/*
* Entagged Audio Tag library
* Copyright (c) 2003-2005 Raphaël Slinckx <raphael@slinckx.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.jaudiotagger.audio.generic;
import org.jaudiotagger.audio.AudioFile;
import org.jaudiotagger.audio.exceptions.CannotReadException;
import org.jaudiotagger.audio.exceptions.InvalidAudioFrameException;
import org.jaudiotagger.audio.exceptions.ReadOnlyFileException;
import org.jaudiotagger.tag.Tag;
import org.jaudiotagger.tag.TagException;
import org.jaudiotagger.logging.ErrorMessage;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.logging.Logger;
import java.util.logging.Level;
/*
* This abstract class is the skeleton for tag readers. It handles the creation/closing of
* the randomaccessfile objects and then call the subclass method getEncodingInfo and getTag.
* These two method have to be implemented in the subclass.
*
*@author Raphael Slinckx
*@version $Id: AudioFileReader.java 933 2010-12-01 12:28:37Z paultaylor $
*@since v0.02
*/
public abstract class AudioFileReader {
// Logger Object
public static Logger logger = Logger.getLogger("org.jaudiotagger.audio.generic");
private static final int MINIMUM_SIZE_FOR_VALID_AUDIO_FILE = 150;
/*
* Returns the encoding info object associated wih the current File.
* The subclass can assume the RAF pointer is at the first byte of the file.
* The RandomAccessFile must be kept open after this function, but can point
* at any offset in the file.
*
* @param raf The RandomAccessFile associtaed with the current file
* @exception IOException is thrown when the RandomAccessFile operations throw it (you should never throw them manually)
* @exception CannotReadException when an error occured during the parsing of the encoding infos
*/
protected abstract GenericAudioHeader getEncodingInfo(RandomAccessFile raf) throws CannotReadException, IOException;
/*
* Same as above but returns the Tag contained in the file, or a new one.
*
* @param raf The RandomAccessFile associted with the current file
* @exception IOException is thrown when the RandomAccessFile operations throw it (you should never throw them manually)
* @exception CannotReadException when an error occured during the parsing of the tag
*/
protected abstract Tag getTag(RandomAccessFile raf) throws CannotReadException, IOException;
/*
* Reads the given file, and return an AudioFile object containing the Tag
* and the encoding infos present in the file. If the file has no tag, an
* empty one is returned. If the encodinginfo is not valid , an exception is thrown.
*
* @param f The file to read
* @exception CannotReadException If anything went bad during the read of this file
*/
public AudioFile read(File f) throws CannotReadException, IOException, TagException, ReadOnlyFileException, InvalidAudioFrameException {
if (logger.isLoggable(Level.INFO)) {
//logger.info(ErrorMessage.GENERAL_READ.getMsg(f.getAbsolutePath()));
}
if (!f.canRead()) {
throw new CannotReadException(ErrorMessage.GENERAL_READ_FAILED_FILE_TOO_SMALL.getMsg(f.getAbsolutePath()));
}
if (f.length() <= MINIMUM_SIZE_FOR_VALID_AUDIO_FILE) {
throw new CannotReadException(ErrorMessage.GENERAL_READ_FAILED_FILE_TOO_SMALL.getMsg(f.getAbsolutePath()));
}
RandomAccessFile raf = null;
try {
raf = new RandomAccessFile(f, "r");
raf.seek(0);
GenericAudioHeader info = getEncodingInfo(raf);
raf.seek(0);
Tag tag = getTag(raf);
return new AudioFile(f, info, tag);
} catch (CannotReadException cre) {
throw cre;
} catch (Exception e) {
logger.log(Level.SEVERE, ErrorMessage.GENERAL_READ.getMsg(f.getAbsolutePath()), e);
throw new CannotReadException(f.getAbsolutePath() + ":" + e.getMessage(), e);
} finally {
try {
if (raf != null) {
raf.close();
}
} catch (Exception ex) {
logger.log(Level.WARNING, ErrorMessage.GENERAL_READ_FAILED_UNABLE_TO_CLOSE_RANDOM_ACCESS_FILE.getMsg(f.getAbsolutePath()));
}
}
}
}