/*
* Copyright 2002-2018 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
*
* 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.jdbc.core;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.dao.DataAccessException;
import org.springframework.lang.Nullable;
Callback interface used by JdbcTemplate's query methods. Implementations of this interface perform the actual work of extracting results from a ResultSet, but don't need to worry about exception handling. SQLExceptions will be caught and handled by the calling JdbcTemplate. This interface is mainly used within the JDBC framework itself. A RowMapper is usually a simpler choice for ResultSet processing, mapping one result object per row instead of one result object for the entire ResultSet.
Note: In contrast to a RowCallbackHandler, a ResultSetExtractor object is typically stateless and thus reusable, as long as it doesn't access stateful resources (such as output streams when streaming LOB contents) or keep result state within the object.
Author: Rod Johnson, Juergen Hoeller Type parameters: - <T> – the result type
See Also: Since: April 24, 2003
/**
* Callback interface used by {@link JdbcTemplate}'s query methods.
* Implementations of this interface perform the actual work of extracting
* results from a {@link java.sql.ResultSet}, but don't need to worry
* about exception handling. {@link java.sql.SQLException SQLExceptions}
* will be caught and handled by the calling JdbcTemplate.
*
* <p>This interface is mainly used within the JDBC framework itself.
* A {@link RowMapper} is usually a simpler choice for ResultSet processing,
* mapping one result object per row instead of one result object for
* the entire ResultSet.
*
* <p>Note: In contrast to a {@link RowCallbackHandler}, a ResultSetExtractor
* object is typically stateless and thus reusable, as long as it doesn't
* access stateful resources (such as output streams when streaming LOB
* contents) or keep result state within the object.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since April 24, 2003
* @param <T> the result type
* @see JdbcTemplate
* @see RowCallbackHandler
* @see RowMapper
* @see org.springframework.jdbc.core.support.AbstractLobStreamingResultSetExtractor
*/
@FunctionalInterface
public interface ResultSetExtractor<T> {
Implementations must implement this method to process the entire ResultSet.
Params: - rs – the ResultSet to extract data from. Implementations should
not close this: it will be closed by the calling JdbcTemplate.
Throws: - SQLException – if an SQLException is encountered getting column
values or navigating (that is, there's no need to catch SQLException)
- DataAccessException – in case of custom exceptions
Returns: an arbitrary result object, or null if none (the extractor will typically be stateful in the latter case).
/**
* Implementations must implement this method to process the entire ResultSet.
* @param rs the ResultSet to extract data from. Implementations should
* not close this: it will be closed by the calling JdbcTemplate.
* @return an arbitrary result object, or {@code null} if none
* (the extractor will typically be stateful in the latter case).
* @throws SQLException if an SQLException is encountered getting column
* values or navigating (that is, there's no need to catch SQLException)
* @throws DataAccessException in case of custom exceptions
*/
@Nullable
T extractData(ResultSet rs) throws SQLException, DataAccessException;
}