/*
 * Copyright (c) "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.procedure;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.neo4j.annotations.api.PublicApi;

/**
 * Declares a method as the result method of an aggregation.
 * <p>
 * This method is called once when the aggregation is done ({@link UserAggregationUpdate}
 *
 * <h2>Output declaration</h2>
 * A function must always return a single value.
 * <p>
 * Valid return types are as follows:
 *
 * <ul>
 *     <li>{@link String}</li>
 *     <li>{@link Long} or {@code long}</li>
 *     <li>{@link Double} or {@code double}</li>
 *     <li>{@link Number}</li>
 *     <li>{@link Boolean} or {@code boolean}</li>
 *     <li>{@link org.neo4j.graphdb.Node}</li>
 *     <li>{@link org.neo4j.graphdb.Relationship}</li>
 *     <li>{@link org.neo4j.graphdb.Path}</li>
 *     <li>{@link java.util.Map} with key {@link String} and value of any type in this list, including {@link java.util.Map}</li>
 *     <li>{@link java.util.List} of elements of any valid field type, including {@link java.util.List}</li>
 *     <li>{@link Object}, meaning any of the valid return types above</li>
 * </ul>
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@PublicApi
public @interface UserAggregationResult {}
