/*

  * 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.core.command;

 import org.mockftpserver.core.CommandSyntaxException;

 import org.mockftpserver.core.session.Session;

 import org.mockftpserver.core.util.Assert;

 import org.mockftpserver.core.util.AssertFailedException;

 import java.text.MessageFormat;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.MissingResourceException;

 /**

  * The abstract superclass for CommandHandler classes that manage the List of InvocationRecord

  * objects corresponding to each invocation of the command handler, and provide helper methods for subclasses.

  *

  * @author Chris Mair

  * @version $Revision: 192 $ - $Date: 2008-12-06 21:52:07 -0500 (Sat, 06 Dec 2008) $

  */

 public abstract class AbstractTrackingCommandHandler extends AbstractCommandHandler implements InvocationHistory {

     private List invocations = new ArrayList();

     // -------------------------------------------------------------------------

     // Template Method

     // -------------------------------------------------------------------------

     /**

      * Handle the specified command for the session. This method is declared to throw Exception,

      * allowing CommandHandler implementations to avoid unnecessary exception-handling. All checked

      * exceptions are expected to be wrapped and handled by the caller.

      *

      * @param command - the Command to be handled

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

      * @throws Exception

      * @throws AssertFailedException - if the command or session is null

      * @see org.mockftpserver.core.command.CommandHandler#handleCommand(org.mockftpserver.core.command.Command,

      *      org.mockftpserver.core.session.Session)

      */

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

         Assert.notNull(command, "command");

         Assert.notNull(session, "session");

         InvocationRecord invocationRecord = new InvocationRecord(command, session.getClientHost());

         invocations.add(invocationRecord);

         try {

             handleCommand(command, session, invocationRecord);

         }

         catch (CommandSyntaxException e) {

             sendReply(session, ReplyCodes.COMMAND_SYNTAX_ERROR, null, null, null);

         }

         invocationRecord.lock();

     }

     /**

      * Handle the specified command for the session. This method is declared to throw Exception,

      * allowing CommandHandler implementations to avoid unnecessary exception-handling. All checked

      * exceptions are expected to be wrapped and handled by the caller.

      *

      * @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 handleCommand(Command command, Session session, InvocationRecord invocationRecord)

             throws Exception;

     // -------------------------------------------------------------------------

     // Utility methods for subclasses

     // -------------------------------------------------------------------------

     /**

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

      * <p/>

      * The reply code is designated by the <code>replyCode</code> property, and the reply text

      * is determined by the following rules:

      * <ol>

      * <li>If the <code>replyText</code> property is non-null, then use that.</li>

      * <li>Otherwise, if <code>replyMessageKey</code> is non-null, the use that to retrieve a

      * localized message from the <code>replyText</code> ResourceBundle.</li>

      * <li>Otherwise, retrieve the reply text from the <code>replyText</code> ResourceBundle,

      * using the reply code as the key.</li>

      * </ol>

      * If the arguments Object[] is not null, then these arguments are substituted within the

      * reply text using the {@link MessageFormat} class.

      *

      * @param session         - the Session

      * @param replyCode       - the reply code

      * @param replyMessageKey - if not null (and replyText is null), this is used as the ResourceBundle

      *                        message key instead of the reply code.

      * @param replyText       - if non-null, this is used as the reply text

      * @param arguments       - the array of arguments to be formatted and substituted within the reply

      *                        text; may be null

      * @throws AssertFailedException - if session is null

      * @see MessageFormat

      */

     protected void sendReply(Session session, int replyCode, String replyMessageKey, String replyText,

                              Object[] arguments) {

         Assert.notNull(session, "session");

         assertValidReplyCode(replyCode);

         String key = (replyMessageKey != null) ? replyMessageKey : Integer.toString(replyCode);

         String text = getTextForReplyCode(replyCode, key, replyText, arguments);

         String replyTextToLog = (text == null) ? "" : " " + text;

         LOG.info("Sending reply [" + replyCode + replyTextToLog + "]");

         session.sendReply(replyCode, text);

     }

     // -------------------------------------------------------------------------

     // InvocationHistory - Support for command history

     // -------------------------------------------------------------------------

     /**

      * @return the number of invocation records stored for this command handler instance

      * @see org.mockftpserver.core.command.InvocationHistory#numberOfInvocations()

      */

     public int numberOfInvocations() {

         return invocations.size();

     }

     /**

      * Return the InvocationRecord representing the command invoction data for the nth invocation

      * for this command handler instance. One InvocationRecord should be stored for each invocation

      * of the CommandHandler.

      *

      * @param index - the index of the invocation record to return. The first record is at index zero.

      * @return the InvocationRecord for the specified index

      * @throws AssertFailedException - if there is no invocation record corresponding to the specified index

      * @see org.mockftpserver.core.command.InvocationHistory#getInvocation(int)

      */

     public InvocationRecord getInvocation(int index) {

         return (InvocationRecord) invocations.get(index);

     }

     /**

      * Clear out the invocation history for this CommandHandler. After invoking this method, the

      * <code>numberOfInvocations()</code> method will return zero.

      *

      * @see org.mockftpserver.core.command.InvocationHistory#clearInvocations()

      */

     public void clearInvocations() {

         invocations.clear();

     }

     // -------------------------------------------------------------------------

     // Internal Helper Methods

     // -------------------------------------------------------------------------

     /**

      * Return the text for the specified reply code, formatted using the message arguments, if

      * supplied. If overrideText is not null, then return that. Otherwise, return the text mapped to

      * the code from the replyText ResourceBundle. If the ResourceBundle contains no mapping, then

      * return null.

      * <p/>

      * If arguments is not null, then the returned reply text if formatted using the

      * {@link MessageFormat} class.

      *

      * @param code         - the reply code

      * @param messageKey   - the key used to retrieve the reply text from the replyTextBundle

      * @param overrideText - if not null, this is used instead of the text from the replyTextBundle.

      * @param arguments    - the array of arguments to be formatted and substituted within the reply

      *                     text; may be null

      * @return the text for the reply code; may be null

      */

     private String getTextForReplyCode(int code, String messageKey, String overrideText, Object[] arguments) {

         try {

             String t = (overrideText == null) ? getReplyTextBundle().getString(messageKey) : overrideText;

             String formattedMessage = MessageFormat.format(t, arguments);

             return (formattedMessage == null) ? null : formattedMessage.trim();

         }

         catch (MissingResourceException e) {

             // No reply text is mapped for the specified key

             LOG.warn("No reply text defined for reply code [" + code + "]");

             return null;

         }

     }

 }