libjava/java/net/ServerSocket.java

   1 /* ServerSocket.java -- Class for implementing server side sockets
   2    Copyright (C) 1998, 1999, 2000, 2002, 2003, 2004
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GNU Classpath.
   6
   7 GNU Classpath is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Classpath is distributed in the hope that it will be useful, but
  13 WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Classpath; see the file COPYING.  If not, write to the
  19 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20 02111-1307 USA.
  21
  22 Linking this library statically or dynamically with other modules is
  23 making a combined work based on this library.  Thus, the terms and
  24 conditions of the GNU General Public License cover the whole
  25 combination.
  26
  27 As a special exception, the copyright holders of this library give you
  28 permission to link this library with independent modules to produce an
  29 executable, regardless of the license terms of these independent
  30 modules, and to copy and distribute the resulting executable under
  31 terms of your choice, provided that you also meet, for each linked
  32 independent module, the terms and conditions of the license of that
  33 module.  An independent module is a module which is not derived from
  34 or based on this library.  If you modify this library, you may extend
  35 this exception to your version of the library, but you are not
  36 obligated to do so.  If you do not wish to do so, delete this
  37 exception statement from your version. */
  38
  39 package java.net;
  40
  41 import gnu.java.net.PlainSocketImpl;
  42
  43 import java.io.IOException;
  44 import java.nio.channels.IllegalBlockingModeException;
  45 import java.nio.channels.ServerSocketChannel;
  46
  47
  48 /* Written using on-line Java Platform 1.2 API Specification.
  49  * Status:  I believe all methods are implemented.
  50  */
  51
  52 /**
  53  * This class models server side sockets.  The basic model is that the
  54  * server socket is created and bound to some well known port.  It then
  55  * listens for and accepts connections.  At that point the client and
  56  * server sockets are ready to communicate with one another utilizing
  57  * whatever application layer protocol they desire.
  58  *
  59  * As with the <code>Socket</code> class, most instance methods of this class
  60  * simply redirect their calls to an implementation class.
  61  *
  62  * @author Aaron M. Renn (arenn@urbanophile.com)
  63  * @author Per Bothner (bothner@cygnus.com)
  64  */
  65 public class ServerSocket
  66 {
  67   /**
  68    * This is the user defined SocketImplFactory, if one is supplied
  69    */
  70   private static SocketImplFactory factory;
  71
  72   /**
  73    * This is the SocketImp object to which most instance methods in this
  74    * class are redirected
  75    */
  76   private SocketImpl impl;
  77
  78   /**
  79    * True if socket is bound.
  80    */
  81   private boolean bound;
  82
  83   /*
  84    * This constructor is only used by java.nio.
  85    */
  86
  87   // FIXME: Workaround a bug in gcj.
  88   //ServerSocket (PlainSocketImpl impl) throws IOException
  89   ServerSocket(SocketImpl impl) throws IOException
  90   {
  91     if (impl == null)
  92       throw new NullPointerException("impl may not be null");
  93
  94     this.impl = impl;
  95     this.impl.create(true);
  96   }
  97
  98   /*
  99    * This method is only used by java.nio.
 100    */
 101
 102   // FIXME: Workaround a bug in gcj.
 103   //PlainSocketImpl getImpl()
 104   SocketImpl getImpl()
 105   {
 106     return impl;
 107   }
 108
 109   /**
 110    * Constructor that simply sets the implementation.
 111    *
 112    * @exception IOException If an error occurs
 113    *
 114    * @specnote This constructor is public since JDK 1.4
 115    */
 116   public ServerSocket() throws IOException
 117   {
 118     if (factory != null)
 119       impl = factory.createSocketImpl();
 120     else
 121       impl = new PlainSocketImpl();
 122
 123     impl.create(true);
 124   }
 125
 126   /**
 127    * Creates a server socket and binds it to the specified port.  If the
 128    * port number is 0, a random free port will be chosen.  The pending
 129    * connection queue on this socket will be set to 50.
 130    *
 131    * @param port The port number to bind to
 132    *
 133    * @exception IOException If an error occurs
 134    * @exception SecurityException If a security manager exists and its
 135    * checkListen method doesn't allow the operation
 136    */
 137   public ServerSocket(int port) throws IOException
 138   {
 139     this(port, 50);
 140   }
 141
 142   /**
 143    * Creates a server socket and binds it to the specified port.  If the
 144    * port number is 0, a random free port will be chosen.  The pending
 145    * connection queue on this socket will be set to the value passed as
 146    * arg2.
 147    *
 148    * @param port The port number to bind to
 149    * @param backlog The length of the pending connection queue
 150    *
 151    * @exception IOException If an error occurs
 152    * @exception SecurityException If a security manager exists and its
 153    * checkListen method doesn't allow the operation
 154    */
 155   public ServerSocket(int port, int backlog) throws IOException
 156   {
 157     this(port, backlog, null);
 158   }
 159
 160   /**
 161    * Creates a server socket and binds it to the specified port.  If the
 162    * port number is 0, a random free port will be chosen.  The pending
 163    * connection queue on this socket will be set to the value passed as
 164    * backlog.  The third argument specifies a particular local address to
 165    * bind t or null to bind to all local address.
 166    *
 167    * @param port The port number to bind to
 168    * @param backlog The length of the pending connection queue
 169    * @param bindAddr The address to bind to, or null to bind to all addresses
 170    *
 171    * @exception IOException If an error occurs
 172    * @exception SecurityException If a security manager exists and its
 173    * checkListen method doesn't allow the operation
 174    *
 175    * @since 1.1
 176    */
 177   public ServerSocket(int port, int backlog, InetAddress bindAddr)
 178     throws IOException
 179   {
 180     this();
 181
 182     // bind/listen socket
 183     bind(new InetSocketAddress(bindAddr, port), backlog);
 184   }
 185
 186   /**
 187    * Binds the server socket to a specified socket address
 188    *
 189    * @param endpoint The socket address to bind to
 190    *
 191    * @exception IOException If an error occurs
 192    * @exception IllegalArgumentException If address type is not supported
 193    * @exception SecurityException If a security manager exists and its
 194    * checkListen method doesn't allow the operation
 195    *
 196    * @since 1.4
 197    */
 198   public void bind(SocketAddress endpoint) throws IOException
 199   {
 200     bind(endpoint, 50);
 201   }
 202
 203   /**
 204    * Binds the server socket to a specified socket address
 205    *
 206    * @param endpoint The socket address to bind to
 207    * @param backlog The length of the pending connection queue
 208    *
 209    * @exception IOException If an error occurs
 210    * @exception IllegalArgumentException If address type is not supported
 211    * @exception SecurityException If a security manager exists and its
 212    * checkListen method doesn't allow the operation
 213    *
 214    * @since 1.4
 215    */
 216   public void bind(SocketAddress endpoint, int backlog)
 217     throws IOException
 218   {
 219     if (isClosed())
 220       throw new SocketException("ServerSocket is closed");
 221
 222     if (! (endpoint instanceof InetSocketAddress))
 223       throw new IllegalArgumentException("Address type not supported");
 224
 225     InetSocketAddress tmp = (InetSocketAddress) endpoint;
 226
 227     SecurityManager s = System.getSecurityManager();
 228     if (s != null)
 229       s.checkListen(tmp.getPort());
 230
 231     InetAddress addr = tmp.getAddress();
 232
 233     // Initialize addr with 0.0.0.0.
 234     if (addr == null)
 235       addr = InetAddress.ANY_IF;
 236
 237     try
 238       {
 239         impl.bind(addr, tmp.getPort());
 240         impl.listen(backlog);
 241         bound = true;
 242       }
 243     catch (IOException exception)
 244       {
 245         close();
 246         throw exception;
 247       }
 248     catch (RuntimeException exception)
 249       {
 250         close();
 251         throw exception;
 252       }
 253     catch (Error error)
 254       {
 255         close();
 256         throw error;
 257       }
 258   }
 259
 260   /**
 261    * This method returns the local address to which this socket is bound
 262    *
 263    * @return The socket's local address
 264    */
 265   public InetAddress getInetAddress()
 266   {
 267     if (! isBound())
 268       return null;
 269
 270     try
 271       {
 272         return (InetAddress) impl.getOption(SocketOptions.SO_BINDADDR);
 273       }
 274     catch (SocketException e)
 275       {
 276         // This never happens as we are bound.
 277         return null;
 278       }
 279   }
 280
 281   /**
 282    * This method returns the local port number to which this socket is bound
 283    *
 284    * @return The socket's port number
 285    */
 286   public int getLocalPort()
 287   {
 288     if (! isBound())
 289       return -1;
 290
 291     return impl.getLocalPort();
 292   }
 293
 294   /**
 295    * Returns the local socket address
 296    *
 297    * @return the local socket address, null if not bound
 298    *
 299    * @since 1.4
 300    */
 301   public SocketAddress getLocalSocketAddress()
 302   {
 303     if (! isBound())
 304       return null;
 305
 306     return new InetSocketAddress(getInetAddress(), getLocalPort());
 307   }
 308
 309   /**
 310    * Accepts a new connection and returns a connected <code>Socket</code>
 311    * instance representing that connection.  This method will block until a
 312    * connection is available.
 313    *
 314    * @return socket object for the just accepted connection
 315    *
 316    * @exception IOException If an error occurs
 317    * @exception SecurityException If a security manager exists and its
 318    * checkListen method doesn't allow the operation
 319    * @exception IllegalBlockingModeException If this socket has an associated
 320    * channel, and the channel is in non-blocking mode
 321    * @exception SocketTimeoutException If a timeout was previously set with
 322    * setSoTimeout and the timeout has been reached
 323    */
 324   public Socket accept() throws IOException
 325   {
 326     SecurityManager sm = System.getSecurityManager();
 327     if (sm != null)
 328       sm.checkListen(impl.getLocalPort());
 329
 330     Socket socket = new Socket();
 331
 332     try
 333       {
 334         implAccept(socket);
 335       }
 336     catch (IOException e)
 337       {
 338         try
 339           {
 340             socket.close();
 341           }
 342         catch (IOException e2)
 343           {
 344             // Ignore.
 345           }
 346
 347         throw e;
 348       }
 349
 350     return socket;
 351   }
 352
 353   /**
 354    * This protected method is used to help subclasses override
 355    * <code>ServerSocket.accept()</code>.  The passed in socket will be
 356    * connected when this method returns.
 357    *
 358    * @param socket The socket that is used for the accepted connection
 359    *
 360    * @exception IOException If an error occurs
 361    * @exception IllegalBlockingModeException If this socket has an associated
 362    * channel, and the channel is in non-blocking mode
 363    *
 364    * @since 1.1
 365    */
 366   protected final void implAccept(Socket socket) throws IOException
 367   {
 368     if (isClosed())
 369       throw new SocketException("ServerSocket is closed");
 370
 371     // The Sun spec says that if we have an associated channel and
 372     // it is in non-blocking mode, we throw an IllegalBlockingModeException.
 373     // However, in our implementation if the channel itself initiated this
 374     // operation, then we must honor it regardless of its blocking mode.
 375     if (getChannel() != null && ! getChannel().isBlocking()
 376         && ! ((PlainSocketImpl) getImpl()).isInChannelOperation())
 377       throw new IllegalBlockingModeException();
 378
 379     impl.accept(socket.impl);
 380     socket.implCreated = true;
 381   }
 382
 383   /**
 384    * Closes this socket and stops listening for connections
 385    *
 386    * @exception IOException If an error occurs
 387    */
 388   public void close() throws IOException
 389   {
 390     if (isClosed())
 391       return;
 392
 393     impl.close();
 394     impl = null;
 395     bound = false;
 396
 397     if (getChannel() != null)
 398       getChannel().close();
 399   }
 400
 401   /**
 402    * Returns the unique ServerSocketChannel object
 403    * associated with this socket, if any.
 404    *
 405    * The socket only has a ServerSocketChannel if its created
 406    * by ServerSocketChannel.open.
 407    *
 408    * @return the associated socket channel, null if none exists
 409    *
 410    * @since 1.4
 411    */
 412   public ServerSocketChannel getChannel()
 413   {
 414     return null;
 415   }
 416
 417   /**
 418    * Returns true when the socket is bound, otherwise false
 419    *
 420    * @return true if socket is bound, false otherwise
 421    *
 422    * @since 1.4
 423    */
 424   public boolean isBound()
 425   {
 426     return bound;
 427   }
 428
 429   /**
 430    * Returns true if the socket is closed, otherwise false
 431    *
 432    * @return true if socket is closed, false otherwise
 433    *
 434    * @since 1.4
 435    */
 436   public boolean isClosed()
 437   {
 438     return impl == null;
 439   }
 440
 441   /**
 442    * Sets the value of SO_TIMEOUT.  A value of 0 implies that SO_TIMEOUT is
 443    * disabled (ie, operations never time out).  This is the number of
 444    * milliseconds a socket operation can block before an
 445    * InterruptedIOException is thrown.
 446    *
 447    * @param timeout The new SO_TIMEOUT value
 448    *
 449    * @exception SocketException If an error occurs
 450    *
 451    * @since 1.1
 452    */
 453   public void setSoTimeout(int timeout) throws SocketException
 454   {
 455     if (isClosed())
 456       throw new SocketException("ServerSocket is closed");
 457
 458     if (timeout < 0)
 459       throw new IllegalArgumentException("SO_TIMEOUT value must be >= 0");
 460
 461     impl.setOption(SocketOptions.SO_TIMEOUT, new Integer(timeout));
 462   }
 463
 464   /**
 465    * Retrieves the current value of the SO_TIMEOUT setting.  A value of 0
 466    * implies that SO_TIMEOUT is disabled (ie, operations never time out).
 467    * This is the number of milliseconds a socket operation can block before
 468    * an InterruptedIOException is thrown.
 469    *
 470    * @return The value of SO_TIMEOUT
 471    *
 472    * @exception IOException If an error occurs
 473    *
 474    * @since 1.1
 475    */
 476   public int getSoTimeout() throws IOException
 477   {
 478     if (isClosed())
 479       throw new SocketException("ServerSocket is closed");
 480
 481     Object timeout = impl.getOption(SocketOptions.SO_TIMEOUT);
 482
 483     if (! (timeout instanceof Integer))
 484       throw new IOException("Internal Error");
 485
 486     return ((Integer) timeout).intValue();
 487   }
 488
 489   /**
 490    * Enables/Disables the SO_REUSEADDR option
 491    *
 492    * @param on true if SO_REUSEADDR should be enabled, false otherwise
 493    *
 494    * @exception SocketException If an error occurs
 495    *
 496    * @since 1.4
 497    */
 498   public void setReuseAddress(boolean on) throws SocketException
 499   {
 500     if (isClosed())
 501       throw new SocketException("ServerSocket is closed");
 502
 503     impl.setOption(SocketOptions.SO_REUSEADDR, Boolean.valueOf(on));
 504   }
 505
 506   /**
 507    * Checks if the SO_REUSEADDR option is enabled
 508    *
 509    * @return true if SO_REUSEADDR is set, false otherwise
 510    *
 511    * @exception SocketException If an error occurs
 512    *
 513    * @since 1.4
 514    */
 515   public boolean getReuseAddress() throws SocketException
 516   {
 517     if (isClosed())
 518       throw new SocketException("ServerSocket is closed");
 519
 520     Object reuseaddr = impl.getOption(SocketOptions.SO_REUSEADDR);
 521
 522     if (! (reuseaddr instanceof Boolean))
 523       throw new SocketException("Internal Error");
 524
 525     return ((Boolean) reuseaddr).booleanValue();
 526   }
 527
 528   /**
 529    * This method sets the value for the system level socket option
 530    * SO_RCVBUF to the specified value.  Note that valid values for this
 531    * option are specific to a given operating system.
 532    *
 533    * @param size The new receive buffer size.
 534    *
 535    * @exception SocketException If an error occurs or Socket is not connected
 536    * @exception IllegalArgumentException If size is 0 or negative
 537    *
 538    * @since 1.4
 539    */
 540   public void setReceiveBufferSize(int size) throws SocketException
 541   {
 542     if (isClosed())
 543       throw new SocketException("ServerSocket is closed");
 544
 545     if (size <= 0)
 546       throw new IllegalArgumentException("SO_RCVBUF value must be > 0");
 547
 548     impl.setOption(SocketOptions.SO_RCVBUF, new Integer(size));
 549   }
 550
 551   /**
 552    * This method returns the value of the system level socket option
 553    * SO_RCVBUF, which is used by the operating system to tune buffer
 554    * sizes for data transfers.
 555    *
 556    * @return The receive buffer size.
 557    *
 558    * @exception SocketException If an error occurs or Socket is not connected
 559    *
 560    * @since 1.4
 561    */
 562   public int getReceiveBufferSize() throws SocketException
 563   {
 564     if (isClosed())
 565       throw new SocketException("ServerSocket is closed");
 566
 567     Object buf = impl.getOption(SocketOptions.SO_RCVBUF);
 568
 569     if (! (buf instanceof Integer))
 570       throw new SocketException("Internal Error: Unexpected type");
 571
 572     return ((Integer) buf).intValue();
 573   }
 574
 575   /**
 576    * Returns the value of this socket as a <code>String</code>.
 577    *
 578    * @return This socket represented as a <code>String</code>.
 579    */
 580   public String toString()
 581   {
 582     if (! isBound())
 583       return "ServerSocket[unbound]";
 584
 585     return ("ServerSocket[addr=" + getInetAddress() + ",port="
 586            + impl.getPort() + ",localport=" + impl.getLocalPort() + "]");
 587   }
 588
 589   /**
 590    * Sets the <code>SocketImplFactory</code> for all
 591    * <code>ServerSocket</code>'s.  This may only be done
 592    * once per virtual machine.  Subsequent attempts will generate an
 593    * exception.  Note that a <code>SecurityManager</code> check is made prior
 594    * to setting the factory.  If insufficient privileges exist to set the
 595    * factory, an exception will be thrown
 596    *
 597    * @param fac the factory to set
 598    *
 599    * @exception SecurityException If this operation is not allowed by the
 600    * <code>SecurityManager</code>.
 601    * @exception SocketException If the factory object is already defined
 602    * @exception IOException If any other error occurs
 603    */
 604   public static synchronized void setSocketFactory(SocketImplFactory fac)
 605     throws IOException
 606   {
 607     factory = fac;
 608   }
 609 }