mailet/src/main/java/org/apache/jsieve/mailet/ActionUtils.java

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 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
 * "License"); you may not use this file except in compliance   *
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package org.apache.jsieve.mailet;

import javax.mail.MessagingException;

import org.apache.mailet.Mail;
import org.apache.mailet.MailAddress;

/**
 * Utility methods helpful for actions.
 */
public class ActionUtils
{
    
    private final static String ATTRIBUTE_PREFIX = ActionUtils.class.getPackage().getName() + ".";

    /**
     * Answers the sole intended recipient for aMail.
     * 
     * @param aMail
     * @return String
     * @throws MessagingException
     */
    public static MailAddress getSoleRecipient(Mail aMail) throws MessagingException
    {
        if (aMail.getRecipients() == null) {
            throw new MessagingException("Invalid number of recipients - 0"
                    + ". Exactly 1 recipient is expected.");
        } else if (1 != aMail.getRecipients().size())
            throw new MessagingException("Invalid number of recipients - "
                    + new Integer(aMail.getRecipients().size()).toString()
                    + ". Exactly 1 recipient is expected.");
        return (MailAddress) aMail.getRecipients().iterator().next();
    }

    /**
     * Detect and handle locally looping mail. External loop detection is left
     * to the MTA.
     * 
     * @param aMail
     * @param context not null
     * @param anAttributeSuffix
     * @throws MessagingException
     */
    public static void detectAndHandleLocalLooping(Mail aMail, ActionContext context, String anAttributeSuffix)
            throws MessagingException
    {
        MailAddress thisRecipient = getSoleRecipient(aMail);
        MailAddress lastRecipient = (MailAddress) aMail
                .getAttribute(ATTRIBUTE_PREFIX + anAttributeSuffix);
        if (null != lastRecipient && lastRecipient.equals(thisRecipient))
        {
            MessagingException ex = new MessagingException(
                    "This message is looping! Message ID: "
                            + aMail.getMessage().getMessageID());
            context.getLog().warn(ex.getMessage(), ex);
            throw ex;
        }
        aMail.setAttribute(ATTRIBUTE_PREFIX + anAttributeSuffix,
                thisRecipient);
    }
}