// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.search.grouping.request;

/**
 * This class represents a document relevance score in a {@link GroupingExpression}. It evaluates to the relevance of
 * the input {@link com.yahoo.search.result.Hit}.
 *
 * @author Simon Thoresen Hult
 * @author bratseth
 */
public class RelevanceValue extends DocumentValue {

    /**
     * Constructs a new instance of this class.
     */
    public RelevanceValue() {
        this(null, null);
    }

    private RelevanceValue(String label, Integer level) {
        super("relevance()", label, level);
    }

    @Override
    public RelevanceValue copy() {
        return new RelevanceValue(getLabel(), getLevelOrNull());
    }

}