/*
 * 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.impl.builder.StAXOMBuilder;
import org.apache.axiom.om.util.StAXUtils;

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;

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

    /**
     * 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.
        StAXOMBuilder builder = new StAXOMBuilder(reader);
        OMDocument omDocument = builder.getDocument();
        Iterator it = omDocument.getChildren();
        while (it.hasNext()) {
            OMNode omNode = (OMNode)it.next();
            // TODO Using serialize and consume
            // caused an axiom bug...falling back to serialize
            // (which is less performant due to om caching)
            //omNode.serializeAndConsume(writer);
            omNode.serialize(writer);
        }
        // Close the reader
        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;
    }
}