/*
 * Copyright 2004-2014 Brian McCallister
 * Copyright 2010-2014 Ning, Inc.
 * Copyright 2014-2020 Groupon, Inc
 * Copyright 2020-2020 Equinix, Inc
 * Copyright 2014-2020 The Billing Project, LLC
 *
 * The Billing Project licenses this file to you under the Apache License, version 2.0
 * (the "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at:
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package org.skife.jdbi.v2;

import java.sql.ResultSet;
import java.sql.SQLException;

/**
 *
 */
public interface Folder2<AccumulatorType>
{
    /**
     * Invoked once per row in the result set from the query.
     *
     * @param accumulator The initial value passed to {@link org.skife.jdbi.v2.Query#fold(Object, Folder)}
     *                    for the first call, the return value from the previous call thereafter.
     * @param rs The actual result set from the query. It will already have been advanced to the
     *           correct row. Callbacks should not call {@link java.sql.ResultSet#next()}
     * @param ctx The statement context for execution
     * @return A value which will be passed to the next invocation of this function. The final
     *         invocation will be returned from the {@link org.skife.jdbi.v2.Query#fold(Object, Folder)} call.
     * @throws java.sql.SQLException will be wrapped and rethrown as a {@link org.skife.jdbi.v2.exceptions.CallbackFailedException}
     */
    AccumulatorType fold(AccumulatorType accumulator, ResultSet rs, StatementContext ctx) throws SQLException;

}
