/*
 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/conn/scheme/SocketFactory.java $
 * $Revision: 645850 $
 * $Date: 2008-04-08 04:08:52 -0700 (Tue, 08 Apr 2008) $
 *
 * ====================================================================
 * 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.http.conn.scheme;

import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

import org.apache.http.conn.ConnectTimeoutException;
import org.apache.http.params.HttpParams;

/**
 * A factory for creating and connecting sockets.
 * The factory encapsulates the logic for establishing a socket connection.
 * <br/>
 * Both {@link java.lang.Object#equals(java.lang.Object) Object.equals()}
 * and {@link java.lang.Object#hashCode() Object.hashCode()}
 * must be overridden for the correct operation of some connection managers.
 * 
 * @author <a href="mailto:rolandw at apache.org">Roland Weber</a>
 * @author Michael Becke
 * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
 */
public interface SocketFactory {

    /**
     * Creates a new, unconnected socket.
     * The socket should subsequently be passed to
     * {@link #connectSocket connectSocket}.
     *
     * @return  a new socket
     * 
     * @throws IOException if an I/O error occurs while creating the socket
     */
    Socket createSocket()
        throws IOException
        ;


    /**
     * Connects a socket to the given host.
     * 
     * @param sock      the socket to connect, as obtained from
     *                  {@link #createSocket createSocket}.
     *                  <code>null</code> indicates that a new socket
     *                  should be created and connected.
     * @param host      the host to connect to
     * @param port      the port to connect to on the host
     * @param localAddress the local address to bind the socket to, or
     *                  <code>null</code> for any
     * @param localPort the port on the local machine,
     *                  0 or a negative number for any
     * @param params    additional {@link HttpParams parameters} for connecting
     * 
     * @return  the connected socket. The returned object may be different
     *          from the <code>sock</code> argument if this factory supports
     *          a layered protocol.
     * 
     * @throws IOException if an I/O error occurs
     * @throws UnknownHostException if the IP address of the target host
     *          can not be determined
     * @throws ConnectTimeoutException if the socket cannot be connected
     *          within the time limit defined in the <code>params</code>
     */
    Socket connectSocket(
        Socket sock,
        String host, 
        int port, 
        InetAddress localAddress, 
        int localPort,
        HttpParams params
    ) throws IOException, UnknownHostException, ConnectTimeoutException;


    /**
     * Checks whether a socket provides a secure connection.
     * The socket must be {@link #connectSocket connected}
     * by this factory.
     * The factory will <i>not</i> perform I/O operations
     * in this method.
     * <br/>
     * As a rule of thumb, plain sockets are not secure and
     * TLS/SSL sockets are secure. However, there may be
     * application specific deviations. For example, a plain
     * socket to a host in the same intranet ("trusted zone")
     * could be considered secure. On the other hand, a
     * TLS/SSL socket could be considered insecure based on
     * the cypher suite chosen for the connection.
     *
     * @param sock      the connected socket to check
     *
     * @return  <code>true</code> if the connection of the socket
     *          should be considered secure, or
     *          <code>false</code> if it should not
     *
     * @throws IllegalArgumentException
     *  if the argument is invalid, for example because it is
     *  not a connected socket or was created by a different
     *  socket factory.
     *  Note that socket factories are <i>not</i> required to
     *  check these conditions, they may simply return a default
     *  value when called with an invalid socket argument.
     */
    boolean isSecure(Socket sock)
        throws IllegalArgumentException
        ;

}