/*
// This software is subject to the terms of the Eclipse Public License v1.0
// Agreement, available at the following URL:
// http://www.eclipse.org/legal/epl-v10.html.
// Copyright (C) 2009-2010 Julian Hyde
// All Rights Reserved.
// You must accept the terms of that agreement to use this software.
*/
package mondrian.spi.impl;
import mondrian.spi.DialectFactory;
import mondrian.spi.Dialect;
import mondrian.olap.Util;
import javax.sql.DataSource;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.sql.*;
/**
* Implementation of {@link mondrian.spi.DialectFactory} for subclasses
* of {@link mondrian.spi.impl.JdbcDialectImpl}.
*
* <p>Assumes that the dialect has a public constructor that takes a
* {@link java.sql.Connection} as a parameter.
*/
public class JdbcDialectFactory implements DialectFactory {
private final Dialect.DatabaseProduct databaseProduct;
private final Constructor<? extends JdbcDialectImpl> constructor;
/**
* Creates a JdbcDialectFactory.
*
* @param dialectClass Dialect class
* @param databaseProduct Database type (e.g. Oracle) if this is a
* common RDBMS, or null if it is an uncommon one
*/
public JdbcDialectFactory(
Class<? extends JdbcDialectImpl> dialectClass,
Dialect.DatabaseProduct databaseProduct)
{
this.databaseProduct = databaseProduct;
try {
constructor = dialectClass.getConstructor(Connection.class);
} catch (NoSuchMethodException e) {
throw Util.newError(
e,
"Class does not contain constructor "
+ "'public <init>(Connection connection)' required "
+ "for subclasses of JdbcDialectImpl");
}
}
/**
* Creates a temporary connection and calls
* {@link mondrian.spi.DialectFactory#createDialect(javax.sql.DataSource, java.sql.Connection)}.
*
* <p>Helper method, called when {@code createDialect} is called without a
* {@link java.sql.Connection} and the dialect factory
* cannot create a dialect with {@link javax.sql.DataSource} alone.
*
* <p>It is a user error if {@code dataSource} is null (since this implies
* that {@code createDialect} was called with {@code dataSource} and
* {@code connection} both null.</p>
*
* @param factory Dialect factory
* @param dataSource Data source, must not be null
* @return Dialect, or null if factory cannot create suitable dialect
*/
public static Dialect createDialectHelper(
DialectFactory factory,
DataSource dataSource)
{
if (dataSource == null) {
throw new IllegalArgumentException(
"Must specify either dataSource or connection");
}
Connection connection = null;
try {
connection = dataSource.getConnection();
if (connection == null) {
// DataSource.getConnection does not return null. But
// a null value here would cause infinite recursion, so
// let's be cautious.
throw new IllegalArgumentException();
}
final Dialect dialect =
factory.createDialect(dataSource, connection);
// Close the connection in such a way that if there is a
// SQLException,
// (a) we propagate the exception,
// (b) we don't try to close the connection again.
Connection connection2 = connection;
connection = null;
connection2.close();
return dialect;
} catch (SQLException e) {
throw Util.newError(
e,
"Error while creating dialect");
} finally {
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
// ignore
}
}
}
}
public Dialect createDialect(DataSource dataSource, Connection connection) {
// If connection is null, create a temporary connection and
// recursively call this method.
if (connection == null) {
return createDialectHelper(this, dataSource);
}
assert connection != null;
if (acceptsConnection(connection)) {
try {
return constructor.newInstance(connection);
} catch (InstantiationException e) {
throw Util.newError(
e, "Error while instantiating dialect");
} catch (IllegalAccessException e) {
throw Util.newError(
e, "Error while instantiating dialect");
} catch (InvocationTargetException e) {
throw Util.newError(
e, "Error while instantiating dialect");
}
}
return null;
}
/**
* Returns whether this dialect is suitable for the given connection.
*
* @param connection Connection
* @return Whether suitable
*/
protected boolean acceptsConnection(Connection connection) {
try {
final DatabaseMetaData metaData = connection.getMetaData();
final String productName = metaData.getDatabaseProductName();
final String productVersion = metaData.getDatabaseProductVersion();
final Dialect.DatabaseProduct product =
JdbcDialectImpl.getProduct(productName, productVersion);
return product == this.databaseProduct;
} catch (SQLException e) {
throw Util.newError(
e, "Error while instantiating dialect");
}
}
}
// End JdbcDialectFactory.java