first version doiing forward with attached original mail

src/main/java/de/srsoftware/widerhall/mail/ImapClient.java

@@ -2,7 +2,6 @@ package de.srsoftware.widerhall.mail;
 
 import com.sun.mail.imap.IMAPFolder;
 import de.srsoftware.widerhall.Constants;
-import org.json.simple.JSONObject;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -15,26 +14,38 @@ public class ImapClient {
     private static final Logger LOG = LoggerFactory.getLogger(ImapClient.class);
     private final int port;
     private final String host, username, password, folderName;
-    private boolean stopped = true;
     private IMAPFolder inbox;
-    private HashSet<MessageHandler> listeners = new HashSet<>();
+    private ListeningThread listeningThread;
+    private Heartbeat heartbeat;
 
     private class ListeningThread extends Thread {
 
         private static final Logger LOG = LoggerFactory.getLogger(ListeningThread.class);
+        private HashSet<MessageHandler> listeners = new HashSet<>();
+        private boolean stopped = false;
+
+        public ListeningThread addListener(MessageHandler messageHandler) {
+            listeners.add(messageHandler);
+            return this;
+        }
+
+        public ListeningThread dropListeners() {
+            listeners.clear();
+            return this;
+        }
 
         @Override
         public void run() {
             while (!stopped) {
+                try {
+                    sleep(5000);
+                } catch (InterruptedException interruptedException) {
+                    interruptedException.printStackTrace();
+                }
                 try {
                     openInbox();
                 } catch (MessagingException e){
                     LOG.warn("Connection problem:",e);
-                    try {
-                        sleep(1000);
-                    } catch (InterruptedException interruptedException) {
-                        interruptedException.printStackTrace();
-                    }
                 }
             }
         }
@@ -78,11 +89,18 @@ public class ImapClient {
             props.put(Constants.PROTOCOL,Constants.IMAPS);
             return props;
         }
+
+        public ListeningThread doStop() {
+            stopped = true;
+            return this;
+        }
     }
 
     private class Heartbeat extends Thread{
 
         private static final Logger LOG = LoggerFactory.getLogger(Heartbeat.class);
+        private boolean stopped = false;
+
         @Override
         public void run() {
             while (!stopped){
@@ -99,6 +117,11 @@ public class ImapClient {
                 }
             }
         }
+
+        public Heartbeat doStop() {
+            stopped = true;
+            return this;
+        }
     }
 
     public ImapClient(String host, int port, String username, String password, String folderName) {
@@ -109,9 +132,9 @@ public class ImapClient {
         this.folderName = folderName;
     }
 
-
     public ImapClient addListener(MessageHandler messageHandler) {
-        listeners.add(messageHandler);
+        if (listeningThread == null) listeningThread = new ListeningThread();
+        listeningThread.addListener(messageHandler);
         return this;
     }
 
@@ -135,15 +158,28 @@ public class ImapClient {
         return folderName;
     }
 
-    public void start() {
-        stopped = false;
+    public ImapClient start() {
+        stop();
+
         LOG.debug("Creating ListeningThread…");
-        new ListeningThread().start();
+        (listeningThread = new ListeningThread()).start();
+
         LOG.debug("Creating Heartbeat…");
-        new Heartbeat().start();
+        (heartbeat = new Heartbeat()).start();
+
+        return this;
     }
 
-    public void stop(){
-        stopped = true;
+    public ImapClient stop(){
+        if (listeningThread != null) {
+            LOG.debug("Stopping old ListeningThread…");
+            listeningThread.dropListeners().doStop();
+            listeningThread = null;
+        }
+        if (heartbeat != null){
+            heartbeat.doStop();
+            heartbeat = null;
+        }
+        return this;
     }
 }