有没有办法在searchTerm (Apache Camel Mail组件)中添加Startswith？

import org.apache.camel.component.mail.SearchTermBuilder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.search.SearchTerm;

public class StartsWithFilter extends SearchTermBuilder {

    private String startsWith;

    public StartsWithFilter(String startsWith) {
        this.startsWith = startsWith;
    }

    @Override
    public SearchTerm match(Message message) throws MessagingException {
        String subject = message.getSubject();
        if (subject != null && subject.startsWith(startsWith)) {
            return new SearchTerm() {
                @Override
                public boolean match(Message msg) {
                    return true;
                }
            };
        }
        return null;
    }
}

from("pop3://pop.gmail.com?username=user@gmail.com&password=secret&delete=true")
    .filter().method(StartsWithFilter.class, "new StartsWithFilter('prefix')")
    .to("direct:processEmails");

from("direct:processEmails")
    .log("Received email: ${body}");