1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.  Oracle designates this
9 * particular file as subject to the "Classpath" exception as provided
10 * by Oracle in the LICENSE file that accompanied this code.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
23 * or visit www.oracle.com if you need additional information or have any
24 * questions.
25 */
26
27package java.net;
28
29import java.io.FileDescriptor;
30import java.io.InputStream;
31import java.io.OutputStream;
32import java.io.IOException;
33import java.io.InterruptedIOException;
34import java.nio.channels.SocketChannel;
35import java.security.AccessController;
36import java.security.PrivilegedExceptionAction;
37import java.security.PrivilegedAction;
38
39/**
40 * This class implements client sockets (also called just
41 * "sockets"). A socket is an endpoint for communication
42 * between two machines.
43 * <p>
44 * The actual work of the socket is performed by an instance of the
45 * <code>SocketImpl</code> class. An application, by changing
46 * the socket factory that creates the socket implementation,
47 * can configure itself to create sockets appropriate to the local
48 * firewall.
49 *
50 * @author  unascribed
51 * @see     java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
52 * @see     java.net.SocketImpl
53 * @see     java.nio.channels.SocketChannel
54 * @since   JDK1.0
55 */
56public
57class Socket implements java.io.Closeable {
58    /**
59     * Various states of this socket.
60     */
61    private boolean created = false;
62    private boolean bound = false;
63    private boolean connected = false;
64    private boolean closed = false;
65    private Object closeLock = new Object();
66    private boolean shutIn = false;
67    private boolean shutOut = false;
68
69    /**
70     * The implementation of this Socket.
71     */
72    SocketImpl impl;
73
74    /**
75     * Are we using an older SocketImpl?
76     */
77    private boolean oldImpl = false;
78
79    /**
80     * Creates an unconnected socket, with the
81     * system-default type of SocketImpl.
82     *
83     * @since   JDK1.1
84     * @revised 1.4
85     */
86    public Socket() {
87        setImpl();
88    }
89
90    /**
91     * Creates an unconnected socket, specifying the type of proxy, if any,
92     * that should be used regardless of any other settings.
93     * <P>
94     * If there is a security manager, its <code>checkConnect</code> method
95     * is called with the proxy host address and port number
96     * as its arguments. This could result in a SecurityException.
97     * <P>
98     * Examples:
99     * <UL> <LI><code>Socket s = new Socket(Proxy.NO_PROXY);</code> will create
100     * a plain socket ignoring any other proxy configuration.</LI>
101     * <LI><code>Socket s = new Socket(new Proxy(Proxy.Type.SOCKS, new InetSocketAddress("socks.mydom.com", 1080)));</code>
102     * will create a socket connecting through the specified SOCKS proxy
103     * server.</LI>
104     * </UL>
105     *
106     * @param proxy a {@link java.net.Proxy Proxy} object specifying what kind
107     *              of proxying should be used.
108     * @throws IllegalArgumentException if the proxy is of an invalid type
109     *          or <code>null</code>.
110     * @throws SecurityException if a security manager is present and
111     *                           permission to connect to the proxy is
112     *                           denied.
113     * @see java.net.ProxySelector
114     * @see java.net.Proxy
115     *
116     * @since   1.5
117     */
118    public Socket(Proxy proxy) {
119        // Create a copy of Proxy as a security measure
120        if (proxy == null) {
121            throw new IllegalArgumentException("Invalid Proxy");
122        }
123        Proxy p = proxy == Proxy.NO_PROXY ? Proxy.NO_PROXY : sun.net.ApplicationProxy.create(proxy);
124        if (p.type() == Proxy.Type.SOCKS) {
125            SecurityManager security = System.getSecurityManager();
126            InetSocketAddress epoint = (InetSocketAddress) p.address();
127            if (epoint.getAddress() != null) {
128                checkAddress (epoint.getAddress(), "Socket");
129            }
130            if (security != null) {
131                if (epoint.isUnresolved())
132                    epoint = new InetSocketAddress(epoint.getHostName(), epoint.getPort());
133                if (epoint.isUnresolved())
134                    security.checkConnect(epoint.getHostName(), epoint.getPort());
135                else
136                    security.checkConnect(epoint.getAddress().getHostAddress(),
137                                  epoint.getPort());
138            }
139            impl = new SocksSocketImpl(p);
140            impl.setSocket(this);
141        } else {
142            if (p == Proxy.NO_PROXY) {
143                if (factory == null) {
144                    impl = new PlainSocketImpl();
145                    impl.setSocket(this);
146                } else
147                    setImpl();
148            } else
149                throw new IllegalArgumentException("Invalid Proxy");
150        }
151    }
152
153    /**
154     * Creates an unconnected Socket with a user-specified
155     * SocketImpl.
156     * <P>
157     * @param impl an instance of a <B>SocketImpl</B>
158     * the subclass wishes to use on the Socket.
159     *
160     * @exception SocketException if there is an error in the underlying protocol,
161     * such as a TCP error.
162     * @since   JDK1.1
163     */
164    protected Socket(SocketImpl impl) throws SocketException {
165        this.impl = impl;
166        if (impl != null) {
167            checkOldImpl();
168            this.impl.setSocket(this);
169        }
170    }
171
172    /**
173     * Creates a stream socket and connects it to the specified port
174     * number on the named host.
175     * <p>
176     * If the specified host is <tt>null</tt> it is the equivalent of
177     * specifying the address as <tt>{@link java.net.InetAddress#getByName InetAddress.getByName}(null)</tt>.
178     * In other words, it is equivalent to specifying an address of the
179     * loopback interface. </p>
180     * <p>
181     * If the application has specified a server socket factory, that
182     * factory's <code>createSocketImpl</code> method is called to create
183     * the actual socket implementation. Otherwise a "plain" socket is created.
184     * <p>
185     * If there is a security manager, its
186     * <code>checkConnect</code> method is called
187     * with the host address and <code>port</code>
188     * as its arguments. This could result in a SecurityException.
189     *
190     * @param      host   the host name, or <code>null</code> for the loopback address.
191     * @param      port   the port number.
192     *
193     * @exception  UnknownHostException if the IP address of
194     * the host could not be determined.
195     *
196     * @exception  IOException  if an I/O error occurs when creating the socket.
197     * @exception  SecurityException  if a security manager exists and its
198     *             <code>checkConnect</code> method doesn't allow the operation.
199     * @exception  IllegalArgumentException if the port parameter is outside
200     *             the specified range of valid port values, which is between
201     *             0 and 65535, inclusive.
202     * @see        java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
203     * @see        java.net.SocketImpl
204     * @see        java.net.SocketImplFactory#createSocketImpl()
205     * @see        SecurityManager#checkConnect
206     */
207    public Socket(String host, int port)
208        throws UnknownHostException, IOException
209    {
210        this(host != null ? new InetSocketAddress(host, port) :
211             new InetSocketAddress(InetAddress.getByName(null), port),
212             (SocketAddress) null, true);
213    }
214
215    /**
216     * Creates a stream socket and connects it to the specified port
217     * number at the specified IP address.
218     * <p>
219     * If the application has specified a socket factory, that factory's
220     * <code>createSocketImpl</code> method is called to create the
221     * actual socket implementation. Otherwise a "plain" socket is created.
222     * <p>
223     * If there is a security manager, its
224     * <code>checkConnect</code> method is called
225     * with the host address and <code>port</code>
226     * as its arguments. This could result in a SecurityException.
227     *
228     * @param      address   the IP address.
229     * @param      port      the port number.
230     * @exception  IOException  if an I/O error occurs when creating the socket.
231     * @exception  SecurityException  if a security manager exists and its
232     *             <code>checkConnect</code> method doesn't allow the operation.
233     * @exception  IllegalArgumentException if the port parameter is outside
234     *             the specified range of valid port values, which is between
235     *             0 and 65535, inclusive.
236     * @exception  NullPointerException if <code>address</code> is null.
237     * @see        java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
238     * @see        java.net.SocketImpl
239     * @see        java.net.SocketImplFactory#createSocketImpl()
240     * @see        SecurityManager#checkConnect
241     */
242    public Socket(InetAddress address, int port) throws IOException {
243        this(address != null ? new InetSocketAddress(address, port) : null,
244             (SocketAddress) null, true);
245    }
246
247    /**
248     * Creates a socket and connects it to the specified remote host on
249     * the specified remote port. The Socket will also bind() to the local
250     * address and port supplied.
251     * <p>
252     * If the specified host is <tt>null</tt> it is the equivalent of
253     * specifying the address as <tt>{@link java.net.InetAddress#getByName InetAddress.getByName}(null)</tt>.
254     * In other words, it is equivalent to specifying an address of the
255     * loopback interface. </p>
256     * <p>
257     * A local port number of <code>zero</code> will let the system pick up a
258     * free port in the <code>bind</code> operation.</p>
259     * <p>
260     * If there is a security manager, its
261     * <code>checkConnect</code> method is called
262     * with the host address and <code>port</code>
263     * as its arguments. This could result in a SecurityException.
264     *
265     * @param host the name of the remote host, or <code>null</code> for the loopback address.
266     * @param port the remote port
267     * @param localAddr the local address the socket is bound to, or
268     *        <code>null</code> for the <code>anyLocal</code> address.
269     * @param localPort the local port the socket is bound to, or
270     *        <code>zero</code> for a system selected free port.
271     * @exception  IOException  if an I/O error occurs when creating the socket.
272     * @exception  SecurityException  if a security manager exists and its
273     *             <code>checkConnect</code> method doesn't allow the operation.
274     * @exception  IllegalArgumentException if the port parameter or localPort
275     *             parameter is outside the specified range of valid port values,
276     *             which is between 0 and 65535, inclusive.
277     * @see        SecurityManager#checkConnect
278     * @since   JDK1.1
279     */
280    public Socket(String host, int port, InetAddress localAddr,
281                  int localPort) throws IOException {
282        this(host != null ? new InetSocketAddress(host, port) :
283               new InetSocketAddress(InetAddress.getByName(null), port),
284             new InetSocketAddress(localAddr, localPort), true);
285    }
286
287    /**
288     * Creates a socket and connects it to the specified remote address on
289     * the specified remote port. The Socket will also bind() to the local
290     * address and port supplied.
291     * <p>
292     * If the specified local address is <tt>null</tt> it is the equivalent of
293     * specifying the address as the AnyLocal address (see <tt>{@link java.net.InetAddress#isAnyLocalAddress InetAddress.isAnyLocalAddress}()</tt>).
294     * <p>
295     * A local port number of <code>zero</code> will let the system pick up a
296     * free port in the <code>bind</code> operation.</p>
297     * <p>
298     * If there is a security manager, its
299     * <code>checkConnect</code> method is called
300     * with the host address and <code>port</code>
301     * as its arguments. This could result in a SecurityException.
302     *
303     * @param address the remote address
304     * @param port the remote port
305     * @param localAddr the local address the socket is bound to, or
306     *        <code>null</code> for the <code>anyLocal</code> address.
307     * @param localPort the local port the socket is bound to or
308     *        <code>zero</code> for a system selected free port.
309     * @exception  IOException  if an I/O error occurs when creating the socket.
310     * @exception  SecurityException  if a security manager exists and its
311     *             <code>checkConnect</code> method doesn't allow the operation.
312     * @exception  IllegalArgumentException if the port parameter or localPort
313     *             parameter is outside the specified range of valid port values,
314     *             which is between 0 and 65535, inclusive.
315     * @exception  NullPointerException if <code>address</code> is null.
316     * @see        SecurityManager#checkConnect
317     * @since   JDK1.1
318     */
319    public Socket(InetAddress address, int port, InetAddress localAddr,
320                  int localPort) throws IOException {
321        this(address != null ? new InetSocketAddress(address, port) : null,
322             new InetSocketAddress(localAddr, localPort), true);
323    }
324
325    /**
326     * Creates a stream socket and connects it to the specified port
327     * number on the named host.
328     * <p>
329     * If the specified host is <tt>null</tt> it is the equivalent of
330     * specifying the address as <tt>{@link java.net.InetAddress#getByName InetAddress.getByName}(null)</tt>.
331     * In other words, it is equivalent to specifying an address of the
332     * loopback interface. </p>
333     * <p>
334     * If the stream argument is <code>true</code>, this creates a
335     * stream socket. If the stream argument is <code>false</code>, it
336     * creates a datagram socket.
337     * <p>
338     * If the application has specified a server socket factory, that
339     * factory's <code>createSocketImpl</code> method is called to create
340     * the actual socket implementation. Otherwise a "plain" socket is created.
341     * <p>
342     * If there is a security manager, its
343     * <code>checkConnect</code> method is called
344     * with the host address and <code>port</code>
345     * as its arguments. This could result in a SecurityException.
346     * <p>
347     * If a UDP socket is used, TCP/IP related socket options will not apply.
348     *
349     * @param      host     the host name, or <code>null</code> for the loopback address.
350     * @param      port     the port number.
351     * @param      stream   a <code>boolean</code> indicating whether this is
352     *                      a stream socket or a datagram socket.
353     * @exception  IOException  if an I/O error occurs when creating the socket.
354     * @exception  SecurityException  if a security manager exists and its
355     *             <code>checkConnect</code> method doesn't allow the operation.
356     * @exception  IllegalArgumentException if the port parameter is outside
357     *             the specified range of valid port values, which is between
358     *             0 and 65535, inclusive.
359     * @see        java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
360     * @see        java.net.SocketImpl
361     * @see        java.net.SocketImplFactory#createSocketImpl()
362     * @see        SecurityManager#checkConnect
363     * @deprecated Use DatagramSocket instead for UDP transport.
364     */
365    @Deprecated
366    public Socket(String host, int port, boolean stream) throws IOException {
367        this(host != null ? new InetSocketAddress(host, port) :
368               new InetSocketAddress(InetAddress.getByName(null), port),
369             (SocketAddress) null, stream);
370    }
371
372    /**
373     * Creates a socket and connects it to the specified port number at
374     * the specified IP address.
375     * <p>
376     * If the stream argument is <code>true</code>, this creates a
377     * stream socket. If the stream argument is <code>false</code>, it
378     * creates a datagram socket.
379     * <p>
380     * If the application has specified a server socket factory, that
381     * factory's <code>createSocketImpl</code> method is called to create
382     * the actual socket implementation. Otherwise a "plain" socket is created.
383     *
384     * <p>If there is a security manager, its
385     * <code>checkConnect</code> method is called
386     * with <code>host.getHostAddress()</code> and <code>port</code>
387     * as its arguments. This could result in a SecurityException.
388     * <p>
389     * If UDP socket is used, TCP/IP related socket options will not apply.
390     *
391     * @param      host     the IP address.
392     * @param      port      the port number.
393     * @param      stream    if <code>true</code>, create a stream socket;
394     *                       otherwise, create a datagram socket.
395     * @exception  IOException  if an I/O error occurs when creating the socket.
396     * @exception  SecurityException  if a security manager exists and its
397     *             <code>checkConnect</code> method doesn't allow the operation.
398     * @exception  IllegalArgumentException if the port parameter is outside
399     *             the specified range of valid port values, which is between
400     *             0 and 65535, inclusive.
401     * @exception  NullPointerException if <code>host</code> is null.
402     * @see        java.net.Socket#setSocketImplFactory(java.net.SocketImplFactory)
403     * @see        java.net.SocketImpl
404     * @see        java.net.SocketImplFactory#createSocketImpl()
405     * @see        SecurityManager#checkConnect
406     * @deprecated Use DatagramSocket instead for UDP transport.
407     */
408    @Deprecated
409    public Socket(InetAddress host, int port, boolean stream) throws IOException {
410        this(host != null ? new InetSocketAddress(host, port) : null,
411             new InetSocketAddress(0), stream);
412    }
413
414    private Socket(SocketAddress address, SocketAddress localAddr,
415                   boolean stream) throws IOException {
416        setImpl();
417
418        // backward compatibility
419        if (address == null)
420            throw new NullPointerException();
421
422        try {
423            createImpl(stream);
424            if (localAddr != null)
425                bind(localAddr);
426            if (address != null)
427                connect(address);
428        } catch (IOException e) {
429            // Do not call #close, classes that extend this class may do not expect a call
430            // to #close coming from the superclass constructor.
431            if (impl != null) {
432                impl.close();
433            }
434            closed = true;
435            throw e;
436        }
437    }
438
439    /**
440     * Creates the socket implementation.
441     *
442     * @param stream a <code>boolean</code> value : <code>true</code> for a TCP socket,
443     *               <code>false</code> for UDP.
444     * @throws IOException if creation fails
445     * @since 1.4
446     */
447     void createImpl(boolean stream) throws SocketException {
448        if (impl == null)
449            setImpl();
450        try {
451            impl.create(stream);
452            created = true;
453        } catch (IOException e) {
454            throw new SocketException(e.getMessage());
455        }
456    }
457
458    private void checkOldImpl() {
459        if (impl == null)
460            return;
461        // SocketImpl.connect() is a protected method, therefore we need to use
462        // getDeclaredMethod, therefore we need permission to access the member
463
464        oldImpl = AccessController.doPrivileged
465                                (new PrivilegedAction<Boolean>() {
466            public Boolean run() {
467                Class[] cl = new Class[2];
468                cl[0] = SocketAddress.class;
469                cl[1] = Integer.TYPE;
470                Class clazz = impl.getClass();
471                while (true) {
472                    try {
473                        clazz.getDeclaredMethod("connect", cl);
474                        return Boolean.FALSE;
475                    } catch (NoSuchMethodException e) {
476                        clazz = clazz.getSuperclass();
477                        // java.net.SocketImpl class will always have this abstract method.
478                        // If we have not found it by now in the hierarchy then it does not
479                        // exist, we are an old style impl.
480                        if (clazz.equals(java.net.SocketImpl.class)) {
481                            return Boolean.TRUE;
482                        }
483                    }
484                }
485            }
486        });
487    }
488
489    /**
490     * Sets impl to the system-default type of SocketImpl.
491     * @since 1.4
492     */
493    void setImpl() {
494        if (factory != null) {
495            impl = factory.createSocketImpl();
496            checkOldImpl();
497        } else {
498            // No need to do a checkOldImpl() here, we know it's an up to date
499            // SocketImpl!
500            impl = new SocksSocketImpl();
501        }
502        if (impl != null)
503            impl.setSocket(this);
504    }
505
506
507    /**
508     * Get the <code>SocketImpl</code> attached to this socket, creating
509     * it if necessary.
510     *
511     * @return  the <code>SocketImpl</code> attached to that ServerSocket.
512     * @throws SocketException if creation fails
513     * @since 1.4
514     */
515    SocketImpl getImpl() throws SocketException {
516        if (!created)
517            createImpl(true);
518        return impl;
519    }
520
521    /**
522     * Connects this socket to the server.
523     *
524     * @param   endpoint the <code>SocketAddress</code>
525     * @throws  IOException if an error occurs during the connection
526     * @throws  java.nio.channels.IllegalBlockingModeException
527     *          if this socket has an associated channel,
528     *          and the channel is in non-blocking mode
529     * @throws  IllegalArgumentException if endpoint is null or is a
530     *          SocketAddress subclass not supported by this socket
531     * @since 1.4
532     * @spec JSR-51
533     */
534    public void connect(SocketAddress endpoint) throws IOException {
535        connect(endpoint, 0);
536    }
537
538    /**
539     * Connects this socket to the server with a specified timeout value.
540     * A timeout of zero is interpreted as an infinite timeout. The connection
541     * will then block until established or an error occurs.
542     *
543     * @param   endpoint the <code>SocketAddress</code>
544     * @param   timeout  the timeout value to be used in milliseconds.
545     * @throws  IOException if an error occurs during the connection
546     * @throws  SocketTimeoutException if timeout expires before connecting
547     * @throws  java.nio.channels.IllegalBlockingModeException
548     *          if this socket has an associated channel,
549     *          and the channel is in non-blocking mode
550     * @throws  IllegalArgumentException if endpoint is null or is a
551     *          SocketAddress subclass not supported by this socket
552     * @since 1.4
553     * @spec JSR-51
554     */
555    public void connect(SocketAddress endpoint, int timeout) throws IOException {
556        if (endpoint == null)
557            throw new IllegalArgumentException("connect: The address can't be null");
558
559        if (timeout < 0)
560          throw new IllegalArgumentException("connect: timeout can't be negative");
561
562        if (isClosed())
563            throw new SocketException("Socket is closed");
564
565        if (!oldImpl && isConnected())
566            throw new SocketException("already connected");
567
568        if (!(endpoint instanceof InetSocketAddress))
569            throw new IllegalArgumentException("Unsupported address type");
570
571        InetSocketAddress epoint = (InetSocketAddress) endpoint;
572        InetAddress addr = epoint.getAddress ();
573        int port = epoint.getPort();
574        checkAddress(addr, "connect");
575
576        SecurityManager security = System.getSecurityManager();
577        if (security != null) {
578            if (epoint.isUnresolved())
579                security.checkConnect(epoint.getHostName(), port);
580            else
581                security.checkConnect(addr.getHostAddress(), port);
582        }
583        if (!created)
584            createImpl(true);
585        if (!oldImpl)
586            impl.connect(epoint, timeout);
587        else if (timeout == 0) {
588            if (epoint.isUnresolved())
589                impl.connect(addr.getHostName(), port);
590            else
591                impl.connect(addr, port);
592        } else
593            throw new UnsupportedOperationException("SocketImpl.connect(addr, timeout)");
594        connected = true;
595        /*
596         * If the socket was not bound before the connect, it is now because
597         * the kernel will have picked an ephemeral port & a local address
598         */
599        bound = true;
600    }
601
602    /**
603     * Binds the socket to a local address.
604     * <P>
605     * If the address is <code>null</code>, then the system will pick up
606     * an ephemeral port and a valid local address to bind the socket.
607     *
608     * @param   bindpoint the <code>SocketAddress</code> to bind to
609     * @throws  IOException if the bind operation fails, or if the socket
610     *                     is already bound.
611     * @throws  IllegalArgumentException if bindpoint is a
612     *          SocketAddress subclass not supported by this socket
613     *
614     * @since   1.4
615     * @see #isBound
616     */
617    public void bind(SocketAddress bindpoint) throws IOException {
618        if (isClosed())
619            throw new SocketException("Socket is closed");
620        if (!oldImpl && isBound())
621            throw new SocketException("Already bound");
622
623        if (bindpoint != null && (!(bindpoint instanceof InetSocketAddress)))
624            throw new IllegalArgumentException("Unsupported address type");
625        InetSocketAddress epoint = (InetSocketAddress) bindpoint;
626        if (epoint != null && epoint.isUnresolved())
627            throw new SocketException("Unresolved address");
628        if (epoint == null) {
629            epoint = new InetSocketAddress(0);
630        }
631        InetAddress addr = epoint.getAddress();
632        int port = epoint.getPort();
633        checkAddress (addr, "bind");
634        getImpl().bind (addr, port);
635        bound = true;
636    }
637
638    private void checkAddress (InetAddress addr, String op) {
639        if (addr == null) {
640            return;
641        }
642        if (!(addr instanceof Inet4Address || addr instanceof Inet6Address)) {
643            throw new IllegalArgumentException(op + ": invalid address type");
644        }
645    }
646
647    /**
648     * set the flags after an accept() call.
649     */
650    final void postAccept() {
651        connected = true;
652        created = true;
653        bound = true;
654    }
655
656    void setCreated() {
657        created = true;
658    }
659
660    void setBound() {
661        bound = true;
662    }
663
664    void setConnected() {
665        connected = true;
666    }
667
668    /**
669     * Returns the address to which the socket is connected.
670     * <p>
671     * If the socket was connected prior to being {@link #close closed},
672     * then this method will continue to return the connected address
673     * after the socket is closed.
674     *
675     * @return  the remote IP address to which this socket is connected,
676     *          or <code>null</code> if the socket is not connected.
677     */
678    public InetAddress getInetAddress() {
679        if (!isConnected())
680            return null;
681        try {
682            return getImpl().getInetAddress();
683        } catch (SocketException e) {
684        }
685        return null;
686    }
687
688    /**
689     * Gets the local address to which the socket is bound.
690     *
691     * @return the local address to which the socket is bound, or
692     *         the {@link InetAddress#isAnyLocalAddress wildcard} address
693     *         if the socket is closed or not bound yet.
694     * @since   JDK1.1
695     */
696    public InetAddress getLocalAddress() {
697        // This is for backward compatibility
698        if (!isBound())
699            return InetAddress.anyLocalAddress();
700        InetAddress in = null;
701        try {
702            in = (InetAddress) getImpl().getOption(SocketOptions.SO_BINDADDR);
703
704            if (!NetUtil.doRevealLocalAddress()) {
705                SecurityManager sm = System.getSecurityManager();
706                if (sm != null)
707                    sm.checkConnect(in.getHostAddress(), -1);
708            }
709            if (in.isAnyLocalAddress()) {
710                in = InetAddress.anyLocalAddress();
711            }
712        } catch (SecurityException e) {
713            in = InetAddress.getLoopbackAddress();
714        } catch (Exception e) {
715            in = InetAddress.anyLocalAddress(); // "0.0.0.0"
716        }
717        return in;
718    }
719
720    /**
721     * Returns the remote port number to which this socket is connected.
722     * <p>
723     * If the socket was connected prior to being {@link #close closed},
724     * then this method will continue to return the connected port number
725     * after the socket is closed.
726     *
727     * @return  the remote port number to which this socket is connected, or
728     *          0 if the socket is not connected yet.
729     */
730    public int getPort() {
731        if (!isConnected())
732            return 0;
733        try {
734            return getImpl().getPort();
735        } catch (SocketException e) {
736            // Shouldn't happen as we're connected
737        }
738        return -1;
739    }
740
741    /**
742     * Returns the local port number to which this socket is bound.
743     * <p>
744     * If the socket was bound prior to being {@link #close closed},
745     * then this method will continue to return the local port number
746     * after the socket is closed.
747     *
748     * @return  the local port number to which this socket is bound or -1
749     *          if the socket is not bound yet.
750     */
751    public int getLocalPort() {
752        if (!isBound())
753            return -1;
754        try {
755            return getImpl().getLocalPort();
756        } catch(SocketException e) {
757            // shouldn't happen as we're bound
758        }
759        return -1;
760    }
761
762    /**
763     * Returns the address of the endpoint this socket is connected to, or
764     * <code>null</code> if it is unconnected.
765     * <p>
766     * If the socket was connected prior to being {@link #close closed},
767     * then this method will continue to return the connected address
768     * after the socket is closed.
769     *
770
771     * @return a <code>SocketAddress</code> representing the remote endpoint of this
772     *         socket, or <code>null</code> if it is not connected yet.
773     * @see #getInetAddress()
774     * @see #getPort()
775     * @see #connect(SocketAddress, int)
776     * @see #connect(SocketAddress)
777     * @since 1.4
778     */
779    public SocketAddress getRemoteSocketAddress() {
780        if (!isConnected())
781            return null;
782        return new InetSocketAddress(getInetAddress(), getPort());
783    }
784
785    /**
786     * Returns the address of the endpoint this socket is bound to, or
787     * <code>null</code> if it is not bound yet.
788     * <p>
789     * If a socket bound to an endpoint represented by an
790     * <code>InetSocketAddress </code> is {@link #close closed},
791     * then this method will continue to return an <code>InetSocketAddress</code>
792     * after the socket is closed. In that case the returned
793     * <code>InetSocketAddress</code>'s address is the
794     * {@link InetAddress#isAnyLocalAddress wildcard} address
795     * and its port is the local port that it was bound to.
796     *
797     * @return a <code>SocketAddress</code> representing the local endpoint of this
798     *         socket, or <code>null</code> if it is not bound yet.
799     * @see #getLocalAddress()
800     * @see #getLocalPort()
801     * @see #bind(SocketAddress)
802     * @since 1.4
803     */
804
805    public SocketAddress getLocalSocketAddress() {
806        if (!isBound())
807            return null;
808        return new InetSocketAddress(getLocalAddress(), getLocalPort());
809    }
810
811    /**
812     * Returns the unique {@link java.nio.channels.SocketChannel SocketChannel}
813     * object associated with this socket, if any.
814     *
815     * <p> A socket will have a channel if, and only if, the channel itself was
816     * created via the {@link java.nio.channels.SocketChannel#open
817     * SocketChannel.open} or {@link
818     * java.nio.channels.ServerSocketChannel#accept ServerSocketChannel.accept}
819     * methods.
820     *
821     * @return  the socket channel associated with this socket,
822     *          or <tt>null</tt> if this socket was not created
823     *          for a channel
824     *
825     * @since 1.4
826     * @spec JSR-51
827     */
828    public SocketChannel getChannel() {
829        return null;
830    }
831
832    /**
833     * Returns an input stream for this socket.
834     *
835     * <p> If this socket has an associated channel then the resulting input
836     * stream delegates all of its operations to the channel.  If the channel
837     * is in non-blocking mode then the input stream's <tt>read</tt> operations
838     * will throw an {@link java.nio.channels.IllegalBlockingModeException}.
839     *
840     * <p>Under abnormal conditions the underlying connection may be
841     * broken by the remote host or the network software (for example
842     * a connection reset in the case of TCP connections). When a
843     * broken connection is detected by the network software the
844     * following applies to the returned input stream :-
845     *
846     * <ul>
847     *
848     *   <li><p>The network software may discard bytes that are buffered
849     *   by the socket. Bytes that aren't discarded by the network
850     *   software can be read using {@link java.io.InputStream#read read}.
851     *
852     *   <li><p>If there are no bytes buffered on the socket, or all
853     *   buffered bytes have been consumed by
854     *   {@link java.io.InputStream#read read}, then all subsequent
855     *   calls to {@link java.io.InputStream#read read} will throw an
856     *   {@link java.io.IOException IOException}.
857     *
858     *   <li><p>If there are no bytes buffered on the socket, and the
859     *   socket has not been closed using {@link #close close}, then
860     *   {@link java.io.InputStream#available available} will
861     *   return <code>0</code>.
862     *
863     * </ul>
864     *
865     * <p> Closing the returned {@link java.io.InputStream InputStream}
866     * will close the associated socket.
867     *
868     * @return     an input stream for reading bytes from this socket.
869     * @exception  IOException  if an I/O error occurs when creating the
870     *             input stream, the socket is closed, the socket is
871     *             not connected, or the socket input has been shutdown
872     *             using {@link #shutdownInput()}
873     *
874     * @revised 1.4
875     * @spec JSR-51
876     */
877    public InputStream getInputStream() throws IOException {
878        if (isClosed())
879            throw new SocketException("Socket is closed");
880        if (!isConnected())
881            throw new SocketException("Socket is not connected");
882        if (isInputShutdown())
883            throw new SocketException("Socket input is shutdown");
884        final Socket s = this;
885        InputStream is = null;
886        try {
887            is = AccessController.doPrivileged(
888                new PrivilegedExceptionAction<InputStream>() {
889                    public InputStream run() throws IOException {
890                        return impl.getInputStream();
891                    }
892                });
893        } catch (java.security.PrivilegedActionException e) {
894            throw (IOException) e.getException();
895        }
896        return is;
897    }
898
899    /**
900     * Returns an output stream for this socket.
901     *
902     * <p> If this socket has an associated channel then the resulting output
903     * stream delegates all of its operations to the channel.  If the channel
904     * is in non-blocking mode then the output stream's <tt>write</tt>
905     * operations will throw an {@link
906     * java.nio.channels.IllegalBlockingModeException}.
907     *
908     * <p> Closing the returned {@link java.io.OutputStream OutputStream}
909     * will close the associated socket.
910     *
911     * @return     an output stream for writing bytes to this socket.
912     * @exception  IOException  if an I/O error occurs when creating the
913     *               output stream or if the socket is not connected.
914     * @revised 1.4
915     * @spec JSR-51
916     */
917    public OutputStream getOutputStream() throws IOException {
918        if (isClosed())
919            throw new SocketException("Socket is closed");
920        if (!isConnected())
921            throw new SocketException("Socket is not connected");
922        if (isOutputShutdown())
923            throw new SocketException("Socket output is shutdown");
924        final Socket s = this;
925        OutputStream os = null;
926        try {
927            os = AccessController.doPrivileged(
928                new PrivilegedExceptionAction<OutputStream>() {
929                    public OutputStream run() throws IOException {
930                        return impl.getOutputStream();
931                    }
932                });
933        } catch (java.security.PrivilegedActionException e) {
934            throw (IOException) e.getException();
935        }
936        return os;
937    }
938
939    /**
940     * Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).
941     *
942     * @param on <code>true</code> to enable TCP_NODELAY,
943     * <code>false</code> to disable.
944     *
945     * @exception SocketException if there is an error
946     * in the underlying protocol, such as a TCP error.
947     *
948     * @since   JDK1.1
949     *
950     * @see #getTcpNoDelay()
951     */
952    public void setTcpNoDelay(boolean on) throws SocketException {
953        if (isClosed())
954            throw new SocketException("Socket is closed");
955        getImpl().setOption(SocketOptions.TCP_NODELAY, Boolean.valueOf(on));
956    }
957
958    /**
959     * Tests if TCP_NODELAY is enabled.
960     *
961     * @return a <code>boolean</code> indicating whether or not TCP_NODELAY is enabled.
962     * @exception SocketException if there is an error
963     * in the underlying protocol, such as a TCP error.
964     * @since   JDK1.1
965     * @see #setTcpNoDelay(boolean)
966     */
967    public boolean getTcpNoDelay() throws SocketException {
968        if (isClosed())
969            throw new SocketException("Socket is closed");
970        return ((Boolean) getImpl().getOption(SocketOptions.TCP_NODELAY)).booleanValue();
971    }
972
973    /**
974     * Enable/disable SO_LINGER with the specified linger time in seconds.
975     * The maximum timeout value is platform specific.
976     *
977     * The setting only affects socket close.
978     *
979     * @param on     whether or not to linger on.
980     * @param linger how long to linger for, if on is true.
981     * @exception SocketException if there is an error
982     * in the underlying protocol, such as a TCP error.
983     * @exception IllegalArgumentException if the linger value is negative.
984     * @since JDK1.1
985     * @see #getSoLinger()
986     */
987    public void setSoLinger(boolean on, int linger) throws SocketException {
988        if (isClosed())
989            throw new SocketException("Socket is closed");
990        if (!on) {
991            getImpl().setOption(SocketOptions.SO_LINGER, new Boolean(on));
992        } else {
993            if (linger < 0) {
994                throw new IllegalArgumentException("invalid value for SO_LINGER");
995            }
996            if (linger > 65535)
997                linger = 65535;
998            getImpl().setOption(SocketOptions.SO_LINGER, new Integer(linger));
999        }
1000    }
1001
1002    /**
1003     * Returns setting for SO_LINGER. -1 returns implies that the
1004     * option is disabled.
1005     *
1006     * The setting only affects socket close.
1007     *
1008     * @return the setting for SO_LINGER.
1009     * @exception SocketException if there is an error
1010     * in the underlying protocol, such as a TCP error.
1011     * @since   JDK1.1
1012     * @see #setSoLinger(boolean, int)
1013     */
1014    public int getSoLinger() throws SocketException {
1015        if (isClosed())
1016            throw new SocketException("Socket is closed");
1017        Object o = getImpl().getOption(SocketOptions.SO_LINGER);
1018        if (o instanceof Integer) {
1019            return ((Integer) o).intValue();
1020        } else {
1021            return -1;
1022        }
1023    }
1024
1025    /**
1026     * Send one byte of urgent data on the socket. The byte to be sent is the lowest eight
1027     * bits of the data parameter. The urgent byte is
1028     * sent after any preceding writes to the socket OutputStream
1029     * and before any future writes to the OutputStream.
1030     * @param data The byte of data to send
1031     * @exception IOException if there is an error
1032     *  sending the data.
1033     * @since 1.4
1034     */
1035    public void sendUrgentData (int data) throws IOException  {
1036        if (!getImpl().supportsUrgentData ()) {
1037            throw new SocketException ("Urgent data not supported");
1038        }
1039        getImpl().sendUrgentData (data);
1040    }
1041
1042    /**
1043     * Enable/disable OOBINLINE (receipt of TCP urgent data)
1044     *
1045     * By default, this option is disabled and TCP urgent data received on a
1046     * socket is silently discarded. If the user wishes to receive urgent data, then
1047     * this option must be enabled. When enabled, urgent data is received
1048     * inline with normal data.
1049     * <p>
1050     * Note, only limited support is provided for handling incoming urgent
1051     * data. In particular, no notification of incoming urgent data is provided
1052     * and there is no capability to distinguish between normal data and urgent
1053     * data unless provided by a higher level protocol.
1054     *
1055     * @param on <code>true</code> to enable OOBINLINE,
1056     * <code>false</code> to disable.
1057     *
1058     * @exception SocketException if there is an error
1059     * in the underlying protocol, such as a TCP error.
1060     *
1061     * @since   1.4
1062     *
1063     * @see #getOOBInline()
1064     */
1065    public void setOOBInline(boolean on) throws SocketException {
1066        if (isClosed())
1067            throw new SocketException("Socket is closed");
1068        getImpl().setOption(SocketOptions.SO_OOBINLINE, Boolean.valueOf(on));
1069    }
1070
1071    /**
1072     * Tests if OOBINLINE is enabled.
1073     *
1074     * @return a <code>boolean</code> indicating whether or not OOBINLINE is enabled.
1075     * @exception SocketException if there is an error
1076     * in the underlying protocol, such as a TCP error.
1077     * @since   1.4
1078     * @see #setOOBInline(boolean)
1079     */
1080    public boolean getOOBInline() throws SocketException {
1081        if (isClosed())
1082            throw new SocketException("Socket is closed");
1083        return ((Boolean) getImpl().getOption(SocketOptions.SO_OOBINLINE)).booleanValue();
1084    }
1085
1086    /**
1087     *  Enable/disable SO_TIMEOUT with the specified timeout, in
1088     *  milliseconds.  With this option set to a non-zero timeout,
1089     *  a read() call on the InputStream associated with this Socket
1090     *  will block for only this amount of time.  If the timeout expires,
1091     *  a <B>java.net.SocketTimeoutException</B> is raised, though the
1092     *  Socket is still valid. The option <B>must</B> be enabled
1093     *  prior to entering the blocking operation to have effect. The
1094     *  timeout must be > 0.
1095     *  A timeout of zero is interpreted as an infinite timeout.
1096     * @param timeout the specified timeout, in milliseconds.
1097     * @exception SocketException if there is an error
1098     * in the underlying protocol, such as a TCP error.
1099     * @since   JDK 1.1
1100     * @see #getSoTimeout()
1101     */
1102    public synchronized void setSoTimeout(int timeout) throws SocketException {
1103        if (isClosed())
1104            throw new SocketException("Socket is closed");
1105        if (timeout < 0)
1106          throw new IllegalArgumentException("timeout can't be negative");
1107
1108        getImpl().setOption(SocketOptions.SO_TIMEOUT, new Integer(timeout));
1109    }
1110
1111    /**
1112     * Returns setting for SO_TIMEOUT.  0 returns implies that the
1113     * option is disabled (i.e., timeout of infinity).
1114     * @return the setting for SO_TIMEOUT
1115     * @exception SocketException if there is an error
1116     * in the underlying protocol, such as a TCP error.
1117     * @since   JDK1.1
1118     * @see #setSoTimeout(int)
1119     */
1120    public synchronized int getSoTimeout() throws SocketException {
1121        if (isClosed())
1122            throw new SocketException("Socket is closed");
1123        Object o = getImpl().getOption(SocketOptions.SO_TIMEOUT);
1124        /* extra type safety */
1125        if (o instanceof Integer) {
1126            return ((Integer) o).intValue();
1127        } else {
1128            return 0;
1129        }
1130    }
1131
1132    /**
1133     * Sets the SO_SNDBUF option to the specified value for this
1134     * <tt>Socket</tt>. The SO_SNDBUF option is used by the platform's
1135     * networking code as a hint for the size to set
1136     * the underlying network I/O buffers.
1137     *
1138     * <p>Because SO_SNDBUF is a hint, applications that want to
1139     * verify what size the buffers were set to should call
1140     * {@link #getSendBufferSize()}.
1141     *
1142     * @exception SocketException if there is an error
1143     * in the underlying protocol, such as a TCP error.
1144     *
1145     * @param size the size to which to set the send buffer
1146     * size. This value must be greater than 0.
1147     *
1148     * @exception IllegalArgumentException if the
1149     * value is 0 or is negative.
1150     *
1151     * @see #getSendBufferSize()
1152     * @since 1.2
1153     */
1154    public synchronized void setSendBufferSize(int size)
1155    throws SocketException{
1156        if (!(size > 0)) {
1157            throw new IllegalArgumentException("negative send size");
1158        }
1159        if (isClosed())
1160            throw new SocketException("Socket is closed");
1161        getImpl().setOption(SocketOptions.SO_SNDBUF, new Integer(size));
1162    }
1163
1164    /**
1165     * Get value of the SO_SNDBUF option for this <tt>Socket</tt>,
1166     * that is the buffer size used by the platform
1167     * for output on this <tt>Socket</tt>.
1168     * @return the value of the SO_SNDBUF option for this <tt>Socket</tt>.
1169     *
1170     * @exception SocketException if there is an error
1171     * in the underlying protocol, such as a TCP error.
1172     *
1173     * @see #setSendBufferSize(int)
1174     * @since 1.2
1175     */
1176    public synchronized int getSendBufferSize() throws SocketException {
1177        if (isClosed())
1178            throw new SocketException("Socket is closed");
1179        int result = 0;
1180        Object o = getImpl().getOption(SocketOptions.SO_SNDBUF);
1181        if (o instanceof Integer) {
1182            result = ((Integer)o).intValue();
1183        }
1184        return result;
1185    }
1186
1187    /**
1188     * Sets the SO_RCVBUF option to the specified value for this
1189     * <tt>Socket</tt>. The SO_RCVBUF option is used by the platform's
1190     * networking code as a hint for the size to set
1191     * the underlying network I/O buffers.
1192     *
1193     * <p>Increasing the receive buffer size can increase the performance of
1194     * network I/O for high-volume connection, while decreasing it can
1195     * help reduce the backlog of incoming data.
1196     *
1197     * <p>Because SO_RCVBUF is a hint, applications that want to
1198     * verify what size the buffers were set to should call
1199     * {@link #getReceiveBufferSize()}.
1200     *
1201     * <p>The value of SO_RCVBUF is also used to set the TCP receive window
1202     * that is advertized to the remote peer. Generally, the window size
1203     * can be modified at any time when a socket is connected. However, if
1204     * a receive window larger than 64K is required then this must be requested
1205     * <B>before</B> the socket is connected to the remote peer. There are two
1206     * cases to be aware of:<p>
1207     * <ol>
1208     * <li>For sockets accepted from a ServerSocket, this must be done by calling
1209     * {@link ServerSocket#setReceiveBufferSize(int)} before the ServerSocket
1210     * is bound to a local address.<p></li>
1211     * <li>For client sockets, setReceiveBufferSize() must be called before
1212     * connecting the socket to its remote peer.<p></li></ol>
1213     * @param size the size to which to set the receive buffer
1214     * size. This value must be greater than 0.
1215     *
1216     * @exception IllegalArgumentException if the value is 0 or is
1217     * negative.
1218     *
1219     * @exception SocketException if there is an error
1220     * in the underlying protocol, such as a TCP error.
1221     *
1222     * @see #getReceiveBufferSize()
1223     * @see ServerSocket#setReceiveBufferSize(int)
1224     * @since 1.2
1225     */
1226    public synchronized void setReceiveBufferSize(int size)
1227    throws SocketException{
1228        if (size <= 0) {
1229            throw new IllegalArgumentException("invalid receive size");
1230        }
1231        if (isClosed())
1232            throw new SocketException("Socket is closed");
1233        getImpl().setOption(SocketOptions.SO_RCVBUF, new Integer(size));
1234    }
1235
1236    /**
1237     * Gets the value of the SO_RCVBUF option for this <tt>Socket</tt>,
1238     * that is the buffer size used by the platform for
1239     * input on this <tt>Socket</tt>.
1240     *
1241     * @return the value of the SO_RCVBUF option for this <tt>Socket</tt>.
1242     * @exception SocketException if there is an error
1243     * in the underlying protocol, such as a TCP error.
1244     * @see #setReceiveBufferSize(int)
1245     * @since 1.2
1246     */
1247    public synchronized int getReceiveBufferSize()
1248    throws SocketException{
1249        if (isClosed())
1250            throw new SocketException("Socket is closed");
1251        int result = 0;
1252        Object o = getImpl().getOption(SocketOptions.SO_RCVBUF);
1253        if (o instanceof Integer) {
1254            result = ((Integer)o).intValue();
1255        }
1256        return result;
1257    }
1258
1259    /**
1260     * Enable/disable SO_KEEPALIVE.
1261     *
1262     * @param on     whether or not to have socket keep alive turned on.
1263     * @exception SocketException if there is an error
1264     * in the underlying protocol, such as a TCP error.
1265     * @since 1.3
1266     * @see #getKeepAlive()
1267     */
1268    public void setKeepAlive(boolean on) throws SocketException {
1269        if (isClosed())
1270            throw new SocketException("Socket is closed");
1271        getImpl().setOption(SocketOptions.SO_KEEPALIVE, Boolean.valueOf(on));
1272    }
1273
1274    /**
1275     * Tests if SO_KEEPALIVE is enabled.
1276     *
1277     * @return a <code>boolean</code> indicating whether or not SO_KEEPALIVE is enabled.
1278     * @exception SocketException if there is an error
1279     * in the underlying protocol, such as a TCP error.
1280     * @since   1.3
1281     * @see #setKeepAlive(boolean)
1282     */
1283    public boolean getKeepAlive() throws SocketException {
1284        if (isClosed())
1285            throw new SocketException("Socket is closed");
1286        return ((Boolean) getImpl().getOption(SocketOptions.SO_KEEPALIVE)).booleanValue();
1287    }
1288
1289    /**
1290     * Sets traffic class or type-of-service octet in the IP
1291     * header for packets sent from this Socket.
1292     * As the underlying network implementation may ignore this
1293     * value applications should consider it a hint.
1294     *
1295     * <P> The tc <B>must</B> be in the range <code> 0 <= tc <=
1296     * 255</code> or an IllegalArgumentException will be thrown.
1297     * <p>Notes:
1298     * <p>For Internet Protocol v4 the value consists of an
1299     * <code>integer</code>, the least significant 8 bits of which
1300     * represent the value of the TOS octet in IP packets sent by
1301     * the socket.
1302     * RFC 1349 defines the TOS values as follows:
1303     * <p>
1304     * <UL>
1305     * <LI><CODE>IPTOS_LOWCOST (0x02)</CODE></LI>
1306     * <LI><CODE>IPTOS_RELIABILITY (0x04)</CODE></LI>
1307     * <LI><CODE>IPTOS_THROUGHPUT (0x08)</CODE></LI>
1308     * <LI><CODE>IPTOS_LOWDELAY (0x10)</CODE></LI>
1309     * </UL>
1310     * The last low order bit is always ignored as this
1311     * corresponds to the MBZ (must be zero) bit.
1312     * <p>
1313     * Setting bits in the precedence field may result in a
1314     * SocketException indicating that the operation is not
1315     * permitted.
1316     * <p>
1317     * As RFC 1122 section 4.2.4.2 indicates, a compliant TCP
1318     * implementation should, but is not required to, let application
1319     * change the TOS field during the lifetime of a connection.
1320     * So whether the type-of-service field can be changed after the
1321     * TCP connection has been established depends on the implementation
1322     * in the underlying platform. Applications should not assume that
1323     * they can change the TOS field after the connection.
1324     * <p>
1325     * For Internet Protocol v6 <code>tc</code> is the value that
1326     * would be placed into the sin6_flowinfo field of the IP header.
1327     *
1328     * @param tc        an <code>int</code> value for the bitset.
1329     * @throws SocketException if there is an error setting the
1330     * traffic class or type-of-service
1331     * @since 1.4
1332     * @see #getTrafficClass
1333     */
1334    public void setTrafficClass(int tc) throws SocketException {
1335        if (tc < 0 || tc > 255)
1336            throw new IllegalArgumentException("tc is not in range 0 -- 255");
1337
1338        if (isClosed())
1339            throw new SocketException("Socket is closed");
1340        getImpl().setOption(SocketOptions.IP_TOS, new Integer(tc));
1341    }
1342
1343    /**
1344     * Gets traffic class or type-of-service in the IP header
1345     * for packets sent from this Socket
1346     * <p>
1347     * As the underlying network implementation may ignore the
1348     * traffic class or type-of-service set using {@link #setTrafficClass(int)}
1349     * this method may return a different value than was previously
1350     * set using the {@link #setTrafficClass(int)} method on this Socket.
1351     *
1352     * @return the traffic class or type-of-service already set
1353     * @throws SocketException if there is an error obtaining the
1354     * traffic class or type-of-service value.
1355     * @since 1.4
1356     * @see #setTrafficClass(int)
1357     */
1358    public int getTrafficClass() throws SocketException {
1359        return ((Integer) (getImpl().getOption(SocketOptions.IP_TOS))).intValue();
1360    }
1361
1362    /**
1363     * Enable/disable the SO_REUSEADDR socket option.
1364     * <p>
1365     * When a TCP connection is closed the connection may remain
1366     * in a timeout state for a period of time after the connection
1367     * is closed (typically known as the <tt>TIME_WAIT</tt> state
1368     * or <tt>2MSL</tt> wait state).
1369     * For applications using a well known socket address or port
1370     * it may not be possible to bind a socket to the required
1371     * <tt>SocketAddress</tt> if there is a connection in the
1372     * timeout state involving the socket address or port.
1373     * <p>
1374     * Enabling <tt>SO_REUSEADDR</tt> prior to binding the socket
1375     * using {@link #bind(SocketAddress)} allows the socket to be
1376     * bound even though a previous connection is in a timeout
1377     * state.
1378     * <p>
1379     * When a <tt>Socket</tt> is created the initial setting
1380     * of <tt>SO_REUSEADDR</tt> is disabled.
1381     * <p>
1382     * The behaviour when <tt>SO_REUSEADDR</tt> is enabled or
1383     * disabled after a socket is bound (See {@link #isBound()})
1384     * is not defined.
1385     *
1386     * @param on  whether to enable or disable the socket option
1387     * @exception SocketException if an error occurs enabling or
1388     *            disabling the <tt>SO_RESUEADDR</tt> socket option,
1389     *            or the socket is closed.
1390     * @since 1.4
1391     * @see #getReuseAddress()
1392     * @see #bind(SocketAddress)
1393     * @see #isClosed()
1394     * @see #isBound()
1395     */
1396    public void setReuseAddress(boolean on) throws SocketException {
1397        if (isClosed())
1398            throw new SocketException("Socket is closed");
1399        getImpl().setOption(SocketOptions.SO_REUSEADDR, Boolean.valueOf(on));
1400    }
1401
1402    /**
1403     * Tests if SO_REUSEADDR is enabled.
1404     *
1405     * @return a <code>boolean</code> indicating whether or not SO_REUSEADDR is enabled.
1406     * @exception SocketException if there is an error
1407     * in the underlying protocol, such as a TCP error.
1408     * @since   1.4
1409     * @see #setReuseAddress(boolean)
1410     */
1411    public boolean getReuseAddress() throws SocketException {
1412        if (isClosed())
1413            throw new SocketException("Socket is closed");
1414        return ((Boolean) (getImpl().getOption(SocketOptions.SO_REUSEADDR))).booleanValue();
1415    }
1416
1417    /**
1418     * Closes this socket.
1419     * <p>
1420     * Any thread currently blocked in an I/O operation upon this socket
1421     * will throw a {@link SocketException}.
1422     * <p>
1423     * Once a socket has been closed, it is not available for further networking
1424     * use (i.e. can't be reconnected or rebound). A new socket needs to be
1425     * created.
1426     *
1427     * <p> Closing this socket will also close the socket's
1428     * {@link java.io.InputStream InputStream} and
1429     * {@link java.io.OutputStream OutputStream}.
1430     *
1431     * <p> If this socket has an associated channel then the channel is closed
1432     * as well.
1433     *
1434     * @exception  IOException  if an I/O error occurs when closing this socket.
1435     * @revised 1.4
1436     * @spec JSR-51
1437     * @see #isClosed
1438     */
1439    public synchronized void close() throws IOException {
1440        synchronized(closeLock) {
1441            if (isClosed())
1442                return;
1443            if (created)
1444                impl.close();
1445            closed = true;
1446        }
1447    }
1448
1449    /**
1450     * Places the input stream for this socket at "end of stream".
1451     * Any data sent to the input stream side of the socket is acknowledged
1452     * and then silently discarded.
1453     * <p>
1454     * If you read from a socket input stream after invoking
1455     * shutdownInput() on the socket, the stream will return EOF.
1456     *
1457     * @exception IOException if an I/O error occurs when shutting down this
1458     * socket.
1459     *
1460     * @since 1.3
1461     * @see java.net.Socket#shutdownOutput()
1462     * @see java.net.Socket#close()
1463     * @see java.net.Socket#setSoLinger(boolean, int)
1464     * @see #isInputShutdown
1465     */
1466    public void shutdownInput() throws IOException
1467    {
1468        if (isClosed())
1469            throw new SocketException("Socket is closed");
1470        if (!isConnected())
1471            throw new SocketException("Socket is not connected");
1472        if (isInputShutdown())
1473            throw new SocketException("Socket input is already shutdown");
1474        getImpl().shutdownInput();
1475        shutIn = true;
1476    }
1477
1478    /**
1479     * Disables the output stream for this socket.
1480     * For a TCP socket, any previously written data will be sent
1481     * followed by TCP's normal connection termination sequence.
1482     *
1483     * If you write to a socket output stream after invoking
1484     * shutdownOutput() on the socket, the stream will throw
1485     * an IOException.
1486     *
1487     * @exception IOException if an I/O error occurs when shutting down this
1488     * socket.
1489     *
1490     * @since 1.3
1491     * @see java.net.Socket#shutdownInput()
1492     * @see java.net.Socket#close()
1493     * @see java.net.Socket#setSoLinger(boolean, int)
1494     * @see #isOutputShutdown
1495     */
1496    public void shutdownOutput() throws IOException
1497    {
1498        if (isClosed())
1499            throw new SocketException("Socket is closed");
1500        if (!isConnected())
1501            throw new SocketException("Socket is not connected");
1502        if (isOutputShutdown())
1503            throw new SocketException("Socket output is already shutdown");
1504        getImpl().shutdownOutput();
1505        shutOut = true;
1506    }
1507
1508    /**
1509     * Converts this socket to a <code>String</code>.
1510     *
1511     * @return  a string representation of this socket.
1512     */
1513    public String toString() {
1514        try {
1515            // Android changed : change localport to localPort, and addr to address.
1516            if (isConnected())
1517                return "Socket[address=" + getImpl().getInetAddress() +
1518                    ",port=" + getImpl().getPort() +
1519                    ",localPort=" + getImpl().getLocalPort() + "]";
1520        } catch (SocketException e) {
1521        }
1522        return "Socket[unconnected]";
1523    }
1524
1525    /**
1526     * Returns the connection state of the socket.
1527     * <p>
1528     * Note: Closing a socket doesn't clear its connection state, which means
1529     * this method will return <code>true</code> for a closed socket
1530     * (see {@link #isClosed()}) if it was successfuly connected prior
1531     * to being closed.
1532     *
1533     * @return true if the socket was successfuly connected to a server
1534     * @since 1.4
1535     */
1536    public boolean isConnected() {
1537        // Before 1.3 Sockets were always connected during creation
1538        return connected || oldImpl;
1539    }
1540
1541    /**
1542     * Returns the binding state of the socket.
1543     * <p>
1544     * Note: Closing a socket doesn't clear its binding state, which means
1545     * this method will return <code>true</code> for a closed socket
1546     * (see {@link #isClosed()}) if it was successfuly bound prior
1547     * to being closed.
1548     *
1549     * @return true if the socket was successfuly bound to an address
1550     * @since 1.4
1551     * @see #bind
1552     */
1553    public boolean isBound() {
1554        // Before 1.3 Sockets were always bound during creation
1555        return bound || oldImpl;
1556    }
1557
1558    /**
1559     * Returns the closed state of the socket.
1560     *
1561     * @return true if the socket has been closed
1562     * @since 1.4
1563     * @see #close
1564     */
1565    public boolean isClosed() {
1566        synchronized(closeLock) {
1567            return closed;
1568        }
1569    }
1570
1571    /**
1572     * Returns whether the read-half of the socket connection is closed.
1573     *
1574     * @return true if the input of the socket has been shutdown
1575     * @since 1.4
1576     * @see #shutdownInput
1577     */
1578    public boolean isInputShutdown() {
1579        return shutIn;
1580    }
1581
1582    /**
1583     * Returns whether the write-half of the socket connection is closed.
1584     *
1585     * @return true if the output of the socket has been shutdown
1586     * @since 1.4
1587     * @see #shutdownOutput
1588     */
1589    public boolean isOutputShutdown() {
1590        return shutOut;
1591    }
1592
1593    /**
1594     * The factory for all client sockets.
1595     */
1596    private static SocketImplFactory factory = null;
1597
1598    /**
1599     * Sets the client socket implementation factory for the
1600     * application. The factory can be specified only once.
1601     * <p>
1602     * When an application creates a new client socket, the socket
1603     * implementation factory's <code>createSocketImpl</code> method is
1604     * called to create the actual socket implementation.
1605     * <p>
1606     * Passing <code>null</code> to the method is a no-op unless the factory
1607     * was already set.
1608     * <p>If there is a security manager, this method first calls
1609     * the security manager's <code>checkSetFactory</code> method
1610     * to ensure the operation is allowed.
1611     * This could result in a SecurityException.
1612     *
1613     * @param      fac   the desired factory.
1614     * @exception  IOException  if an I/O error occurs when setting the
1615     *               socket factory.
1616     * @exception  SocketException  if the factory is already defined.
1617     * @exception  SecurityException  if a security manager exists and its
1618     *             <code>checkSetFactory</code> method doesn't allow the operation.
1619     * @see        java.net.SocketImplFactory#createSocketImpl()
1620     * @see        SecurityManager#checkSetFactory
1621     */
1622    public static synchronized void setSocketImplFactory(SocketImplFactory fac)
1623        throws IOException
1624    {
1625        if (factory != null) {
1626            throw new SocketException("factory already defined");
1627        }
1628        SecurityManager security = System.getSecurityManager();
1629        if (security != null) {
1630            security.checkSetFactory();
1631        }
1632        factory = fac;
1633    }
1634
1635    /**
1636     * Sets performance preferences for this socket.
1637     *
1638     * <p> Sockets use the TCP/IP protocol by default.  Some implementations
1639     * may offer alternative protocols which have different performance
1640     * characteristics than TCP/IP.  This method allows the application to
1641     * express its own preferences as to how these tradeoffs should be made
1642     * when the implementation chooses from the available protocols.
1643     *
1644     * <p> Performance preferences are described by three integers
1645     * whose values indicate the relative importance of short connection time,
1646     * low latency, and high bandwidth.  The absolute values of the integers
1647     * are irrelevant; in order to choose a protocol the values are simply
1648     * compared, with larger values indicating stronger preferences. Negative
1649     * values represent a lower priority than positive values. If the
1650     * application prefers short connection time over both low latency and high
1651     * bandwidth, for example, then it could invoke this method with the values
1652     * <tt>(1, 0, 0)</tt>.  If the application prefers high bandwidth above low
1653     * latency, and low latency above short connection time, then it could
1654     * invoke this method with the values <tt>(0, 1, 2)</tt>.
1655     *
1656     * <p> Invoking this method after this socket has been connected
1657     * will have no effect.
1658     *
1659     * @param  connectionTime
1660     *         An <tt>int</tt> expressing the relative importance of a short
1661     *         connection time
1662     *
1663     * @param  latency
1664     *         An <tt>int</tt> expressing the relative importance of low
1665     *         latency
1666     *
1667     * @param  bandwidth
1668     *         An <tt>int</tt> expressing the relative importance of high
1669     *         bandwidth
1670     *
1671     * @since 1.5
1672     */
1673    public void setPerformancePreferences(int connectionTime,
1674                                          int latency,
1675                                          int bandwidth)
1676    {
1677        /* Not implemented yet */
1678    }
1679
1680    /**
1681     * @hide internal use only
1682     */
1683    public FileDescriptor getFileDescriptor$() {
1684        return impl.getFileDescriptor();
1685    }
1686}
1687