/*
 * Copyright (c) 2002-2020 "Neo4j,"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j. 
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version. 
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.   See the
 * GNU General Public License for more details. 
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.   If not, see <http://www.gnu.org/licenses/>. 
 */
package org.neo4j.graphdb.traversal;

/**
 * Factory for {@link UniquenessFilter} filters, it can supply the
 * created {@link UniquenessFilter} with an optional parameter which is
 * up to the filter itself to validate and make sense of. 
 */
public interface UniquenessFactory
{
    /**
     * Creates a new {@link UniquenessFilter} optionally with a parameter
     * to it, otherwise null if no parameter should be handed to it. 
     *
     * @param optionalParameter an optional parameter to control the behavior
     * of the returned {@link UniquenessFilter}.  It's up to each filter implementation
     * to decide what values are OK and what they mean and the caller of this
     * method need to know that and pass in the correct parameter type. 
     * @return a new {@link UniquenessFilter} of the type that this factory creates. 
     */
    UniquenessFilter create( Object optionalParameter );

    /**
     * Specifies if the {@link UniquenessFilter} must handle start branches eagerly.  Depending on the
     * level of uniqueness it is not always necessary to eagerly exhaust start
     * branches which can speed up the execution of the traversal. 
     *
     * @return {@code true} if eager start branches must be used, otherwise {@code false}. 
     */
    boolean eagerStartBranches();
}
