org.springframework.jdbc.core.ResultSetExtractor Maven / Gradle / Ivy
/*
* 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 {@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.
*
* 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.
*
*
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 the result type
* @see JdbcTemplate
* @see RowCallbackHandler
* @see RowMapper
* @see org.springframework.jdbc.core.support.AbstractLobStreamingResultSetExtractor
*/
@FunctionalInterface
public interface ResultSetExtractor {
/**
* 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 a 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;
}