remotedatabase.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: RemoteDatabase.java,v 1.5 2002/09/18 06:54:13 per_nyfelt Exp $

package org.ozoneDB;

import org.ozoneDB.core.DbRemote.*;

import java.io.IOException;
import java.util.Hashtable;


/**
 * This class represents a remote database server that is connected via
 * a network connection. For a detailed description of the API see {@link
 * OzoneInterface}.
 * 
 * 
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.5 $Date: 2002/09/18 06:54:13 $
 * @see OzoneInterface
 */
public final class RemoteDatabase extends ExternalDatabase {
    
    protected String hostname;
    
    protected int portNum;
    
    protected String userName;
    
    protected String passwd;
    
    
    public RemoteDatabase() {
    }
    
    
    /**
     * Open a new database connection.
     * @param hostName name of the host where the server resides
     * @param portNum port of the server (default server setting: 3000)
     */
    public void open( String hostName, int portNum ) throws Exception {
        String userName = System.getProperty( "user.name" );
        open( hostName, portNum, userName, userName );
    } 
    
    
    /**
     * Open a new database connection.
     * @param hostName name of the host where the server resides
     * @param portNum port of the server (default server setting: 3000)
     * @param userName
     * @param passwd
     */
    public void open( String hostName, int portNum, String userName, String passwd ) throws Exception {
        Hashtable props = new Hashtable();
        props.put( PROP_HOST, hostName );
        props.put( PROP_PORT, new Integer( portNum ) );
        props.put( PROP_USER, userName );
        props.put( PROP_PASSWD, passwd );
        open( props );
    } 
    
    
    /**
     * @param _props The properties for the new connection.
     */
    protected synchronized void open( Hashtable _props ) throws Exception {
        try {
            super.open( _props );
            
            hostname = (String)_props.get( PROP_HOST );
            portNum = 0;
            if (_props.get( PROP_PORT ) != null) {
                portNum = ((Integer)_props.get( PROP_PORT )).intValue();
            } 
            userName = (String)_props.get( PROP_USER );
            passwd = (String)_props.get( PROP_HOST );
            
            if (hostname == null || portNum == 0) {
                throw new RuntimeException( "No host and/or port specified." );
            } 
            
            // try to open one real database connection to see if we are able to
            // connect the server
            DbClient connection = acquirePooledConnection();
            releasePooledConnection( connection );
        }
        catch (Exception e) {
            close();
            throw e;
        }
    } 
    
    
    protected DbClient newConnection() throws Exception,DatabaseNotOpenException,IOException,org.ozoneDB.TransactionException,java.lang.ClassNotFoundException,org.ozoneDB.OzoneObjectException {
        if (portNum == 0) {
            throw new DatabaseNotOpenException();
        } 
        DbClient connection = new DbRemoteClient(this,hostname,portNum,userName);

        sendCommand(new DbOpen(userName),true,connection);

        return connection;
    } 
    
    
    public String toString() {
        return "RemoteDatabase: " + hostname + ", " + portNum;
    } 
    
    
    protected void finalize() throws Exception {
        close();
    } 
    
}