    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 *     https://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, ExtendedProperties and standard Properties.
    030 */
    031public final class ConfigurationConverter {
    032
    033    /** Constant for the default separator for properties with multiple values. */
    034    private static final char DEFAULT_SEPARATOR = ',';
    035
    036    /**
    037     * Convert a standard Properties class into a configuration class.
    038     *
    039     * @param props properties object to convert
    040     * @return Configuration configuration created from the Properties
    041     */
    042    public static Configuration getConfiguration(final Properties props) {
    043        return new MapConfiguration(props);
    044    }
    045
    046    /**
    047     * Convert a Configuration class into a Map class.
    048     *
    049     * @param config Configuration object to convert
    050     * @return Map created from the Configuration
    051     */
    052    public static Map<Object, Object> getMap(final Configuration config) {
    053        return new ConfigurationMap(config);
    054    }
    055
    056    /**
    057     * Convert a Configuration class into a Properties class. List properties are joined into a string using either the list
    058     * delimiter handler of the configuration (if it extends AbstractConfiguration) or with a comma as delimiter otherwise.
    059     * This version of the method exists only for backwards compatibility reason.
    060     *
    061     * @param config Configuration object to convert
    062     * @return Properties created from the Configuration
    063     */
    064    public static Properties getProperties(final Configuration config) {
    065        return getProperties((ImmutableConfiguration) config);
    066    }
    067
    068    /**
    069     * Convert a Configuration class into a Properties class. List properties are joined into a string using either the list
    070     * delimiter handler of the configuration (if it extends AbstractConfiguration) or with a comma as delimiter otherwise.
    071     *
    072     * @param config ImmutableConfiguration object to convert
    073     * @return Properties created from the Configuration
    074     * @since 2.2
    075     */
    076    public static Properties getProperties(final ImmutableConfiguration config) {
    077        final Properties props = new Properties();
    078        final ListDelimiterHandler listHandler;
    079        boolean useDelimiterHandler;
    080
    081        if (config instanceof AbstractConfiguration) {
    082            listHandler = ((AbstractConfiguration) config).getListDelimiterHandler();
    083            useDelimiterHandler = true;
    084        } else {
    085            listHandler = null;
    086            useDelimiterHandler = false;
    087        }
    088
    089        for (final Iterator<String> keys = config.getKeys(); keys.hasNext();) {
    090            final String key = keys.next();
    091            final List<Object> list = config.getList(key);
    092
    093            String propValue;
    094            if (useDelimiterHandler) {
    095                try {
    096                    propValue = String.valueOf(listHandler.escapeList(list, ListDelimiterHandler.NOOP_TRANSFORMER));
    097                } catch (final Exception ex) {
    098                    // obviously, the list handler does not support splitting
    099                    useDelimiterHandler = false;
    100                    propValue = listToString(list);
    101                }
    102            } else {
    103                propValue = listToString(list);
    104            }
    105
    106            props.setProperty(key, propValue);
    107        }
    108
    109        return props;
    110    }
    111
    112    /**
    113     * Helper method for joining all elements of a list to a string using the default value separator.
    114     *
    115     * @param list the list
    116     * @return the resulting string
    117     */
    118    private static String listToString(final List<?> list) {
    119        return StringUtils.join(list, DEFAULT_SEPARATOR);
    120    }
    121
    122    /**
    123     * Private constructor prevents instances from being created.
    124     */
    125    private ConfigurationConverter() {
    126        // to prevent instantiation
    127    }
    128}