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/*
* Copyright 2013-2018 the original author or authors.
*
* Licensed 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.springframework.data.cassandra.core.cql;
import org.springframework.lang.Nullable;
import com.datastax.driver.core.Row;
import com.datastax.driver.core.exceptions.DriverException;
/**
* An interface used by {@link CqlTemplate} for mapping rows of a {@link com.datastax.driver.core.ResultSet} on a
* per-row basis. Implementations of this interface perform the actual work of mapping each row to a result object, but
* don't need to worry about exception handling. {@link DriverException}s will be caught and handled by the calling
* {@link CqlTemplate}.
*
* Typically used either for {@link CqlTemplate}'s query methods or for out parameters of stored procedures.
* {@link RowMapper} objects are typically stateless and thus reusable; they are an ideal choice for implementing
* row-mapping logic in a single place.
*
* @author Matthew T. Adams
* @author Mark Paluch
* @see RowCallbackHandler
* @see ResultSetExtractor
*/
@FunctionalInterface
public interface RowMapper {
/**
* Implementations must implement this method to map each row of data in the
* {@link com.datastax.driver.core.ResultSet}.
*
* @param row the {@link Row} to map, must not be {@literal null}.
* @param rowNum the number of the current row.
* @return the result object for the current row.
* @throws DriverException if a {@link DriverException} is encountered getting column values (that is, there's no need
* to catch {@link DriverException})
*/
@Nullable
T mapRow(Row row, int rowNum) throws DriverException;
}