/**

  * Copyright (c) 2014-2015, jcabi.com

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions

  * are met: 1) Redistributions of source code must retain the above

  * copyright notice, this list of conditions and the following

  * disclaimer. 2) Redistributions in binary form must reproduce the above

  * copyright notice, this list of conditions and the following

  * disclaimer in the documentation and/or other materials provided

  * with the distribution. 3) Neither the name of the jcabi.com nor

  * the names of its contributors may be used to endorse or promote

  * products derived from this software without specific prior written

  * permission.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT

  * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

  * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL

  * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,

  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

  * OF THE POSSIBILITY OF SUCH DAMAGE.

  */

 package com.jcabi.ssh;

 import com.jcraft.jsch.Session;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.OutputStream;

 import java.net.InetAddress;

 import java.net.UnknownHostException;

 import lombok.EqualsAndHashCode;

 import lombok.Getter;

 import lombok.ToString;

 import org.apache.commons.lang3.Validate;

 /**

  * Common module for any ssh shell.

  * @author Jose Volmei Dal Pra Junior (jrdalpra@gmail.com)

  * @version $Id: 49c889e2fc6a75ec150efa6ce1cc75fdbb79569f $

  * @since 1.5.2

  */

 @ToString

 @EqualsAndHashCode(of = { "addr", "port", "login" })

 @Getter

 @SuppressWarnings({ "PMD.UnusedPrivateField", "PMD.SingularField" })

 abstract class AbstractSSHShell implements Shell {

     /**

      * IP address of the server.

      */

     private final transient String addr;

     /**

      * Port to use.

      */

     private final transient int port;

     /**

      * User name.

      */

     private final transient String login;

     /**

      * Constructor.

      * @param adr Address that you want to connect to.

      * @param prt Port that you want to reach.

      * @param user User that will be used when connecting.

      * @throws UnknownHostException when host is unkwon.

      */

     AbstractSSHShell(

         final String adr,

         final int prt,

         final String user) throws UnknownHostException {

         this.addr = InetAddress.getByName(adr).getHostAddress();

         this.port = prt;

         this.login = user;

         Validate.matchesPattern(

             this.addr,

             "\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}",

             "Invalid IP address of the server `%s`",

             this.addr

         );

         Validate.notEmpty(user, "user name can't be empty");

     }

     // @checkstyle ParameterNumberCheck (2 lines)

     @Override

     public int exec(final String command, final InputStream stdin,

                     final OutputStream stdout, final OutputStream stderr)

         throws IOException {

         return new Execution.Default(

             command,

             stdin,

             stdout,

             stderr,

             this.session()

         ).exec();

     }

     /**

      * Create and return a session, connected.

      * @return JSch session

      * @throws IOException If some IO problem inside

      */

     protected abstract Session session()  throws IOException;

 }