructor prevents instances from being created.
    041     */
    042    private ConfigurationConverter()
    043    {
    044        // to prevent instanciation...
    045    }
    046
    047    /**
    048     * Convert a standard Properties class into a configuration class.
    049     *
    050     * @param props properties object to convert
    051     * @return Configuration configuration created from the Properties
    052     */
    053    public static Configuration getConfiguration(final Properties props)
    054    {
    055        return new MapConfiguration(props);
    056    }
    057
    058    /**
    059     * Convert a Configuration class into a Properties class. List properties
    060     * are joined into a string using either the list delimiter handler of the
    061     * configuration (if it extends AbstractConfiguration) or with a comma as
    062     * delimiter otherwise.
    063     *
    064     * @param config ImmutableConfiguration object to convert
    065     * @return Properties created from the Configuration
    066     * @since 2.2
    067     */
    068    public static Properties getProperties(final ImmutableConfiguration config)
    069    {
    070        final Properties props = new Properties();
    071        ListDelimiterHandler listHandler;
    072        boolean useDelimiterHandler;
    073
    074        if (config instanceof AbstractConfiguration)
    075        {
    076            listHandler = ((AbstractConfiguration) config).getListDelimiterHandler();
    077            useDelimiterHandler = true;
    078        }
    079        else
    080        {
    081            listHandler = null;
    082            useDelimiterHandler = false;
    083        }
    084
    085        for (final Iterator<String> keys = config.getKeys(); keys.hasNext();)
    086        {
    087            final String key = keys.next();
    088            final List<Object> list = config.getList(key);
    089
    090            String propValue;
    091            if (useDelimiterHandler)
    092            {
    093                try
    094                {
    095                    propValue =
    096                            String.valueOf(listHandler.escapeList(list,
    097                                    ListDelimiterHandler.NOOP_TRANSFORMER));
    098                }
    099                catch (final Exception ex)
    100                {
    101                    // obviously, the list handler does not support splitting
    102                    useDelimiterHandler = false;
    103                    propValue = listToString(list);
    104                }
    105            }
    106            else
    107            {
    108                propValue = listToString(list);
    109            }
    110
    111            props.setProperty(key, propValue);
    112        }
    113
    114        return props;
    115    }
    116
    117    /**
    118     * Convert a Configuration class into a Properties class. List properties
    119     * are joined into a string using either the list delimiter handler of the
    120     * configuration (if it extends AbstractConfiguration) or with a comma as
    121     * delimiter otherwise.
    122     * This version of the method exists only for backwards compatibility reason.
    123     *
    124     * @param config Configuration object to convert
    125     * @return Properties created from the Configuration
    126     */
    127    public static Properties getProperties(final Configuration config)
    128    {
    129        return getProperties((ImmutableConfiguration) config);
    130    }
    131
    132    /**
    133     * Convert a Configuration class into a Map class.
    134     *
    135     * @param config Configuration object to convert
    136     * @return Map created from the Configuration
    137     */
    138    public static Map<Object, Object> getMap(final Configuration config)
    139    {
    140        return new ConfigurationMap(config);
    141    }
    142
    143    /**
    144     * Helper method for joining all elements of a list to a string using the
    145     * default value separator.
    146     *
    147     * @param list the list
    148     * @return the resulting string
    149     */
    150    private static String listToString(final List<?> list)
    151    {
    152        return StringUtils.join(list, DEFAULT_SEPARATOR);
    153    }
    154}