/*
* Syncany, www.syncany.org
* Copyright (C) 2011-2016 Philipp C. Heckel <philipp.heckel@gmail.com>
*
* 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, either version 3 of the License, or
* (at your option) any later version.
*
* 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 org.syncany.database.dao;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.stream.XMLStreamException;
import org.syncany.chunk.Transformer;
import org.syncany.database.DatabaseVersion;
import org.syncany.database.MemoryDatabase;
import org.syncany.database.VectorClock;
/**
* Serializes a {@link MemoryDatabase} or a list of {@link DatabaseVersion}s to an
* XML-based file format, using a {@link Transformer} to compress/encrypt the file
* before writing, and to decompress/decrypt it before reading.
*
* <p>The class offers a variety of <tt>save()</tt> to serialize and store a memory
* database to a file, and several <tt>load()</tt> methods to load them from disk.
*
* <p>It uses a {@link DatabaseXmlWriter} to write XML files to disk and
* {@link DatabaseXmlParseHandler} to parse them while reading.
*
* @see DatabaseXmlParseHandler
* @see DatabaseXmlWriter
* @author Philipp C. Heckel <philipp.heckel@gmail.com>
*/
public class DatabaseXmlSerializer {
private static final Logger logger = Logger.getLogger(DatabaseXmlSerializer.class.getSimpleName());
public enum DatabaseReadType {
FULL, HEADER_ONLY
}
private Transformer transformer;
public DatabaseXmlSerializer() {
this(null);
}
public DatabaseXmlSerializer(Transformer transformer) {
this.transformer = transformer;
}
public void save(List<DatabaseVersion> databaseVersions, File destinationFile) throws IOException {
save(databaseVersions.iterator(), destinationFile);
}
public void save(Iterator<DatabaseVersion> databaseVersions, File destinationFile) throws IOException {
try {
PrintWriter out;
if (transformer == null) {
out = new PrintWriter(new OutputStreamWriter(
new FileOutputStream(destinationFile), "UTF-8"));
}
else {
out = new PrintWriter(new OutputStreamWriter(
transformer.createOutputStream(new FileOutputStream(destinationFile)), "UTF-8"));
}
// Initialize XML writer
new DatabaseXmlWriter(databaseVersions, out).write();
}
catch (XMLStreamException e) {
throw new IOException(e);
}
}
public void load(MemoryDatabase db, File databaseFile, VectorClock fromVersion, VectorClock toVersion, DatabaseReadType readType)
throws IOException {
InputStream is;
if (transformer == null) {
is = new FileInputStream(databaseFile);
}
else {
is = transformer.createInputStream(new FileInputStream(databaseFile));
}
try {
logger.log(Level.INFO, "- Loading database ({0}) from file {1} ...", new Object[] { readType, databaseFile });
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser saxParser = factory.newSAXParser();
saxParser.parse(is, new DatabaseXmlParseHandler(db, fromVersion, toVersion, readType));
}
catch (Exception e) {
throw new IOException(e);
}
}
}