fixed sonar findings

network/src/main/java/de/muehlencord/shared/network/mail/MailMessageUtils.java

@@ -1,7 +1,6 @@
 /**
- * wrapper classes around javax.mail package
+ * wrapper classes around javax.mail package written by Joern Muehlencord
- * written by Joern Muehlencord
+ *
- * 
  */
 package de.muehlencord.shared.network.mail;
 
@@ -21,13 +20,14 @@ import org.apache.log4j.Logger;
 
 /**
  * Util class to convert between javax.mail.Message and MailMessage objects
+ *
  * @author joern@muehlencord.de
  */
 public abstract class MailMessageUtils {
 
     /** the logging object */
     private static final Logger logger = Logger.getLogger(MailMessageUtils.class.getName());
-    
+
     /** content type of mutipart messages - e.g. multipart_alternative or _mixed */
     private static final String CONTENTTYPE_MULTIPART = "multipart/";
     /** content type of text messages - like text/plain or text/html */
@@ -93,7 +93,6 @@ public abstract class MailMessageUtils {
                         String bodyContentType = getContentType(bp.getContentType());
                         logger.debug("contentType = " + bodyContentType);
 
-
                         if (bodyContentType.contains(CONTENTTYPE_MULTIPART)) {
                             MimeMultipart bodyMultiPart = (MimeMultipart) bp.getContent();
                             int bodyPartCount = bodyMultiPart.getCount();
@@ -145,15 +144,14 @@ public abstract class MailMessageUtils {
                         throw new MailMessageException("Neither plain/text nor text/html content found. Unsupported message format");
                     }
 
-
+                } catch (MailMessageException | IOException | MessagingException ex) {
-                } catch (Exception ex) {
                     throw new MailMessageException("Error while converting multipart mime message. Reason: " + ex.getMessage(), ex);
                 }
             } else if (contentType.equals(CONTENTTYPE_TEXT_PLAIN)) {
                 // plain/text mimmessage
                 try {
                     returnMessage = new MailMessage(subject, mm.getContent().toString(), messageId);
-                } catch (Exception ex) {
+                } catch (IOException | MessagingException ex) {
                     throw new MailMessageException("Error while converting plain/text mime message. Reason: " + ex.getMessage(), ex);
                 }
 
@@ -164,14 +162,14 @@ public abstract class MailMessageUtils {
                     returnMessage = new MailMessage(subject, null, messageId);
                     returnMessage.setContent(contentString, true);
                     // returnMessage.setContent(mm.getContent().toString(), false); 
-                } catch (Exception ex) {
+                } catch (IOException | MessagingException ex) {
                     throw new MailMessageException("Error while converting plain/text mime message. Reason: " + ex.getMessage(), ex);
                 }
             } else if (contentType.contains(CONTENTTYPE_MESSAGE)) {
                 try {
                     Message nestedMessage = (Message) mm.getContent();
                     returnMessage = getInstance(nestedMessage);
-                } catch (Exception ex) {
+                } catch (MailMessageException | IOException | MessagingException ex) {
                     throw new MailMessageException("Error while converting nested message. Reason: " + ex.getMessage(), ex);
                 }
             } else if (contentType.contains(CONTENTTYPE_APPLICATION)) {
@@ -188,22 +186,20 @@ public abstract class MailMessageUtils {
                     logger.debug(mm.getContent().getClass());
                     logger.debug(mm.getContent());
                     logger.error(hint);
-                } catch (Exception ex) {
+                } catch (IOException | MessagingException ex) {
                     logger.error(hint);
                 }
                 throw new MailMessageException(hint);
             }
-        } else if (message instanceof Message) {
+        } else {
             try {
                 String content = message.getContent().toString();
                 String subject = message.getSubject();
                 returnMessage = new MailMessage(subject, content);
 
-            } catch (Exception ex) {
+            } catch (IOException | MessagingException ex) {
                 throw new MailMessageException("Error whilec converting email. Reason: " + ex.getMessage(), ex);
             }
-        } else {
-            throw new MailMessageException("Unsupported messagetype " + message.getClass().toString() + ". Cannot create message");
         }
 
         // TODO add missing parameters
@@ -216,35 +212,37 @@ public abstract class MailMessageUtils {
             returnMessage.setSender(message.getFrom());
             returnMessage.setSentDate(message.getSentDate());
             returnMessage.setSize(message.getSize());
-        } catch (Exception ex) {
+        } catch (MessagingException ex) {
             throw new MailMessageException("Cannot read email. Reason: " + ex.getMessage(), ex);
         }
         return returnMessage;
     }
 
-
     /**
-     * returns the content type based on the content-type header. The messad asures the contentype
+     * returns the content type based on the content-type header. The messad asures the contentype is selected correctly from the string, including trim and
-     * is selected correctly from the string, including trim and tolower case
+     * tolower case
+     *
      * @param contentType the contenttype string read from email header
      * @return the content type of the email (small letters)
      */
-    private static String getContentType(String contentType) {
+    private static String getContentType(final String contentType) {
 
+        String returnValue = contentType;
         if (contentType.contains(";")) {
-            contentType = contentType.substring(0, contentType.indexOf(';'));
+            returnValue = contentType.substring(0, contentType.indexOf(';'));
         }
-        contentType = contentType.toLowerCase();
+        returnValue = returnValue.toLowerCase();
-        contentType = contentType.trim();
+        returnValue = returnValue.trim();
-        return contentType;
+        return returnValue;
     }
 
     /**
-     * returns the content of the given bodypart which needs to be a text based bodypart
+     * returns the content of the given bodypart which needs to be a text based bodypart The method tries to read the messages as it is. In case of an
-     * The method tries to read the messages as it is. In case of an unsupported encoding it reads the message with
+     * unsupported encoding it reads the message with the default encoding (accepting "ugly" characters)
-     * the default encoding (accepting "ugly" characters)
+     *
      * @param bp the body part to read the content from
      * @return the content of the body part
+     *
      * @throws IOException if the content cannot be read
      * @throws MessagingException if the message cannot be processed
      */
@@ -256,9 +254,9 @@ public abstract class MailMessageUtils {
         } catch (java.io.UnsupportedEncodingException ex) {
             logger.debug(ex.getMessage());
         } catch (java.io.IOException ioex) {
-            throw new IOException("Cannot read content from bodypart.", ioex); 
+            throw new IOException("Cannot read content from bodypart.", ioex);
         } catch (MessagingException mex) {
-            throw new MessagingException("Cannot read content from bodypart.", mex); 
+            throw new MessagingException("Cannot read content from bodypart.", mex);
         }
 
         if (returnValue == null) {
@@ -270,20 +268,22 @@ public abstract class MailMessageUtils {
     }
 
     /**
-     * returns the content of the given body part by reading the stream directly. This ommits getting unsupported encoding exceptions, as the content
+     * returns the content of the given body part by reading the stream directly. This ommits getting unsupported encoding exceptions, as the content is read
-     * is read with the given encoding
+     * with the given encoding
+     *
      * @param bp the bodypart to read the content from
      * @param encoding the encoding to force
      * @return the content string read with the given encoding
+     *
      * @throws IOException if the content cannot be read
      * @throws MessagingException if the message cannot be processed
      */
     private static String getContentByStream(BodyPart bp, String encoding) throws IOException, MessagingException {
-        String returnValue; 
+        String returnValue;
         Reader input = null;
         StringWriter output = null;
         try {
-            input = new BufferedReader(new InputStreamReader(bp.getInputStream(), encoding)); 
+            input = new BufferedReader(new InputStreamReader(bp.getInputStream(), encoding));
             output = new StringWriter();
             char[] b = new char[4096];
             while (input.read(b) != -1) {
@@ -291,16 +291,20 @@ public abstract class MailMessageUtils {
             }
             returnValue = output.toString();
         } catch (IOException ioex) {
-            throw new IOException("Cannot read content from bodypart by reading content stream.", ioex); 
+            throw new IOException("Cannot read content from bodypart by reading content stream.", ioex);
         } finally {
             try {
-                output.close();
+                if (output != null) {
+                    output.close();
+                }
             } catch (IOException ex) {
                 logger.debug(ex.getMessage());
                 logger.debug(StringUtil.getStackTraceString(ex));
             }
             try {
-                input.close();
+                if (input != null) {
+                    input.close();
+                }
             } catch (IOException ex) {
                 logger.debug(ex.getMessage());
                 logger.debug(StringUtil.getStackTraceString(ex));
@@ -311,8 +315,10 @@ public abstract class MailMessageUtils {
 
     /**
      * returns the message id from the header of the given message
+     *
      * @param message the message to return the message id from
      * @return either the message id or null if the message id cannot be read
+     *
      * @throws MessagingException if the message cannot be processed
      */
     private static String getMessageId(Message message) throws MessagingException {