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    * 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   *
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   *   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.                                           *
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  package org.apache.james.transport.mailets;
  
  import org.apache.mailet.base.GenericMailet;
  import org.apache.mailet.Mail;
  import org.apache.mailet.MailetException;
  
  import javax.mail.MessagingException;
  import javax.mail.internet.MimeBodyPart;
  import javax.mail.internet.MimeMessage;
  import javax.mail.internet.MimeMultipart;
  
  import java.io.BufferedInputStream;
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Iterator;
  import java.util.Map;
  
  /**
   * <p>
   * This mailet takes an attachment stored in an attribute and attach it back to
   * the message
   * </p>
   * <p>
   * This may be used to place back attachment stripped by StripAttachment and
   * stored in the attribute
   * <code>org.apache.james.transport.mailets.StripAttachment.saved</code>
   * </p>
   * <p>
   * 
   * <pre>
   *   &lt;mailet match=&quot;All&quot; class=&quot;RecoverAttachment&quot; &gt;
   *     &lt;attribute&gt;my.attribute.name&lt;/attribute&gt;
   *   &lt;/mailet &gt;
   * </pre>
   * 
   * </p>
   */
  public class RecoverAttachment extends GenericMailet {
  
      public static final String ATTRIBUTE_PARAMETER_NAME = "attribute";
  
      private String attributeName = null;
  
      /**
       * Checks if the mandatory parameters are present
       * 
       * @throws MailetException
       */
      public void init() throws MailetException {
          attributeName = getInitParameter(ATTRIBUTE_PARAMETER_NAME);
  
          if (attributeName == null) {
              throw new MailetException(ATTRIBUTE_PARAMETER_NAME
                      + " is a mandatory parameter");
          }
  
          log("RecoverAttachment is initialised with attribute [" + attributeName
                  + "]");
      }
  
      /**
       * Service the mail: check for the attribute and attach the attachment to
       * the mail.
       * 
       * @param mail
       *            The mail to service
       * @throws MailetException
       *             Thrown when an error situation is encountered.
       */
      public void service(Mail mail) throws MailetException {
          Map attachments = (Map) mail.getAttribute(attributeName);
          if (attachments != null) {
  
              MimeMessage message = null;
              try {
                  message = mail.getMessage();
              } catch (MessagingException e) {
                  throw new MailetException(
                          "Could not retrieve message from Mail object", e);
             }
 
             Iterator i = attachments.values().iterator();
             try {
                 while (i.hasNext()) {
                     byte[] bytes = (byte[]) i.next();
                     InputStream is = new BufferedInputStream(
                             new ByteArrayInputStream(bytes));
                     MimeBodyPart p = new MimeBodyPart(is);
                     if (!(message.isMimeType("multipart/*") && (message
                             .getContent() instanceof MimeMultipart))) {
                         Object content = message.getContent();
                         String contentType = message.getContentType();
                         MimeMultipart mimeMultipart = new MimeMultipart();
                         message.setContent(mimeMultipart);
                         // This saveChanges is required when the MimeMessage has
                         // been created from
                         // an InputStream, otherwise it is not saved correctly.
                         message.saveChanges();
                         mimeMultipart.setParent(message);
                         MimeBodyPart bodyPart = new MimeBodyPart();
                         mimeMultipart.addBodyPart(bodyPart);
                         bodyPart.setContent(content, contentType);
                     }
                     ((MimeMultipart) message.getContent()).addBodyPart(p);
                 }
                 message.saveChanges();
             } catch (MessagingException e) {
                 log("MessagingException in recoverAttachment", e);
             } catch (IOException e) {
                 log("IOException in recoverAttachment", e);
             }
         }
     }
 
     /**
      * returns a String describing this mailet.
      * 
      * @return A desciption of this mailet
      */
     public String getMailetInfo() {
         return "RecoverAttachment Mailet";
     }
 
 }