Reader2Writer.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.apache.axis2.jaxws.message.util;

import org.apache.axiom.om.OMDocument;
import org.apache.axiom.om.OMNode;
import org.apache.axiom.om.OMXMLBuilderFactory;
import org.apache.axiom.om.OMXMLParserWrapper;
import org.apache.axiom.om.util.StAXUtils;
import org.apache.axis2.jaxws.utility.JavaUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import java.io.StringWriter;
import java.util.Iterator;

/**
 * Reader2Writer This is a simple converter that is constructed with an XMLStreamReader and allows
 * you to write the contents to an XMLStreamWriter.
 */
public class Reader2Writer {

    private XMLStreamReader reader;
    private boolean closeReader = true;
    
    private static final Log log = LogFactory.getLog(Reader2Writer.class);

    /**
     * Construct from a Reader
     *
     * @param reader -- the input to the converter
     */
    public Reader2Writer(XMLStreamReader reader) {
        this.reader = reader;
    }

    /**
     * Construct from a Reader
     * @param reader -- the input to the converter
     * @param closeReader -- close the reader upon completion
     */
    public Reader2Writer(XMLStreamReader reader, boolean closeReader) {
        this(reader);
        this.closeReader = closeReader;
    }

    /**
     * outputTo the writer.
     *
     * @param writer -- the output of the converter
     */
    public void outputTo(XMLStreamWriter writer) throws XMLStreamException {
        // Using OM to convert the reader to a writer.  This seems to be
        // the safest way to make the conversion, and it promotes code re-use.
        OMXMLParserWrapper builder = OMXMLBuilderFactory.createStAXOMBuilder(reader);
        OMDocument omDocument = builder.getDocument();
        Iterator it = omDocument.getChildren();
        while (it.hasNext()) {
            OMNode omNode = (OMNode)it.next();
            omNode.serializeAndConsume(writer);
        }
        // Close the reader if marked to do so
        if (closeReader) {
            if (log.isDebugEnabled()) {
                log.debug("closing reader, builder: " + JavaUtils.stackToString());
            }
            reader.close();
        }
    }

    /**
     * Utility method to write the reader contents to a String
     * @return String
     */
    public String getAsString() throws XMLStreamException {
        StringWriter sw = new StringWriter();
        XMLStreamWriter writer = StAXUtils.createXMLStreamWriter(sw);

        // Write the reader to the writer
        outputTo(writer);

        // Flush the writer and get the String
        writer.flush();
        sw.flush();
        String str = sw.toString();
        writer.close();
        return str;
    }
}