localdatabase.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: LocalDatabase.java,v 1.8 2002/09/18 06:54:13 per_nyfelt Exp $

package org.ozoneDB;

import org.ozoneDB.core.DbRemote.DbClient;
import org.ozoneDB.core.DbRemote.DbLocalClient;
import org.ozoneDB.core.Env;
import org.ozoneDB.tools.Install;
import org.ozoneDB.util.OzoneDebugLevel;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Hashtable;


/**
 * This class represents a local database server that runs inside the same
 * JVM as the client. For a detailed method description see OzoneInterface.
 *
 *
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @author <a href="http://www.medium.net/">SMB</a>
 * @version $Revision: 1.8 $Date: 2002/09/18 06:54:13 $
 * @see OzoneInterface
 */
public final class LocalDatabase extends ExternalDatabase {

    public Env env;

    public String userName;


    public LocalDatabase() {
    }


    /**
     * Create a new database in the given directory using default values
     * for all Setup entries.
     *
     *
     * @param dirName The directory to create the database in
     * @return a StringWriter that holds the status messages
     * @exception java.lang.Exception
     * @see Setup
     */
    public synchronized String create( String dirName ) throws Exception {
        //use default values
        Setup setup = new Setup( env );
        return create( dirName, setup );
    }


    /**
     * Create a new database in the given directory using the values
     * of the given Setup.
     *
     * @param dirName
     * @return a StringWriter that holds the status messages
     * @exception java.lang.Exception
     * @see Setup
     */
    public synchronized String create( String dirName, Setup setup ) throws Exception {
        StringWriter writer = new StringWriter();
        PrintWriter logFile = new PrintWriter( writer, true );
        Install.createDB( dirName, setup, logFile );
        return writer.toString();
    }

    /** opens the database.
     * @param dirName is the path name of the database directory root
    */
    public void open( String dirName) throws Exception {
        String username = System.getProperty( "user.name" );
        open( dirName, null, username, username );
    }

    /**
     *  For backwards compatibility
     *
     *  @deprecated but still needed by legacy software.
     *  use open(String _dirName, String _debugLevel ) instead.
     *  @param dirName is the path name of the database directory root
     *  @param debugLevel should match one of the constants in OzoneDebugLevel.
     *  Overrrides the property ozoneDB.logLevel in config.properties.
     */
    public void open(String dirName, int debugLevel) throws Exception {
        String level = OzoneDebugLevel.toLevel(debugLevel, OzoneDebugLevel.INFO).toString();
        open(dirName, level);
    }

    /**
     * Opens the database.
     * @param dirName is the path name of the database directory root
     * @param debugLevel derived from OzoneDebugLevel.
     * Overrrides the property ozoneDB.logLevel in config.properties. If set to null, the config.properties
     * setting will be used.
     */
    public void open( String dirName, String debugLevel ) throws Exception {
        String username = System.getProperty( "user.name" );
        open( dirName, debugLevel, username, username );
    }

    /**
     * Opens the database.
     * @param dirName
     * @param debugLevel one of the String constants in OzoneDebugLevel (e.g. INFO_STR).
     * Overrrides the property ozoneDB.logLevel in config.properties. If set to null, the config.properties
     * setting will be used.
     * @param userName
     * @param password
     */
    public void open( String dirName, String debugLevel, String userName, String password ) throws Exception {
        Hashtable props = new Hashtable();
        props.put( PROP_DIR, dirName );
        props.put( PROP_USER, userName );
        props.put( PROP_PASSWD, password );
        if (debugLevel != null) {
            props.put( PROP_DEBUG, debugLevel );
        }

        open( props );
    }


    protected synchronized void open( Hashtable props ) throws Exception {
        try {
            super.open( props );

            String dirName = (String)props.get( PROP_DIR );
            userName = (String)props.get( PROP_USER );
            //String passwd = (String)props.get( PROP_PASSWD );
            String debugLevel = ((String)props.get( PROP_DEBUG ));

            env = new Env( dirName, debugLevel);

            // create the user if it doesn't exist yet; in local mode we cannot use
            // the admin tool to do so
            if (env.userManager.userForName( userName ) == null) {
                env.userManager.newUser( userName, userName.hashCode() );
            }
            env.startDeadlockRecognition();
        }
        catch (Exception e) {
            close();
            throw e;
        }
    }


    public boolean isOpen() throws Exception {
        return env != null;
    }


    public synchronized void close() throws Exception {
        super.close();
        if (env != null) {
            try {
                env.shutdown();
            }
            finally {
                env = null;
            }
        }
    }


    protected DbClient newConnection() throws org.ozoneDB.core.UserManagerException,org.ozoneDB.PermissionDeniedException {
        return new DbLocalClient(this,env,userName);
    }


    public String toString() {
        return "LocalDatabase";
    }


    protected void finalize() throws Exception {
        close();
    }

    /* Tells whether a database has been installed in the dbDir directory or not
     * useful for erver when starting up the ExternalDatabase and makes it possible to
     * determine whether to create or open a LocalDatabase
     */
    public boolean exists(String dbDir) {
        return Install.dbExists(dbDir);
    }

}