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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 org.apache.commons.lang3.NotImplementedException;
import org.apache.james.mailbox.MailboxPathLocker;
import org.apache.james.mailbox.MailboxSession;
import org.apache.james.mailbox.exception.MailboxException;
import org.apache.james.mailbox.model.Mailbox;
import org.apache.james.mailbox.model.MailboxId;


/**
 * Abstract base implementation of {@link ModSeqProvider} which uses the given {@link MailboxPathLocker} to lock the {@link Mailbox} during the mod-seq generation.
 */
public abstract class AbstractLockingModSeqProvider implements ModSeqProvider {

    private final MailboxPathLocker locker;

    public AbstractLockingModSeqProvider(MailboxPathLocker locker) {
        this.locker = locker;
    }
    
    @Override
    public long nextModSeq(MailboxSession session, Mailbox mailbox) throws MailboxException {
        boolean writeLock = true;
        return locker.executeWithLock(session, mailbox.generateAssociatedPath(),
            () -> lockedNextModSeq(session, mailbox),
            writeLock);
    }
    
    @Override
    public long nextModSeq(MailboxSession session, MailboxId mailboxId) {
        throw new NotImplementedException("Not implemented");
    }

    /**
     * Generate the next mod-seq for the given {@link Mailbox} while holding a lock on it.
     * 
     * @param session
     * @param mailbox
     * @return nextModSeq
     * @throws MailboxException
     */
    protected abstract long lockedNextModSeq(MailboxSession session, Mailbox mailbox) throws MailboxException;

}
