/*

  * Copyright 2007 the original author or authors.

  * 

  * Licensed 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.

  */

 package org.mockftpserver.stub.command;

 import org.mockftpserver.core.command.AbstractTrackingCommandHandler;

 import org.mockftpserver.core.command.Command;

 import org.mockftpserver.core.command.CommandHandler;

 import org.mockftpserver.core.command.InvocationRecord;

 import org.mockftpserver.core.command.ReplyCodes;

 import org.mockftpserver.core.session.Session;

 import org.mockftpserver.core.util.AssertFailedException;

 /**

  * Abstract superclass for CommandHandlers that read from or write to the data connection.

  * <p/>

  * Return two replies on the control connection: by default a reply code of 150 before the

  * data transfer across the data connection and another reply of 226 after the data transfer

  * is complete.

  * <p/>

  * This class implements the <i>Template Method</i> pattern. Subclasses must implement the abstract

  * <code>processData</code> method to perform read or writes across the data connection.

  * <p/>

  * Subclasses can optionally override the {@link #beforeProcessData(Command, Session, InvocationRecord)}

  * method for logic before the data transfer or the {@link #afterProcessData(Command, Session, InvocationRecord)}

  * method for logic after the data transfer.

  * <p/>

  * Subclasses can optionally override the reply code and/or text for the initial reply (before

  * the data transfer across the data connection) by calling {@link #setPreliminaryReplyCode(int)},

  * {@link #setPreliminaryReplyMessageKey(String)} and/or {@link #setPreliminaryReplyText(String)}

  * methods.

  * <p/>

  * Subclasses can optionally override the reply code and/or text for the final reply (after the

  * the data transfer is complete) by calling {@link #setFinalReplyCode(int)},

  * {@link #setFinalReplyMessageKey(String)} and/or {@link #setFinalReplyText(String)} methods.

  *

  * @author Chris Mair

  * @version $Revision: 193 $ - $Date: 2008-12-07 08:07:10 -0500 (Sun, 07 Dec 2008) $

  */

 public abstract class AbstractStubDataCommandHandler extends AbstractTrackingCommandHandler implements CommandHandler {

     // The completion reply code sent before the data transfer

     protected int preliminaryReplyCode = 0;

     // The text for the preliminary reply. If null, use the default message associated with the reply code.

     // If not null, this value overrides the preliminaryReplyMessageKey - i.e., this text is used instead of

     // a localized message. 

     protected String preliminaryReplyText = null;

     // The message key for the preliminary reply text. If null, use the default message associated with 

     // the reply code.

     protected String preliminaryReplyMessageKey = null;

     // The completion reply code sent after data transfer

     protected int finalReplyCode = 0;

     // The text for the completion reply. If null, use the default message associated with the reply code.

     // If not null, this value overrides the finalReplyMessageKey - i.e., this text is used instead of

     // a localized message. 

     protected String finalReplyText = null;

     // The message key for the completion reply text. If null, use the default message associated with the reply code 

     protected String finalReplyMessageKey = null;

     /**

      * Constructor. Initialize the preliminary and final reply code.

      */

     protected AbstractStubDataCommandHandler() {

         setPreliminaryReplyCode(ReplyCodes.TRANSFER_DATA_INITIAL_OK);

         setFinalReplyCode(ReplyCodes.TRANSFER_DATA_FINAL_OK);

     }

     /**

      * Handle the command. Perform the following steps:

      * <ol>

      * <li>Invoke the <code>beforeProcessData()</code> method</li>

      * <li>Open the data connection</li>

      * <li>Send an preliminary reply, default reply code 150</li>

      * <li>Invoke the <code>processData()</code> method</li>

      * <li>Close the data connection</li>

      * <li>Send the final reply, default reply code 226</li>

      * <li>Invoke the <code>afterProcessData()</code> method</li>

      * </ol>

      *

      * @see org.mockftpserver.core.command.AbstractTrackingCommandHandler#handleCommand(org.mockftpserver.core.command.Command, org.mockftpserver.core.session.Session, org.mockftpserver.core.command.InvocationRecord)

      */

     public final void handleCommand(Command command, Session session, InvocationRecord invocationRecord) throws Exception {

         beforeProcessData(command, session, invocationRecord);

         sendPreliminaryReply(session);

         session.openDataConnection();

         processData(command, session, invocationRecord);

         session.closeDataConnection();

         sendFinalReply(session);

         afterProcessData(command, session, invocationRecord);

     }

     /**

      * Send the final reply. The default implementation sends a reply code of 226 with the

      * corresponding associated reply text.

      *

      * @param session - the Session

      */

     protected void sendFinalReply(Session session) {

         sendReply(session, finalReplyCode, finalReplyMessageKey, finalReplyText, null);

     }

     /**

      * Perform any necessary logic before transferring data across the data connection.

      * Do nothing by default. Subclasses should override to validate command parameters and

      * store information in the InvocationRecord.

      *

      * @param command          - the Command to be handled

      * @param session          - the session on which the Command was submitted

      * @param invocationRecord - the InvocationRecord; CommandHandlers are expected to add

      *                         handler-specific data to the InvocationRecord, as appropriate

      * @throws Exception

      */

     protected void beforeProcessData(Command command, Session session, InvocationRecord invocationRecord) throws Exception {

         // Do nothing by default

     }

     /**

      * Abstract method placeholder for subclass transfer of data across the data connection.

      * Subclasses must override. The data connection is opened before this method and is

      * closed after this method completes.

      *

      * @param command          - the Command to be handled

      * @param session          - the session on which the Command was submitted

      * @param invocationRecord - the InvocationRecord; CommandHandlers are expected to add

      *                         handler-specific data to the InvocationRecord, as appropriate

      * @throws Exception

      */

     protected abstract void processData(Command command, Session session, InvocationRecord invocationRecord) throws Exception;

     /**

      * Perform any necessary logic after transferring data across the data connection.

      * Do nothing by default.

      *

      * @param command          - the Command to be handled

      * @param session          - the session on which the Command was submitted

      * @param invocationRecord - the InvocationRecord; CommandHandlers are expected to add

      *                         handler-specific data to the InvocationRecord, as appropriate

      * @throws Exception

      */

     protected void afterProcessData(Command command, Session session, InvocationRecord invocationRecord) throws Exception {

         // Do nothing by default

     }

     /**

      * Send the preliminary reply for this command on the control connection.

      *

      * @param session - the Session

      */

     private void sendPreliminaryReply(Session session) {

         sendReply(session, preliminaryReplyCode, preliminaryReplyMessageKey, preliminaryReplyText, null);

     }

     /**

      * Set the completion reply code sent after data transfer

      *

      * @param finalReplyCode - the final reply code

      * @throws AssertFailedException - if the finalReplyCode is invalid

      */

     public void setFinalReplyCode(int finalReplyCode) {

         assertValidReplyCode(finalReplyCode);

         this.finalReplyCode = finalReplyCode;

     }

     /**

      * Set the message key for the completion reply text sent after data transfer

      *

      * @param finalReplyMessageKey - the final reply message key

      */

     public void setFinalReplyMessageKey(String finalReplyMessageKey) {

         this.finalReplyMessageKey = finalReplyMessageKey;

     }

     /**

      * Set the text of the completion reply sent after data transfer

      *

      * @param finalReplyText - the final reply text

      */

     public void setFinalReplyText(String finalReplyText) {

         this.finalReplyText = finalReplyText;

     }

     /**

      * Set the completion reply code sent before data transfer

      *

      * @param preliminaryReplyCode - the preliminary reply code to set

      * @throws AssertFailedException - if the preliminaryReplyCode is invalid

      */

     public void setPreliminaryReplyCode(int preliminaryReplyCode) {

         assertValidReplyCode(preliminaryReplyCode);

         this.preliminaryReplyCode = preliminaryReplyCode;

     }

     /**

      * Set the message key for the completion reply text sent before data transfer

      *

      * @param preliminaryReplyMessageKey - the preliminary reply message key

      */

     public void setPreliminaryReplyMessageKey(String preliminaryReplyMessageKey) {

         this.preliminaryReplyMessageKey = preliminaryReplyMessageKey;

     }

     /**

      * Set the text of the completion reply sent before data transfer

      *

      * @param preliminaryReplyText - the preliminary reply text

      */

     public void setPreliminaryReplyText(String preliminaryReplyText) {

         this.preliminaryReplyText = preliminaryReplyText;

     }

 }