S02E06_MailPushEmpfaenger.java

package com.blogspot.debukkitsblog.mailing;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Properties;
import java.util.Random;

import javax.mail.Flags;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;

import com.sun.mail.iap.ProtocolException;
import com.sun.mail.imap.IMAPFolder;
import com.sun.mail.imap.protocol.IMAPProtocol;

public class StartMailPushEmpfaenger {
	
	public static void main(String[] args) {
		
		MailPushEventHandler mailEventHandler = new MailPushEventHandler("imap.gmail.com", Zugangsdaten.USERNAME(), Zugangsdaten.PASSWORD());
		
	}
	
	public static class MailPushEventHandler extends MailPushEmpfaenger {

		public MailPushEventHandler(String host, String username, String password) {
			super(host, username, password);
		}
		
		@Override
		public void onMailReceived(Object[] messages) {
			
			if(messages != null && messages.length > 0) {
				
				for(Object msg : messages) {
					
					try {
						String textFromMessage = getTextFromMessage((Message) msg);
						System.out.println(textFromMessage);
						
					} catch (MessagingException e) {
						e.printStackTrace();
					} catch (IOException e) {
						e.printStackTrace();
					}
					
				}
				
				
			}
			
		}

	}
	
	public static abstract class MailPushEmpfaenger {
		
		private String randomInstanceID;
		private boolean stopped;
		
		private IMAPFolder inbox;
		
		private Thread listeningThread;
		private Thread reconnectionThread;
		
		public MailPushEmpfaenger(String host, String username, String password) {
			
			randomInstanceID = String.valueOf(new Random().nextInt(Integer.MAX_VALUE));
			
			listeningThread = new Thread(new Runnable() {
				@Override
				public void run() {
					
					while(!stopped) {
						
						try {
							System.out.println("[MailRX " + randomInstanceID + "] Connecting and logging in...");
							// Connect with IMAP Server
							Properties props = new Properties();
							props.setProperty("mail.store.protocol", "imaps");
							Session session = Session.getDefaultInstance(props, null);
							Store store = session.getStore("imaps");
							store.connect(host, username, password);
							System.out.println("[MailRX " + randomInstanceID + "] Connected.");
							
							// Open inbox
							inbox = (IMAPFolder) store.getFolder("INBOX");
							inbox.open(IMAPFolder.READ_WRITE);
							
							// initial Mail Check
							checkNewMessages();
							
							while(!stopped) {
								System.out.println("[MailRX " + randomInstanceID + "] IDLE-ing");
								inbox.idle(true);
								checkNewMessages();
							}
							
						} catch (MessagingException e) {
							e.printStackTrace();
						}
						
					}
					
				}
			});
			
			reconnectionThread = new Thread(new Runnable() {
				@Override
				public void run() {
					
					while(!stopped) {
						
						try {
							// Sleep 9 minutes
							Thread.sleep(9 * 60 * 1000);
							
							System.out.println("[MailRX " + randomInstanceID + "] NOOP");
							inbox.doCommand(new IMAPFolder.ProtocolCommand() {
								@Override
								public Object doCommand(IMAPProtocol protocol) throws ProtocolException {
									protocol.simpleCommand("NOOP", null);
									return null;
								}
							});
							
						} catch(Exception e) {
							e.printStackTrace();
						}
						
					}
					
				}
			});
			
			listeningThread.start();
			reconnectionThread.start();
			
		}
		
		private void checkNewMessages() throws MessagingException {
			System.out.println("[MailRX " + randomInstanceID + "] Checking for new messages...");
			
			if(!inbox.isOpen()) {
				inbox.open(IMAPFolder.READ_WRITE);
			}
			
			if(inbox.getMessageCount() > 0) {
				
				ArrayList<Message> msgs = new ArrayList<Message>();
				
				Message[] tempMsgs = inbox.getMessages(inbox.getMessageCount()-10, inbox.getMessageCount());
				for(Message tempMsg : tempMsgs) {
					if(!tempMsg.isSet(Flags.Flag.SEEN)) {
						msgs.add(tempMsg);
						tempMsg.setFlag(Flags.Flag.SEEN, true);
					}
				}
				
				
				
				onMailReceived(msgs.toArray());
				System.out.println("[MailRX " + randomInstanceID + "] Forwarded " + msgs.size() + " E-Mails.");
				
			}
			
		}
		
		public void onMailReceived(Object[] messages) {
			// Overwrite me
		}
		
		/**
		 * Return the primary text content of the message.</br>
		 * Source: https://javaee.github.io/javamail/FAQ#mainbody
		 * 
		 * @param p
		 *            The message
		 * @return The message's main body text content
		 * @throws MessagingException
		 *             If something went wrong
		 * @throws IOException
		 *             If something else went wrong
		 */
		public String getTextFromMessage(Part p) throws MessagingException, IOException {
			if (p.isMimeType("text/*")) {
				String s = (String) p.getContent();
				return s;
			}

			if (p.isMimeType("multipart/alternative")) {
				Multipart mp = (Multipart) p.getContent();
				String text = null;
				for (int i = 0; i < mp.getCount(); i++) {
					Part bp = mp.getBodyPart(i);
					if (bp.isMimeType("text/plain")) {
						if (text == null)
							text = getTextFromMessage(bp);
						continue;
					} else if (bp.isMimeType("text/html")) {
						String s = getTextFromMessage(bp);
						if (s != null)
							return s;
					} else {
						return getTextFromMessage(bp);
					}
				}
				return text;
			} else if (p.isMimeType("multipart/*")) {
				Multipart mp = (Multipart) p.getContent();
				for (int i = 0; i < mp.getCount(); i++) {
					String s = getTextFromMessage(mp.getBodyPart(i));
					if (s != null)
						return s;
				}
			}

			return null;
		}
		
		public void stop() {
			this.stopped = true;
		}
	}
	
	

}