/**

  * Alt2XML

  * Copyright © 2014 František Kučera (frantovo.cz)

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 3 of the License.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. If not, see <http://www.gnu.org/licenses/>.

  */

 package cz.frantovo.alt2xml;

 import java.util.Deque;

 import java.util.HashMap;

 import java.util.LinkedList;

 import java.util.Map;

 import java.util.Map.Entry;

 import java.util.ServiceLoader;

 import javax.xml.parsers.FactoryConfigurationError;

 import javax.xml.parsers.ParserConfigurationException;

 import javax.xml.parsers.SAXParser;

 import javax.xml.parsers.SAXParserFactory;

 import org.xml.sax.SAXException;

 import org.xml.sax.SAXNotRecognizedException;

 import org.xml.sax.SAXNotSupportedException;

 import org.xml.sax.XMLReader;

 /**

  *

  * @author Ing. František Kučera (frantovo.cz)

  */

 public class ParserFactory extends SAXParserFactory implements ReaderFinder {

 	private final Deque<Alt2XmlReaderFactory> readerFactories = new LinkedList();

 	/**

 	 * @see #DEFAULT_FACTORY_PROPERTY

 	 */

 	private SAXParserFactory fallbackFactory;

 	/**

 	 * System property which contains SAXParserFactory class name for XML.

 	 * Will be used as fallback if no alternative factory matches systemId to be parsed.

 	 */

 	public static final String DEFAULT_FACTORY_PROPERTY = "cz.frantovo.alt2xml.fallback.javax.xml.parsers.SAXParserFactory";

 	private final Map<String, Boolean> features = new HashMap<>();

 	public ParserFactory() {

 		super();

 		for (Alt2XmlReaderFactory f : ServiceLoader.load(Alt2XmlReaderFactory.class)) {

 			readerFactories.add(f);

 		}

 		readerFactories.add(new FallbackReaderFactory());

 	}

 	/**

 	 * @return factory to be used for XML documents (default/fallback)

 	 * @throws FactoryConfigurationError if fallback factory is the same one as this – avoid

 	 * infinite recursion.

 	 */

 	public SAXParserFactory getFallbackFactory() {

 		if (fallbackFactory == null) {

 			String className = System.getProperty(DEFAULT_FACTORY_PROPERTY);

 			if (className == null) {

 				fallbackFactory = SAXParserFactory.newInstance();

 			} else {

 				fallbackFactory = SAXParserFactory.newInstance(className, null);

 			}

 		}

 		if (fallbackFactory.getClass().equals(getClass())) {

 			throw new FactoryConfigurationError("Fallback factory is the same class as this one – avoid infinite recursion: " + getClass());

 		} else {

 			return fallbackFactory;

 		}

 	}

 	public void setFallbackFactory(SAXParserFactory fallbackFactory) {

 		this.fallbackFactory = fallbackFactory;

 	}

 	private class FallbackReaderFactory implements Alt2XmlReaderFactory {

 		@Override

 		public boolean canRead(AltInputSource inputSource) {

 			return true;

 		}

 		@Override

 		public XMLReader getReader() throws SAXException {

 			try {

 				return getFallbackFactory().newSAXParser().getXMLReader();

 			} catch (ParserConfigurationException e) {

 				throw new SAXException("Unable to instantiate the fallback factory.", e);

 			}

 		}

 	}

 	@Override

 	public XMLReader findReader(AltInputSource inputSource) throws SAXException {

 		for (Alt2XmlReaderFactory f : readerFactories) {

 			if (f.canRead(inputSource)) {

 				return f.getReader();

 			}

 		}

 		throw new SAXException("Iterated over " + readerFactories.size() + " and was unable to find XMLReader for SystemId: " + inputSource);

 	}

 	@Override

 	public SAXParser newSAXParser() throws ParserConfigurationException, SAXException {

 		SuperReader r = new SuperReader(this);

 		for (Entry<String, Boolean> f : features.entrySet()) {

 			r.setFeature(f.getKey(), f.getValue());

 		}

 		return new AltSAXParser(r);

 	}

 	@Override

 	public void setFeature(String name, boolean value) throws ParserConfigurationException, SAXNotRecognizedException, SAXNotSupportedException {

 		features.put(name, value);

 	}

 	@Override

 	public boolean getFeature(String name) throws ParserConfigurationException, SAXNotRecognizedException, SAXNotSupportedException {

 		return features.get(name);

 	}

 }