GenericDriver.java

/*
 * Copyright 2006-2012 The Scriptella Project Team.
 *
 * 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 scriptella.jdbc;

import scriptella.spi.AbstractScriptellaDriver;
import scriptella.spi.ConnectionParameters;

import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Generic adapter for JDBC drivers.
 *
 * @author Fyodor Kupolov
 * @version 1.0
 */
public class GenericDriver extends AbstractScriptellaDriver {

    private static final Logger LOG = Logger.getLogger(GenericDriver.class.getName());

    static {
        //Redirects DriverManager's logging
        final Logger LOG = Logger.getLogger("scriptella.DriverManagerLog");
        if (LOG.isLoggable(Level.FINE)) {
            if (DriverManager.getLogWriter() == null) {
                DriverManager.setLogWriter(new PrintWriter(System.out) {
                    public void println(String s) {
                        LOG.fine(s);
                    }
                });

            }
        }
    }

    /**
     * Tries to load one of the specified driver class names.
     *
     * @param drivers database driver candidate names.
     * @throws JdbcException if no drivers were loaded
     */
    protected void loadDrivers(String... drivers) {
        if (drivers.length > 0) {
            Throwable throwable = null;
            final boolean debug = LOG.isLoggable(Level.FINE);
            for (String name : drivers) {
                try {
                    try {
                        Class.forName(name);
                    } catch (ClassNotFoundException e) {
                        Class.forName(name, true, Thread.currentThread().getContextClassLoader());
                    }
                    if (debug) {
                        LOG.fine("Found driver class " + name);
                    }
                    throwable = null;
                    break;
                } catch (Throwable t) {
                    if (throwable == null) {
                        throwable = t;
                    } else {
                        if (debug) {
                            LOG.log(Level.FINE, "Failed to load driver class " + name, t);
                        }
                    }
                }
            }
            if (throwable != null) {
                throw new JdbcException("Couldn't find appropriate jdbc driver : " + drivers[0] +
                        ". Please check class path settings", throwable);
            }
        }
    }

    public JdbcConnection connect(ConnectionParameters params) {
        try {
            Properties props = new Properties();
            props.putAll(params.getProperties());
            //according to JDBC spec
            if (params.getUser() != null) {
                props.put("user", params.getUser());
            }
            if (params.getPassword() != null) {
                props.put("password", params.getPassword());
            }
            return connect(params, props);

        } catch (SQLException e) {
            throw new JdbcException("Unable to obtain connection for URL " + params.getUrl(), e);
        }
    }


    /**
     * Creates Scriptella JDBC connection.
     *
     * @param parameters connection parameters
     * @param props      properties to pass to jdbc driver
     * @return Scriptella JDBC connection.
     * @throws SQLException if DB exception occurs.
     */
    protected JdbcConnection connect(ConnectionParameters parameters, Properties props) throws SQLException {
        return new JdbcConnection(getConnection(parameters.getUrl(), props), parameters);
    }

    /**
     * A helper method for subclasses to avoid direct interaction with DriverManager API.
     * <p>Calls {@link DriverManager#getConnection(String,java.util.Properties)}
     */
    protected Connection getConnection(String url, Properties props) throws SQLException {
        return DriverManager.getConnection(url, props);
    }


}