org.springframework.jdbc.object.MappingSqlQuery 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.object;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.lang.Nullable;
/**
* Reusable query in which concrete subclasses must implement the abstract
* mapRow(ResultSet, int) method to convert each row of the JDBC ResultSet
* into an object.
*
* Simplifies MappingSqlQueryWithParameters API by dropping parameters and
* context. Most subclasses won't care about parameters. If you don't use
* contextual information, subclass this instead of MappingSqlQueryWithParameters.
*
* @author Rod Johnson
* @author Thomas Risberg
* @author Jean-Pierre Pawlak
* @param the result type
* @see MappingSqlQueryWithParameters
*/
public abstract class MappingSqlQuery extends MappingSqlQueryWithParameters {
/**
* Constructor that allows use as a JavaBean.
*/
public MappingSqlQuery() {
}
/**
* Convenient constructor with DataSource and SQL string.
* @param ds the DataSource to use to obtain connections
* @param sql the SQL to run
*/
public MappingSqlQuery(DataSource ds, String sql) {
super(ds, sql);
}
/**
* This method is implemented to invoke the simpler mapRow
* template method, ignoring parameters.
* @see #mapRow(ResultSet, int)
*/
@Override
@Nullable
protected final T mapRow(ResultSet rs, int rowNum, @Nullable Object[] parameters, @Nullable Map context)
throws SQLException {
return mapRow(rs, rowNum);
}
/**
* Subclasses must implement this method to convert each row of the
* ResultSet into an object of the result type.
* Subclasses of this class, as opposed to direct subclasses of
* MappingSqlQueryWithParameters, don't need to concern themselves
* with the parameters to the execute method of the query object.
* @param rs the ResultSet we're working through
* @param rowNum row number (from 0) we're up to
* @return an object of the result type
* @throws SQLException if there's an error extracting data.
* Subclasses can simply not catch SQLExceptions, relying on the
* framework to clean up.
*/
@Nullable
protected abstract T mapRow(ResultSet rs, int rowNum) throws SQLException;
}