jodd-mail/src/main/java/jodd/mail/EmailFilter.java
public EmailFilter header(final String headerName, final String pattern) {
		final SearchTerm term = new HeaderTerm(headerName, pattern);
		concat(term);
		return this;
	}
public EmailFilter header(final String headerName, final String pattern) {
		final SearchTerm term = new HeaderTerm(headerName, pattern);
		concat(term);
		return this;
	}
public EmailFilter header ( final String headerName , final String pattern ) { final SearchTerm term = new HeaderTerm ( headerName , pattern ) ; concat ( term ) ; return this ; }
Defines filter for {@link Header}.

@param headerName The name of the {@link Header}.
@param pattern    String pattern to use for headerName.
@return this
Defines filter for { @link Header } .