backuprestore.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: BackupRestore.java,v 1.8 2004/01/03 10:39:41 per_nyfelt Exp $

package org.ozoneDB.core.admin;

import org.ozoneDB.DxLib.DxIterator;
import org.ozoneDB.OzoneCompatible;
import org.ozoneDB.OzoneInterface;
import org.ozoneDB.core.*;
import org.ozoneDB.core.xml.*;
import org.ozoneDB.util.LogWriter;
import org.ozoneDB.xml.util.*;
import org.xml.sax.helpers.AttributesImpl;

import java.io.*;


/**
 * This class handles all backup/restore related operations of the ozone admin
 * system.<p>
 *
 * Note: The backup/restore does not use the object specific object to XML
 * mapping. The backup always uses the standard mapping defined by {@link
 * org.ozoneDB.core.xml.Object2XML}.
 *
 * @version $Revision: 1.8 $ $Date: 2004/01/03 10:39:41 $
 * @author <a href="http://www.smb-tec.com">SMB</a>
 * @see Admin
 */
public class BackupRestore implements XML2ObjectDelegate {

    protected final static String		TMP_FILE_NAME = "oids.tmp";

    protected final static String		BACKUP_ELEMENT_NAME = "ozone-database-backup";

    protected transient Env			env;

    protected transient SAXChunkProducer	backupProducer;

    protected transient DataInputStream		backupIn;

    protected transient SAXChunkConsumer	restoreConsumer;

    protected transient int			idcount;


    public BackupRestore( Env _env ) {
        env = _env;
    }


    public void beginRestore() throws Exception {
        env.logWriter.newEntry( this, "beginRestore()...", LogWriter.INFO );

        if (restoreConsumer != null) {
            throw new IllegalStateException( "There is a restore process already in progress." );
        }
        XML2ObjectContentHandler restoreHandler = new XML2ObjectContentHandler( this );
        restoreConsumer = new SAXChunkConsumer( restoreHandler );
    }


    public void processRestoreChunk( byte[] chunk ) throws Exception {
        if (restoreConsumer == null) {
            throw new IllegalStateException( "Start the restore process first." );
        }
        if (chunk == null) {
            restoreConsumer = null;
        }
        else {
            System.out.println( "" );
            env.logWriter.newEntry( this, "processRestoreChunk(): size=" + chunk.length, LogWriter.INFO );
            restoreConsumer.processChunk( chunk );
        }
    }


    /**
     * This method is inherited from XML2ObjectDelegate. It is called when an
     * entire object is re-constructed from the XML stream.
     */
    public void handleObject( ObjElement element ) {
        System.out.print( '.' );

        OzoneCompatible obj = (OzoneCompatible)element.getObject();
        ObjectID id = new ObjectID( Long.parseLong( (String)element.getOzoneObjectId() ) );
        String name = (String)element.getOzoneObjectName();

        env.logWriter.newEntry( this, "handleObject(): " + element.getClassName() + ": oid=" + id + ", target=" + obj, LogWriter.DEBUG3 );

        try {
            ObjectContainer container = env.transactionManager.currentTA().createObject(null,OzoneInterface.Public,name,null,null,id);

            try {
                container.setTarget( obj );
            } finally {
                container.unpin();
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }


    public void beginBackup() throws Exception {
        if (backupIn != null) {
            throw new IllegalStateException( "There is a backup process already in progress." );
        }

        backupProducer = new SAXChunkProducer( (SAXChunkProducerDelegate)null );
        backupProducer.startDocument();
        backupProducer.startElement( "", BACKUP_ELEMENT_NAME, BACKUP_ELEMENT_NAME, new AttributesImpl() );

        env.logWriter.newEntry( this, "preparing list of object IDs...", LogWriter.INFO );

        idcount = 0;
        DataOutputStream out = new DataOutputStream( new BufferedOutputStream( new FileOutputStream( env.getDatabaseDir() + TMP_FILE_NAME ), 4096 ) );
        DxIterator backupIt = env.storeManager.objectIDIterator();
        while (backupIt.next() != null) {
            out.writeLong( ((ObjectID)backupIt.key()).value() );
            idcount ++;
        }
        out.close();

        env.logWriter.newEntry( this, "preparing list of object IDs... ready. (" + idcount + " IDs)", LogWriter.INFO );
        idcount = 0;

        backupIn = new DataInputStream( new BufferedInputStream( new FileInputStream( env.getDatabaseDir() + TMP_FILE_NAME ), 4096 ) );
    }


    private ObjectID nextBackupID() throws Exception {
        if (backupIn == null) {
            throw new IllegalStateException( "Start backup process first." );
        }
        try {
            return new ObjectID( backupIn.readLong() );
        }
        catch (Exception e) {
            backupIn.close();
            backupIn = null;
            new File( env.getDatabaseDir() + TMP_FILE_NAME ).delete();

            if (e instanceof EOFException) {
                return null;
            } else {
                throw e;
            }
        }
    }


    public byte[] nextBackupChunk() throws Exception {
        Transaction ta = env.transactionManager.currentTA();
        if (env.logWriter.hasTarget(LogWriter.DEBUG3)) {
            env.logWriter.newEntry(this, "current transaction: " + ta, LogWriter.DEBUG3 );
        }
        if (backupProducer == null) {
            return null;
        }

        ChunkOutputStream cos = backupProducer.chunkStream();
        ObjectID id = null;

        // this order of the expressions is important
        while (cos.getState() != ChunkOutputStream.STATE_OVERFLOW && (id=nextBackupID()) != null) {
            if (env.logWriter.hasTarget(LogWriter.DEBUG3)) {
                env.logWriter.newEntry(this, "chunk size: " + cos.size() + " oid: " + id, LogWriter.DEBUG3 );
            }

            ObjectContainer container = ta.acquireObject( id, Lock.LEVEL_READ );

            try {
            OzoneCompatible target = container.target();
            if (env.logWriter.hasTarget(LogWriter.DEBUG3)) {
                env.logWriter.newEntry(this, "target: " + target + "[" + target.getClass().getName() + "]", LogWriter.DEBUG3 );
            }

            if (target instanceof org.ozoneDB.core.admin.AdminImpl) {
                continue;
            }

            Object2XML o2x = new Object2XML( backupProducer, true );
            o2x.toXML( target );
	        } finally {
	        	container.unpin();
	        }
        }

        if (id == null) {
            backupProducer.endElement( "", BACKUP_ELEMENT_NAME, BACKUP_ELEMENT_NAME );
            backupProducer.endDocument();
            cos.setEndFlag();
           // backupIt = null;
            backupProducer = null;
        }
        byte[] temp = cos.toByteArray();
        cos.reset();
        env.logWriter.newEntry( this, "nextBackupChunk(): size=" + temp.length, LogWriter.DEBUG );
        return temp;
    }

}