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    * 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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   * 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.mailet.crypto.mailet;
  
  import org.apache.mailet.Mail;
  
  import javax.mail.MessagingException;
  import javax.mail.internet.MimeBodyPart;
  import javax.mail.internet.MimeMessage;
  import javax.mail.internet.MimeMultipart;
  
  import java.io.IOException;
  
  /**
   * <p>Puts a <I>server-side</I> signature on a message.
   * It is a concrete subclass of {@link AbstractSign}, with very few modifications to it.</p>
   * <p>A text file with an explanation text is attached to the original message,
   * and the resulting message with all its attachments is signed.
   * The resulting appearence of the message is almost unchanged: only an extra attachment
   * and the signature are added.</p>
   *<p>The kind of signuture depends on the value of the &lt;keyHolderClass&gt; init parameter.
   *
   *  <P>Handles the following init parameters (will comment only the differences from {@link AbstractSign}):</P>
   * <ul>
   * <li>&lt;keyHolderClass&gt;: Sets the class of the KeyHolder object that will handle the cryptography functions,
   * for example org.apache.james.security.SMIMEKeyHolder for SMIME.</li>
   * <li>&lt;debug&gt;.</li>
   * <li>&lt;keyStoreFileName&gt;.</li>
   * <li>&lt;keyStorePassword&gt;.</li>
   * <li>&lt;keyAlias&gt;.</li>
   * <li>&lt;keyAliasPassword&gt;.</li>
   * <li>&lt;keyStoreType&gt;.</li>
   * <li>&lt;postmasterSigns&gt;. The default is <CODE>true</CODE>.</li>
   * <li>&lt;rebuildFrom&gt;. The default is <CODE>true</CODE>.</li>
   * <li>&lt;signerName&gt;.</li>
   * <li>&lt;explanationText&gt;. There is a default explanation string template in English,
   * displaying also all the headers of the original message (see {@link #getExplanationText}).</li>
   * </ul>
   * @version CVS $Revision: 744745 $ $Date: 2009-02-15 20:30:17 +0000 (Sun, 15 Feb 2009) $
   * @since 2.2.1
   */
  public class Sign extends AbstractSign {
      
      /**
       * Return a string describing this mailet.
       *
       * @return a string describing this mailet
       */
      public String getMailetInfo() {
          return "Signature Mailet";
      }
      
      /**
       *
       */
      protected  String[] getAllowedInitParameters() {
          String[] allowedArray = {
              "keyHolderClass",
              "debug",
              "keyStoreFileName",
              "keyStorePassword",
              "keyStoreType",
              "keyAlias",
              "keyAliasPassword",
              "signerName",
              "postmasterSigns",
              "rebuildFrom",
              "explanationText"
          };
          return allowedArray;
      }
      
       /* ******************************************************************** */
      /* ****************** Begin of setters and getters ******************** */
      /* ******************************************************************** */    
      
      /**
       * Gets text offering an explanation.
       * If the <CODE>&lt;explanationText&gt;</CODE> init parameter is missing
       * returns the following default explanation template string:
      * <pre><code>
      * The message this file is attached to has been signed on the server by
      *     "[signerName]" <[signerAddress]>
      * to certify that the sender is known and truly has the following address (reverse-path):
      *     [reversePath]
      * and that the original message has the following message headers:
      *
      * [headers]
      *
      * The signature envelopes this attachment too.
      * Please check the signature integrity.
      *
      *     "[signerName]" <[signerAddress]>
      * </code></pre>
      */
     public String getExplanationText() {
         String explanationText = super.getExplanationText();
         if (explanationText == null) {
             explanationText = "The message this file is attached to has been signed on the server by\r\n"
             + "\t\"[signerName]\" <[signerAddress]>"
             + "\r\nto certify that the sender is known and truly has the following address (reverse-path):\r\n"
             + "\t[reversePath]"
             + "\r\nand that the original message has the following message headers:\r\n"
             + "\r\n[headers]"
             + "\r\n\r\nThe signature envelopes this attachment too."
             + "\r\nPlease check the signature integrity."
             + "\r\n\r\n"
             + "\t\"[signerName]\" <[signerAddress]>";
         }
         
         return explanationText;
     }
     
     /**
      * If the <CODE>&lt;postmasterSigns&gt;</CODE> init parameter is missing sets it to <I>true</I>.
      */
     protected void initPostmasterSigns() {
         setPostmasterSigns((getInitParameter("postmasterSigns") == null) ? true : new Boolean(getInitParameter("postmasterSigns")).booleanValue());
     }
     
     /**
      * If the <CODE>&lt;rebuildFrom&gt;</CODE> init parameter is missing sets it to <I>true</I>.
      */
     protected void initRebuildFrom() throws MessagingException {
         setRebuildFrom((getInitParameter("rebuildFrom") == null) ? true : new Boolean(getInitParameter("rebuildFrom")).booleanValue());
         if (isDebug()) {
             if (isRebuildFrom()) {
                 log("Will modify the \"From:\" header.");
             } else {
                 log("Will leave the \"From:\" header unchanged.");
             }
         }
     }
     
     /* ******************************************************************** */
     /* ****************** End of setters and getters ********************** */
     /* ******************************************************************** */
     
     /**
      * A text file with the massaged contents of {@link #getExplanationText}
      * is attached to the original message.
      */    
     protected MimeBodyPart getWrapperBodyPart(Mail mail) throws MessagingException, IOException {
         
         String explanationText = getExplanationText();
         
         // if there is no explanation text there should be no wrapping
         if (explanationText == null) {
             return null;
         }
 
             MimeMessage originalMessage = mail.getMessage();
 
             MimeBodyPart messagePart = new MimeBodyPart();
             MimeBodyPart signatureReason = new MimeBodyPart();
             
             String contentType = originalMessage.getContentType();
             Object content = originalMessage.getContent();
             
             if (contentType != null && content != null) {
             messagePart.setContent(content, contentType);
             } else {
                 throw new MessagingException("Either the content type or the content is null");
             }
             
             String headers = getMessageHeaders(originalMessage);
             
             signatureReason.setText(getReplacedExplanationText(getExplanationText(),
                                                                getSignerName(),
                                                                getKeyHolder().getSignerAddress(),
                                                                mail.getSender().toString(),
                                                                headers));
             
             signatureReason.setFileName("SignatureExplanation.txt");
             
             MimeMultipart wrapperMultiPart = new MimeMultipart();
             
             wrapperMultiPart.addBodyPart(messagePart);
             wrapperMultiPart.addBodyPart(signatureReason);
             
             MimeBodyPart wrapperBodyPart = new MimeBodyPart();
             
             wrapperBodyPart.setContent(wrapperMultiPart);
             
             return wrapperBodyPart;
     }
         
 }