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'databene commons' is an open source Java library by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.
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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * 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.databene.commons.xml;

import java.io.Closeable;
import java.io.OutputStream;
import java.util.Map;

import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;

import org.databene.commons.ConfigurationError;
import org.databene.commons.IOUtil;
import org.databene.commons.StringUtil;
import org.xml.sax.Attributes;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;

/**
 * Writes XML to a stream. The interface is similar to {@link Transformer}, 
 * but setup is easier, methods have been simplified and convenience methods 
 * have been added.
 * Created: 28.11.2010 06:39:04
 * @since 0.5.4
 * @author Volker Bergmann
 */
public class SimpleXMLWriter implements Closeable {

    OutputStream out;
    TransformerHandler handler;

	public SimpleXMLWriter(OutputStream out, String encoding, boolean includeXmlHeader) {
        try {
			// create file and write header
			SAXTransformerFactory tf = (SAXTransformerFactory) SAXTransformerFactory.newInstance();
			handler = tf.newTransformerHandler();
			Transformer transformer = handler.getTransformer();
			transformer.setOutputProperty(OutputKeys.STANDALONE, "yes");
			transformer.setOutputProperty(OutputKeys.ENCODING, encoding);
			transformer.setOutputProperty(OutputKeys.INDENT, "yes");
			transformer.setOutputProperty("{http://xml.apache.org/xslt}" + "indent-amount", "2");
			if (!includeXmlHeader)
				transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
			handler.setResult(new StreamResult(out));
			handler.startDocument();
		} catch (TransformerConfigurationException e) {
			throw new ConfigurationError(e);
		} catch (SAXException e) {
			throw new ConfigurationError("Error in initializing XML file", e);
		}
	}

	public void print(String text) throws SAXException {
		characters(text.toCharArray(), 0, text.length());
	}

	public void text(String text) throws SAXException {
		handler.characters(text.toCharArray(), 0, text.length());
	}

	public void characters(char[] ch, int start, int length) throws SAXException {
		handler.characters(ch, start, length);
	}

	public void comment(char[] ch, int start, int length) throws SAXException {
		handler.comment(ch, start, length);
	}

	public void endCDATA() throws SAXException {
		handler.endCDATA();
	}

	public void endDTD() throws SAXException {
		handler.endDTD();
	}

	public void endDocument() throws SAXException {
		handler.endDocument();
	}

	public void endElement(String name)
			throws SAXException {
		handler.endElement("", "", name);
	}

	public void endEntity(String name) throws SAXException {
		handler.endEntity(name);
	}

	public void endPrefixMapping(String prefix) throws SAXException {
		handler.endPrefixMapping(prefix);
	}

	public String getSystemId() {
		return handler.getSystemId();
	}

	public Transformer getTransformer() {
		return handler.getTransformer();
	}

	public void ignorableWhitespace(char[] ch, int start, int length)
			throws SAXException {
		handler.ignorableWhitespace(ch, start, length);
	}

	public void notationDecl(String name, String publicId, String systemId)
			throws SAXException {
		handler.notationDecl(name, publicId, systemId);
	}

	public void processingInstruction(String target, String data)
			throws SAXException {
		handler.processingInstruction(target, data);
	}

	public void setDocumentLocator(Locator locator) {
		handler.setDocumentLocator(locator);
	}

	public void setResult(Result result) throws IllegalArgumentException {
		handler.setResult(result);
	}

	public void setSystemId(String systemID) {
		handler.setSystemId(systemID);
	}

	public void skippedEntity(String name) throws SAXException {
		handler.skippedEntity(name);
	}

	public void startCDATA() throws SAXException {
		handler.startCDATA();
	}

	public void startDTD(String name, String publicId, String systemId)
			throws SAXException {
		handler.startDTD(name, publicId, systemId);
	}

	public void startDocument() throws SAXException {
		handler.startDocument();
	}

	public void writeElement(String name, Map attributes) throws SAXException {
		startElement(name, attributes);
		endElement(name);
	}

	public void startElement(String name, Map attributes) throws SAXException {
		AttributesImpl atts = null;
		if (attributes != null) {
			atts = new AttributesImpl();
			for (Map.Entry entry : attributes.entrySet())
				addAttribute(entry.getKey(), entry.getValue(), atts);
		}
		handler.startElement("", "", name, atts);
	}

	public void startElement(String name, Attributes atts) throws SAXException {
		handler.startElement("", "", name, atts);
	}

	public void startElement(String name, String... attributeNameValues) throws SAXException {
		AttributesImpl atts = null;
		if (attributeNameValues != null && attributeNameValues.length > 0) {
			if (attributeNameValues.length % 2 == 1)
				throw new IllegalArgumentException("Even number of attribute name/name arguments required");
			atts = new AttributesImpl();
			for (int i = 0; i < attributeNameValues.length; i += 2)
				addAttribute(attributeNameValues[i], attributeNameValues[i+1], atts);
		}
		handler.startElement("", "", name, atts);
	}

	public void startEntity(String name) throws SAXException {
		handler.startEntity(name);
	}

	public void startPrefixMapping(String prefix, String uri)
			throws SAXException {
		handler.startPrefixMapping(prefix, uri);
	}

	public void unparsedEntityDecl(String name, String publicId,
			String systemId, String notationName) throws SAXException {
		handler.unparsedEntityDecl(name, publicId, systemId, notationName);
	}

	@Override
	public void close() {
		try {
			if (handler != null) {
				try {
					handler.endDocument();
				} catch (SAXException e) {
					throw new RuntimeException("Error in closing XML file", e);
				}
				handler = null;
			}
		} finally {
			IOUtil.close(out);
		}
	}

	public static AttributesImpl createAttributes(String attributeName, String attributeValue) {
		AttributesImpl atts = new AttributesImpl();
		if (attributeValue != null)
			addAttribute(attributeName, attributeValue, atts);
		return atts;
	}

	public static AttributesImpl addAttribute(String name, String value, AttributesImpl atts) {
		if (!StringUtil.isEmpty(value)) 
			atts.addAttribute("", "", name, "CDATA", value);
		return atts;
	}

}