org.directwebremoting.convert.DOMConverter Maven / Gradle / Ivy

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DWR is easy Ajax for Java. It makes it simple to call Java code directly from Javascript. It gets rid of almost all the boiler plate code between the web browser and your Java code.
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/*
 * Copyright 2005 Joe Walker
 *
 * 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 org.directwebremoting.convert;

import java.io.StringReader;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.directwebremoting.dwrp.SimpleOutboundVariable;
import org.directwebremoting.extend.Converter;
import org.directwebremoting.extend.InboundContext;
import org.directwebremoting.extend.InboundVariable;
import org.directwebremoting.extend.MarshallException;
import org.directwebremoting.extend.OutboundContext;
import org.directwebremoting.extend.OutboundVariable;
import org.directwebremoting.extend.EnginePrivate;
import org.directwebremoting.util.LocalUtil;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;

/**
 * An implementation of Converter for DOM objects.
 * @author Joe Walker [joe at eireneh dot com]
 * @version $Id: StringConverter.java,v 1.2 2004/11/04 15:54:07 joe_walker Exp $
 */
public class DOMConverter extends BaseV20Converter implements Converter
{
    /* (non-Javadoc)
     * @see org.directwebremoting.Converter#convertInbound(java.lang.Class, org.directwebremoting.InboundVariable, org.directwebremoting.InboundContext)
     */
    public Object convertInbound(Class paramType, InboundVariable iv, InboundContext inctx) throws MarshallException
    {
        String value = LocalUtil.decode(iv.getValue());

        try
        {
            if (buildFactory == null)
            {
                buildFactory = DocumentBuilderFactory.newInstance();
            }

            DocumentBuilder builder = buildFactory.newDocumentBuilder();

            InputSource is = new InputSource(new StringReader(value));
            Document doc = builder.parse(is);

            if (paramType == Document.class)
            {
                return doc;
            }
            else if (paramType == Element.class)
            {
                return doc.getDocumentElement();
            }

            throw new MarshallException(paramType);
        }
        catch (MarshallException ex)
        {
            throw ex;
        }
        catch (Exception ex)
        {
            throw new MarshallException(paramType, ex);
        }
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Converter#convertOutbound(java.lang.Object, org.directwebremoting.OutboundContext)
     */
    public OutboundVariable convertOutbound(Object data, OutboundContext outctx) throws MarshallException
    {
        try
        {
            Transformer transformer = xslFact.newTransformer();

            // Using XSLT to convert to a stream. Setup the source
            Source source;
            if (data instanceof Node)
            {
                Node node = (Node) data;
                source = new DOMSource(node);
            }
            else
            {
                throw new MarshallException(data.getClass());
            }

            // Setup the destination
            StringWriter xml = new StringWriter();
            StreamResult result = new StreamResult(xml);

            transformer.transform(source, result);

            xml.flush();

            String script = EnginePrivate.xmlStringToJavascriptDom(xml.toString());
            OutboundVariable ov = new SimpleOutboundVariable(script, outctx, false);

            outctx.put(data, ov);

            return ov;
        }
        catch (MarshallException ex)
        {
            throw ex;
        }
        catch (Exception ex)
        {
            throw new MarshallException(data.getClass(), ex);
        }
    }

    /**
     * How we create new transformers
     */
    private TransformerFactory xslFact = TransformerFactory.newInstance();

    /**
     * How we create new documents
     */
    private DocumentBuilderFactory buildFactory = null;
}