[mail] Add mail content processing (#14345)

* [mail] Add mail content processing

Signed-off-by: Jan N. Klug <github@klug.nrw>

CODEOWNERS

@@ -185,7 +185,7 @@
 /bundles/org.openhab.binding.luxom/ @jesperskriasoft
 /bundles/org.openhab.binding.luxtronikheatpump/ @sgiehl
 /bundles/org.openhab.binding.magentatv/ @markus7017
-/bundles/org.openhab.binding.mail/ @openhab/add-ons-maintainers
+/bundles/org.openhab.binding.mail/ @J-N-K
 /bundles/org.openhab.binding.max/ @marcelrv
 /bundles/org.openhab.binding.mcd/ @simon-dengler
 /bundles/org.openhab.binding.mcp23017/ @aogorek

bundles/org.openhab.binding.mail/README.md

@@ -40,16 +40,42 @@ Default ports are `143` (for `PLAIN` and `STARTTLS`) and `993` (for `SSL`) in th
 ## Channels
 
 There are no channels for the `smtp` thing.
-The `imap` and `pop3` things can be extended with `mailcount`-type channels.
+The `imap` and `pop3` things can be extended with `mailcount`- and `content`-type channels.
 
 ### Type `mailcount`
 
 Each channel has two parameters: `folder` and `type`.
+
 The `folder` is mandatory and denotes the folder name on the given account.
-You can either use the root folder like (e.g. "INBOX") or a sub directory of your structure (e.g. "INBOX.Sent" or "INBOX.Junk").
+
+You can either use the root folder like (e.g. "INBOX") or a subdirectory of your structure (e.g. "INBOX.Sent" or "INBOX.Junk").
 The `type` parameter can be `UNREAD` or `TOTAL` (default).
 Channels with type `UNREAD` give the number on unread mails in that folder.
 
+### Type `content`
+
+The `content` type channel presents the contents of an unread mail.
+If the message is a MIME- or MIME-multipart message, all parts are concatenated.
+The content is converted to a plain string without processing (i.e. HTML tags are still present).
+In most cases the mail content needs further processing in rules to trigger appropriate action.
+
+Each channel has five parameters: `folder`, `subject`, `sender`, `transformation` and `markAsRead`.
+
+The `folder` is mandatory and denotes the folder name on the given account.
+You can either use the root folder like (e.g. "INBOX") or a subdirectory of your structure (e.g. "INBOX.Sent" or "INBOX.Junk").
+
+`subject` and `sender` can be used to filter the messages that are processed by the channel.
+Filters use regular expressions (e.g. `.*DHL.*` as `sender` would match all From-addresses that contain "DHL").
+If a parameter is left empty, no filter is applied.
+
+The `transformation` is applied before setting the channel status.
+Transformations can be chained by separating them with the mathematical intersection character "∩", e.g. `REGEX:.*Shipment-Status: ([a-z]+).*∩MAP:status.map` would first extract a character string with a regular expression and then apply the given MAP transformation on the result.
+Please note that the values will be discarded if one transformation fails (e.g. REGEX did not match).
+This means that you can also use it to filter certain emails e.g. `REGEX:(.*Sendungsbenachrichtigung.*)` would only match for mails containing the string "Sendungsbenachrichtigung" but output the whole message.
+
+Since with each refresh all unread mails are processed the same message content would be sent to the channel multiple times.
+This can be prevented by setting `markAsRead` to `true` (default is `false`), which marks all processed messages as read.
+
 ## Full Example
 
 mail.things:
@@ -61,6 +87,7 @@ Thing mail:imap:sampleimap [ hostname="imap.example.com", security="SSL", userna
     Channels:
         Type mailcount : inbox_total [ folder="INBOX", type="TOTAL" ]
         Type mailcount : inbox_unread [ folder="INBOX", type="UNREAD" ]
+        Type content : fedex_notification [ folder="INBOX" sender="Fedex.*" markAsRead="true" ]
 }
 ```
 
@@ -69,6 +96,7 @@ mail.items:
 ```java
 Number InboxTotal  "INBOX [%d]"        { channel="mail:imap:sampleimap:inbox_total" }
 Number InboxUnread "INBOX Unread [%d]" { channel="mail:imap:sampleimap:inbox_unread" }
+String FedexNotification               { channel="mail:imap:sampleimap:fedex_notification" }
 ```
 
 mail.sitemap:

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/MailBindingConstants.java

@@ -38,4 +38,5 @@ public class MailBindingConstants {
             Arrays.asList(THING_TYPE_SMTPSERVER, THING_TYPE_IMAPSERVER, THING_TYPE_POP3SERVER));
 
     public static final ChannelTypeUID CHANNEL_TYPE_UID_FOLDER_MAILCOUNT = new ChannelTypeUID(BINDING_ID, "mailcount");
+    public static final ChannelTypeUID CHANNEL_TYPE_UID_MAIL_CONTENT = new ChannelTypeUID(BINDING_ID, "content");
 }

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/MailCountChannelType.java

@@ -12,12 +12,14 @@
  */
 package org.openhab.binding.mail.internal;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+
 /**
  * The {@link MailCountChannelType} enum for folder mail count type
  *
  * @author Jan N. Klug - Initial contribution
  */
-
+@NonNullByDefault
 public enum MailCountChannelType {
     UNREAD,
     TOTAL

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/MailHandlerFactory.java

@@ -29,8 +29,8 @@ import org.osgi.service.component.annotations.Component;
  *
  * @author Jan N. Klug - Initial contribution
  */
-@NonNullByDefault
 @Component(configurationPid = "binding.mail", service = ThingHandlerFactory.class)
+@NonNullByDefault
 public class MailHandlerFactory extends BaseThingHandlerFactory {
 
     @Override

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/POP3IMAPHandler.java

@@ -13,29 +13,41 @@
 package org.openhab.binding.mail.internal;
 
 import static org.openhab.binding.mail.internal.MailBindingConstants.CHANNEL_TYPE_UID_FOLDER_MAILCOUNT;
+import static org.openhab.binding.mail.internal.MailBindingConstants.CHANNEL_TYPE_UID_MAIL_CONTENT;
 
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
 import java.util.Properties;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
+import javax.mail.Address;
 import javax.mail.Flags;
 import javax.mail.Folder;
+import javax.mail.Message;
 import javax.mail.MessagingException;
 import javax.mail.Session;
 import javax.mail.Store;
+import javax.mail.internet.MimeMessage;
+import javax.mail.internet.MimeMultipart;
 import javax.mail.search.FlagTerm;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
-import org.openhab.binding.mail.internal.config.POP3IMAPChannelConfig;
 import org.openhab.binding.mail.internal.config.POP3IMAPConfig;
+import org.openhab.binding.mail.internal.config.POP3IMAPContentChannelConfig;
+import org.openhab.binding.mail.internal.config.POP3IMAPMailCountChannelConfig;
 import org.openhab.core.library.types.DecimalType;
+import org.openhab.core.library.types.StringType;
 import org.openhab.core.thing.Channel;
 import org.openhab.core.thing.ChannelUID;
 import org.openhab.core.thing.Thing;
 import org.openhab.core.thing.ThingStatus;
 import org.openhab.core.thing.ThingStatusDetail;
 import org.openhab.core.thing.binding.BaseThingHandler;
+import org.openhab.core.thing.binding.generic.ChannelTransformation;
 import org.openhab.core.types.Command;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -76,21 +88,14 @@ public class POP3IMAPHandler extends BaseThingHandler {
 
         if (config.port == 0) {
             switch (protocol) {
-                case "imap":
+                case "imap" -> config.port = 143;
-                    config.port = 143;
+                case "imaps" -> config.port = 993;
-                    break;
+                case "pop3" -> config.port = 110;
-                case "imaps":
+                case "pop3s" -> config.port = 995;
-                    config.port = 993;
+                default -> {
-                    break;
-                case "pop3":
-                    config.port = 110;
-                    break;
-                case "pop3s":
-                    config.port = 995;
-                    break;
-                default:
                     updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.CONFIGURATION_ERROR);
                     return;
+                }
             }
         }
 
@@ -109,6 +114,9 @@ public class POP3IMAPHandler extends BaseThingHandler {
     }
 
     private void refresh() {
+        if (Thread.currentThread().isInterrupted()) {
+            return;
+        }
         Properties props = new Properties();
         props.setProperty("mail." + baseProtocol + ".starttls.enable", "true");
         props.setProperty("mail.store.protocol", protocol);
@@ -119,8 +127,8 @@ public class POP3IMAPHandler extends BaseThingHandler {
 
             for (Channel channel : thing.getChannels()) {
                 if (CHANNEL_TYPE_UID_FOLDER_MAILCOUNT.equals(channel.getChannelTypeUID())) {
-                    final POP3IMAPChannelConfig channelConfig = channel.getConfiguration()
+                    final POP3IMAPMailCountChannelConfig channelConfig = channel.getConfiguration()
-                            .as(POP3IMAPChannelConfig.class);
+                            .as(POP3IMAPMailCountChannelConfig.class);
                     final String folderName = channelConfig.folder;
                     if (folderName == null || folderName.isEmpty()) {
                         logger.info("missing or empty folder name in channel {}", channel.getUID());
@@ -133,14 +141,65 @@ public class POP3IMAPHandler extends BaseThingHandler {
                                 updateState(channel.getUID(), new DecimalType(
                                         mailbox.search(new FlagTerm(new Flags(Flags.Flag.SEEN), false)).length));
                             }
-                        } catch (MessagingException e) {
+                        }
-                            throw e;
+                    }
+                } else if (CHANNEL_TYPE_UID_MAIL_CONTENT.equals(channel.getChannelTypeUID())) {
+                    final POP3IMAPContentChannelConfig channelConfig = channel.getConfiguration()
+                            .as(POP3IMAPContentChannelConfig.class);
+                    final String folderName = channelConfig.folder;
+                    if (folderName == null || folderName.isEmpty()) {
+                        logger.info("missing or empty folder name in channel '{}'", channel.getUID());
+                    } else {
+                        try (Folder mailbox = store.getFolder(folderName)) {
+                            mailbox.open(channelConfig.markAsRead ? Folder.READ_WRITE : Folder.READ_ONLY);
+                            Message[] messages = mailbox.search(new FlagTerm(new Flags(Flags.Flag.SEEN), false));
+                            for (Message message : messages) {
+                                String subject = message.getSubject();
+                                Address[] senders = message.getFrom();
+                                String sender = senders == null ? ""
+                                        : Stream.of(senders).map(Address::toString).collect(Collectors.joining(","));
+                                logger.debug("Processing `{}` from `{}`", subject, sender);
+                                if (!channelConfig.subject.isBlank() && !subject.matches(channelConfig.subject)) {
+                                    logger.trace("Subject '{}' did not pass subject filter", subject);
+                                    continue;
+                                }
+                                if (!channelConfig.sender.isBlank() && !sender.matches(channelConfig.sender)) {
+                                    logger.trace("Sender '{}' did not pass filter '{}'", subject, channelConfig.sender);
+                                    continue;
+                                }
+                                Object rawContent = message.getContent();
+                                String contentAsString;
+                                if (rawContent instanceof String) {
+                                    logger.trace("Detected plain text message");
+                                    contentAsString = (String) rawContent;
+                                } else if (rawContent instanceof MimeMessage mimeMessage) {
+                                    logger.trace("Detected MIME message");
+                                    try (ByteArrayOutputStream os = new ByteArrayOutputStream()) {
+                                        mimeMessage.writeTo(os);
+                                        contentAsString = os.toString();
+                                    }
+                                } else if (rawContent instanceof MimeMultipart mimeMultipart) {
+                                    logger.trace("Detected MIME multipart message");
+                                    try (ByteArrayOutputStream os = new ByteArrayOutputStream()) {
+                                        mimeMultipart.writeTo(os);
+                                        contentAsString = os.toString();
+                                    }
+                                } else {
+                                    logger.warn(
+                                            "Failed to convert mail content from '{}' with subject '{}', to String: {}",
+                                            sender, subject, rawContent.getClass());
+                                    continue;
+                                }
+                                logger.trace("Found content '{}'", contentAsString);
+                                new ChannelTransformation(channelConfig.transformation).apply(contentAsString)
+                                        .ifPresent(result -> updateState(channel.getUID(), new StringType(result)));
+                            }
                         }
                     }
                 }
             }
-        } catch (MessagingException e) {
+        } catch (MessagingException | IOException e) {
-            logger.info("error when trying to refresh IMAP: {}", e.getMessage());
+            logger.info("Failed refreshing IMAP for thing '{}': {}", thing.getUID(), e.getMessage());
         }
     }
 }

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/ServerSecurity.java

@@ -12,12 +12,14 @@
  */
 package org.openhab.binding.mail.internal;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+
 /**
  * The {@link ServerSecurity} enum contains security configuration options
  *
  * @author Jan N. Klug - Initial contribution
  */
-
+@NonNullByDefault
 public enum ServerSecurity {
     PLAIN,
     SSL,

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/config/BaseConfig.java

@@ -21,7 +21,6 @@ import org.openhab.binding.mail.internal.ServerSecurity;
  *
  * @author Jan N. Klug - Initial contribution
  */
-
 @NonNullByDefault
 public class BaseConfig {
     public @Nullable String hostname;

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/config/POP3IMAPConfig.java

@@ -19,7 +19,6 @@ import org.eclipse.jdt.annotation.NonNullByDefault;
  *
  * @author Jan N. Klug - Initial contribution
  */
-
 @NonNullByDefault
 public class POP3IMAPConfig extends BaseConfig {
     public int refresh = 60;

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/config/POP3IMAPContentChannelConfig.java

@@ -0,0 +1,31 @@
+/**
+ * Copyright (c) 2010-2023 Contributors to the openHAB project
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.openhab.binding.mail.internal.config;
+
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
+
+/**
+ * The {@link POP3IMAPContentChannelConfig} class contains fields mapping thing configuration parameters.
+ *
+ * @author Jan N. Klug - Initial contribution
+ */
+@NonNullByDefault
+public class POP3IMAPContentChannelConfig {
+    public @Nullable String folder;
+    public String subject = "";
+    public String sender = "";
+    public @Nullable String transformation;
+
+    public boolean markAsRead = false;
+}

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/config/POP3IMAPMailCountChannelConfig.java

@@ -17,13 +17,12 @@ import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.binding.mail.internal.MailCountChannelType;
 
 /**
- * The {@link POP3IMAPChannelConfig} class contains fields mapping thing configuration parameters.
+ * The {@link POP3IMAPMailCountChannelConfig} class contains fields mapping thing configuration parameters.
  *
  * @author Jan N. Klug - Initial contribution
  */
-
 @NonNullByDefault
-public class POP3IMAPChannelConfig {
+public class POP3IMAPMailCountChannelConfig {
     public @Nullable String folder;
     public MailCountChannelType type = MailCountChannelType.TOTAL;
 }

bundles/org.openhab.binding.mail/src/main/java/org/openhab/binding/mail/internal/config/SMTPConfig.java

@@ -20,7 +20,6 @@ import org.eclipse.jdt.annotation.Nullable;
  *
  * @author Jan N. Klug - Initial contribution
  */
-
 @NonNullByDefault
 public class SMTPConfig extends BaseConfig {
     public @Nullable String sender;

bundles/org.openhab.binding.mail/src/main/resources/OH-INF/i18n/mail.properties

@@ -20,6 +20,31 @@ thing-type.config.mail.smtp.port.description = Default values are 25 for plain/S
 thing-type.config.mail.smtp.sender.label = Sender
 thing-type.config.mail.smtp.sender.description = Default sender address for mail
 
+# channel types
+
+channel-type.mail.content.label = Content
+channel-type.mail.content.description = Mail content as String (with subject filter and content transformation).
+channel-type.mail.mailcount.label = Mail Count
+channel-type.mail.mailcount.description = Number of emails in folder
+
+# channel types config
+
+channel-type.config.mail.content.folder.label = Folder Name
+channel-type.config.mail.content.markAsRead.label = Mark As Read
+channel-type.config.mail.content.markAsRead.description = Mark a processed mail as read and prevent further processing.
+channel-type.config.mail.content.sender.label = Sender Filter
+channel-type.config.mail.content.sender.description = A (regular expression) filter for the mail sender address.
+channel-type.config.mail.content.subject.label = Subject Filter
+channel-type.config.mail.content.subject.description = A (regular expression) filter for the mail subject.
+channel-type.config.mail.content.transformation.label = Transformation
+channel-type.config.mail.content.transformation.description = Transformation pattern used when processing messages. Multiple transformation can be chained using "∩".
+channel-type.config.mail.mailcount.folder.label = Folder Name
+channel-type.config.mail.mailcount.type.label = Counter Type
+channel-type.config.mail.mailcount.type.option.UNREAD = Unread
+channel-type.config.mail.mailcount.type.option.TOTAL = Total
+
+# thing types config
+
 config.hostname.label = Server Hostname
 config.password.label = SMTP Server Password
 config.port.label = Server Port
@@ -31,18 +56,6 @@ config.security.option.STARTTLS = STARTTLS
 config.security.option.SSL = SSL/TLS
 config.username.label = SMTP Server Username
 
-# channel types
-
-channel-type.mail.mailcount.label = Mail Count
-channel-type.mail.mailcount.description = Number of emails in folder
-
-# channel types config
-
-channel-type.config.mail.mailcount.folder.label = Folder Name
-channel-type.config.mail.mailcount.type.label = Counter Type
-channel-type.config.mail.mailcount.type.option.UNREAD = Unread
-channel-type.config.mail.mailcount.type.option.TOTAL = Total
-
 # actions
 
 addHeaderActionLabel = add a mail header

bundles/org.openhab.binding.mail/src/main/resources/OH-INF/thing/thing-types.xml

@@ -15,12 +15,12 @@
 			<parameter name="hostname" type="text" required="true">
 				<label>@text/config.hostname.label</label>
 			</parameter>
-			<parameter name="port" type="text" required="false">
+			<parameter name="port" type="text">
 				<label>@text/config.port.label</label>
 				<description>Default values are 25 for plain/STARTTLS and 465 for SSL/TLS</description>
 				<advanced>true</advanced>
 			</parameter>
-			<parameter name="security" type="text" required="false">
+			<parameter name="security" type="text">
 				<label>@text/config.security.label</label>
 				<options>
 					<option value="PLAIN">@text/config.security.option.PLAIN</option>
@@ -30,28 +30,28 @@
 				<limitToOptions>true</limitToOptions>
 				<default>PLAIN</default>
 			</parameter>
-			<parameter name="username" type="text" required="false">
+			<parameter name="username" type="text">
 				<label>@text/config.username.label</label>
 			</parameter>
-			<parameter name="password" type="text" required="false">
+			<parameter name="password" type="text">
 				<label>@text/config.password.label</label>
 				<context>password</context>
 			</parameter>
 		</config-description>
 	</thing-type>
-	<thing-type id="imap" extensible="mailcount">
+	<thing-type id="imap" extensible="mailcount,content">
 		<label>IMAP Server</label>
 		<description>Used for receiving emails</description>
 		<config-description>
 			<parameter name="hostname" type="text" required="true">
 				<label>@text/config.hostname.label</label>
 			</parameter>
-			<parameter name="port" type="text" required="false">
+			<parameter name="port" type="text">
 				<label>@text/config.port.label</label>
 				<description>Default values are 143 for plain/STARTTLS and 993 for SSL/TLS</description>
 				<advanced>true</advanced>
 			</parameter>
-			<parameter name="security" type="text" required="false">
+			<parameter name="security" type="text">
 				<label>@text/config.security.label</label>
 				<options>
 					<option value="PLAIN">@text/config.security.option.PLAIN</option>
@@ -68,26 +68,26 @@
 				<label>@text/config.password.label</label>
 				<context>password</context>
 			</parameter>
-			<parameter name="refresh" type="integer" required="false">
+			<parameter name="refresh" type="integer">
 				<label>@text/config.refresh.label</label>
 				<description>@text/config.refresh.description</description>
 				<default>60</default>
 			</parameter>
 		</config-description>
 	</thing-type>
-	<thing-type id="pop3" extensible="mailcount">
+	<thing-type id="pop3" extensible="mailcount,content">
 		<label>POP3 Server</label>
 		<description>Used for receiving emails</description>
 		<config-description>
 			<parameter name="hostname" type="text" required="true">
 				<label>@text/config.hostname.label</label>
 			</parameter>
-			<parameter name="port" type="text" required="false">
+			<parameter name="port" type="text">
 				<label>@text/config.port.label</label>
 				<description>Default values are 110 for plain/STARTTLS and 995 for SSL/TLS</description>
 				<advanced>true</advanced>
 			</parameter>
-			<parameter name="security" type="text" required="false">
+			<parameter name="security" type="text">
 				<label>@text/config.security.label</label>
 				<options>
 					<option value="PLAIN">@text/config.security.option.PLAIN</option>
@@ -104,7 +104,7 @@
 				<label>@text/config.password.label</label>
 				<context>password</context>
 			</parameter>
-			<parameter name="refresh" type="integer" required="false">
+			<parameter name="refresh" type="integer">
 				<label>@text/config.refresh.label</label>
 				<description>@text/config.refresh.description</description>
 				<default>60</default>
@@ -121,7 +121,7 @@
 			<parameter name="folder" type="text" required="true">
 				<label>Folder Name</label>
 			</parameter>
-			<parameter name="type" type="text" required="false">
+			<parameter name="type" type="text">
 				<label>Counter Type</label>
 				<options>
 					<option value="UNREAD">Unread</option>
@@ -132,4 +132,33 @@
 			</parameter>
 		</config-description>
 	</channel-type>
+
+	<channel-type id="content">
+		<item-type>String</item-type>
+		<label>Content</label>
+		<description>Mail content as String (with subject filter and content transformation).</description>
+		<state readOnly="true"/>
+		<config-description>
+			<parameter name="folder" type="text" required="true">
+				<label>Folder Name</label>
+			</parameter>
+			<parameter name="subject" type="text">
+				<label>Subject Filter</label>
+				<description>A (regular expression) filter for the mail subject.</description>
+			</parameter>
+			<parameter name="sender" type="text">
+				<label>Sender Filter</label>
+				<description>A (regular expression) filter for the mail sender address.</description>
+			</parameter>
+			<parameter name="transformation" type="text">
+				<label>Transformation</label>
+				<description>Transformation pattern used when processing messages. Multiple transformation can be chained using "∩".</description>
+			</parameter>
+			<parameter name="markAsRead" type="boolean">
+				<label>Mark As Read</label>
+				<description>Mark a processed mail as read and prevent further processing.</description>
+				<default>false</default>
+			</parameter>
+		</config-description>
+	</channel-type>
 </thing:thing-descriptions>

bundles/org.openhab.binding.mail/src/test/java/org/openhab/binding/mail/internal/MailBuilderTest.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.mail;
+package org.openhab.binding.mail.internal;
 
 import static org.hamcrest.CoreMatchers.instanceOf;
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -29,15 +29,15 @@ import org.apache.commons.mail.EmailException;
 import org.apache.commons.mail.HtmlEmail;
 import org.apache.commons.mail.MultiPartEmail;
 import org.apache.commons.mail.SimpleEmail;
+import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.junit.jupiter.api.Test;
-import org.openhab.binding.mail.internal.MailBuilder;
 
 /**
  * The {@link MailBuilderTest} class defines tests for the {@link MailBuilder} class
  *
  * @author Jan N. Klug - Initial contribution
  */
-
+@NonNullByDefault
 public class MailBuilderTest {
 
     private static final String TEST_STRING = "test";

tools/static-code-analysis/checkstyle/suppressions.xml

@@ -22,4 +22,9 @@
     <suppress files=".+org.openhab.binding.yeelight.+" checks="OutsideOfLibExternalLibrariesCheck" />
     <!-- suppress header checks for imported and patched apache commons-io files in logreader binding -->
     <suppress files=".+org.openhab.binding.logreader.internal.thirdparty.commonsio.+" checks="ParameterizedRegexpHeaderCheck|AuthorTagCheck" />
+    <!-- Mail: Do not check org.apache.commons.mail usage -->
+    <suppress files=".+[\\/]mail[\\/].+[\\/]MailBuilder\.java" checks="ForbiddenPackageUsageCheck"/>
+    <suppress files=".+[\\/]mail[\\/].+[\\/]MailBuilderTest\.java" checks="ForbiddenPackageUsageCheck"/>
+    <suppress files=".+[\\/]mail[\\/].+[\\/]SMTPHandler\.java" checks="ForbiddenPackageUsageCheck"/>
+    <suppress files=".+[\\/]mail[\\/].+[\\/]SendMailActions\.java" checks="ForbiddenPackageUsageCheck"/>
 </suppressions>