TCPJDBCServer


1   /**
2    * com.mckoi.database.control.TCPJDBCServer  27 Mar 2002
3    *
4    * Mckoi SQL Database ( http://www.mckoi.com/database )
5    * Copyright (C) 2000, 2001, 2002  Diehl and Associates, Inc.
6    *
7    * This program is free software; you can redistribute it and/or
8    * modify it under the terms of the GNU General Public License
9    * Version 2 as published by the Free Software Foundation.
10   *
11   * This program is distributed in the hope that it will be useful,
12   * but WITHOUT ANY WARRANTY; without even the implied warranty of
13   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   * GNU General Public License Version 2 for more details.
15   *
16   * You should have received a copy of the GNU General Public License
17   * Version 2 along with this program; if not, write to the Free Software
18   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
19   *
20   * Change Log:
21   * 
22   * 
23   */
24  
25  package com.mckoi.database.control;
26  
27  import java.net.InetAddress  ;
28  import java.net.UnknownHostException  ;
29  import com.mckoi.database.jdbcserver.TCPServer;
30  
31  /**
32   * Attaches to a DBSystem, and binds a TCP port and serves queries for JDBC
33   * connections.  This object is used to programmatically create a TCP JDBC
34   * server on the local machine.
35   * <p>
36   * Note that multiple servers can be constructed to serve the same DBSystem.
37   * You can not use this object to connect a single TCP server to multiple
38   * DBSystem objects.
39   * <p>
40   * If the underlying database is shut down then this server is also shut down.
41   *
42   * @author Tobias Downer
43   */
44  
45  public class TCPJDBCServer {
46  
47    /**
48     * The default TCP port for Mckoi SQL Database.
49     */
50    private final static int DEFAULT_TCP_PORT = 9157;
51  
52    /**
53     * The DBSystem object that we are serving.
54     */
55    private DBSystem system;
56  
57    /**
58     * An InetAddress representing the interface that server is bound to - useful
59     * for multi-homed machines.  null means we bind to all interfaces.
60     */
61    private InetAddress   bind_address;
62  
63    /**
64     * The TCP port that this server is bound to.
65     */
66    private int tcp_port;
67  
68    /**
69     * The TCPServer object that is managing the connections to this database.
70     */
71    private TCPServer server;
72  
73  
74    /**
75     * Constructs the TCP JDBC with the given DBSystem object, and sets the
76     * inet address and TCP port that we serve the database from.
77     * <p>
78     * Constructing this server does not open the port to receive connections
79     * from outside.  To start the JDBC server you need to call the 'start'
80     * method.
81     */
82    public TCPJDBCServer(DBSystem system,
83                         InetAddress   bind_address, int tcp_port) {
84      this.system = system;
85      this.bind_address = bind_address;
86      this.tcp_port = tcp_port;
87      registerShutdownDelegate();
88    }
89  
90    /**
91     * Constructs the TCP JDBC with the given DBSystem object, and sets the
92     * TCP port that we serve the database from.  This binds the server to all
93     * interfaces on the local machine.
94     * <p>
95     * Constructing this server does not open the port to receive connections
96     * from outside.  To start the JDBC server you need to call the 'start'
97     * method.
98     */
99    public TCPJDBCServer(DBSystem system, int tcp_port) {
100     this(system, null, tcp_port);
101   }
102 
103   /**
104    * Constructs the TCP JDBC with the given DBSystem object, and sets the
105    * TCP port and address (for multi-homed computers) to the setting of the
106    * configuration in 'system'.
107    * <p>
108    * Constructing this server does not open the port to receive connections
109    * from outside.  To start the JDBC server you need to call the 'start'
110    * method.
111    */
112   public TCPJDBCServer(DBSystem system) {
113     this.system = system;
114 
115     DBConfig config = system.getConfig();
116 
117     int jdbc_port = DEFAULT_TCP_PORT;
118     InetAddress   interface_address = null;
119 
120     // Read the JDBC config properties.
121     String   jdbc_port_str = config.getValue("jdbc_server_port");
122     String   interface_addr_str = config.getValue("jdbc_server_address");
123 
124     if (jdbc_port_str != null) {
125       try {
126         jdbc_port = Integer.parseInt(jdbc_port_str);
127       }
128       catch (Exception   e) {
129         throw new RuntimeException  ("Unable to parse 'jdbc_server_port'");
130       }
131     }
132     if (interface_addr_str != null) {
133       try {
134         interface_address = InetAddress.getByName(interface_addr_str);
135       }
136       catch (UnknownHostException   e) {
137         throw new RuntimeException  ("Unknown host: " + e.getMessage());
138       }
139     }
140 
141     // Set up this port and bind address
142     this.tcp_port = jdbc_port;
143     this.bind_address = interface_address;
144 
145     registerShutdownDelegate();
146   }
147 
148   /**
149    * Registers the delegate that closes this server when the database
150    * shuts down.
151    */
152   private void registerShutdownDelegate() {
153     system.getDatabase().registerShutDownDelegate(new Runnable  () {
154       public void run() {
155         if (server != null) {
156           stop();
157         }
158       }
159     });
160   }
161 
162   /**
163    * Starts the server and binds it to the given port.  This method will start
164    * a new thread that listens for incoming connections.
165    */
166   public synchronized void start() {
167     if (server == null) {
168       server = new TCPServer(system.getDatabase());
169       server.start(bind_address, tcp_port, "multi_threaded");
170     }
171     else {
172       throw new RuntimeException  (
173                 "'start' method called when a server was already started.");
174     }
175   }
176 
177   /**
178    * Stops the server running on the given port.  This method will stop any
179    * threads that are listening for incoming connections.
180    * <p>
181    * Note that this does NOT close the underlying DBSystem object.  The
182    * DBSystem object must be closed separately.
183    */
184   public synchronized void stop() {
185     if (server != null) {
186       server.close();
187       server = null;
188     }
189     else {
190       throw new RuntimeException  (
191                         "'stop' method called when no server was started.");
192     }
193   }
194 
195 
196   /**
197    * Returns a string that contains some information about the server that
198    * is running.
199    */
200   public String   toString() {
201     return server.toString();
202   }
203 
204 }
205
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