MemoryMailStatusResult.java

/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.mail.internal;

import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.NoSuchElementException;

import org.xwiki.mail.MailState;
import org.xwiki.mail.MailStatus;

/**
 * Implementation that saves all mail statuses in a Map in memory.
 *
 * This implementation is not meant for scalability. Don't use it if you're sending a large number of emails. Instead
 * use a Database Mail Listener for example.
 *
 * @version $Id: e21c16cfc8b2b2450f198137fd89c16f831f397b $
 * @since 6.4M3
 */
public class MemoryMailStatusResult extends AbstractMailStatusResult
{
    private abstract class AbstractMailStatusIterator implements Iterator<MailStatus>
    {
        private final Iterator<MailStatus> it = statusMap.values().iterator();
        private MailStatus nextStatus;

        abstract boolean match(MailStatus status);

        @Override
        public boolean hasNext()
        {
            while (nextStatus == null && it.hasNext())  {
                nextStatus = it.next();
                if (!match(nextStatus)) {
                    nextStatus = null;
                }
            }
            return (nextStatus != null);
        }

        @Override
        public MailStatus next()
        {
            hasNext();
            if (nextStatus == null) {
                throw new NoSuchElementException();
            }
            try {
                return nextStatus;
            } finally {
                nextStatus = null;
            }
        }

        @Override
        public void remove()
        {
            throw new UnsupportedOperationException();
        }
    }

    /**
     * The Map's key is the unique message ID.
     *
     * Note that we keep the order in which messages are passed (i.e. the first status result will contain the first
     * mail sent, etc).
     */
    private Map<String, MailStatus> statusMap = new LinkedHashMap<>();

    /**
     * Retrieve the status for the given message identifier.
     *
     * @param uniqueMessageId the unique id of the message.
     * @return the mail status for the given message, or null if none were found.
     */
    public MailStatus getStatus(String uniqueMessageId)
    {
        return this.statusMap.get(uniqueMessageId);
    }

    /**
     * Changes the status for the message referenced in the passed status object.
     *
     * @param status the new status. Also contains the message id representing the target message
     */
    public void setStatus(MailStatus status)
    {
        this.statusMap.put(status.getMessageId(), status);
    }

    @Override
    public Iterator<MailStatus> getAll()
    {
        return this.statusMap.values().iterator();
    }

    @Override
    public Iterator<MailStatus> getAllErrors()
    {
        return new AbstractMailStatusIterator() {
            @Override
            boolean match(MailStatus status)
            {
                return status.getState().endsWith("_error");
            }
        };
    }

    @Override
    public Iterator<MailStatus> getByState(final MailState state)
    {
        return new AbstractMailStatusIterator() {
            @Override
            boolean match(MailStatus status)
            {
                return MailState.parse(status.getState()).equals(state);
            }
        };
    }
}