/*******************************************************************************
* Copyright 2012 André Rouél
*
* 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 net.sf.uadetector.datareader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.charset.Charset;
import javax.annotation.Nonnull;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import net.sf.qualitycheck.Check;
import net.sf.uadetector.exception.CanNotOpenStreamException;
import net.sf.uadetector.internal.data.Data;
import net.sf.uadetector.internal.data.DataBuilder;
import net.sf.uadetector.internal.data.XmlDataHandler;
import net.sf.uadetector.internal.util.Closeables;
import net.sf.uadetector.internal.util.UrlUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.SAXException;
/**
* Reader for the XML data for UASparser from <a
* href="http://user-agent-string.info/">http://user-agent-string.info</a>.<br>
* <br>
* This reader is safe when used concurrently by multiple threads.
*
* @author André Rouél
*/
public final class XmlDataReader implements DataReader {
protected static final class XmlParser {
private static final String MSG_NOT_PARSED_AS_EXPECTED = "The UAS data has not been parsed as expected.";
public static void parse(@Nonnull final InputStream stream, @Nonnull final DataBuilder builder)
throws ParserConfigurationException, SAXException, IOException {
final SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setValidating(true);
final SAXParser parser = factory.newSAXParser();
final XmlDataHandler handler = new XmlDataHandler(builder);
parser.parse(stream, handler);
validate(handler);
}
protected static void validate(@Nonnull final XmlDataHandler handler) {
if (handler.hasError()) {
throw new IllegalStateException(MSG_NOT_PARSED_AS_EXPECTED);
}
}
private XmlParser() {
// This class is not intended to create objects from it.
}
}
/**
* Default character set to read UAS data
*/
private static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
/**
* Corresponding default logger for this class
*/
private static final Logger LOG = LoggerFactory.getLogger(XmlDataReader.class);
/**
* Reads the <em>UAS data</em> in XML format based on the given URL.<br>
* <br>
* When during the reading errors occur which lead to a termination of the read operation, the information will be
* written to a log. The termination of the read operation will not lead to a program termination and in this case
* this method returns {@link Data#EMPTY}.
*
* @param inputStream
* an input stream for reading <em>UAS data</em>
* @param charset
* the character set in which the data should be read
* @return read in <em>UAS data</em> as {@code Data} instance
* @throws net.sf.qualitycheck.exception.IllegalNullArgumentException
* if any of the given arguments is {@code null}
* @throws net.sf.uadetector.exception.CanNotOpenStreamException
* if no stream to the given {@code URL} can be established
*/
protected static Data readXml(@Nonnull final InputStream inputStream, @Nonnull final Charset charset) {
Check.notNull(inputStream, "inputStream");
Check.notNull(charset, "charset");
final DataBuilder builder = new DataBuilder();
boolean hasErrors = false;
try {
XmlParser.parse(inputStream, builder);
} catch (final ParserConfigurationException e) {
hasErrors = true;
LOG.warn(e.getLocalizedMessage());
} catch (final SAXException e) {
hasErrors = true;
LOG.warn(e.getLocalizedMessage());
} catch (final IOException e) {
hasErrors = true;
LOG.warn(e.getLocalizedMessage());
} catch (final IllegalStateException e) {
hasErrors = true;
LOG.warn(e.getLocalizedMessage());
} catch (final Exception e) {
hasErrors = true;
LOG.warn(e.getLocalizedMessage(), e);
} finally {
Closeables.closeAndConvert(inputStream, true);
}
return hasErrors ? Data.EMPTY : builder.build();
}
/**
* Reads the <em>UAS data</em> in XML format from the given string.
*
* @param data
* <em>UAS data</em> as string
* @return read in User-Agent data as {@code Data} instance otherwise {@link Data#EMPTY}
*
* @throws net.sf.qualitycheck.exception.IllegalNullArgumentException
* if any of the given argument is {@code null}
*/
@Override
public Data read(@Nonnull final String data) {
Check.notNull(data, "data");
return readXml(new ByteArrayInputStream(data.getBytes(DEFAULT_CHARSET)), DEFAULT_CHARSET);
}
/**
* Reads the <em>UAS data</em> in XML format based on the given URL.
*
* @param url
* {@code URL} to User-Agent informations
* @param charset
* the character set in which the data should be read
* @return read in User-Agent data as {@code Data} instance otherwise {@link Data#EMPTY}
*
* @throws net.sf.qualitycheck.exception.IllegalNullArgumentException
* if any of the given arguments is {@code null}
*/
@Override
public Data read(@Nonnull final URL url, @Nonnull final Charset charset) {
Check.notNull(url, "url");
Check.notNull(charset, "charset");
Data data = Data.EMPTY;
try {
data = readXml(UrlUtil.open(url), charset);
} catch (final CanNotOpenStreamException e) {
LOG.warn(e.getLocalizedMessage());
}
return data;
}
}