/*
 *   Copyright (C) 2005 Christian Schulte <cs@schulte.it>
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     o Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     o Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 *   THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 *   AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 *   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT,
 *   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *   THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *   $JOMC: JomcResourceTransformer.java 5135 2016-04-08 13:53:07Z schulte $
 *
 */
package org.jomc.mojo;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.util.JAXBResult;
import javax.xml.bind.util.JAXBSource;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamSource;
import org.apache.maven.plugins.shade.relocation.Relocator;
import org.apache.maven.plugins.shade.resource.ResourceTransformer;
import org.codehaus.plexus.logging.AbstractLogEnabled;
import org.codehaus.plexus.util.StringUtils;
import org.jomc.model.ModelObject;
import org.jomc.model.Module;
import org.jomc.model.Modules;
import org.jomc.model.modlet.DefaultModelProvider;
import org.jomc.modlet.DefaultModelContext;
import org.jomc.modlet.DefaultModletProvider;
import org.jomc.modlet.ModelContext;
import org.jomc.modlet.ModelContextFactory;
import org.jomc.modlet.ModelException;
import org.jomc.modlet.Modlet;
import org.jomc.modlet.ModletObject;
import org.jomc.modlet.Modlets;

/**
 * Maven Shade Plugin {@code ResourceTransformer} implementation for shading JOMC resources.
 *
 * <p>
 * <b>Maven Shade Plugin Usage</b><pre>
 * &lt;transformer implementation="org.jomc.mojo.JomcResourceTransformer"&gt;
 *   &lt;model&gt;http://jomc.org/model&lt;/model&gt;
 *   &lt;modelContextFactoryClassName&gt;class name&lt;/modelContextFactoryClassName&gt;
 *     &lt;modelContextAttributes&gt;
 *       &lt;modelContextAttribute&gt;
 *         &lt;key&gt;The name of the attribute&lt;/key&gt;
 *         &lt;value&gt;The name of the attribute&lt;/value&gt;
 *         &lt;type&gt;The name of the class of the object.&lt;/type&gt;
 *       &lt;/modelContextAttribute&gt;
 *     &lt;/modelContextAttributes/&gt;
 *   &lt;moduleEncoding&gt;${project.build.sourceEncoding}&lt;/moduleEncoding&gt;
 *   &lt;moduleName&gt;${project.name}&lt;/moduleName&gt;
 *   &lt;moduleVersion&gt;${project.version}&lt;/moduleVersion&gt;
 *   &lt;moduleVendor&gt;${project.organization.name}&lt;/moduleVendor&gt;
 *   &lt;moduleResource&gt;META-INF/custom-jomc.xml&lt;/moduleResource&gt;
 *   &lt;moduleResources&gt;
 *     &lt;moduleResource&gt;META-INF/jomc.xml&lt;/moduleResource&gt;
 *   &lt;/moduleResources&gt;
 *   &lt;moduleIncludes&gt;
 *     &lt;moduleInclude&gt;module name&lt;/moduleInclude&gt;
 *   &lt;/moduleIncludes&gt;
 *   &lt;moduleExcludes&gt;
 *     &lt;moduleExclude&gt;module name&lt;/moduleExclude&gt;
 *   &lt;/moduleExcludes&gt;
 *   &lt;modletEncoding&gt;${project.build.sourceEncoding}&lt;/modletEncoding&gt;
 *   &lt;modletName&gt;${project.name}&lt;/modletName&gt;
 *   &lt;modletVersion&gt;${project.version}&lt;/modletVersion&gt;
 *   &lt;modletVendor&gt;${project.organization.name}&lt;/modletVendor&gt;
 *   &lt;modletResource&gt;META-INF/custom-jomc-modlet.xml&lt;/modletResource&gt;
 *   &lt;modletResources&gt;
 *     &lt;modletResource&gt;META-INF/jomc-modlet.xml&lt;/modletResource&gt;
 *   &lt;/modletResources&gt;
 *   &lt;modletIncludes&gt;
 *     &lt;modletInclude&gt;modlet name&lt;/modletInclude&gt;
 *   &lt;/modletIncludes&gt;
 *   &lt;modletExcludes&gt;
 *     &lt;modletExclude&gt;modlet name&lt;/modletExclude&gt;
 *   &lt;/modletExcludes&gt;
 *   &lt;modelObjectStylesheet&gt;Location of a XSLT document to use for transforming the merged model document.&lt;/modelObjectStylesheet&gt;
 *   &lt;modletObjectStylesheet&gt;Location of a XSLT document to use for transforming the merged modlet document.&lt;/modletObjectStylesheet&gt;
 *   &lt;providerLocation&gt;META-INF/custom-services&lt;/providerLocation&gt;
 *   &lt;platformProviderLocation&gt;${java.home}/jre/lib/custom-jomc.properties&lt;/platformProviderLocation&gt;
 *   &lt;modletLocation&gt;META-INF/custom-jomc-modlet.xml&lt;/modletLocation&gt;
 *   &lt;modletSchemaSystemId&gt;http://custom.host.tld/custom/path/jomc-modlet-1.9.xsd&lt;/modletSchemaSystemId&gt;
 * &lt;/transformer&gt;
 * </pre></p>
 *
 * @author <a href="mailto:cs@schulte.it">Christian Schulte</a>
 * @version $JOMC: JomcResourceTransformer.java 5135 2016-04-08 13:53:07Z schulte $
 * @plexus.component role="org.apache.maven.plugins.shade.resource.ResourceTransformer"
 * role-hint="JOMC"
 */
public class JomcResourceTransformer extends AbstractLogEnabled implements ResourceTransformer
{

    /**
     * Type of a resource.
     */
    private enum ResourceType
    {

        /**
         * Model object resource.
         */
        MODEL_OBJECT_RESOURCE,
        /**
         * Modlet object resource.
         */
        MODLET_OBJECT_RESOURCE

    }

    /**
     * Prefix prepended to log messages.
     */
    private static final String LOG_PREFIX = "[JOMC] ";

    /**
     * The identifier of the model to process.
     */
    private String model = ModelObject.MODEL_PUBLIC_ID;

    /**
     * The encoding of the assembled module.
     */
    private String moduleEncoding;

    /**
     * The name of the assembled module.
     */
    private String moduleName;

    /**
     * The version of the assembled module.
     */
    private String moduleVersion;

    /**
     * The vendor of the assembled module.
     */
    private String moduleVendor;

    /**
     * The resource name of the assembled module.
     */
    private String moduleResource = DefaultModelProvider.getDefaultModuleLocation();

    /**
     * Names of resources to process.
     */
    private String[] moduleResources =
    {
        DefaultModelProvider.getDefaultModuleLocation()
    };

    /**
     * Included modules.
     */
    private List<String> moduleIncludes;

    /**
     * Excluded modules.
     */
    private List<String> moduleExcludes;

    /**
     * The encoding of the assembled modlet.
     */
    private String modletEncoding;

    /**
     * The name of the assembled modlet.
     */
    private String modletName;

    /**
     * The version of the assembled modlet.
     */
    private String modletVersion;

    /**
     * The vendor of the assembled modlet.
     */
    private String modletVendor;

    /**
     * The resource name of the assembled modlet resources.
     */
    private String modletResource = DefaultModletProvider.getDefaultModletLocation();

    /**
     * Names of modlet resources to process.
     */
    private String[] modletResources =
    {
        DefaultModletProvider.getDefaultModletLocation()
    };

    /**
     * Included modlets.
     */
    private List<String> modletIncludes;

    /**
     * Excluded modlets.
     */
    private List<String> modletExcludes;

    /**
     * Location of a XSLT document to use for transforming the merged model document.
     */
    private String modelObjectStylesheet;

    /**
     * Location of a XSLT document to use for transforming the merged modlet document.
     */
    private String modletObjectStylesheet;

    /**
     * The location to search for providers.
     */
    private String providerLocation;

    /**
     * The location to search for platform providers.
     */
    private String platformProviderLocation;

    /**
     * The system id of the modlet schema.
     */
    private String modletSchemaSystemId;

    /**
     * The location to search for modlets.
     */
    private String modletLocation;

    /**
     * Name of the {@code ModelContext} implementation class.
     *
     * @since 1.2
     */
    private String modelContextFactoryClassName;

    /**
     * {@code ModelContext} attributes to apply.
     *
     * @since 1.2
     */
    private List<ModelContextAttribute> modelContextAttributes;

    /**
     * Modlet resources.
     */
    private Modlets modlets = new Modlets();

    /**
     * Model resources.
     */
    private Modules modules = new Modules();

    /**
     * Type of the currently processed resource or {@code null}.
     */
    private ResourceType currentResourceType;

    /**
     * The JOMC JAXB marshaller of the instance.
     */
    private Marshaller jomcMarshaller;

    /**
     * The JOMC JAXB unmarshaller of the instance.
     */
    private Unmarshaller jomcUnmarshaller;

    /**
     * The modlet JAXB marshaller of the instance.
     */
    private Marshaller modletMarshaller;

    /**
     * The modlet JAXB unmarshaller of the instance.
     */
    private Unmarshaller modletUnmarshaller;

    /**
     * Creates a new {@code JomcResourceTransformer} instance.
     */
    public JomcResourceTransformer()
    {
        super();
    }

    public boolean canTransformResource( final String arg )
    {
        boolean transformable = false;
        this.currentResourceType = null;
        final String name = normalizeResourceName( arg );

        if ( name != null )
        {
            if ( this.moduleResources != null )
            {
                for ( final String r : this.moduleResources )
                {
                    if ( name.equals( normalizeResourceName( r ) ) )
                    {
                        this.currentResourceType = ResourceType.MODEL_OBJECT_RESOURCE;

                        if ( this.getLogger() != null && this.getLogger().isDebugEnabled() )
                        {
                            this.getLogger().debug( LOG_PREFIX + Messages.getMessage(
                                "processingModuleResource", arg ) );

                        }

                        transformable = true;
                        break;
                    }
                }
            }

            if ( !transformable && this.modletResources != null )
            {
                for ( final String r : this.modletResources )
                {
                    if ( name.equals( normalizeResourceName( r ) ) )
                    {
                        this.currentResourceType = ResourceType.MODLET_OBJECT_RESOURCE;

                        if ( this.getLogger() != null && this.getLogger().isDebugEnabled() )
                        {
                            this.getLogger().debug( LOG_PREFIX + Messages.getMessage(
                                "processingModletResource", arg ) );

                        }

                        transformable = true;
                        break;
                    }
                }
            }

            if ( !transformable && ( name.equals( normalizeResourceName( this.modletResource ) )
                                     || name.equals( normalizeResourceName( this.moduleResource ) ) ) )
            {
                if ( this.getLogger() != null && this.getLogger().isWarnEnabled() )
                {
                    this.getLogger().warn( LOG_PREFIX + Messages.getMessage( "overridingResource", arg ) );
                }

                transformable = true;
                this.currentResourceType = null;
            }
        }

        return transformable;
    }

    public void processResource( final InputStream in ) throws IOException
    {
        try
        {
            if ( in != null && this.currentResourceType != null )
            {
                switch ( this.currentResourceType )
                {
                    case MODEL_OBJECT_RESOURCE:
                        Object modelObject = this.unmarshalModelObject( in );

                        if ( modelObject instanceof JAXBElement<?> )
                        {
                            modelObject = ( (JAXBElement<?>) modelObject ).getValue();
                        }
                        if ( modelObject instanceof Modules )
                        {
                            this.modules.getModule().addAll( ( (Modules) modelObject ).getModule() );
                        }
                        if ( modelObject instanceof Module )
                        {
                            this.modules.getModule().add( (Module) modelObject );
                        }
                        break;

                    case MODLET_OBJECT_RESOURCE:
                        Object modletObject = this.unmarshalModletObject( in );

                        if ( modletObject instanceof JAXBElement<?> )
                        {
                            modletObject = ( (JAXBElement<?>) modletObject ).getValue();
                        }
                        if ( modletObject instanceof Modlets )
                        {
                            this.modlets.getModlet().addAll( ( (Modlets) modletObject ).getModlet() );
                        }
                        if ( modletObject instanceof Modlet )
                        {
                            this.modlets.getModlet().add( (Modlet) modletObject );
                        }
                        break;

                    default:
                        throw new AssertionError( this.currentResourceType );

                }
            }
        }
        catch ( final InstantiationException e )
        {
            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( Messages.getMessage( e ) ).initCause( e );
        }
        catch ( final JAXBException e )
        {
            String message = Messages.getMessage( e );
            if ( message == null && e.getLinkedException() != null )
            {
                message = Messages.getMessage( e.getLinkedException() );
            }

            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( message ).initCause( e );
        }
        catch ( final ModelException e )
        {
            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( Messages.getMessage( e ) ).initCause( e );
        }
    }

    public void processResource( final String name, final InputStream in, final List<Relocator> relocators )
        throws IOException
    {
        this.processResource( in );
    }

    public boolean hasTransformedResource()
    {
        return !( this.modules.getModule().isEmpty() && this.modlets.getModlet().isEmpty() );
    }

    public void modifyOutputStream( final JarOutputStream out ) throws IOException
    {
        if ( StringUtils.isEmpty( this.model ) )
        {
            throw new IOException( Messages.getMessage( "mandatoryParameter", "model" ) );
        }
        if ( StringUtils.isEmpty( this.modletName ) )
        {
            throw new IOException( Messages.getMessage( "mandatoryParameter", "modletName" ) );
        }
        if ( StringUtils.isEmpty( this.modletResource ) )
        {
            throw new IOException( Messages.getMessage( "mandatoryParameter", "modletResource" ) );
        }
        if ( StringUtils.isEmpty( this.moduleName ) )
        {
            throw new IOException( Messages.getMessage( "mandatoryParameter", "moduleName" ) );
        }
        if ( StringUtils.isEmpty( this.moduleResource ) )
        {
            throw new IOException( Messages.getMessage( "mandatoryParameter", "moduleResource" ) );
        }

        try
        {
            if ( !this.modules.getModule().isEmpty() )
            {
                if ( this.moduleIncludes != null )
                {
                    for ( final Iterator<Module> it = this.modules.getModule().iterator(); it.hasNext(); )
                    {
                        final Module m = it.next();

                        if ( !this.moduleIncludes.contains( m.getName() ) )
                        {
                            it.remove();

                            if ( this.getLogger() != null && this.getLogger().isInfoEnabled() )
                            {
                                this.getLogger().info( LOG_PREFIX + Messages.getMessage(
                                    "excludingModule", m.getName() ) );

                            }
                        }
                    }
                }

                if ( this.moduleExcludes != null )
                {
                    for ( final String exclude : this.moduleExcludes )
                    {
                        final Module excluded = this.modules.getModule( exclude );

                        if ( excluded != null )
                        {
                            this.modules.getModule().remove( excluded );

                            if ( this.getLogger() != null && this.getLogger().isInfoEnabled() )
                            {
                                this.getLogger().info( LOG_PREFIX + Messages.getMessage(
                                    "excludingModule", excluded.getName() ) );

                            }
                        }
                    }
                }

                if ( this.getLogger() != null && this.getLogger().isInfoEnabled() )
                {
                    for ( final Module m : this.modules.getModule() )
                    {
                        this.getLogger().info( LOG_PREFIX + Messages.getMessage( "includingModule", m.getName() ) );
                    }
                }

                final Module mergedModule = this.modules.getMergedModule( this.moduleName );
                mergedModule.setVersion( this.moduleVersion );
                mergedModule.setVendor( this.moduleVendor );

                final JAXBElement<Module> transformedModule = this.transformModelObject(
                    new org.jomc.model.ObjectFactory().createModule( mergedModule ), Module.class );

                out.putNextEntry( new JarEntry( normalizeResourceName( this.moduleResource ) ) );
                this.marshalModelObject( transformedModule, out );
            }

            if ( !this.modlets.getModlet().isEmpty() )
            {
                if ( this.modletIncludes != null )
                {
                    for ( final Iterator<Modlet> it = this.modlets.getModlet().iterator(); it.hasNext(); )
                    {
                        final Modlet m = it.next();

                        if ( !this.modletIncludes.contains( m.getName() ) )
                        {
                            it.remove();

                            if ( this.getLogger() != null && this.getLogger().isInfoEnabled() )
                            {
                                this.getLogger().info( LOG_PREFIX + Messages.getMessage(
                                    "excludingModlet", m.getName() ) );

                            }
                        }
                    }
                }

                if ( this.modletExcludes != null )
                {
                    for ( final String exclude : this.modletExcludes )
                    {
                        final Modlet excluded = this.modlets.getModlet( exclude );

                        if ( excluded != null )
                        {
                            this.modlets.getModlet().remove( excluded );

                            if ( this.getLogger() != null && this.getLogger().isInfoEnabled() )
                            {
                                this.getLogger().info( LOG_PREFIX + Messages.getMessage(
                                    "excludingModlet", excluded.getName() ) );

                            }
                        }
                    }
                }

                if ( this.getLogger() != null && this.getLogger().isInfoEnabled() )
                {
                    for ( final Modlet m : this.modlets.getModlet() )
                    {
                        this.getLogger().info( LOG_PREFIX + Messages.getMessage( "includingModlet", m.getName() ) );
                    }
                }

                final Modlet mergedModlet = this.modlets.getMergedModlet( this.modletName, this.model );
                mergedModlet.setVendor( this.modletVendor );
                mergedModlet.setVersion( this.modletVersion );

                final JAXBElement<Modlet> transformedModlet = this.transformModletObject(
                    new org.jomc.modlet.ObjectFactory().createModlet( mergedModlet ), Modlet.class );

                out.putNextEntry( new JarEntry( normalizeResourceName( this.modletResource ) ) );
                this.marshalModletObject( transformedModlet, out );
            }
        }
        catch ( final InstantiationException e )
        {
            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( Messages.getMessage( e ) ).initCause( e );
        }
        catch ( final TransformerConfigurationException e )
        {
            String message = Messages.getMessage( e );
            if ( message == null && e.getException() != null )
            {
                message = Messages.getMessage( e.getException() );
            }

            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( message ).initCause( e );
        }
        catch ( final TransformerException e )
        {
            String message = Messages.getMessage( e );
            if ( message == null && e.getException() != null )
            {
                message = Messages.getMessage( e.getException() );
            }

            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( message ).initCause( e );
        }
        catch ( final JAXBException e )
        {
            String message = Messages.getMessage( e );
            if ( message == null && e.getLinkedException() != null )
            {
                message = Messages.getMessage( e.getLinkedException() );
            }

            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( message ).initCause( e );
        }
        catch ( final ModelException e )
        {
            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( Messages.getMessage( e ) ).initCause( e );
        }
        catch ( final URISyntaxException e )
        {
            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( Messages.getMessage( e ) ).initCause( e );
        }
        finally
        {
            this.modlets = new Modlets();
            this.modules = new Modules();
            this.jomcMarshaller = null;
            this.jomcUnmarshaller = null;
            this.modletMarshaller = null;
            this.modletUnmarshaller = null;
        }
    }

    /**
     * Creates an {@code URL} for a given resource location.
     * <p>
     * This method first searches the class loader of the class for a single resource matching {@code location}. If
     * such a resource is found, the URL of that resource is returned. If no such resource is found, an attempt is made
     * to parse the given location to an URL. On successful parsing, that URL is returned. Failing that, the given
     * location is interpreted as a file name. If that file is found, the URL of that file is returned. Otherwise an
     * {@code IOException} is thrown.
     * </p>
     *
     * @param location The location to create an {@code URL} from.
     *
     * @return An {@code URL} for {@code location}.
     *
     * @throws NullPointerException if {@code location} is {@code null}.
     * @throws IOException if creating an URL fails.
     *
     * @since 1.2
     */
    protected URL getResource( final String location ) throws IOException
    {
        if ( location == null )
        {
            throw new NullPointerException( "location" );
        }

        try
        {
            String absolute = location;
            if ( !absolute.startsWith( "/" ) )
            {
                absolute = "/" + location;
            }

            URL resource = this.getClass().getResource( absolute );
            if ( resource == null )
            {
                try
                {
                    resource = new URL( location );
                }
                catch ( final MalformedURLException e )
                {
                    if ( this.getLogger() != null && this.getLogger().isDebugEnabled() )
                    {
                        this.getLogger().debug( Messages.getMessage( e ), e );
                    }

                    resource = null;
                }
            }

            if ( resource == null )
            {
                final File f = new File( location );

                if ( f.isFile() )
                {
                    resource = f.toURI().toURL();
                }
            }

            if ( resource == null )
            {
                throw new IOException( Messages.getMessage( "resourceNotFound", location ) );
            }

            return resource;
        }
        catch ( final MalformedURLException e )
        {
            String m = Messages.getMessage( e );
            m = m == null ? "" : " " + m;

            // JDK: As of JDK 6, "new IOException( message, cause )".
            throw (IOException) new IOException( Messages.getMessage(
                "malformedLocation", location, m ) ).initCause( e );

        }
    }

    private Object unmarshalModelObject( final InputStream in )
        throws ModelException, JAXBException, InstantiationException
    {
        if ( in == null )
        {
            throw new NullPointerException( "in" );
        }

        if ( this.jomcUnmarshaller == null )
        {
            this.jomcUnmarshaller = this.createModelContext().createUnmarshaller( this.model );
        }

        return this.jomcUnmarshaller.unmarshal( in );
    }

    private void marshalModelObject( final JAXBElement<? extends ModelObject> element, final OutputStream out )
        throws ModelException, JAXBException, InstantiationException
    {
        if ( element == null )
        {
            throw new NullPointerException( "element" );
        }
        if ( out == null )
        {
            throw new NullPointerException( "out" );
        }

        if ( this.jomcMarshaller == null )
        {
            final ModelContext modelContext = this.createModelContext();
            this.jomcMarshaller = modelContext.createMarshaller( this.model );
            this.jomcMarshaller.setSchema( modelContext.createSchema( this.model ) );
            this.jomcMarshaller.setProperty( Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE );

            if ( this.moduleEncoding != null )
            {
                this.jomcMarshaller.setProperty( Marshaller.JAXB_ENCODING, this.moduleEncoding );
            }
        }

        this.jomcMarshaller.marshal( element, out );
    }

    private <T> JAXBElement<T> transformModelObject( final JAXBElement<? extends ModelObject> element,
                                                     final Class<T> boundType )
        throws ModelException, TransformerException, JAXBException, IOException, URISyntaxException,
               InstantiationException
    {
        if ( element == null )
        {
            throw new NullPointerException( "element" );
        }
        if ( !boundType.isInstance( element.getValue() ) )
        {
            throw new IllegalArgumentException( element.toString() );
        }

        @SuppressWarnings( "unchecked" )
        JAXBElement<T> transformed = (JAXBElement<T>) element;

        if ( this.modelObjectStylesheet != null )
        {
            final Transformer transformer = TransformerFactory.newInstance().newTransformer(
                new StreamSource( this.getResource( this.modelObjectStylesheet ).toURI().toASCIIString() ) );

            final ModelContext modelContext = this.createModelContext();
            final Marshaller marshaller = modelContext.createMarshaller( this.model );
            final Unmarshaller unmarshaller = modelContext.createUnmarshaller( this.model );
            final JAXBSource source = new JAXBSource( marshaller, element );
            final JAXBResult result = new JAXBResult( unmarshaller );

            for ( final Map.Entry<Object, Object> e : System.getProperties().entrySet() )
            {
                transformer.setParameter( e.getKey().toString(), e.getValue() );
            }

            transformer.transform( source, result );

            if ( result.getResult() instanceof JAXBElement<?>
                     && boundType.isInstance( ( (JAXBElement<?>) result.getResult() ).getValue() ) )
            {
                @SuppressWarnings( "unchecked" ) final JAXBElement<T> e = (JAXBElement<T>) result.getResult();
                transformed = e;
            }
            else
            {
                throw new ModelException( Messages.getMessage(
                    "illegalModuleTransformationResult", this.modelObjectStylesheet ) );

            }
        }

        return transformed;
    }

    private Object unmarshalModletObject( final InputStream in )
        throws ModelException, JAXBException, InstantiationException
    {
        if ( in == null )
        {
            throw new NullPointerException( "in" );
        }

        if ( this.modletUnmarshaller == null )
        {
            this.modletUnmarshaller = this.createModelContext().createUnmarshaller( ModletObject.MODEL_PUBLIC_ID );
        }

        return this.modletUnmarshaller.unmarshal( in );
    }

    private void marshalModletObject( final JAXBElement<? extends ModletObject> element, final OutputStream out )
        throws ModelException, JAXBException, InstantiationException
    {
        if ( element == null )
        {
            throw new NullPointerException( "element" );
        }
        if ( out == null )
        {
            throw new NullPointerException( "out" );
        }

        if ( this.modletMarshaller == null )
        {
            final ModelContext modletContext = this.createModelContext();
            this.modletMarshaller = modletContext.createMarshaller( ModletObject.MODEL_PUBLIC_ID );
            this.modletMarshaller.setSchema( modletContext.createSchema( ModletObject.MODEL_PUBLIC_ID ) );
            this.modletMarshaller.setProperty( Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE );

            if ( this.modletEncoding != null )
            {
                this.modletMarshaller.setProperty( Marshaller.JAXB_ENCODING, this.modletEncoding );
            }
        }

        this.modletMarshaller.marshal( element, out );
    }

    private <T> JAXBElement<T> transformModletObject( final JAXBElement<? extends ModletObject> element,
                                                      final Class<T> boundType )
        throws ModelException, TransformerException, JAXBException, IOException, URISyntaxException,
               InstantiationException
    {
        if ( element == null )
        {
            throw new NullPointerException( "element" );
        }
        if ( !boundType.isInstance( element.getValue() ) )
        {
            throw new IllegalArgumentException( element.toString() );
        }

        @SuppressWarnings( "unchecked" )
        JAXBElement<T> transformed = (JAXBElement<T>) element;

        if ( this.modletObjectStylesheet != null )
        {
            final Transformer transformer = TransformerFactory.newInstance().newTransformer(
                new StreamSource( this.getResource( this.modletObjectStylesheet ).toURI().toASCIIString() ) );

            final ModelContext modletContext = this.createModelContext();
            final Marshaller marshaller = modletContext.createMarshaller( ModletObject.MODEL_PUBLIC_ID );
            final Unmarshaller unmarshaller = modletContext.createUnmarshaller( ModletObject.MODEL_PUBLIC_ID );
            final JAXBSource source = new JAXBSource( marshaller, element );
            final JAXBResult result = new JAXBResult( unmarshaller );

            for ( final Map.Entry<Object, Object> e : System.getProperties().entrySet() )
            {
                transformer.setParameter( e.getKey().toString(), e.getValue() );
            }

            transformer.transform( source, result );

            if ( result.getResult() instanceof JAXBElement<?>
                     && boundType.isInstance( ( (JAXBElement<?>) result.getResult() ).getValue() ) )
            {
                @SuppressWarnings( "unchecked" ) final JAXBElement<T> e = (JAXBElement<T>) result.getResult();
                transformed = e;
            }
            else
            {
                throw new ModelException( Messages.getMessage(
                    "illegalModletTransformationResult", this.modletObjectStylesheet ) );

            }
        }

        return transformed;
    }

    private static String normalizeResourceName( final String name )
    {
        String normalized = name;

        if ( normalized != null )
        {
            normalized = normalized.replace( '\\', '/' );

            if ( normalized.startsWith( "/" ) )
            {
                normalized = normalized.substring( 1 );
            }

            if ( normalized.endsWith( "/" ) )
            {
                normalized = normalized.substring( 0, normalized.length() );
            }
        }

        return normalized;
    }

    private ModelContext createModelContext() throws ModelException, InstantiationException
    {
        final ModelContextFactory modelContextFactory;
        if ( this.modelContextFactoryClassName != null )
        {
            modelContextFactory = ModelContextFactory.newInstance( this.modelContextFactoryClassName );
        }
        else
        {
            modelContextFactory = ModelContextFactory.newInstance();
        }

        final ModelContext modelContext = modelContextFactory.newModelContext();
        modelContext.setModletSchemaSystemId( this.modletSchemaSystemId );

        if ( this.providerLocation != null )
        {
            modelContext.setAttribute( DefaultModelContext.PROVIDER_LOCATION_ATTRIBUTE_NAME, this.providerLocation );
        }

        if ( this.platformProviderLocation != null )
        {
            modelContext.setAttribute( DefaultModelContext.PLATFORM_PROVIDER_LOCATION_ATTRIBUTE_NAME,
                                       this.platformProviderLocation );

        }

        if ( this.modletLocation != null )
        {
            modelContext.setAttribute( DefaultModletProvider.MODLET_LOCATION_ATTRIBUTE_NAME, this.modletLocation );
        }

        if ( this.modelContextAttributes != null )
        {
            for ( final ModelContextAttribute e : this.modelContextAttributes )
            {
                final Object object = e.getObject( modelContext );

                if ( object != null )
                {
                    modelContext.setAttribute( e.getKey(), object );
                }
                else
                {
                    modelContext.clearAttribute( e.getKey() );
                }
            }
        }

        return modelContext;
    }

}