Refactoring classes to solve the issue

#27

src/main/java/com/jcabi/ssh/AbstractSSHShell.java

@@ -0,0 +1,114 @@
+/**
+ * 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 ([email protected])
+ * @version $Id$
+ * @since 2.0
+ */
+@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.
+     */
+    public 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 (6 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;
+
+}

src/main/java/com/jcabi/ssh/SSH.java

@@ -37,8 +37,6 @@
 import com.jcraft.jsch.Session;
 import java.io.File;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
 import java.net.InetAddress;
 import java.net.URL;
 import java.net.UnknownHostException;
@@ -48,7 +46,6 @@
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.CharEncoding;
-import org.apache.commons.lang3.Validate;
 
 /**
  * Single SSH Channel.
@@ -67,39 +64,21 @@
  * <p>It is highly recommended to use classes from {@link Shell} interface,
  * they will simplify operations.</p>
  *
- * @todo #21:30min This class has common data, implementation of exec() and
- *  constructor validations with SSHByPassword class. Common functionality
- *  should be extracted into a separate module.
  * @author Yegor Bugayenko ([email protected])
  * @version $Id$
  * @since 1.0
  * @see <a href="http://www.yegor256.com/2014/09/02/java-ssh-client.html">article by Yegor Bugayenko</a>
  */
 @ToString
-@EqualsAndHashCode(of = { "addr", "port", "login", "key" })
+@EqualsAndHashCode(of = { "key" }, callSuper = true)
 @SuppressWarnings("PMD.TooManyMethods")
-public final class SSH implements Shell {
+public final class SSH extends AbstractSSHShell implements Shell {
 
     /**
      * Default SSH port.
      */
     public static final int PORT = 22;
 
-    /**
-     * 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;
-
     /**
      * Private SSH key.
      */
@@ -198,27 +177,8 @@ public SSH(final InetAddress adr, final int prt,
      */
     public SSH(final String adr, final int prt,
         final String user, final String priv) throws UnknownHostException {
-        this.addr = InetAddress.getByName(adr).getHostAddress();
-        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
-        );
-        this.login = user;
-        Validate.notEmpty(this.login, "user name can't be empty");
+        super(adr, prt, user);
         this.key = priv;
-        this.port = prt;
-    }
-
-    // @checkstyle ParameterNumberCheck (5 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();
     }
 
     /**
@@ -230,11 +190,7 @@ public static String escape(final String arg) {
         return String.format("'%s'", arg.replace("'", "'\\''"));
     }
 
-    /**
-     * Create and return a session, connected.
-     * @return JSch session
-     * @throws IOException If some IO problem inside
-     */
+    @Override
     @RetryOnFailure(
         attempts = Tv.SEVEN,
         delay = 1,
@@ -243,7 +199,7 @@ public static String escape(final String arg) {
         randomize = true,
         types = IOException.class
     )
-    private Session session() throws IOException {
+    public Session session() throws IOException {
         try {
             JSch.setConfig("StrictHostKeyChecking", "no");
             JSch.setLogger(new JschLogger());
@@ -262,14 +218,14 @@ private Session session() throws IOException {
             Logger.debug(
                 this,
                 "Opening SSH session to %s@%s:%s (%d bytes in RSA key)...",
-                this.login, this.addr, this.port,
+                this.getLogin(), this.getAddr(), this.getPort(),
                 file.length()
             );
             final Session session = jsch.getSession(
-                this.login, this.addr, this.port
+                this.getLogin(), this.getAddr(), this.getPort()
             );
             session.setServerAliveInterval(
-                (int) TimeUnit.SECONDS.toMillis((long) Tv.TEN)
+                (int) TimeUnit.SECONDS.toMillis(Tv.TEN)
             );
             session.setServerAliveCountMax(Tv.MILLION);
             session.connect();

src/main/java/com/jcabi/ssh/SSHByPassword.java

@@ -36,14 +36,10 @@
 import com.jcraft.jsch.JSchException;
 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 java.util.concurrent.TimeUnit;
 import lombok.EqualsAndHashCode;
 import lombok.ToString;
-import org.apache.commons.lang3.Validate;
 
 /**
  * SSH channel with authentication by password.
@@ -53,23 +49,8 @@
  * @see SSH For SSH channel with authenticaton using private key.
  */
 @ToString
-@EqualsAndHashCode(of = { "addr", "port", "login", "password" })
-public final class SSHByPassword 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;
+@EqualsAndHashCode(of = { "password" }, callSuper = true)
+public final class SSHByPassword extends AbstractSSHShell implements Shell {
 
     /**
      * User password.
@@ -86,36 +67,13 @@ public final class SSHByPassword implements Shell {
      * @checkstyle ParameterNumberCheck (6 lines)
      */
     public SSHByPassword(final String adr, final int prt,
-        final String user, final String passwd)
+                    final String user, final String passwd)
         throws UnknownHostException {
-        this.addr = InetAddress.getByName(adr).getHostAddress();
-        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
-        );
-        this.port = prt;
-        this.login = user;
-        Validate.notEmpty(this.login, "user name can't be empty");
+        super(adr, prt, user);
         this.password = passwd;
     }
 
-    // @checkstyle ParameterNumberCheck (6 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
-     */
     @RetryOnFailure(
         attempts = Tv.SEVEN,
         delay = 1,
@@ -124,22 +82,22 @@ public int exec(final String command, final InputStream stdin,
         randomize = true,
         types = IOException.class
     )
-    private Session session() throws IOException {
+    public Session session() throws IOException {
         try {
             JSch.setConfig("StrictHostKeyChecking", "no");
             JSch.setLogger(new JschLogger());
             final JSch jsch = new JSch();
             Logger.debug(
                 this,
                 "Opening SSH session to %s@%s:%s (auth with password)...",
-                this.login, this.addr, this.port
+                this.getLogin(), this.getAddr(), this.getPort()
             );
             final Session session = jsch.getSession(
-                this.login, this.addr, this.port
+                this.getLogin(), this.getAddr(), this.getPort()
             );
             session.setPassword(this.password);
             session.setServerAliveInterval(
-                (int) TimeUnit.SECONDS.toMillis((long) Tv.TEN)
+                (int) TimeUnit.SECONDS.toMillis(Tv.TEN)
             );
             session.setServerAliveCountMax(Tv.MILLION);
             session.connect();