/**
* Copyright © 2012 Alcatel-Lucent.
*
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
* Licensed 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 com.alu.e3.tdr.rotator;
import java.io.IOException;
import java.io.Writer;
import java.util.concurrent.atomic.AtomicInteger;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Element;
import com.alu.e3.common.performance.PerfWatch;
/**
* Writes arbitrary XML to a {@link Writer} (a character stream), which is obtained
* from a {@link WriterProvider}.
*
*/
public class XmlStreamWriter {
private final DocumentBuilder docBuilder;
private Transformer transformer = null;
// source of the current Writer
private final WriterProvider outputWriterProvider;
private static PerfWatch perfWatch;
public PerfWatch getPerfWatch() {
if (perfWatch == null )
perfWatch = new PerfWatch();
return perfWatch;
}
public XmlStreamWriter(WriterProvider outputWriterProvider)throws TransformerConfigurationException {
this.outputWriterProvider = outputWriterProvider;
TransformerFactory factory = TransformerFactory.newInstance();
this.transformer = factory.newTransformer();
this.transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
this.transformer.setOutputProperty(OutputKeys.INDENT, "yes");
try {
docBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
} catch (ParserConfigurationException e) {
throw new RuntimeException("DOM Builder error: ", e);
}
}
public DocumentBuilder getDocBuilder() {
return docBuilder;
}
/**
* Writes the specified DOM tree in XML format to the current character output stream.
*
* @param root top of the DOM tree to be written
* @throws TransformerException
* @throws IOException
*/
public void writeXml(Element root) throws TransformerException, IOException {
Long startTime = System.nanoTime();
Source source = new DOMSource(root.cloneNode(true));
synchronized (outputWriterProvider.getSynchroLock()) { // ensure atomicity of the entire DOM write
Writer outputWriter = outputWriterProvider.getWriter(); // get current output stream
Result result = new StreamResult(outputWriter);
transformer.transform(source, result); // write out the XML
}
getPerfWatch().getElapsedTime().addAndGet(System.nanoTime()-startTime);
getPerfWatch().getIterationCount().getAndIncrement();
getPerfWatch().log("XmlStreamWriter.writeXml()");
}
public void stop() {
synchronized (outputWriterProvider.getSynchroLock()) {
outputWriterProvider.stop();
}
}
}