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/*
* Copyright 2016-2023 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
*
* https://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.reactivestreams.Publisher;
import org.springframework.dao.DataAccessException;
import org.springframework.data.cassandra.ReactiveResultSet;
import org.springframework.util.Assert;
import com.datastax.oss.driver.api.core.DriverException;
/**
* Adapter implementation of the {@link ReactiveResultSetExtractor} interface that delegates to a {@link RowMapper}
* which is supposed to create an object for each row. Each object is emitted through the {@link Publisher} of this
* {@link ReactiveResultSetExtractor}.
*
* Useful for the typical case of one object per row in the database table. The number of entries in the results will
* match the number of rows.
*
* Note that a {@link RowMapper} object is typically stateless and thus reusable.
*
* @author Mark Paluch
* @since 2.0
* @see RowMapper
* @see ReactiveCqlTemplate
*/
public class ReactiveRowMapperResultSetExtractor implements ReactiveResultSetExtractor {
private final RowMapper rowMapper;
/**
* Create a new {@link ReactiveRowMapperResultSetExtractor}.
*
* @param rowMapper the {@link RowMapper} which creates an object for each row, must not be {@literal null}.
*/
public ReactiveRowMapperResultSetExtractor(RowMapper rowMapper) {
Assert.notNull(rowMapper, "RowMapper is must not be null");
this.rowMapper = rowMapper;
}
@Override
public Publisher extractData(ReactiveResultSet resultSet) throws DriverException, DataAccessException {
return resultSet.rows().handle((row, sink) -> {
T value = this.rowMapper.mapRow(row, 0);
if (value != null) {
sink.next(value);
}
});
}
}