/* Copyright (c) 2008 Google Inc.
*
* 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 com.google.gdata.wireformats;
import com.google.gdata.util.common.base.Preconditions;
import com.google.gdata.util.common.xml.parsing.SecureXMLParsing;
import com.google.gdata.data.XmlEventSource;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.helpers.ParserAdapter;
import java.io.IOException;
import java.io.Reader;
import java.util.logging.Logger;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
/**
* {@link XmlEventSource} implementation based on SAX.
*
*
*/
public class SaxEventSource implements XmlEventSource {
private static final Logger logger =
Logger.getLogger(SaxEventSource.class.getCanonicalName());
/** The SAXParserFactory used to create underlying SAXParser instances. */
private static final SAXParserFactory parserFactory =
createSAXParserFactory();
/** Creates a secure SAX parser, which is secured against XXE attacks. */
private static SAXParserFactory createSAXParserFactory() {
try {
SAXParserFactory factory = SecureXMLParsing.getSAXParserFactory();
factory.setNamespaceAware(true);
return factory;
} catch (ParserConfigurationException e) {
// The parser factory failing for any reasons should be considered
// a bug in this class, since the parser configuration is hardcoded.
throw new IllegalStateException("Invalid parser configuration", e);
} catch (SAXException e) {
throw new IllegalStateException(
"Failed to create a SAX parser factory", e);
}
}
/** Reader used by this parser. */
private final Reader reader;
/**
* Creates a SAX event source backed by a reader
* and a charset.
*/
public SaxEventSource(Reader reader) {
Preconditions.checkNotNull(reader, "reader");
this.reader = reader;
}
public void parse(DefaultHandler handler) throws IOException, SAXException {
SAXParser sp = createSaxParser();
ParserAdapter pa = new ParserAdapter(sp.getParser());
pa.setContentHandler(handler);
pa.parse(new InputSource(reader));
}
private SAXParser createSaxParser() {
try {
return parserFactory.newSAXParser();
} catch (ParserConfigurationException e) {
// The parser factory failing for any reasons should be considered
// a bug in this class, since the parser configuration is hardcoded.
throw new IllegalStateException("Invalid parser configuration", e);
} catch (SAXException e) {
throw new IllegalStateException("Failed to create a SAX parser", e);
}
}
}