/**
    * Copyright 2005-2013 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.kuali.rice.krad.datadictionary;
  
  import org.apache.commons.beanutils.PropertyUtils;
  import org.apache.commons.collections.ListUtils;
  import org.apache.commons.lang.ArrayUtils;
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.kuali.rice.core.api.config.property.ConfigContext;
  import org.kuali.rice.core.api.util.ClassLoaderUtils;
  import org.kuali.rice.krad.bo.PersistableBusinessObjectExtension;
  import org.kuali.rice.krad.datadictionary.exception.AttributeValidationException;
  import org.kuali.rice.krad.datadictionary.exception.CompletionException;
  import org.kuali.rice.krad.datadictionary.parse.StringListConverter;
  import org.kuali.rice.krad.datadictionary.parse.StringMapConverter;
  import org.kuali.rice.krad.datadictionary.uif.UifDictionaryIndex;
  import org.kuali.rice.krad.service.KRADServiceLocator;
  import org.kuali.rice.krad.service.PersistenceStructureService;
  import org.kuali.rice.krad.uif.UifConstants.ViewType;
  import org.kuali.rice.krad.uif.util.ComponentBeanPostProcessor;
  import org.kuali.rice.krad.uif.util.UifBeanFactoryPostProcessor;
  import org.kuali.rice.krad.uif.view.View;
  import org.kuali.rice.krad.util.ObjectUtils;
  import org.springframework.beans.PropertyValues;
  import org.springframework.beans.factory.config.BeanPostProcessor;
  import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
  import org.springframework.beans.factory.support.KualiDefaultListableBeanFactory;
  import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
  import org.springframework.context.expression.StandardBeanExpressionResolver;
  import org.springframework.core.convert.support.GenericConversionService;
  import org.springframework.core.io.DefaultResourceLoader;
  import org.springframework.core.io.Resource;
  
  import java.beans.PropertyDescriptor;
  import java.io.File;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.TreeMap;
  
  /**
   * Encapsulates a bean factory and indexes to the beans within the factory for providing
   * framework metadata
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class DataDictionary {
      private static final Log LOG = LogFactory.getLog(DataDictionary.class);
  
      protected static boolean validateEBOs = true;
  
      protected KualiDefaultListableBeanFactory ddBeans = new KualiDefaultListableBeanFactory();
      protected XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(ddBeans);
  
      protected DataDictionaryIndex ddIndex = new DataDictionaryIndex(ddBeans);
      protected UifDictionaryIndex uifIndex = new UifDictionaryIndex(ddBeans);
  
      protected DataDictionaryMapper ddMapper = new DataDictionaryIndexMapper();
  
      protected Map<String, List<String>> moduleDictionaryFiles = new HashMap<String, List<String>>();
      protected List<String> moduleLoadOrder = new ArrayList<String>();
  
      protected ArrayList<String> beanValidationFiles = new ArrayList<String>();
  
      /**
       * Populates and processes the dictionary bean factory based on the configured files and
       * performs indexing
       *
       * @param allowConcurrentValidation - indicates whether the indexing should occur on a different thread
       * or the same thread
       */
      public void parseDataDictionaryConfigurationFiles(boolean allowConcurrentValidation) {
          setupProcessor(ddBeans);
  
          loadDictionaryBeans(ddBeans, moduleDictionaryFiles, ddIndex, beanValidationFiles);
  
          performDictionaryPostProcessing(allowConcurrentValidation);
      }
  
     /**
      * Sets up the bean post processor and conversion service
      *
      * @param beans - The bean factory for the the dictionary beans
      */
     public static void setupProcessor(KualiDefaultListableBeanFactory beans) {
         try {
             // UIF post processor that sets component ids
             BeanPostProcessor idPostProcessor = ComponentBeanPostProcessor.class.newInstance();
             beans.addBeanPostProcessor(idPostProcessor);
             beans.setBeanExpressionResolver(new StandardBeanExpressionResolver());
 
             // special converters for shorthand map and list property syntax
             GenericConversionService conversionService = new GenericConversionService();
             conversionService.addConverter(new StringMapConverter());
             conversionService.addConverter(new StringListConverter());
 
             beans.setConversionService(conversionService);
         } catch (Exception e1) {
             throw new DataDictionaryException("Cannot create component decorator post processor: " + e1.getMessage(),
                     e1);
         }
     }
 
     /**
      * Populates and processes the dictionary bean factory based on the configured files
      *
      * @param beans - The bean factory for the dictionary bean
      * @param moduleDictionaryFiles - List of bean xml files
      * @param index - Index of the data dictionary beans
      * @param validationFiles - The List of bean xml files loaded into the bean file
      */
     public void loadDictionaryBeans(KualiDefaultListableBeanFactory beans,
             Map<String, List<String>> moduleDictionaryFiles, DataDictionaryIndex index,
             ArrayList<String> validationFiles) {
         // expand configuration locations into files
         LOG.info("Starting DD XML File Load");
 
         List<String> allBeanNames = new ArrayList<String>();
         for (String namespaceCode : moduleLoadOrder) {
             List<String> moduleDictionaryLocations = moduleDictionaryFiles.get(namespaceCode);
 
             if (moduleDictionaryLocations == null) {
                continue;
             }
 
             XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(beans);
 
             String configFileLocationsArray[] = new String[moduleDictionaryLocations.size()];
             configFileLocationsArray = moduleDictionaryLocations.toArray(configFileLocationsArray);
             for (int i = 0; i < configFileLocationsArray.length; i++) {
                 validationFiles.add(configFileLocationsArray[i]);
             }
 
             try {
                 xmlReader.loadBeanDefinitions(configFileLocationsArray);
 
                 // get updated bean names from factory and compare to our previous list to get those that
                 // were added by the last namespace
                 List<String> addedBeanNames = Arrays.asList(beans.getBeanDefinitionNames());
                 addedBeanNames = ListUtils.removeAll(addedBeanNames, allBeanNames);
                 index.addBeanNamesToNamespace(namespaceCode, addedBeanNames);
 
                 allBeanNames.addAll(addedBeanNames);
             } catch (Exception e) {
                 throw new DataDictionaryException("Error loading bean definitions: " + e.getLocalizedMessage());
             }
         }
 
         LOG.info("Completed DD XML File Load");
     }
 
     /**
      * Invokes post processors and builds indexes for the beans contained in the dictionary
      *
      * @param allowConcurrentValidation - indicates whether the indexing should occur on a different thread
      * or the same thread
      */
     public void performDictionaryPostProcessing(boolean allowConcurrentValidation) {
         PropertyPlaceholderConfigurer propertyPlaceholderConfigurer = new PropertyPlaceholderConfigurer();
         propertyPlaceholderConfigurer.setProperties(ConfigContext.getCurrentContextConfig().getProperties());
         propertyPlaceholderConfigurer.postProcessBeanFactory(ddBeans);
 
         DictionaryBeanFactoryPostProcessor dictionaryBeanPostProcessor = new DictionaryBeanFactoryPostProcessor(this,
                 ddBeans);
         dictionaryBeanPostProcessor.postProcessBeanFactory();
 
         // post processes UIF beans for pulling out expressions within property values
         UifBeanFactoryPostProcessor factoryPostProcessor = new UifBeanFactoryPostProcessor();
         factoryPostProcessor.postProcessBeanFactory(ddBeans);
 
         if (allowConcurrentValidation) {
             Thread t = new Thread(ddIndex);
             t.start();
 
             Thread t2 = new Thread(uifIndex);
             t2.start();
         } else {
             ddIndex.run();
             uifIndex.run();
         }
     }
 
     public void validateDD(boolean validateEbos) {
         DataDictionary.validateEBOs = validateEbos;
 
         /*  ValidationController validator = new ValidationController();
     String files[] = new String[beanValidationFiles.size()];
     files = beanValidationFiles.toArray(files);
     validator.validate(files, xmlReader.getResourceLoader(), ddBeans, LOG, false);*/
 
         Map<String, DataObjectEntry> doBeans = ddBeans.getBeansOfType(DataObjectEntry.class);
         for (DataObjectEntry entry : doBeans.values()) {
             entry.completeValidation();
         }
 
         Map<String, DocumentEntry> docBeans = ddBeans.getBeansOfType(DocumentEntry.class);
         for (DocumentEntry entry : docBeans.values()) {
             entry.completeValidation();
         }
     }
 
     public void validateDD() {
         validateDD(true);
     }
 
     /**
      * Adds a location of files or a individual resource to the data dictionary
      *
      * <p>
      * The location can either be an XML file on the classpath or a file or folder location within the
      * file system. If a folder location is given, the folder and all sub-folders will be traversed and any
      * XML files will be added to the dictionary
      * </p>
      *
      * @param namespaceCode - namespace the beans loaded from the location should be associated with
      * @param location - classpath resource or file system location
      * @throws IOException
      */
     public void addConfigFileLocation(String namespaceCode, String location) throws IOException {
         // add module to load order so we load in the order modules were configured
         if (!moduleLoadOrder.contains(namespaceCode)) {
             moduleLoadOrder.add(namespaceCode);
         }
 
         indexSource(namespaceCode, location);
     }
 
     /**
      * Processes a given source for XML files to populate the dictionary with
      *
      * @param namespaceCode - namespace the beans loaded from the location should be associated with
      * @param sourceName - a file system or classpath resource locator
      * @throws IOException
      */
     protected void indexSource(String namespaceCode, String sourceName) throws IOException {
         if (sourceName == null) {
             throw new DataDictionaryException("Source Name given is null");
         }
 
         if (!sourceName.endsWith(".xml")) {
             Resource resource = getFileResource(sourceName);
             if (resource.exists()) {
                 try {
                     indexSource(namespaceCode, resource.getFile());
                 } catch (IOException e) {
                     // ignore resources that exist and cause an error here
                     // they may be directories resident in jar files
                     LOG.debug("Skipped existing resource without absolute file path");
                 }
             } else {
                 LOG.warn("Could not find " + sourceName);
                 throw new DataDictionaryException("DD Resource " + sourceName + " not found");
             }
         } else {
             if (LOG.isDebugEnabled()) {
                 LOG.debug("adding sourceName " + sourceName + " ");
             }
 
             Resource resource = getFileResource(sourceName);
             if (!resource.exists()) {
                 throw new DataDictionaryException("DD Resource " + sourceName + " not found");
             }
 
             addModuleDictionaryFile(namespaceCode, sourceName);
         }
     }
 
     protected Resource getFileResource(String sourceName) {
         DefaultResourceLoader resourceLoader = new DefaultResourceLoader(ClassLoaderUtils.getDefaultClassLoader());
 
         return resourceLoader.getResource(sourceName);
     }
 
     protected void indexSource(String namespaceCode, File dir) {
         for (File file : dir.listFiles()) {
             if (file.isDirectory()) {
                 indexSource(namespaceCode, file);
             } else if (file.getName().endsWith(".xml")) {
                 addModuleDictionaryFile(namespaceCode, "file:" + file.getAbsolutePath());
             } else {
                 if (LOG.isDebugEnabled()) {
                     LOG.debug("Skipping non xml file " + file.getAbsolutePath() + " in DD load");
                 }
             }
         }
     }
 
     /**
      * Adds a file location to the list of dictionary files for the given namespace code
      *
      * @param namespaceCode - namespace to add location for
      * @param location - file or resource location to add
      */
     protected void addModuleDictionaryFile(String namespaceCode, String location) {
         List<String> moduleFileLocations = new ArrayList<String>();
         if (moduleDictionaryFiles.containsKey(namespaceCode)) {
             moduleFileLocations = moduleDictionaryFiles.get(namespaceCode);
         }
         moduleFileLocations.add(location);
 
         moduleDictionaryFiles.put(namespaceCode, moduleFileLocations);
     }
 
     /**
      * Mapping of namespace codes to dictionary files that are associated with
      * that namespace
      *
      * @return Map<String, List<String>> where map key is namespace code, and value is list of dictionary
      *         file locations
      */
     public Map<String, List<String>> getModuleDictionaryFiles() {
         return moduleDictionaryFiles;
     }
 
     /**
      * Setter for the map of module dictionary files
      *
      * @param moduleDictionaryFiles
      */
     public void setModuleDictionaryFiles(Map<String, List<String>> moduleDictionaryFiles) {
         this.moduleDictionaryFiles = moduleDictionaryFiles;
     }
 
     /**
      * Order modules should be loaded into the dictionary
      *
      * <p>
      * Modules are loaded in the order they are found in this list. If not explicity set, they will be loaded in
      * the order their dictionary file locations are added
      * </p>
      *
      * @return List<String> list of namespace codes indicating the module load order
      */
     public List<String> getModuleLoadOrder() {
         return moduleLoadOrder;
     }
 
     /**
      * Setter for the list of namespace codes indicating the module load order
      *
      * @param moduleLoadOrder
      */
     public void setModuleLoadOrder(List<String> moduleLoadOrder) {
         this.moduleLoadOrder = moduleLoadOrder;
     }
 
     /**
      * Sets the DataDictionaryMapper
      *
      * @param mapper the datadictionary mapper
      */
     public void setDataDictionaryMapper(DataDictionaryMapper mapper) {
         this.ddMapper = mapper;
     }
 
     /**
      * @param className
      * @return BusinessObjectEntry for the named class, or null if none exists
      */
     @Deprecated
     public BusinessObjectEntry getBusinessObjectEntry(String className) {
         return ddMapper.getBusinessObjectEntry(ddIndex, className);
     }
 
     /**
      * @param className
      * @return BusinessObjectEntry for the named class, or null if none exists
      */
     public DataObjectEntry getDataObjectEntry(String className) {
         return ddMapper.getDataObjectEntry(ddIndex, className);
     }
 
     /**
      * This method gets the business object entry for a concrete class
      *
      * @param className
      * @return
      */
     public BusinessObjectEntry getBusinessObjectEntryForConcreteClass(String className) {
         return ddMapper.getBusinessObjectEntryForConcreteClass(ddIndex, className);
     }
 
     /**
      * @return List of businessObject classnames
      */
     public List<String> getBusinessObjectClassNames() {
         return ddMapper.getBusinessObjectClassNames(ddIndex);
     }
 
     /**
      * @return Map of (classname, BusinessObjectEntry) pairs
      */
     public Map<String, BusinessObjectEntry> getBusinessObjectEntries() {
         return ddMapper.getBusinessObjectEntries(ddIndex);
     }
 
     /**
      * @param className
      * @return DataDictionaryEntryBase for the named class, or null if none
      *         exists
      */
     public DataDictionaryEntry getDictionaryObjectEntry(String className) {
         return ddMapper.getDictionaryObjectEntry(ddIndex, className);
     }
 
     /**
      * Returns the KNS document entry for the given lookup key.  The documentTypeDDKey is interpreted
      * successively in the following ways until a mapping is found (or none if found):
      * <ol>
      * <li>KEW/workflow document type</li>
      * <li>business object class name</li>
      * <li>maintainable class name</li>
      * </ol>
      * This mapping is compiled when DataDictionary files are parsed on startup (or demand).  Currently this
      * means the mapping is static, and one-to-one (one KNS document maps directly to one and only
      * one key).
      *
      * @param documentTypeDDKey the KEW/workflow document type name
      * @return the KNS DocumentEntry if it exists
      */
     public DocumentEntry getDocumentEntry(String documentTypeDDKey) {
         return ddMapper.getDocumentEntry(ddIndex, documentTypeDDKey);
     }
 
     /**
      * Note: only MaintenanceDocuments are indexed by businessObject Class
      *
      * This is a special case that is referenced in one location. Do we need
      * another map for this stuff??
      *
      * @param businessObjectClass
      * @return DocumentEntry associated with the given Class, or null if there
      *         is none
      */
     public MaintenanceDocumentEntry getMaintenanceDocumentEntryForBusinessObjectClass(Class<?> businessObjectClass) {
         return ddMapper.getMaintenanceDocumentEntryForBusinessObjectClass(ddIndex, businessObjectClass);
     }
 
     public Map<String, DocumentEntry> getDocumentEntries() {
         return ddMapper.getDocumentEntries(ddIndex);
     }
 
     /**
      * Returns the View entry identified by the given id
      *
      * @param viewId unique id for view
      * @return View instance associated with the id
      */
     public View getViewById(String viewId) {
         return ddMapper.getViewById(uifIndex, viewId);
     }
 
     /**
      * Returns the View entry identified by the given id, meant for view readonly
      * access (not running the lifecycle but just checking configuration)
      *
      * @param viewId unique id for view
      * @return View instance associated with the id
      */
     public View getImmutableViewById(String viewId) {
         return ddMapper.getImmutableViewById(uifIndex, viewId);
     }
 
     /**
      * Returns View instance identified by the view type name and index
      *
      * @param viewTypeName - type name for the view
      * @param indexKey - Map of index key parameters, these are the parameters the
      * indexer used to index the view initially and needs to identify
      * an unique view instance
      * @return View instance that matches the given index
      */
     public View getViewByTypeIndex(ViewType viewTypeName, Map<String, String> indexKey) {
         return ddMapper.getViewByTypeIndex(uifIndex, viewTypeName, indexKey);
     }
 
     /**
      * Returns the view id for the view that matches the given view type and index
      *
      * @param viewTypeName type name for the view
      * @param indexKey Map of index key parameters, these are the parameters the
      * indexer used to index the view initially and needs to identify
      * an unique view instance
      * @return id for the view that matches the view type and index or null if a match is not found
      */
     public String getViewIdByTypeIndex(ViewType viewTypeName, Map<String, String> indexKey) {
         return ddMapper.getViewIdByTypeIndex(uifIndex, viewTypeName, indexKey);
     }
 
     /**
      * Indicates whether a <code>View</code> exists for the given view type and index information
      *
      * @param viewTypeName - type name for the view
      * @param indexKey - Map of index key parameters, these are the parameters the
      * indexer used to index the view initially and needs to identify
      * an unique view instance
      * @return boolean true if view exists, false if not
      */
     public boolean viewByTypeExist(ViewType viewTypeName, Map<String, String> indexKey) {
         return ddMapper.viewByTypeExist(uifIndex, viewTypeName, indexKey);
     }
 
     /**
      * Gets all <code>View</code> prototypes configured for the given view type
      * name
      *
      * @param viewTypeName - view type name to retrieve
      * @return List<View> view prototypes with the given type name, or empty
      *         list
      */
     public List<View> getViewsForType(ViewType viewTypeName) {
         return ddMapper.getViewsForType(uifIndex, viewTypeName);
     }
 
     /**
      * Returns an object from the dictionary by its spring bean name
      *
      * @param beanName - id or name for the bean definition
      * @return Object object instance created or the singleton being maintained
      */
     public Object getDictionaryObject(String beanName) {
         return ddBeans.getBean(beanName);
     }
 
     /**
      * Indicates whether the data dictionary contains a bean with the given id
      *
      * @param id - id of the bean to check for
      * @return boolean true if dictionary contains bean, false otherwise
      */
     public boolean containsDictionaryObject(String id) {
         return ddBeans.containsBean(id);
     }
 
     /**
      * Retrieves the configured property values for the view bean definition associated with the given id
      *
      * <p>
      * Since constructing the View object can be expensive, when metadata only is needed this method can be used
      * to retrieve the configured property values. Note this looks at the merged bean definition
      * </p>
      *
      * @param viewId - id for the view to retrieve
      * @return PropertyValues configured on the view bean definition, or null if view is not found
      */
     public PropertyValues getViewPropertiesById(String viewId) {
         return ddMapper.getViewPropertiesById(uifIndex, viewId);
     }
 
     /**
      * Retrieves the configured property values for the view bean definition associated with the given type and
      * index
      *
      * <p>
      * Since constructing the View object can be expensive, when metadata only is needed this method can be used
      * to retrieve the configured property values. Note this looks at the merged bean definition
      * </p>
      *
      * @param viewTypeName - type name for the view
      * @param indexKey - Map of index key parameters, these are the parameters the indexer used to index
      * the view initially and needs to identify an unique view instance
      * @return PropertyValues configured on the view bean definition, or null if view is not found
      */
     public PropertyValues getViewPropertiesByType(ViewType viewTypeName, Map<String, String> indexKey) {
         return ddMapper.getViewPropertiesByType(uifIndex, viewTypeName, indexKey);
     }
 
     /**
      * Retrieves the list of dictionary bean names that are associated with the given namespace code
      *
      * @param namespaceCode - namespace code to retrieve associated bean names for
      * @return List<String> bean names associated with the namespace
      */
     public List<String> getBeanNamesForNamespace(String namespaceCode) {
         List<String> namespaceBeans = new ArrayList<String>();
 
         Map<String, List<String>> dictionaryBeansByNamespace = ddIndex.getDictionaryBeansByNamespace();
         if (dictionaryBeansByNamespace.containsKey(namespaceCode)) {
             namespaceBeans = dictionaryBeansByNamespace.get(namespaceCode);
         }
 
         return namespaceBeans;
     }
 
     /**
      * Retrieves the namespace code the given bean name is associated with
      *
      * @param beanName - name of the dictionary bean to find namespace code for
      * @return String namespace code the bean is associated with, or null if a namespace was not found
      */
     public String getNamespaceForBeanDefinition(String beanName) {
         String beanNamespace = null;
 
         Map<String, List<String>> dictionaryBeansByNamespace = ddIndex.getDictionaryBeansByNamespace();
         for (Map.Entry<String, List<String>> moduleDefinitions : dictionaryBeansByNamespace.entrySet()) {
             List<String> namespaceBeans = moduleDefinitions.getValue();
             if (namespaceBeans.contains(beanName)) {
                 beanNamespace = moduleDefinitions.getKey();
                 break;
             }
         }
 
         return beanNamespace;
     }
 
     /**
      * @param targetClass
      * @param propertyName
      * @return true if the given propertyName names a property of the given class
      * @throws CompletionException if there is a problem accessing the named property on the given class
      */
     public static boolean isPropertyOf(Class targetClass, String propertyName) {
         if (targetClass == null) {
             throw new IllegalArgumentException("invalid (null) targetClass");
         }
         if (StringUtils.isBlank(propertyName)) {
             throw new IllegalArgumentException("invalid (blank) propertyName");
         }
 
         PropertyDescriptor propertyDescriptor = buildReadDescriptor(targetClass, propertyName);
 
         boolean isPropertyOf = (propertyDescriptor != null);
         return isPropertyOf;
     }
 
     /**
      * @param targetClass
      * @param propertyName
      * @return true if the given propertyName names a Collection property of the given class
      * @throws CompletionException if there is a problem accessing the named property on the given class
      */
     public static boolean isCollectionPropertyOf(Class targetClass, String propertyName) {
         boolean isCollectionPropertyOf = false;
 
         PropertyDescriptor propertyDescriptor = buildReadDescriptor(targetClass, propertyName);
         if (propertyDescriptor != null) {
             Class clazz = propertyDescriptor.getPropertyType();
 
             if ((clazz != null) && Collection.class.isAssignableFrom(clazz)) {
                 isCollectionPropertyOf = true;
             }
         }
 
         return isCollectionPropertyOf;
     }
 
     public static PersistenceStructureService persistenceStructureService;
 
     /**
      * @return the persistenceStructureService
      */
     public static PersistenceStructureService getPersistenceStructureService() {
         if (persistenceStructureService == null) {
             persistenceStructureService = KRADServiceLocator.getPersistenceStructureService();
         }
         return persistenceStructureService;
     }
 
     /**
      * This method determines the Class of the attributeName passed in. Null will be returned if the member is not
      * available, or if
      * a reflection exception is thrown.
      *
      * @param boClass - Class that the attributeName property exists in.
      * @param attributeName - Name of the attribute you want a class for.
      * @return The Class of the attributeName, if the attribute exists on the rootClass. Null otherwise.
      */
     public static Class getAttributeClass(Class boClass, String attributeName) {
 
         // fail loudly if the attributeName isnt a member of rootClass
         if (!isPropertyOf(boClass, attributeName)) {
             throw new AttributeValidationException(
                     "unable to find attribute '" + attributeName + "' in rootClass '" + boClass.getName() + "'");
         }
 
         //Implementing Externalizable Business Object Services...
         //The boClass can be an interface, hence handling this separately, 
         //since the original method was throwing exception if the class could not be instantiated.
         if (boClass.isInterface()) {
             return getAttributeClassWhenBOIsInterface(boClass, attributeName);
         } else {
             return getAttributeClassWhenBOIsClass(boClass, attributeName);
         }
 
     }
 
     /**
      * This method gets the property type of the given attributeName when the bo class is a concrete class
      *
      * @param boClass
      * @param attributeName
      * @return
      */
     private static Class getAttributeClassWhenBOIsClass(Class boClass, String attributeName) {
         Object boInstance;
         try {
             boInstance = boClass.newInstance();
         } catch (Exception e) {
             throw new RuntimeException("Unable to instantiate Data Object: " + boClass, e);
         }
 
         // attempt to retrieve the class of the property
         try {
             return ObjectUtils.getPropertyType(boInstance, attributeName, getPersistenceStructureService());
         } catch (Exception e) {
             throw new RuntimeException(
                     "Unable to determine property type for: " + boClass.getName() + "." + attributeName, e);
         }
     }
 
     /**
      * This method gets the property type of the given attributeName when the bo class is an interface
      * This method will also work if the bo class is not an interface,
      * but that case requires special handling, hence a separate method getAttributeClassWhenBOIsClass
      *
      * @param boClass
      * @param attributeName
      * @return
      */
     private static Class getAttributeClassWhenBOIsInterface(Class boClass, String attributeName) {
         if (boClass == null) {
             throw new IllegalArgumentException("invalid (null) boClass");
         }
         if (StringUtils.isBlank(attributeName)) {
             throw new IllegalArgumentException("invalid (blank) attributeName");
         }
 
         PropertyDescriptor propertyDescriptor = null;
 
         String[] intermediateProperties = attributeName.split("\\.");
         int lastLevel = intermediateProperties.length - 1;
         Class currentClass = boClass;
 
         for (int i = 0; i <= lastLevel; ++i) {
 
             String currentPropertyName = intermediateProperties[i];
             propertyDescriptor = buildSimpleReadDescriptor(currentClass, currentPropertyName);
 
             if (propertyDescriptor != null) {
 
                 Class propertyType = propertyDescriptor.getPropertyType();
                 if (propertyType.equals(PersistableBusinessObjectExtension.class)) {
                     propertyType = getPersistenceStructureService().getBusinessObjectAttributeClass(currentClass,
                             currentPropertyName);
                 }
                 if (Collection.class.isAssignableFrom(propertyType)) {
                     // TODO: determine property type using generics type definition
                     throw new AttributeValidationException(
                             "Can't determine the Class of Collection elements because when the business object is an (possibly ExternalizableBusinessObject) interface.");
                 } else {
                     currentClass = propertyType;
                 }
             } else {
                 throw new AttributeValidationException(
                         "Can't find getter method of " + boClass.getName() + " for property " + attributeName);
             }
         }
         return currentClass;
     }
 
     /**
      * This method determines the Class of the elements in the collectionName passed in.
      *
      * @param boClass Class that the collectionName collection exists in.
      * @param collectionName the name of the collection you want the element class for
      * @return
      */
     public static Class getCollectionElementClass(Class boClass, String collectionName) {
         if (boClass == null) {
             throw new IllegalArgumentException("invalid (null) boClass");
         }
         if (StringUtils.isBlank(collectionName)) {
             throw new IllegalArgumentException("invalid (blank) collectionName");
         }
 
         PropertyDescriptor propertyDescriptor = null;
 
         String[] intermediateProperties = collectionName.split("\\.");
         Class currentClass = boClass;
 
         for (int i = 0; i < intermediateProperties.length; ++i) {
 
             String currentPropertyName = intermediateProperties[i];
             propertyDescriptor = buildSimpleReadDescriptor(currentClass, currentPropertyName);
 
             if (propertyDescriptor != null) {
 
                 Class type = propertyDescriptor.getPropertyType();
                 if (Collection.class.isAssignableFrom(type)) {
 
                     if (getPersistenceStructureService().isPersistable(currentClass)) {
 
                         Map<String, Class> collectionClasses = new HashMap<String, Class>();
                         collectionClasses = getPersistenceStructureService().listCollectionObjectTypes(currentClass);
                         currentClass = collectionClasses.get(currentPropertyName);
 
                     } else {
                         throw new RuntimeException(
                                 "Can't determine the Class of Collection elements because persistenceStructureService.isPersistable("
                                         +
                                         currentClass.getName()
                                         +
                                         ") returns false.");
                     }
 
                 } else {
 
                     currentClass = propertyDescriptor.getPropertyType();
 
                 }
             }
         }
 
         return currentClass;
     }
 
     static private Map<String, Map<String, PropertyDescriptor>> cache =
             new TreeMap<String, Map<String, PropertyDescriptor>>();
 
     /**
      * @param propertyClass
      * @param propertyName
      * @return PropertyDescriptor for the getter for the named property of the given class, if one exists.
      */
     public static PropertyDescriptor buildReadDescriptor(Class propertyClass, String propertyName) {
         if (propertyClass == null) {
             throw new IllegalArgumentException("invalid (null) propertyClass");
         }
         if (StringUtils.isBlank(propertyName)) {
             throw new IllegalArgumentException("invalid (blank) propertyName");
         }
 
         PropertyDescriptor propertyDescriptor = null;
 
         String[] intermediateProperties = propertyName.split("\\.");
         int lastLevel = intermediateProperties.length - 1;
         Class currentClass = propertyClass;
 
         for (int i = 0; i <= lastLevel; ++i) {
 
             String currentPropertyName = intermediateProperties[i];
             propertyDescriptor = buildSimpleReadDescriptor(currentClass, currentPropertyName);
 
             if (i < lastLevel) {
 
                 if (propertyDescriptor != null) {
 
                     Class propertyType = propertyDescriptor.getPropertyType();
                     if (propertyType.equals(PersistableBusinessObjectExtension.class)) {
                         propertyType = getPersistenceStructureService().getBusinessObjectAttributeClass(currentClass,
                                 currentPropertyName);
                     }
                     if (Collection.class.isAssignableFrom(propertyType)) {
 
                         if (getPersistenceStructureService().isPersistable(currentClass)) {
 
                             Map<String, Class> collectionClasses = new HashMap<String, Class>();
                             collectionClasses = getPersistenceStructureService().listCollectionObjectTypes(
                                     currentClass);
                             currentClass = collectionClasses.get(currentPropertyName);
 
                         } else {
 
                             throw new RuntimeException(
                                     "Can't determine the Class of Collection elements because persistenceStructureService.isPersistable("
                                             +
                                             currentClass.getName()
                                             +
                                             ") returns false.");
 
                         }
 
                     } else {
 
                         currentClass = propertyType;
 
                     }
 
                 }
 
             }
 
         }
 
         return propertyDescriptor;
     }
 
     /**
      * @param propertyClass
      * @param propertyName
      * @return PropertyDescriptor for the getter for the named property of the given class, if one exists.
      */
     public static PropertyDescriptor buildSimpleReadDescriptor(Class propertyClass, String propertyName) {
         if (propertyClass == null) {
             throw new IllegalArgumentException("invalid (null) propertyClass");
         }
         if (StringUtils.isBlank(propertyName)) {
             throw new IllegalArgumentException("invalid (blank) propertyName");
         }
 
         PropertyDescriptor p = null;
 
         // check to see if we've cached this descriptor already. if yes, return true.
         String propertyClassName = propertyClass.getName();
         Map<String, PropertyDescriptor> m = cache.get(propertyClassName);
         if (null != m) {
             p = m.get(propertyName);
             if (null != p) {
                 return p;
             }
         }
 
         // Use PropertyUtils.getPropertyDescriptors instead of manually constructing PropertyDescriptor because of
         // issues with introspection and generic/co-variant return types
         // See https://issues.apache.org/jira/browse/BEANUTILS-340 for more details
 
         PropertyDescriptor[] descriptors = PropertyUtils.getPropertyDescriptors(propertyClass);
         if (ArrayUtils.isNotEmpty(descriptors)) {
             for (PropertyDescriptor descriptor : descriptors) {
                 if (descriptor.getName().equals(propertyName)) {
                     p = descriptor;
                 }
             }
         }
 
         // cache the property descriptor if we found it.
         if (p != null) {
             if (m == null) {
                 m = new TreeMap<String, PropertyDescriptor>();
                 cache.put(propertyClassName, m);
             }
             m.put(propertyName, p);
         }
 
         return p;
     }
 
     public Set<InactivationBlockingMetadata> getAllInactivationBlockingMetadatas(Class blockedClass) {
         return ddMapper.getAllInactivationBlockingMetadatas(ddIndex, blockedClass);
     }
 
     /**
      * This method gathers beans of type BeanOverride and invokes each one's performOverride() method.
      */
     // KULRICE-4513
     public void performBeanOverrides() {
         Collection<BeanOverride> beanOverrides = ddBeans.getBeansOfType(BeanOverride.class).values();
 
         if (beanOverrides.isEmpty()) {
             LOG.info("DataDictionary.performOverrides(): No beans to override");
         }
         for (BeanOverride beanOverride : beanOverrides) {
 
             Object bean = ddBeans.getBean(beanOverride.getBeanName());
             beanOverride.performOverride(bean);
             LOG.info("DataDictionary.performOverrides(): Performing override on bean: " + bean.toString());
         }
     }
 
 }