import java.util.Map;
import java.util.Set;

/**
 * A webpage index.
 * 
 * @author CIS-121 Staff
 */
public class WebpageIndex {

	/**
	 * Adds a {@link WebpageIndexEntryI} to this index.
	 * 
	 * @param entry the {@link WebpageIndexEntryI} to add.
	 */
	public void addEntry(WebpageIndexEntryI entry) {

	}

	/**
	 * Creates a map from keywords to {@link WebpageIndexEntryI} where a
	 * {@link WebpageIndexEntryI} is in the set of a particular keyword if that
	 * keyword appears at least {@code frequency} number of times in the entry.
	 * 
	 * @param frequency the number of times a keyword must appear in an entry to
	 *            be counted for that keyword's set.
	 * @return a map from keywords to {@link WebpageIndexEntryI} where a
	 *         {@link WebpageIndexEntryI} is in the set of a particular keyword
	 *         if that keyword appears at least {@code frequency} number of
	 *         times in the entry
	 */
	public Map<String, Set<WebpageIndexEntryI>> keywordMap(int frequency) {

		return null;
	}
}