/**
* Copyright (c) 2011, Jilles van Gurp
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package com.github.jsonj.tools;
import java.util.Map.Entry;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import nu.xom.Document;
import nu.xom.Element;
import nu.xom.IllegalNameException;
import nu.xom.converters.DOMConverter;
import org.w3c.dom.DOMImplementation;
import com.github.jsonj.JsonArray;
import com.github.jsonj.JsonElement;
import com.github.jsonj.JsonObject;
import com.github.jsonj.JsonPrimitive;
/**
* Helper class to get a DOM representation of a json element. This may be
* useful for example to apply xpath or xsl to a json document. The algorithm
* for converting is very straight forward:
* <ol>
* <li>You have to pick a root element name because json doesn't name its
* elements (except dictionary keys).</li>
* <li>Dictionary keys become tags. If needed the names are prepended with an
* underscore to produce valid xml tag names. E.g. {"1":"one"} becomes <_1>one</_1>
* <li>Arrays become ordered lists with an outer ol tag and li tags for each
* element. Just like in HTML</li>
* <li>Primitives are rendered as TEXT. Where needed XML escaping is used.</li>
* </ol>
*
* This class uses an optional maven dependency xom. If you want to use the
* functionality in this class, you will need to add this dependency to your own
* project.
*
*/
public class JsonXmlConverter {
private static void append(Element e, JsonPrimitive p) {
e.appendChild(p.asString());
}
private static void append(Element e, JsonObject o) {
for(Entry<String, JsonElement> entry:o.entrySet()) {
Element child;
try {
child = new Element(entry.getKey());
} catch (IllegalNameException exc1) {
child = new Element("_" + entry.getKey());
}
JsonElement value = entry.getValue();
if(value.isArray()) {
append(child, value.asArray());
} else if(value.isObject()) {
append(child, value.asObject());
} else {
append(child, value.asPrimitive());
}
e.appendChild(child);
}
}
private static void append(Element e, JsonArray p) {
Element list = new Element("ol");
for(JsonElement value: p) {
Element li = new Element("li");
if(value.isArray()) {
append(li, value.asArray());
} else if(value.isObject()) {
append(li, value.asObject());
} else {
append(li, value.asPrimitive());
}
list.appendChild(li);
}
e.appendChild(list);
}
/**
* Convert any JsonElement into an w3c DOM tree with a default root tag of <root>.
* @param value a json element
* @return a Document with a default root tag of <root>
*/
public static org.w3c.dom.Document getW3cDocument(JsonElement value) {
return getW3cDocument(value,"root");
}
/**
* Convert any JsonElement into an w3c DOM tree.
* @param value a json element
* @param rootName the root name of the xml
* @return a Document
*/
public static org.w3c.dom.Document getW3cDocument(JsonElement value, String rootName) {
Element root = getElement(value, rootName);
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();
DOMImplementation impl = builder.getDOMImplementation();
return DOMConverter.convert(new Document(root), impl);
} catch (ParserConfigurationException e) {
throw new IllegalStateException(e);
}
}
static Element getElement(JsonElement value, String rootName) {
Element root = new Element(rootName);
if(value.isArray()) {
append(root, value.asArray());
} else if(value.isObject()) {
append(root, value.asObject());
} else {
append(root, value.asPrimitive());
}
return root;
}
}