/****************************************************************
 * 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                 *
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 * 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.apache.james.smtpserver;

import org.apache.james.util.mail.dsn.DSNStatus;

/**
  * Default command handler for handling unknown commands
  */
public class UnknownCmdHandler implements CommandHandler {

    /**
     * The name of the command handled by the command handler
     */
    public static final String UNKNOWN_COMMAND = "UNKNOWN";

    /**
     * Handler method called upon receipt of an unrecognized command.
     * Returns an error response and logs the command.
     *
     * @see org.apache.james.smtpserver.CommandHandler#onCommand(SMTPSession)
    **/
    public void onCommand(SMTPSession session) {

        //If there was message failure, don't consider it as an unknown command
        if (session.getState().get(SMTPSession.MESG_FAILED) != null) {
            return;
        }

        session.getResponseBuffer().append("500 "+DSNStatus.getStatus(DSNStatus.PERMANENT, DSNStatus.DELIVERY_INVALID_CMD))
                      .append(" Command ")
                      .append(session.getCommandName())
                      .append(" unrecognized.");
        String responseString = session.clearResponseBuffer();

        session.writeResponse(responseString);
    }

}