    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
    018    package org.apache.commons.configuration;
    019
    020    import java.io.File;
    021    import java.io.PrintWriter;
    022    import java.io.Reader;
    023    import java.io.Writer;
    024    import java.net.URL;
    025    import java.util.Iterator;
    026    import java.util.List;
    027
    028    import javax.xml.parsers.SAXParser;
    029    import javax.xml.parsers.SAXParserFactory;
    030
    031    import org.apache.commons.lang.StringEscapeUtils;
    032    import org.apache.commons.lang.StringUtils;
    033    import org.xml.sax.Attributes;
    034    import org.xml.sax.EntityResolver;
    035    import org.xml.sax.InputSource;
    036    import org.xml.sax.XMLReader;
    037    import org.xml.sax.helpers.DefaultHandler;
    038
    039    /**
    040     * This configuration implements the XML properties format introduced in Java
    041     * 5.0, see http://java.sun.com/j2se/1.5.0/docs/api/java/util/Properties.html.
    042     * An XML properties file looks like this:
    043     *
    044     * <pre>
    045     * &lt;?xml version="1.0"?>
    046     * &lt;!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
    047     * &lt;properties>
    048     *   &lt;comment>Description of the property list&lt;/comment>
    049     *   &lt;entry key="key1">value1&lt;/entry>
    050     *   &lt;entry key="key2">value2&lt;/entry>
    051     *   &lt;entry key="key3">value3&lt;/entry>
    052     * &lt;/properties>
    053     * </pre>
    054     *
    055     * The Java 5.0 runtime is not required to use this class. The default encoding
    056     * for this configuration format is UTF-8. Note that unlike
    057     * {@code PropertiesConfiguration}, {@code XMLPropertiesConfiguration}
    058     * does not support includes.
    059     *
    060     * <em>Note:</em>Configuration objects of this type can be read concurrently
    061     * by multiple threads. However if one of these threads modifies the object,
    062     * synchronization has to be performed manually.
    063     *
    064     * @author Emmanuel Bourg
    065     * @author Alistair Young
    066     * @version $Id: XMLPropertiesConfiguration.java 1210207 2011-12-04 20:43:50Z oheger $
    067     * @since 1.1
    068     */
    069    public class XMLPropertiesConfiguration extends PropertiesConfiguration
    070    {
    071        /**
    072         * The default encoding (UTF-8 as specified by http://java.sun.com/j2se/1.5.0/docs/api/java/util/Properties.html)
    073         */
    074        private static final String DEFAULT_ENCODING = "UTF-8";
    075
    076        // initialization block to set the encoding before loading the file in the constructors
    077        {
    078            setEncoding(DEFAULT_ENCODING);
    079        }
    080
    081        /**
    082         * Creates an empty XMLPropertyConfiguration object which can be
    083         * used to synthesize a new Properties file by adding values and
    084         * then saving(). An object constructed by this C'tor can not be
    085         * tickled into loading included files because it cannot supply a
    086         * base for relative includes.
    087         */
    088        public XMLPropertiesConfiguration()
    089        {
    090            super();
    091        }
    092
    093        /**
    094         * Creates and loads the xml properties from the specified file.
    095         * The specified file can contain "include" properties which then
    096         * are loaded and merged into the properties.
    097         *
    098         * @param fileName The name of the properties file to load.
    099         * @throws ConfigurationException Error while loading the properties file
    100         */
    101        public XMLPropertiesConfiguration(String fileName) throws ConfigurationException
    102        {
    103            super(fileName);
    104        }
    105
    106        /**
    107         * Creates and loads the xml properties from the specified file.
    108         * The specified file can contain "include" properties which then
    109         * are loaded and merged into the properties.
    110         *
    111         * @param file The properties file to load.
    112         * @throws ConfigurationException Error while loading the properties file
    113         */
    114        public XMLPropertiesConfiguration(File file) throws ConfigurationException
    115        {
    116            super(file);
    117        }
    118
    119        /**
    120         * Creates and loads the xml properties from the specified URL.
    121         * The specified file can contain "include" properties which then
    122         * are loaded and merged into the properties.
    123         *
    124         * @param url The location of the properties file to load.
    125         * @throws ConfigurationException Error while loading the properties file
    126         */
    127        public XMLPropertiesConfiguration(URL url) throws ConfigurationException
    128        {
    129            super(url);
    130        }
    131
    132        @Override
    133        public void load(Reader in) throws ConfigurationException
    134        {
    135            SAXParserFactory factory = SAXParserFactory.newInstance();
    136            factory.setNamespaceAware(false);
    137            factory.setValidating(true);
    138
    139            try
    140            {
    141                SAXParser parser = factory.newSAXParser();
    142
    143                XMLReader xmlReader = parser.getXMLReader();
    144                xmlReader.setEntityResolver(new EntityResolver()
    145                {
    146                    public InputSource resolveEntity(String publicId, String systemId)
    147                    {
    148                        return new InputSource(getClass().getClassLoader().getResourceAsStream("properties.dtd"));
    149                    }
    150                });
    151                xmlReader.setContentHandler(new XMLPropertiesHandler());
    152                xmlReader.parse(new InputSource(in));
    153            }
    154            catch (Exception e)
    155            {
    156                throw new ConfigurationException("Unable to parse the configuration file", e);
    157            }
    158
    159            // todo: support included properties ?
    160        }
    161
    162        @Override
    163        public void save(Writer out) throws ConfigurationException
    164        {
    165            PrintWriter writer = new PrintWriter(out);
    166
    167            String encoding = getEncoding() != null ? getEncoding() : DEFAULT_ENCODING;
    168            writer.println("<?xml version=\"1.0\" encoding=\"" + encoding + "\"?>");
    169            writer.println("<!DOCTYPE properties SYSTEM \"http://java.sun.com/dtd/properties.dtd\">");
    170            writer.println("<properties>");
    171
    172            if (getHeader() != null)
    173            {
    174                writer.println("  <comment>" + StringEscapeUtils.escapeXml(getHeader()) + "</comment>");
    175            }
    176
    177            Iterator<String> keys = getKeys();
    178            while (keys.hasNext())
    179            {
    180                String key = keys.next();
    181                Object value = getProperty(key);
    182
    183                if (value instanceof List)
    184                {
    185                    writeProperty(writer, key, (List<?>) value);
    186                }
    187                else
    188                {
    189                    writeProperty(writer, key, value);
    190                }
    191            }
    192
    193            writer.println("</properties>");
    194            writer.flush();
    195        }
    196
    197        /**
    198         * Write a property.
    199         *
    200         * @param out the output stream
    201         * @param key the key of the property
    202         * @param value the value of the property
    203         */
    204        private void writeProperty(PrintWriter out, String key, Object value)
    205        {
    206            // escape the key
    207            String k = StringEscapeUtils.escapeXml(key);
    208
    209            if (value != null)
    210            {
    211                // escape the value
    212                String v = StringEscapeUtils.escapeXml(String.valueOf(value));
    213                v = StringUtils.replace(v, String.valueOf(getListDelimiter()), "\\" + getListDelimiter());
    214
    215                out.println("  <entry key=\"" + k + "\">" + v + "</entry>");
    216            }
    217            else
    218            {
    219                out.println("  <entry key=\"" + k + "\"/>");
    220            }
    221        }
    222
    223        /**
    224         * Write a list property.
    225         *
    226         * @param out the output stream
    227         * @param key the key of the property
    228         * @param values a list with all property values
    229         */
    230        private void writeProperty(PrintWriter out, String key, List<?> values)
    231        {
    232            for (Object value : values)
    233            {
    234                writeProperty(out, key, value);
    235            }
    236        }
    237
    238        /**
    239         * SAX Handler to parse a XML properties file.
    240         *
    241         * @author Alistair Young
    242         * @since 1.2
    243         */
    244        private class XMLPropertiesHandler extends DefaultHandler
    245        {
    246            /** The key of the current entry being parsed. */
    247            private String key;
    248
    249            /** The value of the current entry being parsed. */
    250            private StringBuilder value = new StringBuilder();
    251
    252            /** Indicates that a comment is being parsed. */
    253            private boolean inCommentElement;
    254
    255            /** Indicates that an entry is being parsed. */
    256            private boolean inEntryElement;
    257
    258            @Override
    259            public void startElement(String uri, String localName, String qName, Attributes attrs)
    260            {
    261                if ("comment".equals(qName))
    262                {
    263                    inCommentElement = true;
    264                }
    265
    266                if ("entry".equals(qName))
    267                {
    268                    key = attrs.getValue("key");
    269                    inEntryElement = true;
    270                }
    271            }
    272
    273            @Override
    274            public void endElement(String uri, String localName, String qName)
    275            {
    276                if (inCommentElement)
    277                {
    278                    // We've just finished a <comment> element so set the header
    279                    setHeader(value.toString());
    280                    inCommentElement = false;
    281                }
    282
    283                if (inEntryElement)
    284                {
    285                    // We've just finished an <entry> element, so add the key/value pair
    286                    addProperty(key, value.toString());
    287                    inEntryElement = false;
    288                }
    289
    290                // Clear the element value buffer
    291                value = new StringBuilder();
    292            }
    293
    294            @Override
    295            public void characters(char[] chars, int start, int length)
    296            {
    297                /**
    298                 * We're currently processing an element. All character data from now until
    299                 * the next endElement() call will be the data for this  element.
    300                 */
    301                value.append(chars, start, length);
    302            }
    303        }
    304    }