/*
    * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/oac.hc3x/trunk/src/java/org/apache/commons/httpclient/HttpConnection.java $
    * $Revision$
    * $Date$
    *
    * ====================================================================
    *
    *  Licensed to the Apache Software Foundation (ASF) under one or more
    *  contributor license agreements.  See the NOTICE file distributed with
   *  this work for additional information regarding copyright ownership.
   *  The ASF licenses this file to You under the Apache License, Version 2.0
   *  (the "License"); you may not use this file except in compliance with
   *  the License.  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.commons.httpclient;
  
  import java.io.BufferedInputStream;
  import java.io.BufferedOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InterruptedIOException;
  import java.io.OutputStream;
  import java.lang.reflect.Method;
  import java.net.InetAddress;
  import java.net.Socket;
  import java.net.SocketException;
  
  import org.apache.commons.httpclient.params.HttpConnectionParams;
  import org.apache.commons.httpclient.protocol.Protocol;
  import org.apache.commons.httpclient.protocol.ProtocolSocketFactory;
  import org.apache.commons.httpclient.protocol.SecureProtocolSocketFactory;
  import org.apache.commons.httpclient.util.EncodingUtil;
  import org.apache.commons.httpclient.util.ExceptionUtil;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /***
   * An abstraction of an HTTP {@link InputStream} and {@link OutputStream}
   * pair, together with the relevant attributes.
   * <p>
   * The following options are set on the socket before getting the input/output 
   * streams in the {@link #open()} method:
   * <table border=1><tr>
   *    <th>Socket Method
   *    <th>Sockets Option
   *    <th>Configuration
   * </tr><tr>
   *    <td>{@link java.net.Socket#setTcpNoDelay(boolean)}
   *    <td>SO_NODELAY
   *    <td>{@link HttpConnectionParams#setTcpNoDelay(boolean)}
   * </tr><tr>
   *    <td>{@link java.net.Socket#setSoTimeout(int)}
   *    <td>SO_TIMEOUT
   *    <td>{@link HttpConnectionParams#setSoTimeout(int)}
   * </tr><tr>
   *    <td>{@link java.net.Socket#setSendBufferSize(int)}
   *    <td>SO_SNDBUF
   *    <td>{@link HttpConnectionParams#setSendBufferSize(int)}
   * </tr><tr>
   *    <td>{@link java.net.Socket#setReceiveBufferSize(int)}
   *    <td>SO_RCVBUF
   *    <td>{@link HttpConnectionParams#setReceiveBufferSize(int)}
   * </tr></table>
   *
   * @author Rod Waldhoff
   * @author Sean C. Sullivan
   * @author Ortwin Glueck
   * @author <a href="mailto:jsdever@apache.org">Jeff Dever</a>
   * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
   * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
   * @author Michael Becke
   * @author Eric E Johnson
   * @author Laura Werner
   * 
   * @version   $Revision$ $Date$
   */
  public class HttpConnection {
  
      // ----------------------------------------------------------- Constructors
  
      /***
       * Creates a new HTTP connection for the given host and port.
       *
      * @param host the host to connect to
      * @param port the port to connect to
      */
     public HttpConnection(String host, int port) {
         this(null, -1, host, null, port, Protocol.getProtocol("http"));
     }
 
     /***
      * Creates a new HTTP connection for the given host and port
      * using the given protocol.
      *
      * @param host the host to connect to
      * @param port the port to connect to
      * @param protocol the protocol to use
      */
     public HttpConnection(String host, int port, Protocol protocol) {
         this(null, -1, host, null, port, protocol);
     }
 
     /***
      * Creates a new HTTP connection for the given host with the virtual 
      * alias and port using given protocol.
      *
      * @param host the host to connect to
      * @param virtualHost the virtual host requests will be sent to
      * @param port the port to connect to
      * @param protocol the protocol to use
      */
     public HttpConnection(String host, String virtualHost, int port, Protocol protocol) {
         this(null, -1, host, virtualHost, port, protocol);
     }
 
     /***
      * Creates a new HTTP connection for the given host and port via the 
      * given proxy host and port using the default protocol.
      *
      * @param proxyHost the host to proxy via
      * @param proxyPort the port to proxy via
      * @param host the host to connect to
      * @param port the port to connect to
      */
     public HttpConnection(
         String proxyHost,
         int proxyPort,
         String host,
         int port) {
         this(proxyHost, proxyPort, host, null, port, Protocol.getProtocol("http"));
     }
 
     /***
      * Creates a new HTTP connection for the given host configuration.
      * 
      * @param hostConfiguration the host/proxy/protocol to use
      */
     public HttpConnection(HostConfiguration hostConfiguration) {
         this(hostConfiguration.getProxyHost(),
              hostConfiguration.getProxyPort(),
              hostConfiguration.getHost(),
              hostConfiguration.getPort(),
              hostConfiguration.getProtocol());
         this.localAddress = hostConfiguration.getLocalAddress();
     }
 
     /***
      * Creates a new HTTP connection for the given host with the virtual 
      * alias and port via the given proxy host and port using the given 
      * protocol.
      * 
      * @param proxyHost the host to proxy via
      * @param proxyPort the port to proxy via
      * @param host the host to connect to. Parameter value must be non-null.
      * @param virtualHost No longer applicable. 
      * @param port the port to connect to
      * @param protocol The protocol to use. Parameter value must be non-null.
      * 
      * @deprecated use #HttpConnection(String, int, String, int, Protocol)
      */
     public HttpConnection(
         String proxyHost,
         int proxyPort,
         String host,
         String virtualHost,
         int port,
         Protocol protocol) {
     	this(proxyHost, proxyPort, host, port, protocol);
     }
 
     /***
      * Creates a new HTTP connection for the given host with the virtual 
      * alias and port via the given proxy host and port using the given 
      * protocol.
      * 
      * @param proxyHost the host to proxy via
      * @param proxyPort the port to proxy via
      * @param host the host to connect to. Parameter value must be non-null.
      * @param port the port to connect to
      * @param protocol The protocol to use. Parameter value must be non-null.
      */
     public HttpConnection(
         String proxyHost,
         int proxyPort,
         String host,
         int port,
         Protocol protocol) {
 
         if (host == null) {
             throw new IllegalArgumentException("host parameter is null");
         }
         if (protocol == null) {
             throw new IllegalArgumentException("protocol is null");
         }
 
         proxyHostName = proxyHost;
         proxyPortNumber = proxyPort;
         hostName = host;
         portNumber = protocol.resolvePort(port);
         protocolInUse = protocol;
     }
 
     // ------------------------------------------ Attribute Setters and Getters
 
     /***
      * Returns the connection socket.
      *
      * @return the socket.
      * 
      * @since 3.0
      */
     protected Socket getSocket() {
         return this.socket;
     }
 
     /***
      * Returns the host.
      *
      * @return the host.
      */
     public String getHost() {
         return hostName;
     }
 
     /***
      * Sets the host to connect to.
      *
      * @param host the host to connect to. Parameter value must be non-null.
      * @throws IllegalStateException if the connection is already open
      */
     public void setHost(String host) throws IllegalStateException {
         if (host == null) {
             throw new IllegalArgumentException("host parameter is null");
         }
         assertNotOpen();
         hostName = host;
     }
 
     /***
      * Returns the target virtual host.
      *
      * @return the virtual host.
      * 
      * @deprecated no longer applicable
      */
 
     public String getVirtualHost() {
         return this.hostName;
     }
 
     /***
      * Sets the virtual host to target.
      *
      * @param host the virtual host name that should be used instead of 
      *        physical host name when sending HTTP requests. Virtual host 
      *        name can be set to <tt> null</tt> if virtual host name is not
      *        to be used
      * 
      * @throws IllegalStateException if the connection is already open
      * 
      * @deprecated no longer applicable
      */
 
     public void setVirtualHost(String host) throws IllegalStateException {
         assertNotOpen();
     }
 
     /***
      * Returns the port of the host.
      *
      * If the port is -1 (or less than 0) the default port for
      * the current protocol is returned.
      *
      * @return the port.
      */
     public int getPort() {
         if (portNumber < 0) {
             return isSecure() ? 443 : 80;
         } else {
             return portNumber;
         }
     }
 
     /***
      * Sets the port to connect to.
      *
      * @param port the port to connect to
      * 
      * @throws IllegalStateException if the connection is already open
      */
     public void setPort(int port) throws IllegalStateException {
         assertNotOpen();
         portNumber = port;
     }
 
     /***
      * Returns the proxy host.
      *
      * @return the proxy host.
      */
     public String getProxyHost() {
         return proxyHostName;
     }
 
     /***
      * Sets the host to proxy through.
      *
      * @param host the host to proxy through.
      * 
      * @throws IllegalStateException if the connection is already open
      */
     public void setProxyHost(String host) throws IllegalStateException {
         assertNotOpen();
         proxyHostName = host;
     }
 
     /***
      * Returns the port of the proxy host.
      *
      * @return the proxy port.
      */
     public int getProxyPort() {
         return proxyPortNumber;
     }
 
     /***
      * Sets the port of the host to proxy through.
      *
      * @param port the port of the host to proxy through.
      * 
      * @throws IllegalStateException if the connection is already open
      */
     public void setProxyPort(int port) throws IllegalStateException {
         assertNotOpen();
         proxyPortNumber = port;
     }
 
     /***
      * Returns <tt>true</tt> if the connection is established over 
      * a secure protocol.
      *
      * @return <tt>true</tt> if connected over a secure protocol.
      */
     public boolean isSecure() {
         return protocolInUse.isSecure();
     }
 
     /***
      * Returns the protocol used to establish the connection.
      * @return The protocol
      */
     public Protocol getProtocol() {
         return protocolInUse;
     }
 
     /***
      * Sets the protocol used to establish the connection
      * 
      * @param protocol The protocol to use.
      * 
      * @throws IllegalStateException if the connection is already open
      */
     public void setProtocol(Protocol protocol) {
         assertNotOpen();
 
         if (protocol == null) {
             throw new IllegalArgumentException("protocol is null");
         }
 
         protocolInUse = protocol;
 
     }
 
     /***
      * Return the local address used when creating the connection.
      * If <tt>null</tt>, the default address is used.
      * 
      * @return InetAddress the local address to be used when creating Sockets
      */
     public InetAddress getLocalAddress() {
         return this.localAddress;
     }
     
     /***
      * Set the local address used when creating the connection.
      * If unset or <tt>null</tt>, the default address is used.
      * 
      * @param localAddress the local address to use
      */
     public void setLocalAddress(InetAddress localAddress) {
         assertNotOpen();
         this.localAddress = localAddress;
     }
 
     /***
      * Tests if the connection is open. 
      *
      * @return <code>true</code> if the connection is open
      */
     public boolean isOpen() {
         return isOpen;
     }
 
     /***
      * Closes the connection if stale.
      * 
      * @return <code>true</code> if the connection was stale and therefore closed, 
      * <code>false</code> otherwise.
      * 
      * @see #isStale()
      * 
      * @since 3.0
      */
     public boolean closeIfStale() throws IOException {
         if (isOpen && isStale()) {
             LOG.debug("Connection is stale, closing...");
             close();
             return true;
         }
         return false;
     }
     
     /***
      * Tests if stale checking is enabled.
      * 
      * @return <code>true</code> if enabled
      * 
      * @see #isStale()
      * 
      * @deprecated Use {@link HttpConnectionParams#isStaleCheckingEnabled()},
      * {@link HttpConnection#getParams()}.
      */
     public boolean isStaleCheckingEnabled() {
         return this.params.isStaleCheckingEnabled();
     }
 
     /***
      * Sets whether or not isStale() will be called when testing if this connection is open.
      * 
      * <p>Setting this flag to <code>false</code> will increase performance when reusing
      * connections, but it will also make them less reliable.  Stale checking ensures that
      * connections are viable before they are used.  When set to <code>false</code> some
      * method executions will result in IOExceptions and they will have to be retried.</p>
      * 
      * @param staleCheckEnabled <code>true</code> to enable isStale()
      * 
      * @see #isStale()
      * @see #isOpen()
      * 
      * @deprecated Use {@link HttpConnectionParams#setStaleCheckingEnabled(boolean)},
      * {@link HttpConnection#getParams()}.
      */
     public void setStaleCheckingEnabled(boolean staleCheckEnabled) {
         this.params.setStaleCheckingEnabled(staleCheckEnabled);
     }
 
     /***
      * Determines whether this connection is "stale", which is to say that either
      * it is no longer open, or an attempt to read the connection would fail.
      *
      * <p>Unfortunately, due to the limitations of the JREs prior to 1.4, it is
      * not possible to test a connection to see if both the read and write channels
      * are open - except by reading and writing.  This leads to a difficulty when
      * some connections leave the "write" channel open, but close the read channel
      * and ignore the request.  This function attempts to ameliorate that
      * problem by doing a test read, assuming that the caller will be doing a
      * write followed by a read, rather than the other way around.
      * </p>
      *
      * <p>To avoid side-effects, the underlying connection is wrapped by a
      * {@link BufferedInputStream}, so although data might be read, what is visible
      * to clients of the connection will not change with this call.</p.
      *
      * @throws IOException if the stale connection test is interrupted.
      * 
      * @return <tt>true</tt> if the connection is already closed, or a read would
      * fail.
      */
     protected boolean isStale() throws IOException {
         boolean isStale = true;
         if (isOpen) {
             // the connection is open, but now we have to see if we can read it
             // assume the connection is not stale.
             isStale = false;
             try {
                 if (inputStream.available() <= 0) {
                     try {
                         socket.setSoTimeout(1);
                         inputStream.mark(1);
                         int byteRead = inputStream.read();
                         if (byteRead == -1) {
                             // again - if the socket is reporting all data read,
                             // probably stale
                             isStale = true;
                         } else {
                             inputStream.reset();
                         }
                     } finally {
                         socket.setSoTimeout(this.params.getSoTimeout());
                     }
                 }
             } catch (InterruptedIOException e) {
                 if (!ExceptionUtil.isSocketTimeoutException(e)) {
                     throw e;
                 }
                 // aha - the connection is NOT stale - continue on!
             } catch (IOException e) {
                 // oops - the connection is stale, the read or soTimeout failed.
                 LOG.debug(
                     "An error occurred while reading from the socket, is appears to be stale",
                     e
                 );
                 isStale = true;
             }
         }
 
         return isStale;
     }
 
     /***
      * Returns <tt>true</tt> if the connection is established via a proxy,
      * <tt>false</tt> otherwise.
      *
      * @return <tt>true</tt> if a proxy is used to establish the connection, 
      * <tt>false</tt> otherwise.
      */
     public boolean isProxied() {
         return (!(null == proxyHostName || 0 >= proxyPortNumber));
     }
 
     /***
      * Set the state to keep track of the last response for the last request.
      *
      * <p>The connection managers use this to ensure that previous requests are
      * properly closed before a new request is attempted.  That way, a GET
      * request need not be read in its entirety before a new request is issued.
      * Instead, this stream can be closed as appropriate.</p>
      *
      * @param inStream  The stream associated with an HttpMethod.
      */
     public void setLastResponseInputStream(InputStream inStream) {
         lastResponseInputStream = inStream;
     }
 
     /***
      * Returns the stream used to read the last response's body.
      *
      * <p>Clients will generally not need to call this function unless
      * using HttpConnection directly, instead of calling {@link HttpClient#executeMethod}.
      * For those clients, call this function, and if it returns a non-null stream,
      * close the stream before attempting to execute a method.  Note that
      * calling "close" on the stream returned by this function <i>may</i> close
      * the connection if the previous response contained a "Connection: close" header. </p>
      *
      * @return An {@link InputStream} corresponding to the body of the last
      *  response.
      */
     public InputStream getLastResponseInputStream() {
         return lastResponseInputStream;
     }
 
     // --------------------------------------------------- Other Public Methods
 
     /***
      * Returns {@link HttpConnectionParams HTTP protocol parameters} associated with this method.
      *
      * @return HTTP parameters.
      *
      * @since 3.0
      */
     public HttpConnectionParams getParams() {
         return this.params;
     }
 
     /***
      * Assigns {@link HttpConnectionParams HTTP protocol parameters} for this method.
      * 
      * @since 3.0
      * 
      * @see HttpConnectionParams
      */
     public void setParams(final HttpConnectionParams params) {
         if (params == null) {
             throw new IllegalArgumentException("Parameters may not be null");
         }
         this.params = params;
     }
 
     /***
      * Set the {@link Socket}'s timeout, via {@link Socket#setSoTimeout}.  If the
      * connection is already open, the SO_TIMEOUT is changed.  If no connection
      * is open, then subsequent connections will use the timeout value.
      * <p>
      * Note: This is not a connection timeout but a timeout on network traffic!
      *
      * @param timeout the timeout value
      * @throws SocketException - if there is an error in the underlying
      * protocol, such as a TCP error.
      * 
      * @deprecated Use {@link HttpConnectionParams#setSoTimeout(int)},
      * {@link HttpConnection#getParams()}.
      */
     public void setSoTimeout(int timeout)
         throws SocketException, IllegalStateException {
         this.params.setSoTimeout(timeout);
         if (this.socket != null) {
             this.socket.setSoTimeout(timeout);
         }
     }
 
     /***
      * Sets <code>SO_TIMEOUT</code> value directly on the underlying {@link Socket socket}. 
      * This method does not change the default read timeout value set via 
      * {@link HttpConnectionParams}.
      *
      * @param timeout the timeout value
      * @throws SocketException - if there is an error in the underlying
      * protocol, such as a TCP error.
      * @throws IllegalStateException if not connected
      * 
      * @since 3.0
      */
     public void setSocketTimeout(int timeout)
         throws SocketException, IllegalStateException {
         assertOpen();
         if (this.socket != null) {
             this.socket.setSoTimeout(timeout);
         }
     }
 
     /***
      * Returns the {@link Socket}'s timeout, via {@link Socket#getSoTimeout}, if the
      * connection is already open. If no connection is open, return the value subsequent 
      * connection will use.
      * <p>
      * Note: This is not a connection timeout but a timeout on network traffic!
      *
      * @return the timeout value
      * 
      * @deprecated Use {@link HttpConnectionParams#getSoTimeout()},
      * {@link HttpConnection#getParams()}.
      */
     public int getSoTimeout() throws SocketException {
         return this.params.getSoTimeout();
     }
 
     /***
      * Sets the connection timeout. This is the maximum time that may be spent
      * until a connection is established. The connection will fail after this
      * amount of time.
      * @param timeout The timeout in milliseconds. 0 means timeout is not used.
      * 
      * @deprecated Use {@link HttpConnectionParams#setConnectionTimeout(int)},
      * {@link HttpConnection#getParams()}.
      */
     public void setConnectionTimeout(int timeout) {
         this.params.setConnectionTimeout(timeout);
     }
 
     /***
      * Establishes a connection to the specified host and port
      * (via a proxy if specified).
      * The underlying socket is created from the {@link ProtocolSocketFactory}.
      *
      * @throws IOException if an attempt to establish the connection results in an
      *   I/O error.
      */
     public void open() throws IOException {
         LOG.trace("enter HttpConnection.open()");
 
         final String host = (proxyHostName == null) ? hostName : proxyHostName;
         final int port = (proxyHostName == null) ? portNumber : proxyPortNumber;
         assertNotOpen();
         
         if (LOG.isDebugEnabled()) {
             LOG.debug("Open connection to " + host + ":" + port);
         }
         
         try {
             if (this.socket == null) {
                 usingSecureSocket = isSecure() && !isProxied();
                 // use the protocol's socket factory unless this is a secure
                 // proxied connection
                 ProtocolSocketFactory socketFactory = null;
                 if (isSecure() && isProxied()) {
                     Protocol defaultprotocol = Protocol.getProtocol("http");
                     socketFactory = defaultprotocol.getSocketFactory();
                 } else {
                     socketFactory = this.protocolInUse.getSocketFactory();
                 }
                 this.socket = socketFactory.createSocket(
                             host, port, 
                             localAddress, 0,
                             this.params);
             }
 
             /*
             "Nagling has been broadly implemented across networks, 
             including the Internet, and is generally performed by default 
             - although it is sometimes considered to be undesirable in 
             highly interactive environments, such as some client/server 
             situations. In such cases, nagling may be turned off through 
             use of the TCP_NODELAY sockets option." */
 
             socket.setTcpNoDelay(this.params.getTcpNoDelay());
             socket.setSoTimeout(this.params.getSoTimeout());
             
             int linger = this.params.getLinger();
             if (linger >= 0) {
                 socket.setSoLinger(linger > 0, linger);
             }
             
             int sndBufSize = this.params.getSendBufferSize();
             if (sndBufSize >= 0) {
                 socket.setSendBufferSize(sndBufSize);
             }        
             int rcvBufSize = this.params.getReceiveBufferSize();
             if (rcvBufSize >= 0) {
                 socket.setReceiveBufferSize(rcvBufSize);
             }        
             int outbuffersize = socket.getSendBufferSize();
             if ((outbuffersize > 2048) || (outbuffersize <= 0)) {
                 outbuffersize = 2048;
             }
             int inbuffersize = socket.getReceiveBufferSize();
             if ((inbuffersize > 2048) || (inbuffersize <= 0)) {
                 inbuffersize = 2048;
             }
             inputStream = new BufferedInputStream(socket.getInputStream(), inbuffersize);
             outputStream = new BufferedOutputStream(socket.getOutputStream(), outbuffersize);
             isOpen = true;
         } catch (IOException e) {
             // Connection wasn't opened properly
             // so close everything out
             closeSocketAndStreams();
             throw e;
         }
     }
 
     /***
      * Instructs the proxy to establish a secure tunnel to the host. The socket will 
      * be switched to the secure socket. Subsequent communication is done via the secure 
      * socket. The method can only be called once on a proxied secure connection.
      *
      * @throws IllegalStateException if connection is not secure and proxied or
      * if the socket is already secure.
      * @throws IOException if an attempt to establish the secure tunnel results in an
      *   I/O error.
      */
     public void tunnelCreated() throws IllegalStateException, IOException {
         LOG.trace("enter HttpConnection.tunnelCreated()");
 
         if (!isSecure() || !isProxied()) {
             throw new IllegalStateException(
                 "Connection must be secure "
                     + "and proxied to use this feature");
         }
 
         if (usingSecureSocket) {
             throw new IllegalStateException("Already using a secure socket");
         }
         
         if (LOG.isDebugEnabled()) {
             LOG.debug("Secure tunnel to " + this.hostName + ":" + this.portNumber);
         }
 
         SecureProtocolSocketFactory socketFactory =
             (SecureProtocolSocketFactory) protocolInUse.getSocketFactory();
 
         socket = socketFactory.createSocket(socket, hostName, portNumber, true);
         int sndBufSize = this.params.getSendBufferSize();
         if (sndBufSize >= 0) {
             socket.setSendBufferSize(sndBufSize);
         }        
         int rcvBufSize = this.params.getReceiveBufferSize();
         if (rcvBufSize >= 0) {
             socket.setReceiveBufferSize(rcvBufSize);
         }        
         int outbuffersize = socket.getSendBufferSize();
         if (outbuffersize > 2048) {
             outbuffersize = 2048;
         }
         int inbuffersize = socket.getReceiveBufferSize();
         if (inbuffersize > 2048) {
             inbuffersize = 2048;
         }
         inputStream = new BufferedInputStream(socket.getInputStream(), inbuffersize);
         outputStream = new BufferedOutputStream(socket.getOutputStream(), outbuffersize);
         usingSecureSocket = true;
         tunnelEstablished = true;
     }
 
     /***
      * Indicates if the connection is completely transparent from end to end.
      *
      * @return true if conncetion is not proxied or tunneled through a transparent
      * proxy; false otherwise.
      */
     public boolean isTransparent() {
         return !isProxied() || tunnelEstablished;
     }
 
     /***
      * Flushes the output request stream.  This method should be called to 
      * ensure that data written to the request OutputStream is sent to the server.
      * 
      * @throws IOException if an I/O problem occurs
      */
     public void flushRequestOutputStream() throws IOException {
         LOG.trace("enter HttpConnection.flushRequestOutputStream()");
         assertOpen();
         outputStream.flush();
     }
 
     /***
      * Returns an {@link OutputStream} suitable for writing the request.
      *
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      * @return a stream to write the request to
      */
     public OutputStream getRequestOutputStream()
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.getRequestOutputStream()");
         assertOpen();
         OutputStream out = this.outputStream;
         if (Wire.CONTENT_WIRE.enabled()) {
             out = new WireLogOutputStream(out, Wire.CONTENT_WIRE);
         }
         return out;
     }
 
     /***
      * Return a {@link InputStream} suitable for reading the response.
      * @return InputStream The response input stream.
      * @throws IOException If an IO problem occurs
      * @throws IllegalStateException If the connection isn't open.
      */
     public InputStream getResponseInputStream()
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.getResponseInputStream()");
         assertOpen();
         return inputStream;
     }
 
     /***
      * Tests if input data avaialble. This method returns immediately
      * and does not perform any read operations on the input socket
      * 
      * @return boolean <tt>true</tt> if input data is available, 
      *                 <tt>false</tt> otherwise.
      * 
      * @throws IOException If an IO problem occurs
      * @throws IllegalStateException If the connection isn't open.
      */
     public boolean isResponseAvailable() 
         throws IOException {
         LOG.trace("enter HttpConnection.isResponseAvailable()");
         if (this.isOpen) {
             return this.inputStream.available() > 0;
         } else {
             return false;
         }
     }
 
     /***
      * Tests if input data becomes available within the given period time in milliseconds.
      * 
      * @param timeout The number milliseconds to wait for input data to become available 
      * @return boolean <tt>true</tt> if input data is availble, 
      *                 <tt>false</tt> otherwise.
      * 
      * @throws IOException If an IO problem occurs
      * @throws IllegalStateException If the connection isn't open.
      */
     public boolean isResponseAvailable(int timeout) 
         throws IOException {
         LOG.trace("enter HttpConnection.isResponseAvailable(int)");
         if (!this.isOpen) {
             return false;
         }
         boolean result = false;
         if (this.inputStream.available() > 0) {
             result = true;
         } else {
             try {
                 this.socket.setSoTimeout(timeout);
                 inputStream.mark(1);
                 int byteRead = inputStream.read();
                 if (byteRead != -1) {
                     inputStream.reset();
                     LOG.debug("Input data available");
                     result = true;
                 } else {
                     LOG.debug("Input data not available");
                 }
             } catch (InterruptedIOException e) {
                 if (!ExceptionUtil.isSocketTimeoutException(e)) {
                     throw e;
                 }
                 if (LOG.isDebugEnabled()) {
                     LOG.debug("Input data not available after " + timeout + " ms");
                 }
             } finally {
                 try {
                     socket.setSoTimeout(this.params.getSoTimeout());
                 } catch (IOException ioe) {
                     LOG.debug("An error ocurred while resetting soTimeout, we will assume that"
                         + " no response is available.",
                         ioe);
                     result = false;
                 }
             }
         }
         return result;
     }
 
     /***
      * Writes the specified bytes to the output stream.
      *
      * @param data the data to be written
      * @throws IllegalStateException if not connected
      * @throws IOException if an I/O problem occurs
      * @see #write(byte[],int,int)
      */
     public void write(byte[] data)
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.write(byte[])");
         this.write(data, 0, data.length);
     }
 
     /***
      * Writes <i>length</i> bytes in <i>data</i> starting at
      * <i>offset</i> to the output stream.
      *
      * The general contract for
      * write(b, off, len) is that some of the bytes in the array b are written
      * to the output stream in order; element b[off] is the first byte written
      * and b[off+len-1] is the last byte written by this operation.
      *
      * @param data array containing the data to be written.
      * @param offset the start offset in the data.
      * @param length the number of bytes to write.
      * @throws IllegalStateException if not connected
      * @throws IOException if an I/O problem occurs
      */
     public void write(byte[] data, int offset, int length)
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.write(byte[], int, int)");
 
         if (offset < 0) {
             throw new IllegalArgumentException("Array offset may not be negative");
         }
         if (length < 0) {
             throw new IllegalArgumentException("Array length may not be negative");
         }
         if (offset + length > data.length) {
             throw new IllegalArgumentException("Given offset and length exceed the array length");
         }
         assertOpen();
         this.outputStream.write(data, offset, length);
     }
 
     /***
      * Writes the specified bytes, followed by <tt>"\r\n".getBytes()</tt> to the
      * output stream.
      *
      * @param data the bytes to be written
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      */
     public void writeLine(byte[] data)
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.writeLine(byte[])");
         write(data);
         writeLine();
     }
 
     /***
      * Writes <tt>"\r\n".getBytes()</tt> to the output stream.
      *
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      */
     public void writeLine()
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.writeLine()");
         write(CRLF);
     }
 
     /***
      * @deprecated Use {@link #print(String, String)}
      * 
      * Writes the specified String (as bytes) to the output stream.
      *
      * @param data the string to be written
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      */
     public void print(String data)
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.print(String)");
         write(EncodingUtil.getBytes(data, "ISO-8859-1"));
     }
 
     /***
      * Writes the specified String (as bytes) to the output stream.
      *
      * @param data the string to be written
      * @param charset the charset to use for writing the data
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      * 
      * @since 3.0
      */
     public void print(String data, String charset)
     	throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.print(String)");
         write(EncodingUtil.getBytes(data, charset));
     }
     
     /***
      * @deprecated Use {@link #printLine(String, String)}
      * 
      * Writes the specified String (as bytes), followed by
      * <tt>"\r\n".getBytes()</tt> to the output stream.
      *
      * @param data the data to be written
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      */
     public void printLine(String data)
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.printLine(String)");
         writeLine(EncodingUtil.getBytes(data, "ISO-8859-1"));
     }
 
     /***
      * Writes the specified String (as bytes), followed by
      * <tt>"\r\n".getBytes()</tt> to the output stream.
      *
      * @param data the data to be written
      * @param charset the charset to use for writing the data
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      * 
      * @since 3.0
      */
     public void printLine(String data, String charset)
     	throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.printLine(String)");
         writeLine(EncodingUtil.getBytes(data, charset));
     }    
     
     /***
      * Writes <tt>"\r\n".getBytes()</tt> to the output stream.
      *
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      */
     public void printLine()
         throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.printLine()");
         writeLine();
     }
 
     /***
      * Reads up to <tt>"\n"</tt> from the (unchunked) input stream.
      * If the stream ends before the line terminator is found,
      * the last part of the string will still be returned.
      *
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      * @return a line from the response
      * 
      * @deprecated use #readLine(String)
      */
     public String readLine() throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.readLine()");
 
         assertOpen();
         return HttpParser.readLine(inputStream);
     }
 
     /***
      * Reads up to <tt>"\n"</tt> from the (unchunked) input stream.
      * If the stream ends before the line terminator is found,
      * the last part of the string will still be returned.
      * 
      * @param charset the charset to use for reading the data
      *
      * @throws IllegalStateException if the connection is not open
      * @throws IOException if an I/O problem occurs
      * @return a line from the response
      * 
      * @since 3.0
      */
     public String readLine(final String charset) throws IOException, IllegalStateException {
         LOG.trace("enter HttpConnection.readLine()");
 
         assertOpen();
         return HttpParser.readLine(inputStream, charset);
     }
 
     /***
      * Attempts to shutdown the {@link Socket}'s output, via Socket.shutdownOutput()
      * when running on JVM 1.3 or higher.
      * 
      * @deprecated unused
      */
     public void shutdownOutput() {
         LOG.trace("enter HttpConnection.shutdownOutput()");
 
         try {
             // Socket.shutdownOutput is a JDK 1.3
             // method. We'll use reflection in case
             // we're running in an older VM
             Class[] paramsClasses = new Class[0];
             Method shutdownOutput =
                 socket.getClass().getMethod("shutdownOutput", paramsClasses);
             Object[] params = new Object[0];
             shutdownOutput.invoke(socket, params);
         } catch (Exception ex) {
             LOG.debug("Unexpected Exception caught", ex);
             // Ignore, and hope everything goes right
         }
         // close output stream?
     }
 
     /***
      * Closes the socket and streams.
      */
     public void close() {
         LOG.trace("enter HttpConnection.close()");
         closeSocketAndStreams();
     }
 
     /***
      * Returns the httpConnectionManager.
      * @return HttpConnectionManager
      */
     public HttpConnectionManager getHttpConnectionManager() {
         return httpConnectionManager;
     }
 
     /***
      * Sets the httpConnectionManager.
      * @param httpConnectionManager The httpConnectionManager to set
      */
     public void setHttpConnectionManager(HttpConnectionManager httpConnectionManager) {
         this.httpConnectionManager = httpConnectionManager;
     }
 
     /***
      * Releases the connection. If the connection is locked or does not have a connection
      * manager associated with it, this method has no effect. Note that it is completely safe 
      * to call this method multiple times.
      */
     public void releaseConnection() {
         LOG.trace("enter HttpConnection.releaseConnection()");
         if (locked) {
             LOG.debug("Connection is locked.  Call to releaseConnection() ignored.");
         } else if (httpConnectionManager != null) {
             LOG.debug("Releasing connection back to connection manager.");
             httpConnectionManager.releaseConnection(this);
         } else {
             LOG.warn("HttpConnectionManager is null.  Connection cannot be released.");
         }
     }
 
     /***
      * Tests if the connection is locked. Locked connections cannot be released. 
      * An attempt to release a locked connection will have no effect.
      * 
      * @return <tt>true</tt> if the connection is locked, <tt>false</tt> otherwise.
      * 
      * @since 3.0
      */
     protected boolean isLocked() {
         return locked;
     }
 
     /***
      * Locks or unlocks the connection. Locked connections cannot be released. 
      * An attempt to release a locked connection will have no effect.
      * 
      * @param locked <tt>true</tt> to lock the connection, <tt>false</tt> to unlock
      *  the connection.
      * 
      * @since 3.0
      */
     protected void setLocked(boolean locked) {
         this.locked = locked;
     }
     // ------------------------------------------------------ Protected Methods
 
     /***
      * Closes everything out.
      */
     protected void closeSocketAndStreams() {
         LOG.trace("enter HttpConnection.closeSockedAndStreams()");
 
         isOpen = false;
         
         // no longer care about previous responses...
         lastResponseInputStream = null;
 
         if (null != outputStream) {
             OutputStream temp = outputStream;
             outputStream = null;
             try {
                 temp.close();
             } catch (Exception ex) {
                 LOG.debug("Exception caught when closing output", ex);
                 // ignored
             }
         }
 
         if (null != inputStream) {
             InputStream temp = inputStream;
             inputStream = null;
             try {
                 temp.close();
             } catch (Exception ex) {
                 LOG.debug("Exception caught when closing input", ex);
                 // ignored
             }
         }
 
         if (null != socket) {
             Socket temp = socket;
             socket = null;
             try {
                 temp.close();
             } catch (Exception ex) {
                 LOG.debug("Exception caught when closing socket", ex);
                 // ignored
             }
         }
         
         tunnelEstablished = false;
         usingSecureSocket = false;
     }
 
     /***
      * Throws an {@link IllegalStateException} if the connection is already open.
      *
      * @throws IllegalStateException if connected
      */
     protected void assertNotOpen() throws IllegalStateException {
         if (isOpen) {
             throw new IllegalStateException("Connection is open");
         }
     }
 
     /***
      * Throws an {@link IllegalStateException} if the connection is not open.
      *
      * @throws IllegalStateException if not connected
      */
     protected void assertOpen() throws IllegalStateException {
         if (!isOpen) {
             throw new IllegalStateException("Connection is not open");
         }
     }
 
     /***
      * Gets the socket's sendBufferSize.
      * 
      * @return the size of the buffer for the socket OutputStream, -1 if the value
      * has not been set and the socket has not been opened
      * 
      * @throws SocketException if an error occurs while getting the socket value
      * 
      * @see Socket#getSendBufferSize()
      */
     public int getSendBufferSize() throws SocketException {
         if (socket == null) {
             return -1;
         } else {
             return socket.getSendBufferSize();
         }
     }
 
     /***
      * Sets the socket's sendBufferSize.
      * 
      * @param sendBufferSize the size to set for the socket OutputStream
      * 
      * @throws SocketException if an error occurs while setting the socket value
      * 
      * @see Socket#setSendBufferSize(int)
      * 
      * @deprecated Use {@link HttpConnectionParams#setSendBufferSize(int)},
      * {@link HttpConnection#getParams()}.
      */
     public void setSendBufferSize(int sendBufferSize) throws SocketException {
         this.params.setSendBufferSize(sendBufferSize);
     }
 
     // ------------------------------------------------------- Static Variable
 
     /*** <tt>"\r\n"</tt>, as bytes. */
     private static final byte[] CRLF = new byte[] {(byte) 13, (byte) 10};
 
     /*** Log object for this class. */
     private static final Log LOG = LogFactory.getLog(HttpConnection.class);
     
     // ----------------------------------------------------- Instance Variables
     
     /*** My host. */
     private String hostName = null;
     
     /*** My port. */
     private int portNumber = -1;
     
     /*** My proxy host. */
     private String proxyHostName = null;
     
     /*** My proxy port. */
     private int proxyPortNumber = -1;
     
     /*** My client Socket. */
     private Socket socket = null;
     
     /*** My InputStream. */
     private InputStream inputStream = null;
 
     /*** My OutputStream. */
     private OutputStream outputStream = null;
     
     /*** An {@link InputStream} for the response to an individual request. */
     private InputStream lastResponseInputStream = null;
     
     /*** Whether or not the connection is connected. */
     protected boolean isOpen = false;
     
     /*** the protocol being used */
     private Protocol protocolInUse;
     
     /*** Collection of HTTP parameters associated with this HTTP connection*/
     private HttpConnectionParams params = new HttpConnectionParams();
     
     /*** flag to indicate if this connection can be released, if locked the connection cannot be 
      * released */
     private boolean locked = false;
     
     /*** Whether or not the socket is a secure one. */
     private boolean usingSecureSocket = false;
     
     /*** Whether the connection is open via a secure tunnel or not */
     private boolean tunnelEstablished = false;
     
     /*** the connection manager that created this connection or null */
     private HttpConnectionManager httpConnectionManager;
     
     /*** The local interface on which the connection is created, or null for the default */
     private InetAddress localAddress;
 }