org.jiemamy.utils.sql.DriverUtil.java Source code

Introduction

Here is the source code for org.jiemamy.utils.sql.DriverUtil.java

Source

/*
 * Copyright 2007-2012 Jiemamy Project and the Others.
 * Created on 2008/07/26
 *
 * This file is part of Jiemamy.
 *
 * 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.jiemamy.utils.sql;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.sql.Driver;
import java.util.Collection;
import java.util.jar.JarFile;

import com.google.common.collect.Lists;

import org.apache.commons.lang.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.jiemamy.JiemamyError;
import org.jiemamy.utils.ClassTraversal;
import org.jiemamy.utils.ClassTraversal.ClassHandler;
import org.jiemamy.utils.LogMarker;
import org.jiemamy.utils.TraversalHandlerException;
import org.jiemamy.utils.reflect.ClassUtil;

/**
 * JDBC??
 * 
 * @version $Id$
 * @author daisuke
 */
public final class DriverUtil {

    private static Logger logger = LoggerFactory.getLogger(DriverUtil.class);

    /**
     * JAR???Driver???
     * 
     * @param paths JAR?URL??
     * @return Driver?
     * @throws IOException ????
     * @throws IllegalArgumentException ?{@code null}????????{@code null}??
     * @throws IllegalArgumentException URI??????URL????????
     * @throws FileNotFoundException paths???JAR????????
     */
    public static Collection<Class<? extends Driver>> getDriverClasses(URL[] paths) throws IOException {
        Validate.noNullElements(paths);

        URLClassLoader classLoader = new URLClassLoader(paths);

        Collection<Class<? extends Driver>> driverList = Lists.newArrayList();

        for (URL path : paths) {
            try {
                File file = new File(path.toURI());
                if (file.exists() == false) {
                    throw new FileNotFoundException(file.getAbsolutePath());
                }
                JarFile jarFile = new JarFile(file);
                ClassTraversal.forEach(jarFile, new GetDriverClassesFromJarHandler(driverList, classLoader));
            } catch (URISyntaxException e) {
                throw new IllegalArgumentException(path.toString(), e);
            } catch (TraversalHandlerException e) {
                logger.error(LogMarker.DETAIL, "fail to handle jar entry.", e);
            }
        }
        return driverList;
    }

    /**
     * JAR?????
     * 
     * @param paths JAR?URL??
     * @param fqcn ????
     * @return ??
     * @throws IllegalAccessException ????????
     * @throws InstantiationException ????????
     * @throws DriverNotFoundException ?????????
     * @throws FileNotFoundException paths???JAR????????
     * @throws IOException I/O????
     * @throws IllegalArgumentException {@code paths}?{@code null}????????{@code null}???
     */
    public static Driver getDriverInstance(URL[] paths, String fqcn)
            throws InstantiationException, IllegalAccessException, DriverNotFoundException, IOException {
        Validate.noNullElements(paths);
        Validate.notNull(fqcn);
        Driver driver = null;

        Collection<Class<? extends Driver>> classes = getDriverClasses(paths);
        for (Class<? extends Driver> clazz : classes) {
            if (clazz.getName().equals(fqcn)) {
                driver = clazz.newInstance();
                break;
            }
        }

        if (driver == null) {
            try {
                driver = (Driver) Class.forName(fqcn).newInstance();
            } catch (ClassNotFoundException e) {
                throw new DriverNotFoundException(fqcn);
            }
        }
        return driver;
    }

    private DriverUtil() {
    }

    /**
     * JAR??{@link Driver}????
     * 
     * @author daisuke
     */
    private static final class GetDriverClassesFromJarHandler implements ClassHandler {

        private final Collection<Class<? extends Driver>> driverList;

        private final URLClassLoader classLoader;

        /**
         * ??
         * 
         * @param driverList ????????
         * @param classLoader ??
         */
        private GetDriverClassesFromJarHandler(Collection<Class<? extends Driver>> driverList,
                URLClassLoader classLoader) {
            assert driverList != null;
            assert classLoader != null;
            this.driverList = driverList;
            this.classLoader = classLoader;
        }

        public void processClass(String packageName, String shortClassName) throws TraversalHandlerException {
            String fqcn = ClassUtil.concatName(packageName, shortClassName);
            try {
                Class<?> clazz = classLoader.loadClass(fqcn);
                Class<?>[] interfaceClasses = clazz.getInterfaces();
                for (Class<?> interfaceClass : interfaceClasses) {
                    if (interfaceClass.equals(Driver.class)) {
                        // ??reflection??????????
                        @SuppressWarnings("unchecked")
                        Class<? extends Driver> driverClass = (Class<? extends Driver>) clazz;
                        driverList.add(driverClass);
                    }
                }
            } catch (NoClassDefFoundError e) {
                // ignore
            } catch (ClassNotFoundException e) {
                throw new JiemamyError("Class must to be in classpath: " + fqcn, e);
            } catch (Throwable t) {
                throw new TraversalHandlerException(t);
            }
        }
    }
}