org.apache.james.mailetcontainer.impl.matchers.Xor.java Source code

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Here is the source code for org.apache.james.mailetcontainer.impl.matchers.Xor.java

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package org.apache.james.mailetcontainer.impl.matchers;

import java.util.Collection;
import java.util.ArrayList;

import org.apache.mailet.MailAddress;
import org.apache.mailet.Mail;
import javax.mail.MessagingException;
import org.apache.mailet.Matcher;

import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;

public class Xor extends GenericCompositeMatcher {

    /**
     * This is the Xor CompositeMatcher - consider it to be the inequality
     * operator for recipients. If any recipients match other matcher results
     * then the result does not include that recipient.
     * 
     * @return Collection of Recipients from the Xor composition of the child
     *         matchers.
     */
    public Collection<MailAddress> match(Mail mail) throws MessagingException {
        Collection<MailAddress> finalResult = null;
        boolean first = true;
        for (Matcher matcher : getMatchers()) {
            Collection<MailAddress> matchedAddresses = Optional.fromNullable(matcher.match(mail))
                    .or(new ArrayList<MailAddress>());

            if (first) {
                finalResult = matchedAddresses;
                first = false;
            } else {
                finalResult = performXor(finalResult, matchedAddresses);
            }
        }
        return finalResult;
    }

    private Collection<MailAddress> performXor(Collection<MailAddress> collection1,
            Collection<MailAddress> collection2) {
        ImmutableSet<MailAddress> set1 = ImmutableSet.copyOf(collection1);
        ImmutableSet<MailAddress> set2 = ImmutableSet.copyOf(collection2);
        return Sets.difference(Sets.union(set1, set2), Sets.intersection(set1, set2)).immutableCopy();
    }

}