server/mailet/mailets/src/main/java/org/apache/james/transport/matchers/RemoteDeliveryFailedWithSMTPCode.java

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package org.apache.james.transport.matchers;

import static org.apache.james.transport.mailets.remote.delivery.Bouncer.DELIVERY_ERROR_CODE;

import java.util.Collection;

import javax.mail.MessagingException;

import org.apache.james.core.MailAddress;
import org.apache.mailet.AttributeUtils;
import org.apache.mailet.Mail;
import org.apache.mailet.base.GenericMatcher;
import org.apache.mailet.base.MailetUtil;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;

/**
 * <p>
 * Checks the SMTP error code attached to remote delivery failures 
 * </p>
 */
public class RemoteDeliveryFailedWithSMTPCode extends GenericMatcher {

    private Integer errorCode;

    @Override
    public void init() throws MessagingException {
        this.errorCode = MailetUtil.getInitParameterAsStrictlyPositiveInteger(getCondition());
        Preconditions.checkArgument(errorCode >= 101 && errorCode <= 554, "Invalid SMTP code");
    }

    @Override
    public Collection<MailAddress> match(Mail mail) {
        return AttributeUtils.getValueAndCastFromMail(mail, DELIVERY_ERROR_CODE, Integer.class)
            .filter(errorCode::equals)
            .map(any -> mail.getRecipients())
            .orElse(ImmutableList.of());
    }
}