com.google.feedserver.util.XmlUtil.java Source code

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Here is the source code for com.google.feedserver.util.XmlUtil.java

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/* Copyright 2008 Google Inc.
 *
 * Licensed 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 com.google.feedserver.util;

import org.apache.commons.lang.StringEscapeUtils;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import java.beans.IntrospectionException;
import java.io.IOException;
import java.io.StringReader;
import java.lang.reflect.InvocationTargetException;
import java.text.ParseException;
import java.util.Map;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

/**
 * Utils for handling XML entities.
 */
public class XmlUtil {

    private SAXParserFactory parserFactory;

    protected BeanUtil beanUtil = new BeanUtil();

    public XmlUtil() {
        parserFactory = SAXParserFactory.newInstance();
        parserFactory.setValidating(false);
    }

    /**
     * Converts a a map of properties into an entity XML representation as used
     * in the content section of FeedStore entries:
     *<pre>
     * &lt;entity&gt;
     *   &lt;name0&gt;value0&lt;/name0&gt;
     *   &lt;name1&gt;value1&lt;/name1&gt;
     *   ...
     * &lt;/entity&gt;
     *</pre>
     */
    public String convertPropertiesToXml(Map<String, Object> properties) {
        return convertPropertiesToXml(properties, XmlHandler.ENTITY);
    }

    /**
     * Converts a a map of properties into an entity XML representation as used
     * in the content section of FeedStore entries:
     *<pre>
     * &lt;topLevelElement&gt;
     *   &lt;name0&gt;value0&lt;/name0&gt;
     *   &lt;name1&gt;value1&lt;/name1&gt;
     *   ...
     * &lt;/topLevelElement&gt;
     *</pre>
     */
    public String convertPropertiesToXml(Map<String, Object> properties, String topLevelElement) {
        StringBuilder builder = new StringBuilder();

        builder.append("<");
        builder.append(topLevelElement);
        builder.append(">");

        addMapValue(properties, builder);

        builder.append("</");
        builder.append(topLevelElement);
        builder.append(">");

        return builder.toString();
    }

    private void addMapValue(Map<String, Object> properties, StringBuilder builder) {
        for (String name : properties.keySet()) {
            Object value = properties.get(name);
            if (value instanceof Object[]) {
                Object[] values = (Object[]) value;
                if (values.length == 0) {
                    addPropertyXml(builder, name, null, true);
                } else {
                    for (int i = 0; i < values.length; i++) {
                        addPropertyXml(builder, name, values[i], i == 0);
                    }
                }
            } else {
                addPropertyXml(builder, name, value, false);
            }
        }
    }

    private void addPropertyXml(StringBuilder builder, String propertyName, Object value, boolean isRepeatable) {
        if (value == null) {
            value = "";
        }
        builder.append("<");
        builder.append(propertyName);
        if (isRepeatable) {
            builder.append(" ");
            builder.append(XmlHandler.REPEATABLE);
            builder.append("=\"true\"");
        }
        builder.append(">");
        addValue(builder, value);
        builder.append("</");
        builder.append(propertyName);
        builder.append(">");
    }

    /**
     * @param builder
     * @param value
     */
    @SuppressWarnings("unchecked")
    private void addValue(StringBuilder builder, Object value) {
        if (value instanceof Map) {
            addMapValue((Map) value, builder);
        } else {
            builder.append(StringEscapeUtils.escapeXml(value.toString()));
        }
    }

    /**
     * Converts XML representation of an entity into properties.
     */
    public Map<String, Object> convertXmlToProperties(String xmlText)
            throws SAXException, IOException, ParserConfigurationException {
        return convertXmlToProperties(xmlText, XmlHandler.ENTITY);
    }

    /**
     * Converts XML representation of an entity into properties.
     */
    public Map<String, Object> convertXmlToProperties(String xmlText, String topLevelELement)
            throws SAXException, IOException, ParserConfigurationException {
        InputSource input = new InputSource(new StringReader(xmlText));
        XmlHandler xmlHandler = new XmlHandler(topLevelELement);
        getParser().parse(input, xmlHandler);
        return xmlHandler.getValueMap();
    }

    /**
     * Creates a new SAXParser. Note that SAXParser.parse() is not thread-safe, so
     * we need to create a new one. Alternatively, we could synchronize parsing
     * which is most likely less efficient though.
     */
    protected SAXParser getParser() throws SAXException, ParserConfigurationException {
        return parserFactory.newSAXParser();
    }

    /**
     * Converts XML representation of an entity into a JavaBean.
     * @param xmlText XML text of entity
     * @param bean JavaBean to fill
     * @throws IllegalArgumentException
     * @throws IntrospectionException
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     * @throws SAXException
     * @throws IOException
     * @throws ParserConfigurationException
     * @throws ParseException 
     */
    public void convertXmlToBean(String xmlText, Object bean)
            throws IllegalArgumentException, IntrospectionException, IllegalAccessException,
            InvocationTargetException, SAXException, IOException, ParserConfigurationException, ParseException {
        beanUtil.convertPropertiesToBean(convertXmlToProperties(xmlText), bean);
    }
}