org.springframework.jdbc.object.UpdatableSqlQuery Maven / Gradle / Ivy
/*
* Copyright 2002-2005 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.jdbc.object;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.jdbc.core.ResultReader;
/**
* Reusable RDBMS query in which concrete subclasses must implement
* the abstract updateRow(ResultSet, int, context) method to update each
* row of the JDBC ResultSet and optionally map contents into an object.
*
* Subclasses can be constructed providing SQL, parameter types
* and a DataSource. SQL will often vary between subclasses.
*
* @author Thomas Risberg
* @see org.springframework.jdbc.object.SqlQuery
*/
public abstract class UpdatableSqlQuery extends SqlQuery {
/**
* Constructor to allow use as a JavaBean
*/
public UpdatableSqlQuery() {
setUpdatableResults(true);
}
/**
* Convenient constructor with DataSource and SQL string.
* @param ds DataSource to use to get connections
* @param sql SQL to run
*/
public UpdatableSqlQuery(DataSource ds, String sql) {
super(ds, sql);
setUpdatableResults(true);
}
/**
* Implementation of protected abstract method. This invokes the subclass's
* implementation of the updateRow() method.
*/
protected ResultReader newResultReader(int rowsExpected, Object[] parameters, Map context) {
return new ResultReaderImpl(rowsExpected, context);
}
/**
* Subclasses must implement this method to update each row of the
* ResultSet and optionally create object of the result type.
* @param rs ResultSet we're working through
* @param rowNum row number (from 0) we're up to
* @param context passed to the execute() method.
* It can be null if no contextual information is need. If you
* need to pass in data for each row, you can pass in a HashMap with
* the primary key of the row being the key for the HashMap. That way
* it is easy to locate the updates for each row
* @return an object of the result type
* @throws SQLException if there's an error updateing data.
* Subclasses can simply not catch SQLExceptions, relying on the
* framework to clean up.
*/
protected abstract Object updateRow(ResultSet rs, int rowNum, Map context) throws SQLException;
/**
* Implementation of ResultReader that calls the enclosing
* class's updateRow() method for each row.
*/
protected class ResultReaderImpl implements ResultReader {
/** List to save results in */
private final List results;
private final Map context;
private int rowNum = 0;
/**
* Use an array results. More efficient if we know how many results to expect.
*/
public ResultReaderImpl(int rowsExpected, Map context) {
// use the more efficient collection if we know how many rows to expect
this.results = (rowsExpected > 0) ? (List) new ArrayList(rowsExpected) : (List) new LinkedList();
this.context = context;
}
public void processRow(ResultSet rs) throws SQLException {
this.results.add(updateRow(rs, this.rowNum++, this.context));
rs.updateRow();
}
public List getResults() {
return this.results;
}
}
}