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package org.apache.james.mailetcontainer.lib.matchers;
import java.util.Collection;
import java.util.Iterator;
import java.util.ArrayList;
import org.apache.mailet.MailAddress;
import org.apache.mailet.Mail;
import javax.mail.MessagingException;
import org.apache.mailet.Matcher;
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 match(Mail mail) throws MessagingException {
Collection finalResult = null;
Matcher matcher = null;
boolean first = true;
for (Iterator matcherIter = iterator(); matcherIter.hasNext();) {
matcher = (Matcher) (matcherIter.next());
Collection result = matcher.match(mail);
if (result == null) {
result = new ArrayList(0);
}
// log("Matching with " +
// matcher.getMatcherConfig().getMatcherName() +
// " result="+result.toString() );
if (first) {
finalResult = result;
first = false;
} else {
// Check if we need to Xor ...
// if the finalResult and the subsequent result are the same
// collection, then it contains the same recipients
// so we can short-circuit building the XOR and return an empty
// set
if (finalResult == result) {
// the XOR of the same collection is empty
finalResult.clear();
// log("same collection - so clear");
} else {
// the two results are different collections, so we XOR them
// Ensure that the finalResult does not contain recipients
// in the result collection
MailAddress recipient = null;
for (Iterator i = result.iterator(); i.hasNext();) {
recipient = (MailAddress) (i.next());
if (!finalResult.contains(recipient)) {
finalResult.add(recipient);
} else {
finalResult.remove(recipient);
}
}
recipient = null;
// log("xor recipients into new finalResult="+finalResult);
}
// basically the finalResult gets replaced with a smaller result
// otherwise finalResult would have been equal to result (in all
// cases)
}
result = null;
}
return finalResult;
}
}