package org.andromda.core.engine;
   
   import java.text.Collator;
   import java.util.ArrayList;
   import java.util.Arrays;
   import java.util.Collection;
   import java.util.Collections;
   import java.util.Comparator;
   import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.andromda.core.ModelValidationException;
  import org.andromda.core.cartridge.Cartridge;
  import org.andromda.core.common.AndroMDALogger;
  import org.andromda.core.common.BuildInformation;
  import org.andromda.core.common.ComponentContainer;
  import org.andromda.core.common.ExceptionRecorder;
  import org.andromda.core.common.Introspector;
  import org.andromda.core.common.ResourceWriter;
  import org.andromda.core.common.XmlObjectFactory;
  import org.andromda.core.configuration.Configuration;
  import org.andromda.core.configuration.Filters;
  import org.andromda.core.configuration.Model;
  import org.andromda.core.configuration.Namespace;
  import org.andromda.core.configuration.Namespaces;
  import org.andromda.core.configuration.Property;
  import org.andromda.core.metafacade.MetafacadeFactory;
  import org.andromda.core.metafacade.ModelAccessFacade;
  import org.andromda.core.metafacade.ModelValidationMessage;
  import org.andromda.core.namespace.NamespaceComponents;
  import org.andromda.core.repository.Repositories;
  import org.apache.commons.collections.comparators.ComparatorChain;
  import org.apache.commons.lang.StringUtils;
  import org.apache.log4j.Logger;
  
  
  /***
   * <p>
   * Handles the processing of models. Facilitates Model Driven
   * Architecture by enabling the generation of source code, configuration files, and other such artifacts from a single
   * or multiple models. </p>
   *
   * @author Chad Brandon
   */
  public class ModelProcessor
  {
      /***
       * The logger instance.
       */
      private static final Logger logger = Logger.getLogger(ModelProcessor.class);
  
      /***
       * Creates a new instance the ModelProcessor.
       *
       * @return the shared ModelProcessor instance.
       */
      public static ModelProcessor newInstance()
      {
          return new ModelProcessor();
      }
  
      private ModelProcessor()
      {
          // - do not allow instantiation
      }
  
      /***
       * Re-configures this model processor from the given <code>configuration</code>
       * instance (if different from that of the one passed in during the call to
       * {@link #initialize(Configuration)}), and runs the model processor.
       *
       * @param configuration the configuration from which to configure this model
       *        processor instance.
       * @return any model validation messages collected during model processing (if
       *         model validation is enabled).
       */
      public ModelValidationMessage[] process(final Configuration configuration)
      {
          this.configure(configuration);
          final List messages = this.process(configuration.getRepositories());
          return messages != null ? (ModelValidationMessage[])messages.toArray(new ModelValidationMessage[0])
                                  : new ModelValidationMessage[0];
      }
  
      /***
       * Configures (or re-configures) the model processor if configuration
       * is required (the configuration has changed since the previous, or has
       * yet to be used).
       *
       * @param configuration the AndroMDA configuration instance.
       */
      private void configure(final Configuration configuration)
      {
          if (this.requiresConfiguration(configuration))
          {
              configuration.initialize();
              this.reset();
             final Property[] properties = configuration.getProperties();
             final int propertyNumber = properties.length;
             final Introspector introspector = Introspector.instance();
             for (int ctr = 0; ctr < propertyNumber; ctr++)
             {
                 final Property property = properties[ctr];
                 try
                 {
                     introspector.setProperty(
                         this,
                         property.getName(),
                         property.getValue());
                 }
                 catch (final Throwable throwable)
                 {
                     AndroMDALogger.warn(
                         "Could not set model processor property '" + property.getName() + "' with a value of '" +
                         property.getValue() + "'");
                 }
             }
             this.currentConfiguration = configuration;
         }
     }
 
     /***
      * Processes all models contained within the <code>repositories</code>
      * with the discovered cartridges.
      *
      * @return any model validation messages that may have been collected during model loading/validation.
      */
     private List process(final org.andromda.core.configuration.Repository[] repositories)
     {
         List messages = null;
         final long startTime = System.currentTimeMillis();
         final int repositoryNumber = repositories.length;
         for (int ctr = 0; ctr < repositoryNumber; ctr++)
         {
             final org.andromda.core.configuration.Repository repository = repositories[ctr];
             if (repository != null)
             {
                 final String repositoryName = repository.getName();
 
                 // - filter out any invalid models (ones that don't have any uris defined)
                 final Model[] models = this.filterInvalidModels(repository.getModels());
                 if (models.length > 0)
                 {
                     messages = this.processModels(
                             repositoryName,
                             models);
                     AndroMDALogger.info(
                         "completed model processing --> TIME: " + this.getDurationInSeconds(startTime) +
                         "[s], RESOURCES WRITTEN: " + ResourceWriter.instance().getWrittenCount());
                 }
                 else
                 {
                     AndroMDALogger.warn("No model(s) found to process for repository '" + repositoryName + "'");
                 }
             }
         }
         return messages == null ? Collections.EMPTY_LIST : messages;
     }
 
     /***
      * The shared metafacade factory instance.
      */
     private final MetafacadeFactory factory = MetafacadeFactory.getInstance();
 
     /***
      * The shared namespaces instance.
      */
     private final Namespaces namespaces = Namespaces.instance();
 
     /***
      * The shared repositories instance.
      */
     private final Repositories repositories = Repositories.instance();
 
     /***
      * Processes multiple <code>models</code>.
      *
      * @param repositoryName the name of the repository that loads/reads the model.
      * @param models the Model(s) to process.
      * @return any model validation messages that may have been collected during validation/loading of
      *         the <code>models</code>.
      */
     private List processModels(
         final String repositoryName,
         final Model[] models)
     {
         List messages = null;
         String cartridgeName = null;
         try
         {
             boolean lastModifiedCheck = true;
             long lastModified = 0;
             final ResourceWriter writer = ResourceWriter.instance();
 
             // - get the time from the model that has the latest modified time
             for (int ctr = 0; ctr < models.length; ctr++)
             {
                 final Model model = models[ctr];
                 writer.resetHistory(model.getUris()[0]);
                 lastModifiedCheck = model.isLastModifiedCheck() && lastModifiedCheck;
 
                 // - we go off the model that was most recently modified.
                 if (model.getLastModified() > lastModified)
                 {
                     lastModified = model.getLastModified();
                 }
             }
 
             if (!lastModifiedCheck || writer.isHistoryBefore(lastModified))
             {
                 final Collection cartridges = ComponentContainer.instance().findComponentsOfType(Cartridge.class);
                 if (cartridges.isEmpty())
                 {
                     AndroMDALogger.warn("WARNING! No cartridges found, check your classpath!");
                 }
                 
                 final Map cartridgesByNamespace = this.loadCartridgesByNamespace(cartridges);
                 
                 // - we want to process by namespace so that the order within the configuration is kept
                 final Collection namespaces = this.namespaces.getNamespaces();
 
                 // - pre-load the models
                 messages = this.loadIfNecessary(models);
                 for (final Iterator iterator = namespaces.iterator(); iterator.hasNext();)
                 {
                     final Namespace namespace = (Namespace)iterator.next();
                     final Cartridge cartridge = (Cartridge)cartridgesByNamespace.get(namespace.getName());
                     if (cartridge != null)
                     {
                         cartridgeName = cartridge.getNamespace();
                         if (this.shouldProcess(cartridgeName))
                         {
                             // - set the active namespace on the shared factory and profile instances
                             this.factory.setNamespace(cartridgeName);
                             cartridge.initialize();
     
                             // - process each model with the cartridge
                             for (int ctr = 0; ctr < models.length; ctr++)
                             {
                                 final Model model = models[ctr];
     
                                 // - set the namespace on the metafacades instance so we know the 
                                 //   correct facades to use
                                 this.factory.setModel(
                                     this.repositories.getImplementation(repositoryName).getModel(),
                                     model.getType());
                                 cartridge.processModelElements(this.factory);
                                 writer.writeHistory();
                             }
                             cartridge.shutdown();
                         }
                     }
                 }
             }
         }
         catch (final ModelValidationException exception)
         {
             // - we don't want to record model validation exceptions
             throw exception;
         }
         catch (final Throwable throwable)
         {
             final String messsage =
                 "Error performing ModelProcessor.process with model(s) --> '" + StringUtils.join(
                     models,
                     ",") + "'";
             logger.error(messsage);
             ExceptionRecorder.instance().record(
                 messsage,
                 throwable,
                 cartridgeName);
             throw new ModelProcessorException(messsage, throwable);
         }
         return messages == null ? Collections.EMPTY_LIST : messages;
     }
     
     /***
      * Loads the given list of <code>cartridges</code> into a map keyed by namespace.
      * 
      * @param cartridges the cartridges loaded.
      * @return the loaded cartridge map.
      */
     private Map loadCartridgesByNamespace(final Collection cartridges)
     {
         final Map cartridgesByNamespace = new LinkedHashMap();
         for (final Iterator iterator = cartridges.iterator(); iterator.hasNext();)
         {
             final Cartridge cartridge = (Cartridge)iterator.next();
             cartridgesByNamespace.put(cartridge.getNamespace(), cartridge);
         }
         return cartridgesByNamespace;
     }
 
     /***
      * Initializes this model processor instance with the given
      * configuration.  This configuration information is overridden (if changed)
      * when calling {@link #process(Configuration)}
      *
      * @param configuration the configuration instance by which to initialize this
      *        model processor instance.
      */
     public void initialize(final Configuration configuration)
     {
         final long startTime = System.currentTimeMillis();
 
         // - first, print the AndroMDA header
         this.printConsoleHeader();
 
         // - second, configure this model processor 
         // - the ordering of this step is important: it needs to occur
         //   before everything else in the framework is initialized so that 
         //   we have all configuration information available (such as the
         //   namespace properties)
         this.configure(configuration);
 
         // - the logger configuration may have changed - re-init the logger.
         AndroMDALogger.initialize();
 
         // - discover all namespace components
         NamespaceComponents.instance().discover();
 
         // - find and initialize any repositories
         repositories.initialize();
 
         // - finally initialize the metafacade factory
         this.factory.initialize();
         this.printWorkCompleteMessage(
             "core initialization",
             startTime);
     }
 
     /***
      * Loads the model into the repository only when necessary (the model has a timestamp
      * later than the last timestamp of the loaded model).
      *
      * @param model the model to be loaded.
      */
     protected final List loadModelIfNecessary(final Model model)
     {
         final List validationMessages = new ArrayList();
         final long startTime = System.currentTimeMillis();
         if (this.repositories.loadModel(model))
         {
             this.printWorkCompleteMessage(
                 "loading",
                 startTime);
 
             // - validate the model since loading has successfully occurred
             final org.andromda.core.configuration.Repository repository = model.getRepository();
             final String repositoryName = repository != null ? repository.getName() : null;
             validationMessages.addAll(this.validateModel(
                     repositoryName,
                     model));
         }
         return validationMessages;
     }
 
     /***
      * Validates the entire model with each cartridge namespace,
      * and returns any validation messages that occurred during validation
      * (also logs any validation failures).
      *
      * @param repositoryName the name of the repository storing the model to validate.
      * @return any {@link ModelValidationMessage} instances that may have been collected
      *         during validation.
      */
     private List validateModel(
         final String repositoryName,
         final Model model)
     {
         final Filters constraints = model != null ? model.getConstraints() : null;
         final List validationMessages = new ArrayList();
         if (this.modelValidation)
         {
             final long startTime = System.currentTimeMillis();
             AndroMDALogger.info("- validating model -");
             final Collection cartridges = ComponentContainer.instance().findComponentsOfType(Cartridge.class);
             final ModelAccessFacade modelAccessFacade =
                 this.repositories.getImplementation(repositoryName).getModel();
 
             // - clear out the factory's caches (such as any previous validation messages, etc.)
             this.factory.clearCaches();
             this.factory.setModel(
                 modelAccessFacade,
                 model.getType());
             for (final Iterator iterator = cartridges.iterator(); iterator.hasNext();)
             {
                 final Cartridge cartridge = (Cartridge)iterator.next();
                 final String cartridgeName = cartridge.getNamespace();
                 if (this.shouldProcess(cartridgeName))
                 {
                     // - set the active namespace on the shared factory and profile instances
                     this.factory.setNamespace(cartridgeName);
                     this.factory.validateAllMetafacades();
                 }
             }
             final List messages = this.factory.getValidationMessages();
             this.filterAndSortValidationMessages(
                 messages,
                 constraints);
             this.printValidationMessages(messages);
             this.printWorkCompleteMessage(
                 "validation",
                 startTime);
             if (messages != null && !messages.isEmpty())
             {
                 validationMessages.addAll(messages);
             }
         }
         return validationMessages;
     }
 
     /***
      * Prints a work complete message using the type of <code>unitOfWork</code> and
      * <code>startTime</code> as input.
      * @param unitOfWork the type of unit of work that was completed
      * @param startTime the time the unit of work was started.
      */
     private void printWorkCompleteMessage(
         final String unitOfWork,
         final long startTime)
     {
         AndroMDALogger.info("- " + unitOfWork + " complete: " + this.getDurationInSeconds(startTime) + "[s] -");
     }
 
     /***
      * Calcuates the duration in seconds between the
      * given <code>startTime</code> and the current time.
      * @param startTime the time to compare against.
      * @return the duration of time in seconds.
      */
     private double getDurationInSeconds(final long startTime)
     {
         return ((System.currentTimeMillis() - startTime) / 1000.0);
     }
 
     /***
      * Prints any model validation errors stored within the <code>factory</code>.
      */
     private void printValidationMessages(final List messages)
     {
         // - log all error messages
         if (messages != null && !messages.isEmpty())
         {
             final StringBuffer header =
                 new StringBuffer("Model Validation Failed - " + messages.size() + " VALIDATION ERROR");
             if (messages.size() > 1)
             {
                 header.append("S");
             }
             AndroMDALogger.error(header);
             final Iterator iterator = messages.iterator();
             for (int ctr = 1; iterator.hasNext(); ctr++)
             {
                 final ModelValidationMessage message = (ModelValidationMessage)iterator.next();
                 AndroMDALogger.error(ctr + ") " + message);
             }
             AndroMDALogger.reset();
             if (this.failOnValidationErrors)
             {
                 throw new ModelValidationException("Model validation failed!");
             }
         }
     }
 
     /***
      * The current configuration of this model processor.
      */
     private Configuration currentConfiguration = null;
 
     /***
      * Determines whether or not this model processor needs to be reconfigured.
      * This is based on whether or not the new configuration is different
      * than the <code>currentConfiguration</code>.  We determine this checking
      * if their contents are equal or not, if not equal this method will
      * return true, otherwise false.
      *
      * @param configuration the configuration to compare to the lastConfiguration.
      * @return true/false
      */
     private boolean requiresConfiguration(final Configuration configuration)
     {
         boolean requiresConfiguration =
             this.currentConfiguration == null || this.currentConfiguration.getContents() == null ||
             configuration.getContents() == null;
         if (!requiresConfiguration)
         {
             requiresConfiguration = !this.currentConfiguration.getContents().equals(configuration.getContents());
         }
         return requiresConfiguration;
     }
 
     /***
      * Checks to see if <em>any</em> of the repositories contain models
      * that need to be reloaded, and if so, re-loads them.
      *
      * @param repositories the repositories from which to load the model(s).
      */
     final List loadIfNecessary(final org.andromda.core.configuration.Repository[] repositories)
     {
         final List messages = new ArrayList();
         if (repositories != null && repositories.length > 0)
         {
             final int repositoryNumber = repositories.length;
             for (int repositoryCtr = 0; repositoryCtr < repositoryNumber; repositoryCtr++)
             {
                 final org.andromda.core.configuration.Repository repository = repositories[repositoryCtr];
                 if (repository != null)
                 {
                     messages.addAll(this.loadIfNecessary(repository.getModels()));
                 }
             }
         }
         return messages;
     }
 
     /***
      * Checks to see if <em>any</em> of the models need to be reloaded, and if so, re-loads them.
      *
      * @param models that will be loaded (if necessary).
      * @return any validation messages collected during loading.
      */
     private List loadIfNecessary(final Model[] models)
     {
         final List messages = new ArrayList();
         if (models != null && models.length > 0)
         {
             final int modelNumber = models.length;
             for (int modelCtr = 0; modelCtr < modelNumber; modelCtr++)
             {
                 messages.addAll(this.loadModelIfNecessary(models[modelCtr]));
             }
         }
         return messages;
     }
 
     /***
      * Stores the current version of AndroMDA.
      */
     private static final String VERSION = BuildInformation.instance().getBuildVersion();
 
     /***
      * Prints the console header.
      */
     protected void printConsoleHeader()
     {
         AndroMDALogger.info("");
         AndroMDALogger.info("A n d r o M D A  -  " + VERSION);
         AndroMDALogger.info("");
     }
 
     /***
      * Whether or not model validation should be performed.
      */
     private boolean modelValidation = true;
 
     /***
      * Sets whether or not model validation should occur. This is useful for
      * performance reasons (i.e. if you have a large model it can significatly descrease the amount of time it takes for
      * AndroMDA to process a model). By default this is set to <code>true</code>.
      *
      * @param modelValidation true/false on whether model validation should be performed or not.
      */
     public void setModelValidation(final boolean modelValidation)
     {
         this.modelValidation = modelValidation;
     }
 
     /***
      * A flag indicating whether or not failure should occur
      * when model validation errors are present.
      */
     private boolean failOnValidationErrors = true;
 
     /***
      * Sets whether or not processing should fail when validation errors occur, default is <code>true</code>.
      *
      * @param failOnValidationErrors whether or not processing should fail if any validation errors are present.
      */
     public void setFailOnValidationErrors(final boolean failOnValidationErrors)
     {
         this.failOnValidationErrors = failOnValidationErrors;
     }
 
     /***
      * Stores the cartridge filter.
      */
     private List cartridgeFilter = null;
 
     /***
      * Denotes whether or not the complement of filtered cartridges should be processed
      */
     private boolean negateCartridgeFilter = false;
 
     /***
      * Indicates whether or not the <code>namespace</code> should be processed. This is determined in conjunction with
      * {@link #setCartridgeFilter(String)}. If the <code>cartridgeFilter</code> is not defined and the namespace is
      * present within the configuration, then this method will <strong>ALWAYS </strong> return true.
      *
      * @param namespace the name of the namespace to check whether or not it should be processed.
      * @return true/false on whether or not it should be processed.
      */
     protected boolean shouldProcess(final String namespace)
     {
         boolean shouldProcess = this.namespaces.namespacePresent(namespace);
         if (shouldProcess)
         {
             shouldProcess = this.cartridgeFilter == null || this.cartridgeFilter.isEmpty();
             if (!shouldProcess)
             {
                 shouldProcess =
                     this.negateCartridgeFilter ^ this.cartridgeFilter.contains(StringUtils.trimToEmpty(namespace));
             }
         }
         return shouldProcess;
     }
 
     /***
      * The prefix used for cartridge filter negation.
      */
     private static final String CARTRIDGE_FILTER_NEGATOR = "~";
 
     /***
      * <p/>
      * Sets the current cartridge filter. This is a comma seperated list of namespaces (matching cartridges names) that
      * should be processed. </p>
      * <p/>
      * If this filter is defined, then any cartridge names found in this list <strong>will be processed </strong>, while
      * any other discovered cartridges <strong>will not be processed </strong>. </p>
      *
      * @param namespaces a comma seperated list of the cartridge namespaces to be processed.
      */
     public void setCartridgeFilter(String namespaces)
     {
         if (namespaces != null)
         {
             namespaces = StringUtils.deleteWhitespace(namespaces);
             if (namespaces.startsWith(CARTRIDGE_FILTER_NEGATOR))
             {
                 this.negateCartridgeFilter = true;
                 namespaces = namespaces.substring(1);
             }
             else
             {
                 this.negateCartridgeFilter = false;
             }
             if (StringUtils.isNotBlank(namespaces))
             {
                 this.cartridgeFilter = Arrays.asList(namespaces.split(","));
             }
         }
     }
 
     /***
      * Sets the encoding (UTF-8, ISO-8859-1, etc) for all output
      * produced during model processing.
      *
      * @param outputEncoding the encoding.
      */
     public void setOutputEncoding(final String outputEncoding)
     {
         ResourceWriter.instance().setEncoding(outputEncoding);
     }
 
     /***
      * Sets <code>xmlValidation</code> to be true/false. This defines whether XML resources loaded by AndroMDA (such as
      * plugin descriptors) should be validated. Sometimes underlying parsers don't support XML Schema validation and in
      * that case, we want to be able to turn it off.
      *
      * @param xmlValidation true/false on whether we should validate XML resources used by AndroMDA
      */
     public void setXmlValidation(final boolean xmlValidation)
     {
         XmlObjectFactory.setDefaultValidating(xmlValidation);
     }
 
     /***
      * <p/>
      * Sets the <code>loggingConfigurationUri</code> for AndroMDA. This is the URI to an external logging configuration
      * file. This is useful when you want to override the default logging configuration of AndroMDA. </p>
      * <p/>
      * You can retrieve the default log4j.xml contained within the {@link org.andromda.core.common}package, customize
      * it, and then specify the location of this logging file with this operation. </p>
      *
      * @param loggingConfigurationUri the URI to the external logging configuation file.
      */
     public void setLoggingConfigurationUri(final String loggingConfigurationUri)
     {
         AndroMDALogger.setLoggingConfigurationUri(loggingConfigurationUri);
     }
 
     /***
      * Filters out any <em>invalid</em> models. This means models that either are null within the specified
      * <code>models</code> array or those that don't have URLs set.
      *
      * @param models the models to filter.
      * @return the array of valid models
      */
     private Model[] filterInvalidModels(final Model[] models)
     {
         final Collection validModels = new ArrayList(Arrays.asList(models));
         for (final Iterator iterator = validModels.iterator(); iterator.hasNext();)
         {
             final Model model = (Model)iterator.next();
             if (!(model != null && model.getUris() != null && model.getUris().length > 0))
             {
                 iterator.remove();
             }
         }
         return (Model[])validModels.toArray(new Model[0]);
     }
 
     /***
      * Shuts down the model processor (reclaims any
      * resources).
      */
     public void shutdown()
     {
         // - shutdown the metafacade factory instance
         this.factory.shutdown();
 
         // - shutdown the configuration namespaces instance
         this.namespaces.clear();
 
         // - shutdown the container instance
         ComponentContainer.instance().shutdown();
 
         // - shutdown the namespace components registry
         NamespaceComponents.instance().shutdown();
 
         // - shutdown the introspector
         Introspector.instance().shutdown();
 
         // - clear out any caches used by the configuration
         Configuration.clearCaches();
 
         // - clear out any repositories
         this.repositories.clear();
     }
 
     /***
      * Reinitializes the model processor's resources.
      */
     private void reset()
     {
         this.factory.reset();
         this.cartridgeFilter = null;
         this.setXmlValidation(true);
         this.setOutputEncoding(null);
         this.setModelValidation(true);
         this.setLoggingConfigurationUri(null);
         this.setFailOnValidationErrors(true);
     }
 
     /***
      * Filters out any messages that should not be applied according to the AndroMDA configuration's
      * constraints and sorts the resulting <code>messages</code> first by type (i.e. the metafacade class)
      * and then by the <code>name</code> of the model element to which the validation message applies.
      *
      * @param messages the collection of messages to sort.
      * @param constraints any constraint filters to apply to the validation messages.
      */
     protected void filterAndSortValidationMessages(
         final List messages,
         final Filters constraints)
     {
         if (constraints != null)
         {
             // - perform constraint filtering (if any applies)
             for (final Iterator iterator = messages.iterator(); iterator.hasNext();)
             {
                 final ModelValidationMessage message = (ModelValidationMessage)iterator.next();
                 if (message != null && !constraints.isApply(message.getName()))
                 {
                     iterator.remove();
                 }
             }
         }
 
         if (messages != null && !messages.isEmpty())
         {
             final ComparatorChain chain = new ComparatorChain();
             chain.addComparator(new ValidationMessageTypeComparator());
             chain.addComparator(new ValidationMessageNameComparator());
             Collections.sort(
                 messages,
                 chain);
         }
     }
 
     /***
      * Used to sort validation messages by <code>metafacadeClass</code>.
      */
     private final static class ValidationMessageTypeComparator
         implements Comparator
     {
         private final Collator collator = Collator.getInstance();
 
         ValidationMessageTypeComparator()
         {
             collator.setStrength(Collator.PRIMARY);
         }
 
         public int compare(
             final Object objectA,
             final Object objectB)
         {
             final ModelValidationMessage a = (ModelValidationMessage)objectA;
             final ModelValidationMessage b = (ModelValidationMessage)objectB;
             return collator.compare(
                 a.getMetafacadeClass().getName(),
                 b.getMetafacadeClass().getName());
         }
     }
 
     /***
      * Used to sort validation messages by <code>modelElementName</code>.
      */
     private final static class ValidationMessageNameComparator
         implements Comparator
     {
         private final Collator collator = Collator.getInstance();
 
         ValidationMessageNameComparator()
         {
             collator.setStrength(Collator.PRIMARY);
         }
 
         public int compare(
             final Object objectA,
             final Object objectB)
         {
             final ModelValidationMessage a = (ModelValidationMessage)objectA;
             final ModelValidationMessage b = (ModelValidationMessage)objectB;
             return collator.compare(
                 StringUtils.trimToEmpty(a.getMetafacadeName()),
                 StringUtils.trimToEmpty(b.getMetafacadeName()));
         }
     }
 }