Can not modify email by using spring framework (Mail-Receiving) - spring

Question

I am working on a project that requires loading incoming emails, process the email that only passed the filtering criteria, in the end mark the email has been SEEN and modify the subject.
There are couple of issues I couldn't figure out:
mail-filter-expression is not working for me. I want to find out the mails that has subject start with "AAA" and the sender's email is "BBB#gmail.com".
Here is my expression:
"(subject matches '(?i)AAA.*')|(sender matches '(?i).BBB#gmail.com.')"
The way how to set user defined flag is very slow. I have to load all email from the open folder and find the email that match with the message Id of current reading message. Is there any better and faster way to do this?
spring-context.xml
<int-mail:imap-idle-channel-adapter id="customAdapter"
store-uri="imaps://XXXX:XXXX#imap.gmail.com:993/inbox"
channel="receiveChannel"
auto-startup="true"
should-delete-messages="false"
should-mark-messages-as-read="true"
java-mail-properties="mailProperties"
mail-filter-expression="(subject matches '(?i)AAA.*')|(sender matches '(?i).*BBB#gmail.com.*')"/>/>
<bean id="mailReceiver" class="com.mfr.email.EmailReceiver"/>
<int:service-activator input-channel="receiveChannel" ref="mailReceiver" method="process"/>
EmailReceiver.java
public void process(Message message) {
System.out.println("Got mail match with filter criteria!");
try {
String subject = message.getSubject();
.........
Folder folder = message.getFolder();
folder.open(Folder.READ_WRITE);
String messageId = ((MimeMessage)message).getMessageID();
Message[] messages = folder.getMessages();
FetchProfile contentsProfile = new FetchProfile();
contentsProfile.add(FetchProfile.Item.ENVELOPE);
contentsProfile.add(FetchProfile.Item.CONTENT_INFO);
contentsProfile.add(FetchProfile.Item.FLAGS);
folder.fetch(messages, contentsProfile);
for (int i = 0; i < messages.length; i++) {
Message loopMsg = messages[i];
String loopMsgId = ((MimeMessage)loopMsg ).getMessageID();
if (loopMsgId.equals(messageId)) {
Flags processedFlag = new Flags();
processedFlag.add(Flags.Flag.ANSWERED);
processedFlag.add(Flags.Flag.SEEN);
loopMsg.setFlags(processedFlag, true);
break;
}
}
folder.expunge();
folder.close(true);
} catch (Exception e) {
e.printStackTrace();
}
}

Answer 1

The common folder protocols (IMAP, POP3) do not allow you to modify messages. You can set the SEEN flag with IMAP, although accessing the message will typically set that for you automatically. Depending on why you're trying to change the Subject, you might be better off setting a user-defined Flag on the message. If you really need to change the Subject, you'll need to copy the message using the MimeMessage copy constructor, modify the copy, append the copy to the folder, and delete the original.
Also, your code above appears to be using a Message object unrelated to the Folder you're opening. You shouldn't do that. Once you close a Folder, all the Message objects from that Folder are invalid. If you reopen the Folder, you need to get a new Message object corresponding to the message you're dealing with (e.g., by looking it up using the UID of the message).