Hbm2DdlMojo

+
+    package de.juplo.plugins.hibernate4;
+
+    /*
+     * Copyright 2001-2005 The Apache Software Foundation.
+     *
+     * 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.
+     */
+
+    import com.pyx4j.log4j.MavenLogAppender;
+    import java.io.File;
+    import java.io.FileInputStream;
+    import java.io.FileNotFoundException;
+    import java.io.FileOutputStream;
+    import java.io.IOException;
+    import java.io.InputStream;
+    import java.io.ObjectInputStream;
+    import java.io.ObjectOutputStream;
+    import java.math.BigInteger;
+    import java.net.URL;
+    import java.net.URLClassLoader;
+    import java.security.MessageDigest;
+    import java.security.NoSuchAlgorithmException;
+    import java.sql.Connection;
+    import java.sql.Driver;
+    import java.sql.DriverManager;
+    import java.sql.DriverPropertyInfo;
+    import java.sql.SQLException;
+    import java.sql.SQLFeatureNotSupportedException;
+    import java.util.Comparator;
+    import java.util.Enumeration;
+    import java.util.HashMap;
+    import java.util.HashSet;
+    import java.util.List;
+    import java.util.Map;
+    import java.util.Map.Entry;
+    import java.util.Properties;
+    import java.util.Set;
+    import java.util.TreeSet;
+    import java.util.logging.Logger;
+    import java.util.regex.Matcher;
+    import java.util.regex.Pattern;
+    import javax.persistence.Embeddable;
+    import javax.persistence.Entity;
+    import javax.persistence.MappedSuperclass;
+    import org.apache.maven.artifact.Artifact;
+    import org.apache.maven.model.Resource;
+    import org.apache.maven.plugin.AbstractMojo;
+    import org.apache.maven.plugin.MojoExecutionException;
+    import org.apache.maven.plugin.MojoFailureException;
+    import org.apache.maven.project.MavenProject;
+    import org.hibernate.cfg.Configuration;
+    import org.hibernate.cfg.NamingStrategy;
+    import org.hibernate.envers.configuration.spi.AuditConfiguration;
+    import org.hibernate.tool.hbm2ddl.SchemaExport;
+    import org.hibernate.tool.hbm2ddl.SchemaExport.Type;
+    import org.hibernate.tool.hbm2ddl.Target;
+    import org.scannotation.AnnotationDB;
+
+
+    /**
+     * Goal which extracts the hibernate-mapping-configuration and
+     * exports an according SQL-database-schema.
+     *
+     * @goal export
+     * @phase process-classes
+     * @threadSafe
+     * @requiresDependencyResolution runtime
+     */
+    public class Hbm2DdlMojo extends AbstractMojo
+    {
+      public final static String EXPORT_SKIPPED_PROPERTY = "hibernate.export.skipped";
+
+      public final static String DRIVER_CLASS = "hibernate.connection.driver_class";
+      public final static String URL = "hibernate.connection.url";
+      public final static String USERNAME = "hibernate.connection.username";
+      public final static String PASSWORD = "hibernate.connection.password";
+      public final static String DIALECT = "hibernate.dialect";
+      public final static String NAMING_STRATEGY="hibernate.ejb.naming_strategy";
+      public final static String ENVERS = "hibernate.export.envers";
+
+      public final static String MD5S = "hibernate4-generatedschema.md5s";
+
+      private final static Pattern split = Pattern.compile("[^,\\s]+");
+
+
+      /**
+       * The maven project.
+       * <p>
+       * Only needed internally.
+       *
+       * @parameter property="project"
+       * @required
+       * @readonly
+       */
+      private MavenProject project;
+
+      /**
+       * Build-directory.
+       * <p>
+       * Only needed internally.
+       *
+       * @parameter property="project.build.directory"
+       * @required
+       * @readonly
+       */
+      private String buildDirectory;
+
+      /**
+       * Classes-Directory to scan.
+       * <p>
+       * This parameter defaults to the maven build-output-directory for classes.
+       * Additionally, all dependencies are scanned for annotated classes.
+       *
+       * @parameter property="project.build.outputDirectory"
+       * @since 1.0
+       */
+      private String outputDirectory;
+
+      /**
+       * Whether to scan test-classes too, or not.
+       * <p>
+       * If this parameter is set to <code>true</code> the test-classes of the
+       * artifact will be scanned for hibernate-annotated classes additionally.
+       *
+       * @parameter property="hibernate.export.scan_testclasses" default-value="false"
+       * @since 1.0.1
+       */
+      private boolean scanTestClasses;
+
+      /**
+       * Dependency-Scopes, that should be scanned for annotated classes.
+       * <p>
+       * By default, only dependencies in the scope <code>compile</code> are
+       * scanned for annotated classes. Multiple scopes can be seperated by
+       * white space or commas.
+       * <p>
+       * The plugin does not scan for annotated classes in transitive
+       * dependencies. If some of your annotated classes are hidden in a
+       * transitive dependency, you can simply add that dependency explicitly.
+       *
+       * @parameter property="hibernate.export.scan_dependencies" default-value="compile"
+       * @since 1.0.3
+       */
+      private String scanDependencies;
+
+      /**
+       * Test-Classes-Directory to scan.
+       * <p>
+       * This parameter defaults to the maven build-output-directory for
+       * test-classes.
+       * <p>
+       * This parameter is only used, when <code>scanTestClasses</code> is set
+       * to <code>true</code>!
+       *
+       * @parameter property="project.build.testOutputDirectory"
+       * @since 1.0.2
+       */
+      private String testOutputDirectory;
+
+      /**
+       * Skip execution
+       * <p>
+       * If set to <code>true</code>, the execution is skipped.
+       * <p>
+       * A skipped execution is signaled via the maven-property
+       * <code>${hibernate.export.skipped}</code>.
+       * <p>
+       * The execution is skipped automatically, if no modified or newly added
+       * annotated classes are found and the dialect was not changed.
+       *
+       * @parameter property="hibernate.skip" default-value="${maven.test.skip}"
+       * @since 1.0
+       */
+      private boolean skip;
+
+      /**
+       * Force execution
+       * <p>
+       * Force execution, even if no modified or newly added annotated classes
+       * where found and the dialect was not changed.
+       * <p>
+       * <code>skip</code> takes precedence over <code>force</code>.
+       *
+       * @parameter property="hibernate.export.force" default-value="false"
+       * @since 1.0
+       */
+      private boolean force;
+
+      /**
+       * SQL-Driver name.
+       *
+       * @parameter property="hibernate.connection.driver_class"
+       * @since 1.0
+       */
+      private String driverClassName;
+
+      /**
+       * Database URL.
+       *
+       * @parameter property="hibernate.connection.url"
+       * @since 1.0
+       */
+      private String url;
+
+      /**
+       * Database username
+       *
+       * @parameter property="hibernate.connection.username"
+       * @since 1.0
+       */
+      private String username;
+
+      /**
+       * Database password
+       *
+       * @parameter property="hibernate.connection.password"
+       * @since 1.0
+       */
+      private String password;
+
+      /**
+       * Hibernate dialect.
+       *
+       * @parameter property="hibernate.dialect"
+       * @since 1.0
+       */
+      private String hibernateDialect;
+
+      /**
+       * Hibernate Naming Strategy
+       *
+       * @parameter property="hibernate.ejb.naming_strategy"
+       * @since 1.0.2
+       */
+      private String hibernateNamingStrategy;
+
+      /**
+       * Path to Hibernate configuration file.
+       *
+       * @parameter default-value="${project.build.outputDirectory}/hibernate.properties"
+       * @since 1.0
+       */
+      private String hibernateProperties;
+
+      /**
+       * List of Hibernate-Mapping-Files (XML).
+       * Multiple files can be separated with white-spaces and/or commas.
+       *
+       * @parameter property="hibernate.mapping"
+       * @since 1.0.2
+       */
+      private String hibernateMapping;
+
+      /**
+       * Target of execution:
+       * <ul>
+       *   <li><strong>NONE</strong> only export schema to SQL-script (forces execution, signals skip)</li>
+       *   <li><strong>EXPORT</strong> create database (<strong>DEFAULT!</strong>). forces execution, signals skip)</li>
+       *   <li><strong>SCRIPT</strong> export schema to SQL-script and print it to STDOUT</li>
+       *   <li><strong>BOTH</strong></li>
+       * </ul>
+       *
+       * A database connection is only needed for EXPORT and BOTH, but a
+       * Hibernate-Dialect must always be chosen.
+       *
+       * @parameter property="hibernate.export.target" default-value="EXPORT"
+       * @since 1.0
+       */
+      private String target;
+
+      /**
+       * Type of execution.
+       * <ul>
+       *   <li><strong>NONE</strong> do nothing - just validate the configuration</li>
+       *   <li><strong>CREATE</strong> create database-schema</li>
+       *   <li><strong>DROP</strong> drop database-schema</li>
+       *   <li><strong>BOTH</strong> (<strong>DEFAULT!</strong>)</li>
+       * </ul>
+       *
+       * If NONE is choosen, no databaseconnection is needed.
+       *
+       * @parameter property="hibernate.export.type" default-value="BOTH"
+       * @since 1.0
+       */
+      private String type;
+
+      /**
+       * Output file.
+       *
+       * @parameter property="hibernate.export.schema.filename" default-value="${project.build.directory}/schema.sql"
+       * @since 1.0
+       */
+      private String outputFile;
+
+      /**
+       * Delimiter in output-file.
+       *
+       * @parameter property="hibernate.export.schema.delimiter" default-value=";"
+       * @since 1.0
+       */
+      private String delimiter;
+
+      /**
+       * Format output-file.
+       *
+       * @parameter property="hibernate.export.schema.format" default-value="true"
+       * @since 1.0
+       */
+      private boolean format;
+
+      /**
+       * Generate envers schema for auditing tables.
+       *
+       * @parameter property="hibernate.export.envers" default-value="false"
+       * @since 1.0.3
+       */
+      private boolean envers;
+
+
+      @Override
+      public void execute()
+        throws
+          MojoFailureException,
+          MojoExecutionException
+      {
+        if (skip)
+        {
+          getLog().info("Execution of hibernate4-maven-plugin:export was skipped!");
+          project.getProperties().setProperty(EXPORT_SKIPPED_PROPERTY, "true");
+          return;
+        }
+
+        Map<String,String> md5s;
+        boolean modified = false;
+        File saved = new File(buildDirectory + File.separator + MD5S);
+
+        if (saved.isFile() && saved.length() > 0)
+        {
+          try
+          {
+            FileInputStream fis = new FileInputStream(saved);
+            ObjectInputStream ois = new ObjectInputStream(fis);
+            md5s = (HashMap<String,String>)ois.readObject();
+            ois.close();
+          }
+          catch (Exception e)
+          {
+            md5s = new HashMap<String,String>();
+            getLog().warn("Cannot read timestamps from saved: " + e);
+          }
+        }
+        else
+        {
+          md5s = new HashMap<String,String>();
+          try
+          {
+            saved.createNewFile();
+          }
+          catch (IOException e)
+          {
+            getLog().debug("Cannot create file \"" + saved.getPath() + "\" for timestamps: " + e);
+          }
+        }
+
+        ClassLoader classLoader = null;
+        try
+        {
+          getLog().debug("Creating ClassLoader for project-dependencies...");
+          List<String> classpathFiles = project.getCompileClasspathElements();
+          if (scanTestClasses)
+            classpathFiles.addAll(project.getTestClasspathElements());
+          URL[] urls = new URL[classpathFiles.size()];
+          for (int i = 0; i < classpathFiles.size(); ++i)
+          {
+            getLog().debug("Dependency: " + classpathFiles.get(i));
+            urls[i] = new File(classpathFiles.get(i)).toURI().toURL();
+          }
+          classLoader = new URLClassLoader(urls, getClass().getClassLoader());
+        }
+        catch (Exception e)
+        {
+          getLog().error("Error while creating ClassLoader!", e);
+          throw new MojoExecutionException(e.getMessage());
+        }
+
+        Set<Class<?>> classes =
+            new TreeSet<Class<?>>(
+                new Comparator<Class<?>>() {
+                  @Override
+                  public int compare(Class<?> a, Class<?> b)
+                  {
+                    return a.getName().compareTo(b.getName());
+                  }
+                }
+              );
+
+        try
+        {
+          AnnotationDB db = new AnnotationDB();
+          File dir = new File(outputDirectory);
+          if (dir.exists())
+          {
+            getLog().info("Scanning directory " + outputDirectory + " for annotated classes...");
+            URL dirUrl = dir.toURI().toURL();
+            db.scanArchives(dirUrl);
+          }
+          if (scanTestClasses)
+          {
+            dir = new File(testOutputDirectory);
+            if (dir.exists())
+            {
+              getLog().info("Scanning directory " + testOutputDirectory + " for annotated classes...");
+              URL dirUrl = dir.toURI().toURL();
+              db.scanArchives(dirUrl);
+            }
+          }
+          if (scanDependencies != null)
+          {
+            Matcher matcher = split.matcher(scanDependencies);
+            while (matcher.find())
+            {
+              getLog().info("Scanning dependencies for scope " + matcher.group());
+              for (Artifact artifact : project.getDependencyArtifacts())
+              {
+                if (!artifact.getScope().equalsIgnoreCase(matcher.group()))
+                  continue;
+                if (artifact.getFile() == null)
+                {
+                  getLog().warn(
+                      "Cannot scan dependency " +
+                      artifact.getId() +
+                      ": no JAR-file available!"
+                      );
+                  continue;
+                }
+                getLog().info(
+                    "Scanning dependency " +
+                    artifact.getId() +
+                    " for annotated classes..."
+                    );
+                db.scanArchives(artifact.getFile().toURI().toURL());
+              }
+            }
+          }
+
+          Set<String> classNames = new HashSet<String>();
+          if (db.getAnnotationIndex().containsKey(Entity.class.getName()))
+            classNames.addAll(db.getAnnotationIndex().get(Entity.class.getName()));
+          if (db.getAnnotationIndex().containsKey(MappedSuperclass.class.getName()))
+            classNames.addAll(db.getAnnotationIndex().get(MappedSuperclass.class.getName()));
+          if (db.getAnnotationIndex().containsKey(Embeddable.class.getName()))
+            classNames.addAll(db.getAnnotationIndex().get(Embeddable.class.getName()));
+
+          MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
+          for (String name : classNames)
+          {
+            Class<?> annotatedClass = classLoader.loadClass(name);
+            classes.add(annotatedClass);
+            String resourceName = annotatedClass.getName();
+            resourceName = resourceName.substring(resourceName.lastIndexOf(".") + 1, resourceName.length()) + ".class";
+            InputStream is =
+                annotatedClass
+                    .getResourceAsStream(resourceName);
+            byte[] buffer = new byte[1024*4]; // copy data in 4MB-chunks
+            int i;
+            while((i = is.read(buffer)) > -1)
+              digest.update(buffer, 0, i);
+            is.close();
+            byte[] bytes = digest.digest();
+            BigInteger bi = new BigInteger(1, bytes);
+            String newMd5 = String.format("%0" + (bytes.length << 1) + "x", bi);
+            String oldMd5 = !md5s.containsKey(name) ? "" : md5s.get(name);
+            if (!newMd5.equals(oldMd5))
+            {
+              getLog().debug("Found new or modified annotated class: " + name);
+              modified = true;
+              md5s.put(name, newMd5);
+            }
+            else
+            {
+              getLog().debug(oldMd5 + " -> class unchanged: " + name);
+            }
+          }
+        }
+        catch (ClassNotFoundException e)
+        {
+          getLog().error("Error while adding annotated classes!", e);
+          throw new MojoExecutionException(e.getMessage());
+        }
+        catch (Exception e)
+        {
+          getLog().error("Error while scanning!", e);
+          throw new MojoFailureException(e.getMessage());
+        }
+
+        if (classes.isEmpty())
+        {
+          if (hibernateMapping == null || hibernateMapping.isEmpty())
+            throw new MojoFailureException("No annotated classes found in directory " + outputDirectory);
+        }
+        else
+        {
+          getLog().debug("Detected classes with mapping-annotations:");
+          for (Class<?> annotatedClass : classes)
+            getLog().debug("  " + annotatedClass.getName());
+        }
+
+
+        Properties properties = new Properties();
+
+        /** Try to read configuration from properties-file */
+        try
+        {
+          File file = new File(hibernateProperties);
+          if (file.exists())
+          {
+            getLog().info("Reading properties from file " + hibernateProperties + "...");
+            properties.load(new FileInputStream(file));
+          }
+          else
+            getLog().info("No hibernate-properties-file found! (Checked path: " + hibernateProperties + ")");
+        }
+        catch (IOException e)
+        {
+          getLog().error("Error while reading properties!", e);
+          throw new MojoExecutionException(e.getMessage());
+        }
+
+        /** Overwrite values from properties-file or set, if given */
+        if (driverClassName != null)
+        {
+          if (properties.containsKey(DRIVER_CLASS))
+            getLog().debug(
+                "Overwriting property " +
+                DRIVER_CLASS + "=" + properties.getProperty(DRIVER_CLASS) +
+                " with the value " + driverClassName
+              );
+          else
+            getLog().debug("Using the value " + driverClassName);
+          properties.setProperty(DRIVER_CLASS, driverClassName);
+        }
+        if (url != null)
+        {
+          if (properties.containsKey(URL))
+            getLog().debug(
+                "Overwriting property " +
+                URL + "=" + properties.getProperty(URL) +
+                " with the value " + url
+              );
+          else
+            getLog().debug("Using the value " + url);
+          properties.setProperty(URL, url);
+        }
+        if (username != null)
+        {
+          if (properties.containsKey(USERNAME))
+            getLog().debug(
+                "Overwriting property " +
+                USERNAME + "=" + properties.getProperty(USERNAME) +
+                " with the value " + username
+              );
+          else
+            getLog().debug("Using the value " + username);
+          properties.setProperty(USERNAME, username);
+        }
+        if (password != null)
+        {
+          if (properties.containsKey(PASSWORD))
+            getLog().debug(
+                "Overwriting property " +
+                PASSWORD + "=" + properties.getProperty(PASSWORD) +
+                " with value " + password
+              );
+          else
+            getLog().debug("Using value " + password + " for property " + PASSWORD);
+          properties.setProperty(PASSWORD, password);
+        }
+        if (hibernateDialect != null)
+        {
+          if (properties.containsKey(DIALECT))
+            getLog().debug(
+                "Overwriting property " +
+                DIALECT + "=" + properties.getProperty(DIALECT) +
+                " with value " + hibernateDialect
+              );
+          else
+            getLog().debug(
+                "Using value " + hibernateDialect + " for property " + DIALECT
+                );
+          properties.setProperty(DIALECT, hibernateDialect);
+        }
+        if ( hibernateNamingStrategy != null )
+        {
+          if ( properties.contains(NAMING_STRATEGY))
+            getLog().debug(
+                "Overwriting property " +
+                NAMING_STRATEGY + "=" + properties.getProperty(NAMING_STRATEGY) +
+                " with value " + hibernateNamingStrategy
+               );
+          else
+            getLog().debug(
+                "Using value " + hibernateNamingStrategy + " for property " +
+                NAMING_STRATEGY
+                );
+          properties.setProperty(NAMING_STRATEGY, hibernateNamingStrategy);
+        }
+
+        /** The generated SQL varies with the dialect! */
+        if (md5s.containsKey(DIALECT))
+        {
+          String dialect = properties.getProperty(DIALECT);
+          if (md5s.get(DIALECT).equals(dialect))
+            getLog().debug("SQL-dialect unchanged.");
+          else
+          {
+            modified = true;
+            if (dialect == null)
+            {
+              getLog().debug("SQL-dialect was unset.");
+              md5s.remove(DIALECT);
+            }
+            else
+            {
+              getLog().debug("SQL-dialect changed: " + dialect);
+              md5s.put(DIALECT, dialect);
+            }
+          }
+        }
+        else
+        {
+          String dialect = properties.getProperty(DIALECT);
+          if (dialect != null)
+          {
+            modified = true;
+            md5s.put(DIALECT, properties.getProperty(DIALECT));
+          }
+        }
+
+        /** The generated SQL varies with the envers-configuration */
+        if (md5s.get(ENVERS) != null)
+        {
+          if (md5s.get(ENVERS).equals(Boolean.toString(envers)))
+            getLog().debug("Envers-Configuration unchanged. Enabled: " + envers);
+          else
+          {
+            getLog().debug("Envers-Configuration changed. Enabled: " + envers);
+            modified = true;
+            md5s.put(ENVERS, Boolean.toString(envers));
+          }
+        }
+        else
+        {
+          modified = true;
+          md5s.put(ENVERS, Boolean.toString(envers));
+        }
+
+        if (properties.isEmpty())
+        {
+          getLog().error("No properties set!");
+          throw new MojoFailureException("Hibernate configuration is missing!");
+        }
+
+        final Configuration config = new ValidationConfiguration(hibernateDialect);
+
+        config.setProperties(properties);
+
+        if ( properties.containsKey(NAMING_STRATEGY))
+        {
+          String namingStrategy = properties.getProperty(NAMING_STRATEGY);
+          getLog().debug("Explicitly set NamingStrategy: " + namingStrategy);
+          try
+          {
+            @SuppressWarnings("unchecked")
+            Class<NamingStrategy> namingStrategyClass = (Class<NamingStrategy>) Class.forName(namingStrategy);
+            config.setNamingStrategy(namingStrategyClass.newInstance());
+          }
+          catch (Exception e)
+          {
+            getLog().error("Error setting NamingStrategy", e);
+            throw new MojoExecutionException(e.getMessage());
+          }
+        }
+
+        getLog().debug("Adding annotated classes to hibernate-mapping-configuration...");
+        for (Class<?> annotatedClass : classes)
+        {
+          getLog().debug("Class " + annotatedClass);
+          config.addAnnotatedClass(annotatedClass);
+        }
+
+        if (hibernateMapping != null)
+        {
+          try
+          {
+            MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
+            for (String filename : hibernateMapping.split("[\\s,]+"))
+            {
+              // First try the filename as absolute/relative path
+              File file = new File(filename);
+              if (!file.exists())
+              {
+                // If the file was not found, search for it in the resource-directories
+                for (Resource resource : project.getResources())
+                {
+                  file = new File(resource.getDirectory() + File.separator + filename);
+                  if (file.exists())
+                    break;
+                }
+              }
+              if (file != null && file.exists())
+              {
+                InputStream is = new FileInputStream(file);
+                byte[] buffer = new byte[1024*4]; // copy data in 4MB-chunks
+                int i;
+                while((i = is.read(buffer)) > -1)
+                  digest.update(buffer, 0, i);
+                is.close();
+                byte[] bytes = digest.digest();
+                BigInteger bi = new BigInteger(1, bytes);
+                String newMd5 = String.format("%0" + (bytes.length << 1) + "x", bi);
+                String oldMd5 = !md5s.containsKey(filename) ? "" : md5s.get(filename);
+                if (!newMd5.equals(oldMd5))
+                {
+                  getLog().debug("Found new or modified mapping-file: " + filename);
+                  modified = true;
+                  md5s.put(filename, newMd5);
+                }
+                else
+                {
+                  getLog().debug(oldMd5 + " -> mapping-file unchanged: " + filename);
+                }
+                getLog().debug("Adding mappings from XML-configurationfile: " + file);
+                config.addFile(file);
+              }
+              else
+                throw new MojoFailureException("File " + filename + " could not be found in any of the configured resource-directories!");
+            }
+          }
+          catch (NoSuchAlgorithmException e)
+          {
+            throw new MojoFailureException("Cannot calculate MD5 sums!", e);
+          }
+          catch (FileNotFoundException e)
+          {
+            throw new MojoFailureException("Cannot calculate MD5 sums!", e);
+          }
+          catch (IOException e)
+          {
+            throw new MojoFailureException("Cannot calculate MD5 sums!", e);
+          }
+        }
+
+        Target target = null;
+        try
+        {
+          target = Target.valueOf(this.target.toUpperCase());
+        }
+        catch (IllegalArgumentException e)
+        {
+          getLog().error("Invalid value for configuration-option \"target\": " + this.target);
+          getLog().error("Valid values are: NONE, SCRIPT, EXPORT, BOTH");
+          throw new MojoExecutionException("Invalid value for configuration-option \"target\"");
+        }
+        Type type = null;
+        try
+        {
+          type = Type.valueOf(this.type.toUpperCase());
+        }
+        catch (IllegalArgumentException e)
+        {
+          getLog().error("Invalid value for configuration-option \"type\": " + this.type);
+          getLog().error("Valid values are: NONE, CREATE, DROP, BOTH");
+          throw new MojoExecutionException("Invalid value for configuration-option \"type\"");
+        }
+
+        if (target.equals(Target.SCRIPT) || target.equals(Target.NONE))
+        {
+          project.getProperties().setProperty(EXPORT_SKIPPED_PROPERTY, "true");
+        }
+        if (
+            !modified
+            && !target.equals(Target.SCRIPT)
+            && !target.equals(Target.NONE)
+            && !force
+          )
+        {
+          getLog().info("No modified annotated classes or mapping-files found and dialect unchanged.");
+          getLog().info("Skipping schema generation!");
+          project.getProperties().setProperty(EXPORT_SKIPPED_PROPERTY, "true");
+          return;
+        }
+
+        getLog().info("Gathered hibernate-configuration (turn on debugging for details):");
+        for (Entry<Object,Object> entry : properties.entrySet())
+          getLog().info("  " + entry.getKey() + " = " + entry.getValue());
+
+        Connection connection = null;
+        try
+        {
+          /**
+           * The connection must be established outside of hibernate, because
+           * hibernate does not use the context-classloader of the current
+           * thread and, hence, would not be able to resolve the driver-class!
+           */
+          getLog().debug("Target: " + target + ", Type: " + type);
+          switch (target)
+          {
+            case EXPORT:
+            case BOTH:
+              switch (type)
+              {
+                case CREATE:
+                case DROP:
+                case BOTH:
+                  Class driverClass = classLoader.loadClass(properties.getProperty(DRIVER_CLASS));
+                  getLog().debug("Registering JDBC-driver " + driverClass.getName());
+                  DriverManager.registerDriver(new DriverProxy((Driver)driverClass.newInstance()));
+                  getLog().debug(
+                      "Opening JDBC-connection to "
+                      + properties.getProperty(URL)
+                      + " as "
+                      + properties.getProperty(USERNAME)
+                      + " with password "
+                      + properties.getProperty(PASSWORD)
+                      );
+                  connection = DriverManager.getConnection(
+                      properties.getProperty(URL),
+                      properties.getProperty(USERNAME),
+                      properties.getProperty(PASSWORD)
+                      );
+              }
+          }
+        }
+        catch (ClassNotFoundException e)
+        {
+          getLog().error("Dependency for driver-class " + properties.getProperty(DRIVER_CLASS) + " is missing!");
+          throw new MojoExecutionException(e.getMessage());
+        }
+        catch (Exception e)
+        {
+          getLog().error("Cannot establish connection to database!");
+          Enumeration<Driver> drivers = DriverManager.getDrivers();
+          if (!drivers.hasMoreElements())
+            getLog().error("No drivers registered!");
+          while (drivers.hasMoreElements())
+            getLog().debug("Driver: " + drivers.nextElement());
+          throw new MojoExecutionException(e.getMessage());
+        }
+
+        ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+        MavenLogAppender.startPluginLog(this);
+        try
+        {
+          /**
+           * Change class-loader of current thread, so that hibernate can
+           * see all dependencies!
+           */
+          Thread.currentThread().setContextClassLoader(classLoader);
+
+          config.buildMappings();
+
+          if (envers)
+          {
+            getLog().info("Automatic auditing via hibernate-envers enabled!");
+            AuditConfiguration.getFor(config);
+          }
+
+          SchemaExport export = new SchemaExport(config, connection);
+          export.setDelimiter(delimiter);
+          export.setFormat(format);
+
+          File outF = new File(outputFile);
+
+          if (!outF.isAbsolute())
+          {
+            // Interpret relative file path relative to build directory
+            outF = new File(buildDirectory, outputFile);
+            getLog().info("Adjusted relative path, resulting path is " + outF.getPath());
+          }
+
+          // Ensure that directory path for specified file exists
+          File outFileParentDir = outF.getParentFile();
+          if (null != outFileParentDir && !outFileParentDir.exists())
+          {
+            try
+            {
+              getLog().info("Creating directory path for output file:" + outFileParentDir.getPath());
+              outFileParentDir.mkdirs();
+            }
+            catch (Exception e)
+            {
+              getLog().error("Error creating directory path for output file: " + e.getLocalizedMessage());
+            }
+          }
+
+          export.setOutputFile(outF.getPath());
+          export.execute(target, type);
+
+          for (Object exception : export.getExceptions())
+            getLog().debug(exception.toString());
+        }
+        finally
+        {
+          /** Stop Log-Capturing */
+          MavenLogAppender.endPluginLog(this);
+
+          /** Restore the old class-loader (TODO: is this really necessary?) */
+          Thread.currentThread().setContextClassLoader(contextClassLoader);
+
+          /** Close the connection */
+          try
+          {
+            if (connection != null)
+              connection.close();
+          }
+          catch (SQLException e)
+          {
+            getLog().error("Error while closing connection: " + e.getMessage());
+          }
+        }
+
+        /** Write md5-sums for annotated classes to file */
+        try
+        {
+          FileOutputStream fos = new FileOutputStream(saved);
+          ObjectOutputStream oos = new ObjectOutputStream(fos);
+          oos.writeObject(md5s);
+          oos.close();
+          fos.close();
+        }
+        catch (Exception e)
+        {
+          getLog().error("Cannot write md5-sums to file: " + e);
+        }
+      }
+
+      /**
+       * Needed, because DriverManager won't pick up drivers, that were not
+       * loaded by the system-classloader!
+       * See:
+       * http://stackoverflow.com/questions/288828/how-to-use-a-jdbc-driver-fromodifiedm-an-arbitrary-location
+       */
+      static final class DriverProxy implements Driver
+      {
+        private final Driver target;
+
+        DriverProxy(Driver target)
+        {
+          if (target == null)
+            throw new NullPointerException();
+          this.target = target;
+        }
+
+        public java.sql.Driver getTarget()
+        {
+          return target;
+        }
+
+        @Override
+        public boolean acceptsURL(String url) throws SQLException
+        {
+          return target.acceptsURL(url);
+        }
+
+        @Override
+        public java.sql.Connection connect(
+            String url,
+            java.util.Properties info
+          )
+          throws
+            SQLException
+        {
+          return target.connect(url, info);
+        }
+
+        @Override
+        public int getMajorVersion()
+        {
+          return target.getMajorVersion();
+        }
+
+        @Override
+        public int getMinorVersion()
+        {
+          return target.getMinorVersion();
+        }
+
+        @Override
+        public DriverPropertyInfo[] getPropertyInfo(
+             String url,
+             Properties info
+           )
+           throws
+             SQLException
+         {
+           return target.getPropertyInfo(url, info);
+         }
+
+         @Override
+         public boolean jdbcCompliant()
+         {
+           return target.jdbcCompliant();
+         }
+
+         /**
+          * This Method cannot be annotated with @Override, becaus the plugin
+          * will not compile then under Java 1.6!
+          */
+         public Logger getParentLogger() throws SQLFeatureNotSupportedException
+         {
+           throw new SQLFeatureNotSupportedException("Not supported, for backward-compatibility with Java 1.6");
+         }
+
+         @Override
+         public String toString()
+         {
+           return "Proxy: " + target;
+         }
+
+         @Override
+         public int hashCode()
+         {
+           return target.hashCode();
+         }
+
+         @Override
+         public boolean equals(Object obj)
+         {
+           if (!(obj instanceof DriverProxy))
+             return false;
+           DriverProxy other = (DriverProxy) obj;
+           return this.target.equals(other.target);
+         }
+       }
+     }
+