backupworker.java

Java的面向对象数据库系统的源代码

// You can redistribute this software and/or modify it under the terms of
// the Ozone Library License version 1 published by ozone-db.org.
//
// The original code and portions created by SMB are
// Copyright (C) 1997-@year@ by SMB GmbH. All rights reserved.
//
// $Id: BackupWorker.java,v 1.2 2003/03/27 16:50:11 per_nyfelt Exp $
package org.ozoneDB.adminGui.feature.data;

import org.ozoneDB.ExternalDatabase;
import org.ozoneDB.ExternalTransaction;
import org.ozoneDB.adminGui.main.AdminGui;
import org.ozoneDB.xml.util.SAXChunkConsumer;
import org.ozoneDB.xml.util.SAXChunkProducer;
import org.ozoneDB.xml.util.SAXChunkProducerDelegate;
import org.ozoneDB.core.admin.Admin;
import org.apache.xml.serialize.XMLSerializer;
import org.apache.xml.serialize.OutputFormat;
import org.xml.sax.InputSource;
import org.xml.sax.helpers.ParserAdapter;

import javax.xml.parsers.SAXParserFactory;
import javax.xml.parsers.SAXParser;
import java.io.*;

/**
 * @author Per Nyfelt
 */
public final class BackupWorker {

    public static void backup(File backupFile) throws Exception {
        ExternalDatabase db = AdminGui.instance().getDb();
        Admin admin = db.admin();

        ExternalTransaction tx = db.newTransaction();
        tx.begin();

        try {
            admin.beginBackup();

            if (backupFile.exists() && !backupFile.canWrite()) {
                throw new Exception("File " + backupFile.getAbsolutePath() + " exists and is not writable");
            }

            OutputStream out = new FileOutputStream(backupFile);
            OutputFormat outputFormat = new OutputFormat("xml", "UTF-8", true);
            //System.out.println("outputformat = " + outputFormat);
            XMLSerializer serializer = new XMLSerializer(out, outputFormat);
            //System.out.println("serializer = " + serializer);
            SAXChunkConsumer consumer = new SAXChunkConsumer(serializer.asContentHandler());

            byte[] bytes = null;
            int i = 0;
            while ((bytes = admin.nextBackupChunk()) != null) {
                System.out.println("writing chunk " + ++i);
                consumer.processChunk(bytes);
            }
            out.flush();
            out.close();
            tx.commit();
            System.out.println("done");
        } catch (Exception e) {
            tx.rollback();
            throw e;
        }

    }

    public static void restore(File backupFile) throws Exception {
        ExternalDatabase db = AdminGui.instance().getDb();
        final Admin admin = db.admin();
        ExternalTransaction tx = db.newTransaction();
        tx.begin();

        try {

            if (!backupFile.exists() || !backupFile.canRead()) {
                throw new Exception("File " + backupFile.getAbsolutePath() + " is not accessible");
            }

            admin.beginRestore();

            try {
                InputStream in = new FileInputStream(backupFile);
                InputSource xmlSource = new InputSource(in);
                SAXChunkProducer producer = new SAXChunkProducer(new SAXChunkProducerDelegate() {
                    public void processChunk(SAXChunkProducer producer) throws Exception {
                        admin.processRestoreChunk(producer.chunkStream().toByteArray());
                    }
                });
                SAXParserFactory parserFactory = SAXParserFactory.newInstance();
                SAXParser parser = parserFactory.newSAXParser();
                ParserAdapter adapter = new ParserAdapter(parser.getParser());
                adapter.setContentHandler(producer);
                adapter.parse(xmlSource);
                tx.commit();
            } finally {
                admin.processRestoreChunk(null);
            }
        } catch (Exception e) {
            tx.rollback();
            throw e;
        }
    }
}