/**
* Copyright (c) 2012, The National Archives <pronom@nationalarchives.gsi.gov.uk>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following
* conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of the The National Archives nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package uk.gov.nationalarchives.droid.signature;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import uk.gov.nationalarchives.droid.core.interfaces.signature.ErrorCode;
import uk.gov.nationalarchives.droid.core.interfaces.signature.SignatureFileException;
import uk.gov.nationalarchives.droid.profile.referencedata.Format;
/**
* @author rflitcroft
*
*/
public class SaxSignatureFileParser implements SignatureParser {
private static final String INVALID_SIGNATURE_FILE = "Invalid signature file [%s]";
private Log log = LogFactory.getLog(this.getClass());
private File file;
/**
* @param filePath
* the URI of the signature file to parse
* @throws SignatureFileException
* if the Signature file could not be parsed
*/
public SaxSignatureFileParser(URI filePath) throws SignatureFileException {
file = openFile(filePath);
}
/**
* {@inheritDoc}
*/
@Override
public void formats(FormatCallback callback) throws SignatureFileException {
FileFormatHandler handler = new FileFormatHandler(callback);
SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
try {
SAXParser saxParser = saxParserFactory.newSAXParser();
saxParser.parse(file, handler);
} catch (SAXException e) {
throw new SignatureFileException(String.format(
INVALID_SIGNATURE_FILE, file.toURI()), e,
ErrorCode.INVALID_SIGNATURE_FILE);
} catch (ParserConfigurationException e) {
log.error(e);
throw new RuntimeException(e.getMessage(), e);
} catch (IOException e) {
log.error(e);
throw new RuntimeException(e.getMessage(), e);
}
}
/**
* Opens a signature file for parsing.
*
* @param filePath
* the file location (relative or absolute) of the signature file
* to parse.
* @throws SignatureFileException
* if the path specified was not a valid signature file.
*/
private File openFile(URI filePath) throws SignatureFileException {
File f = new File(filePath);
if (!f.exists()) {
throw new SignatureFileException(String.format(
"Signature file does not exist [%s]", filePath),
ErrorCode.FILE_NOT_FOUND);
}
if (!f.isFile()) {
throw new SignatureFileException(String.format(
INVALID_SIGNATURE_FILE, filePath),
ErrorCode.INVALID_SIGNATURE_FILE);
}
return f;
}
/**
* Handler for <FileFormat> elements.
*
*/
private static final class FileFormatHandler extends DefaultHandler {
private FormatCallback callback;
public FileFormatHandler(FormatCallback callback) {
this.callback = callback;
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) {
if ("FileFormat".equals(qName)) {
Format format = new Format();
format.setPuid(notNull(attributes.getValue("PUID")));
format.setName(notNull(attributes.getValue("Name")));
format.setMimeType(notNull(attributes.getValue("MIMEType")));
format.setVersion(notNull(attributes.getValue("Version")));
callback.onFormat(format);
}
}
private String notNull(final String value) {
return value == null ? "" : value;
}
}
}