commons/http/src/main/java/org/ldp4j/http/Languages.java
public static boolean includes(final Language language1, final Language language2) {
		if(language1==null || language2==null) {
			return false;
		}
		if(language1.isWildcard()) {
			return true;
		}
		if(language2.isWildcard()) {
			return false;
		}
		return
			language1.primaryTag().equals(language2.primaryTag()) &&
			(language1.subTag().isEmpty() || language1.subTag().equals(language2.subTag()));
	}
public static boolean includes(final Language language1, final Language language2) {
		if(language1==null || language2==null) {
			return false;
		}
		if(language1.isWildcard()) {
			return true;
		}
		if(language2.isWildcard()) {
			return false;
		}
		return
			language1.primaryTag().equals(language2.primaryTag()) &&
			(language1.subTag().isEmpty() || language1.subTag().equals(language2.subTag()));
	}
Implements Basic Filtering matching algorithm defined in
<a href="https://tools.ietf.org/html/rfc4647#section-3.3.1">Section
3.3.1</a> of the <b>Matching of Language Tags</b> (BCP 47)

@param language1
the including language
@param language2
the language that will be checked for inclusion
@return true, if the {@code language1} includes {@code language2}
attending to the aforementioned algorithm.