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 *  to you under the Apache License, Version 2.0 (the
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package org.apache.cayenne.dba.mysql;

import org.apache.cayenne.configuration.server.DbAdapterDetector;
import org.apache.cayenne.dba.DbAdapter;
import org.apache.cayenne.di.AdhocObjectFactory;
import org.apache.cayenne.di.Inject;

import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * Detects MySQL database from JDBC metadata.
 * 
 * @since 1.2
 */
public class MySQLSniffer implements DbAdapterDetector {

	protected AdhocObjectFactory objectFactory;

	public MySQLSniffer(@Inject AdhocObjectFactory objectFactory) {
		this.objectFactory = objectFactory;
	}

	@Override
	public DbAdapter createAdapter(DatabaseMetaData md) throws SQLException {
		String dbName = md.getDatabaseProductName();
		if (dbName == null || !dbName.toUpperCase().contains("MYSQL")) {
			return null;
		}

		// if InnoDB is used as a default engine, allow PK

		String adapterStorageEngine = MySQLAdapter.DEFAULT_STORAGE_ENGINE;

		try (Statement statement = md.getConnection().createStatement();) {
			// http://dev.mysql.com/doc/refman/5.0/en/storage-engines.html
			// per link above "table type" concept is deprecated in favor of
			// "storage
			// engine". Not sure if we should check "storage_engine" variable
			// and in what
			// version of MySQL it got introduced...

			try (ResultSet rs = statement.executeQuery("SHOW VARIABLES LIKE 'table_type'");) {
				if (rs.next()) {
					String storageEngine = rs.getString(2);
					if (storageEngine != null) {
						adapterStorageEngine = storageEngine;
					}
				}
			}
		}

		MySQLAdapter adapter = objectFactory.newInstance(MySQLAdapter.class, MySQLAdapter.class.getName());
		adapter.setStorageEngine(adapterStorageEngine);
		return adapter;
	}
}