Glassfish example source code file (JDBCDriverLoader.java)

This example Glassfish source code file (JDBCDriverLoader.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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The Glassfish JDBCDriverLoader.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2009-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
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 * If you wish your version of this file to be governed by only the CDDL or
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 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
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 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
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 */

package org.glassfish.osgijdbc;

import com.sun.enterprise.util.SystemPropertyConstants;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.Modifier;
import java.util.*;
import java.util.jar.Attributes;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.zip.ZipEntry;

public class JDBCDriverLoader {

    private static Logger logger = Logger.getLogger(JDBCDriverLoader.class.getPackage().getName());

    private static final String DRIVER_INTERFACE_NAME = "java.sql.Driver";
    private static final String META_INF_SERVICES_DRIVER_FILE = "META-INF/services/java.sql.Driver";
    private static final String DBVENDOR_MAPPINGS_ROOT =
            System.getProperty(SystemPropertyConstants.INSTALL_ROOT_PROPERTY) + File.separator +
                    "lib" + File.separator + "install" + File.separator + "databases" +
                    File.separator + "dbvendormapping" + File.separator;

    private static final String DS_PROPERTIES = "ds.properties";
    private static final String CPDS_PROPERTIES = "cpds.properties";
    private static final String XADS_PROPERTIES = "xads.properties";
    private static final String DRIVER_PROPERTIES = "driver.properties";
    private static final String VENDOR_PROPERTIES = "dbvendor.properties";


    public static final Map<String, Map dbVendorMappings = new HashMap>();

    static{
        loadMappings();
    }

    private ClassLoader cl;
    
    public JDBCDriverLoader(ClassLoader cl){
        this.cl = cl;
    }

    private static void loadMappings(){
        dbVendorMappings.put(Constants.DS, ((Map)loadProperties(DS_PROPERTIES)));
        dbVendorMappings.put(Constants.CPDS, ((Map)loadProperties(CPDS_PROPERTIES)));
        dbVendorMappings.put(Constants.XADS, ((Map)loadProperties(XADS_PROPERTIES)));
        dbVendorMappings.put(Constants.DRIVER, ((Map)loadProperties(DRIVER_PROPERTIES)));
        dbVendorMappings.put(Constants.DBVENDOR, ((Map)loadProperties(VENDOR_PROPERTIES)));
    }

    private static Properties loadProperties(String type){
        Properties fileProperties = new Properties();
        String fileName = DBVENDOR_MAPPINGS_ROOT + type;
        File mappingFile = new File(fileName);

        if (mappingFile.exists()) {
            try {
                FileInputStream fis = new FileInputStream(mappingFile);
                try {
                    fileProperties.load(fis);
                } finally {
                    fis.close();
                }
            } catch (IOException ioe) {
                logger.fine("IO Exception while loading properties file" +
                        " [ "+mappingFile.getAbsolutePath()+" ] : " +  ioe);
            }
        } else {
            logger.warning("File not found : " + mappingFile.getAbsolutePath());
        }
        return fileProperties;
    }

    /**
     * Get a set of common database vendor names supported in GlassFish.
     * @return database vendor names set.
     */
    private Set<String> getDatabaseVendorNames() {
        Map vendors = dbVendorMappings.get(Constants.DBVENDOR);
        return vendors.keySet();
    }

    private String getDBVendor(String className, String type) {
        String dbVendor = null;
        Map map = dbVendorMappings.get(type);
        Set entrySet = map.entrySet();
        Iterator entryIterator = entrySet.iterator();
        while(entryIterator.hasNext()){
            Map.Entry entry = (Map.Entry)entryIterator.next();
            if(((String)entry.getValue()).equalsIgnoreCase(className)){
                dbVendor = (String)entry.getKey();
                break;
            }
        }
        return dbVendor;
    }

    private String getImplClassNameFromMapping(String dbVendor, String resType) {
        Map fileProperties = dbVendorMappings.get(resType);
        if(fileProperties == null){
            throw new IllegalStateException("Unknown resource type [ " + resType + " ]");
        }
        return (String)fileProperties.get(dbVendor.toUpperCase());
    }


    public Properties loadDriverInformation(File f) {
        String implClass;
        JarFile jarFile = null;

        Properties properties = new Properties();
        try {
            jarFile = new JarFile(f);
            Enumeration e = jarFile.entries();
            while (e.hasMoreElements()) {

                ZipEntry zipEntry = (ZipEntry) e.nextElement();

                if (zipEntry != null) {

                    String entry = zipEntry.getName();
                    if (META_INF_SERVICES_DRIVER_FILE.equals(entry)) {

                        InputStream metaInf = jarFile.getInputStream(zipEntry);
                        implClass = processMetaInfServicesDriverFile(metaInf);
                        if (implClass != null) {
                            if (isLoaded(implClass, Constants.DRIVER, cl)) {
                                String vendor = getVendorFromManifest(f);

                                Set<String> dbVendorNames = getDatabaseVendorNames();
                                if (vendor != null && dbVendorNames.contains(vendor)) {

                                    String dsClassName = getImplClassNameFromMapping(vendor, Constants.DS);
                                    String cpdsClassName = getImplClassNameFromMapping(vendor, Constants.CPDS);
                                    String xadsClassName = getImplClassNameFromMapping(vendor, Constants.XADS);
                                    //String driverClassName = getImplClassNameFromMapping(vendor,DRIVER);
                                    String driverClassName = implClass;

                                    properties.put(Constants.DS, dsClassName);
                                    properties.put(Constants.CPDS, cpdsClassName);
                                    properties.put(Constants.XADS, xadsClassName);
                                    properties.put(Constants.DRIVER, driverClassName);

                                    return properties;

                                } else if (vendor != null) {

                                    Set<String> dsClasses = getImplClassesByIteration(f, Constants.DS, vendor, cl);
                                    if (dsClasses.size() == 1) {
                                        properties.put(Constants.DS, dsClasses.toArray()[0]);
                                    }

                                    Set<String> cpdsClasses = getImplClassesByIteration(f, Constants.CPDS, vendor, cl);
                                    if (cpdsClasses.size() == 1) {
                                        properties.put(Constants.CPDS, cpdsClasses.toArray()[0]);
                                    }

                                    Set<String> xadsClasses = getImplClassesByIteration(f, Constants.XADS, vendor, cl);
                                    if (xadsClasses.size() == 1) {
                                        properties.put(Constants.XADS, xadsClasses.toArray()[0]);
                                    }
                                    properties.put(Constants.DRIVER, implClass);

                                    return properties;
                                }
                            }
                        }
                        logger.finest("Driver loader : implClass = " + implClass);

                    }
                    if (entry.endsWith(".class")) {
                        //Read from MANIFEST.MF file for all jdbc40 drivers and resType
                        //java.sql.Driver.TODO : this should go outside .class check.
                        //TODO : Some classnames might not have these strings
                        //in their classname. Logic should be flexible in such cases.
                        if (entry.toUpperCase().contains("DATASOURCE")) {
                            implClass = getClassName(entry);
                            if (implClass != null) {
                                if (isLoaded(implClass, Constants.XADS, cl)) {
                                    String dbVendor = getDBVendor(implClass, Constants.XADS);
                                    if (dbVendor != null) {
                                        detectImplClasses(properties, dbVendor);
                                        return properties;
                                    } else {
                                        properties.put(Constants.XADS, implClass);
                                    }
                                } else if (isLoaded(implClass, Constants.CPDS, cl)) {
                                    String dbVendor = getDBVendor(implClass, Constants.CPDS);
                                    if (dbVendor != null) {
                                        detectImplClasses(properties, dbVendor);
                                        return properties;
                                    } else {
                                        properties.put(Constants.CPDS, implClass);
                                    }
                                } else if (isLoaded(implClass, Constants.DS, cl)) {
                                    String dbVendor = getDBVendor(implClass, Constants.DS);
                                    if (dbVendor != null) {
                                        detectImplClasses(properties, dbVendor);
                                        return properties;
                                    } else {
                                        properties.put(Constants.DS, implClass);
                                    }
                                }
                            }
                        } else if (entry.toUpperCase().contains("DRIVER")) {
                            implClass = getClassName(entry);
                            if (implClass != null) {
                                if (isLoaded(implClass, Constants.DRIVER, cl)) {
                                    String dbVendor = getDBVendor(implClass, Constants.DRIVER);
                                    if (dbVendor != null) {
                                        detectImplClasses(properties, dbVendor);
                                        return properties;
                                    } else {
                                        properties.put(Constants.DRIVER, implClass);
                                    }
                                }
                            }
                        }
                    }
                }
            }
        } catch (IOException ex) {
            logger.log(Level.WARNING, "Error while getting Jdbc driver classnames ", ex);
        } finally {
            if (jarFile != null) {
                try {
                    jarFile.close();
                } catch (IOException ex) {
                    logger.log(Level.FINE, "Exception while closing JarFile '"
                            + jarFile.getName() + "' :", ex);
                }
            }
        }
        if (properties.get(Constants.DRIVER) != null) {
            return properties;
        } else {
            throw new RuntimeException("Unable to introspect jar [ "+f.getName()+" ] for Driver Class, " +
                    "no implementation for java.sql.Driver is found");
        }
    }

    private void detectImplClasses(Properties properties, String dbVendor) {
        String xads = getImplClassNameFromMapping(dbVendor, Constants.XADS);
        String cpds = getImplClassNameFromMapping(dbVendor, Constants.CPDS);
        String ds = getImplClassNameFromMapping(dbVendor, Constants.DS);
        String driver = getImplClassNameFromMapping(dbVendor, Constants.DRIVER);

        properties.put(Constants.XADS, xads);
        properties.put(Constants.CPDS, cpds);
        properties.put(Constants.DS, ds);
        properties.put(Constants.DRIVER, driver);
    }


    private Set<String> getImplClassesByIteration(File f, String resType, String dbVendor, ClassLoader cl) {
        SortedSet<String> implClassNames = new TreeSet();
        String implClass = null;
        JarFile jarFile = null;
        try {
            jarFile = new JarFile(f);
            Enumeration e = jarFile.entries();
            while (e.hasMoreElements()) {

                ZipEntry zipEntry = (ZipEntry) e.nextElement();

                if (zipEntry != null) {

                    String entry = zipEntry.getName();
                    if (DRIVER_INTERFACE_NAME.equals(resType)) {
                        if (META_INF_SERVICES_DRIVER_FILE.equals(entry)) {

                            InputStream inputStream = jarFile.getInputStream(zipEntry);
                            implClass = processMetaInfServicesDriverFile(inputStream);
                            if (implClass != null) {
                                if (isLoaded(implClass, resType, cl)) {
                                    //Add to the implClassNames only if vendor name matches.
                                    if (isVendorSpecific(f, dbVendor, implClass)) {
                                        implClassNames.add(implClass);
                                    }
                                }
                            }
                            logger.finest("Driver loader : implClass = " + implClass);

                        }
                    }
                    if (entry.endsWith(".class")) {
                        //Read from metainf file for all jdbc40 drivers and resType
                        //java.sql.Driver.TODO : this should go outside .class check.
                        //TODO : Some classnames might not have these strings
                        //in their classname. Logic should be flexible in such cases.
                        if (entry.toUpperCase().indexOf("DATASOURCE") != -1 ||
                                entry.toUpperCase().indexOf("DRIVER") != -1) {
                            implClass = getClassName(entry);
                            if (implClass != null) {
                                if (isLoaded(implClass, resType, cl)) {
                                    if (isVendorSpecific(f, dbVendor, implClass)) {
                                        implClassNames.add(implClass);
                                    }
                                }
                            }
                        }
                    }
                }
            }
        } catch (IOException ex) {
            logger.log(Level.WARNING, "Error while getting Jdbc driver classnames ", ex);
        } finally {
            if (jarFile != null) {
                try {
                    jarFile.close();
                } catch (IOException ex) {
                    logger.log(Level.FINE, "Exception while closing JarFile '"
                            + jarFile.getName() + "' :", ex);
                }
            }
        }
        //Could be one or many depending on the connection definition class name 
        return implClassNames;
    }

    private boolean isNotAbstract(Class cls) {
        int modifier = cls.getModifiers();
        return !Modifier.isAbstract(modifier);
    }

    /**
     * Reads the META-INF/services/java.sql.Driver file contents and returns
     * the driver implementation class name.
     * In case of JDBC-4.0 drivers or above, the META-INF/services/java.sql.Driver file
     * contains the name of the driver class.
     *
     * @param inputStream
     * @return driver implementation class name
     */
    private String processMetaInfServicesDriverFile(InputStream inputStream) {
        String driverClassName = null;
        InputStreamReader reader = null;
        BufferedReader bufferedReader = null;
        try {
            reader = new InputStreamReader(inputStream);
            bufferedReader = new BufferedReader(reader);
            String line;
            while ((line = bufferedReader.readLine()) != null) {
                driverClassName = line;
            }
        } catch (IOException ioex) {
            logger.finest("DriverLoader : exception while processing " +
                    "META-INF directory for DriverClassName " + ioex);
        } finally {
            try {
                if (bufferedReader != null)
                    bufferedReader.close();
            } catch (IOException ex) {
                logger.log(Level.FINE, "Error while closing file handle after reading META-INF file : ", ex);
            }
            try {
                if (reader != null)
                    reader.close();
            } catch (IOException ex) {
                logger.log(Level.FINE, "Error while closing file handle after reading META-INF file : ", ex);
            }
        }
        return driverClassName;
    }

    /**
     * Check if the class has been loaded and if it is a Driver or a
     * DataSource impl.
     *
     * @param classname class
     * @return boolean indicating whether the class is loaded or not
     */
    private boolean isLoaded(String classname, String resType, ClassLoader loader) {
        Class cls = null;
        try {
            cls = loader.loadClass(classname);
        } catch (Throwable t) {
            cls = null;
        }
        return (isResType(cls, resType));
    }

    /**
     * Find if the particular class has any implementations of java.sql.Driver or
     * javax.sql.DataSource or any other resTypes passed.
     *
     * @param cls     class to be introspected
     * @param resType resource-type
     * @return boolean indicating the status
     */
    private boolean isResType(Class cls, String resType) {
        boolean isResType = false;
        if (cls != null) {
            if (Constants.DS.equals(resType)) {
                if (javax.sql.DataSource.class.isAssignableFrom(cls)) {
                    isResType = isNotAbstract(cls);
                }
            } else if (Constants.CPDS.equals(resType)) {
                if (javax.sql.ConnectionPoolDataSource.class.isAssignableFrom(cls)) {
                    isResType = isNotAbstract(cls);
                }
            } else if (Constants.XADS.equals(resType)) {
                if (javax.sql.XADataSource.class.isAssignableFrom(cls)) {
                    isResType = isNotAbstract(cls);
                }
            } else if (Constants.DRIVER.equals(resType)) {
                if (java.sql.Driver.class.isAssignableFrom(cls)) {
                    isResType = isNotAbstract(cls);
                }
            }
        }
        return isResType;
    }


    private String getClassName(String classname) {
        classname = classname.replaceAll("/", ".");
        classname = classname.substring(0, classname.lastIndexOf(".class"));
        return classname;
    }

    private boolean isVendorSpecific(File f, String dbVendor, String className) {
        //File could be a jdbc jar file or a normal jar file
        boolean isVendorSpecific = false;
        String vendor = getVendorFromManifest(f);

        if (vendor == null) {
            //might have to do this part by going through the class names or some other method.
            //dbVendor might be used in this portion
            if (isVendorSpecific(dbVendor, className)) {
                isVendorSpecific = true;
            }
        } else {
            //Got from Manifest file.
            if (vendor.equalsIgnoreCase(dbVendor) ||
                    vendor.toUpperCase().indexOf(dbVendor.toUpperCase()) != -1) {
                isVendorSpecific = true;
            }
        }
        return isVendorSpecific;
    }

    /**
     * Utility method that checks if a classname is vendor specific.
     * This method is used for jar files that do not have a manifest file to
     * look up the classname.
     *
     * @param dbVendor  DB vendor name
     * @param className class name
     * @return true if the className in question is vendor specific.
     */
    private boolean isVendorSpecific(String dbVendor, String className) {
        return className.toUpperCase().indexOf(dbVendor.toUpperCase()) != -1;
    }

    /**
     * Get a vendor name from a Manifest entry in the file.
     *
     * @param f file
     * @return null if no manifest entry found.
     */
    private String getVendorFromManifest(File f) {
        String vendor = null;
        JarFile jarFile = null;
        try {
            jarFile = new JarFile(f);
            Manifest manifest = jarFile.getManifest();
            if (manifest != null) {
                Attributes mainAttributes = manifest.getMainAttributes();
                if (mainAttributes != null) {
                    vendor = mainAttributes.getValue(Attributes.Name.IMPLEMENTATION_VENDOR.toString());
                    if (vendor == null) {
                        vendor = mainAttributes.getValue(Attributes.Name.IMPLEMENTATION_VENDOR_ID.toString());
                    }
                }
            }
        } catch (IOException ex) {
            logger.log(Level.WARNING, "Exception while reading manifest file : ", ex);
        } finally {
            if (jarFile != null) {
                try {
                    jarFile.close();
                } catch (IOException ex) {
                    logger.log(Level.FINE, "Exception while closing JarFile '"
                            + jarFile.getName() + "' :", ex);
                }
            }
        }
        return vendor;
    }
}