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 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
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package org.apache.james.mailbox.store.mail;

import java.util.Optional;

import org.apache.james.mailbox.MailboxSession;
import org.apache.james.mailbox.MessageUid;
import org.apache.james.mailbox.exception.MailboxException;
import org.apache.james.mailbox.model.Mailbox;
import org.apache.james.mailbox.model.MailboxId;

/**
 * Take care of provide uids for a given {@link Mailbox}. Be aware that implementations
 * need to be thread-safe!
 * 
 *
 */
public interface UidProvider {

    /**
     * Return the next uid which can be used while append a MailboxMessage to the {@link Mailbox}.
     * Its important that the returned uid is higher then the last used and that the next call of this method does return a higher
     * one
     */
    MessageUid nextUid(MailboxSession session, Mailbox mailbox) throws MailboxException;
    
    /**
     * Return the last uid which were used for storing a MailboxMessage in the {@link Mailbox}
     */
    Optional<MessageUid> lastUid(MailboxSession session, Mailbox mailbox) throws MailboxException;
    
    MessageUid nextUid(MailboxSession session, MailboxId mailboxId) throws MailboxException;
}
