/*

  * Copyright 2006-2011 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.service.impl;

 import org.apache.ojb.broker.metadata.ClassDescriptor;

 import org.apache.ojb.broker.metadata.ClassNotPersistenceCapableException;

 import org.apache.ojb.broker.metadata.DescriptorRepository;

 import org.apache.ojb.broker.metadata.FieldDescriptor;

 import org.apache.ojb.broker.metadata.ObjectReferenceDescriptor;

 import org.kuali.rice.core.api.config.property.ConfigContext;

 import org.kuali.rice.core.framework.persistence.jpa.OrmUtils;

 import org.kuali.rice.core.framework.persistence.jpa.metadata.EntityDescriptor;

 import org.kuali.rice.core.framework.persistence.jpa.metadata.MetadataManager;

 import org.kuali.rice.core.framework.persistence.jpa.metadata.ObjectDescriptor;

 import org.kuali.rice.core.framework.persistence.ojb.BaseOjbConfigurer;

 import org.kuali.rice.krad.bo.PersistableBusinessObject;

 import org.kuali.rice.krad.bo.PersistableBusinessObjectExtension;

 import org.kuali.rice.krad.exception.ClassNotPersistableException;

 import org.kuali.rice.krad.util.spring.CacheNoCopy;

 import java.util.ArrayList;

 import java.util.List;

 public class PersistenceServiceStructureImplBase {

         private DescriptorRepository descriptorRepository;

         /**

          * Constructs a PersistenceServiceImpl instance.

          */

         public PersistenceServiceStructureImplBase() {

                 String ojbPropertyFileLocation = ConfigContext.getCurrentContextConfig().getProperty(BaseOjbConfigurer.RICE_OJB_PROPERTIES_PARAM);

         String currentValue = System.getProperty(BaseOjbConfigurer.OJB_PROPERTIES_PROP);

                 try {

                         System.setProperty(BaseOjbConfigurer.OJB_PROPERTIES_PROP, ojbPropertyFileLocation);

                         org.apache.ojb.broker.metadata.MetadataManager metadataManager = org.apache.ojb.broker.metadata.MetadataManager.getInstance();

                         descriptorRepository = metadataManager.getGlobalRepository();

             } finally {

                 if (currentValue == null) {

                     System.getProperties().remove(BaseOjbConfigurer.OJB_PROPERTIES_PROP);

                 } else {

                     System.setProperty(BaseOjbConfigurer.OJB_PROPERTIES_PROP, currentValue);

                 }

             }

         }

         /**

          * @return DescriptorRepository containing everything OJB knows about persistable classes

          */

         protected DescriptorRepository getDescriptorRepository() {

                 return descriptorRepository;

         }

         /**

          *

          * This method returns a list of primary key field names.  This method uses the CacheNoCopy caching method.

          * "NoCopy" is the faster of the caching annotations, but because it does not make a copy the list that is

          * returned must not be modified.  To enforce this the returned list is wrapped in a Collections.unmodifiableList

          * method.  This will cause an exception to be thrown if the list is altered.

          *

          * @param clazz

          * @return unmodifiableList of field names.  Any attempt to alter list will result in an UnsupportedOperationException

          */

         @CacheNoCopy

         public List listPrimaryKeyFieldNames(Class clazz) {

             // Rice JPA MetadataManager

                 if (isJpaEnabledForKradClass(clazz)) {

                         List fieldNames = new ArrayList();

                     EntityDescriptor descriptor = MetadataManager.getEntityDescriptor(clazz);

                     for (org.kuali.rice.core.framework.persistence.jpa.metadata.FieldDescriptor field : descriptor.getPrimaryKeys()) {

                             fieldNames.add(field.getName());

                     }

                     return fieldNames;

                 } else {

                     // Legacy OJB

                         List fieldNamesLegacy = new ArrayList();

                         ClassDescriptor classDescriptor = getClassDescriptor(clazz);

                         FieldDescriptor keyDescriptors[] = classDescriptor.getPkFields();

                         for (int i = 0; i < keyDescriptors.length; ++i) {

                                 FieldDescriptor keyDescriptor = keyDescriptors[i];

                                 fieldNamesLegacy.add(keyDescriptor.getAttributeName());

                         }

                         return fieldNamesLegacy;

                 }

         }

         /* Not used anywhere... need to check KFS and batch stuff */

         /**

          * @param classDescriptor

          * @return name of the database table associated with given classDescriptor,

          *         stripped of its leading schemaName

          */

         /*

         @CacheNoCopy

         protected String getTableName(ClassDescriptor classDescriptor) {

                 String schemaName = classDescriptor.getSchema();

                 String fullTableName = classDescriptor.getFullTableName();

                 String tableName = null;

                 if (StringUtils.isNotBlank(schemaName)) {

                         tableName = StringUtils.substringAfter(fullTableName, schemaName + ".");

                 }

                 if (StringUtils.isBlank(tableName)) {

                         tableName = fullTableName;

                 }

                 return tableName;

         }

         */

         /**

          * @param persistableClass

          * @return ClassDescriptor for the given Class

          * @throws IllegalArgumentException

          *             if the given Class is null

          * @throws ClassNotPersistableException

          *             if the given Class is unknown to OJB

          */

         // Legacy OJB - no need for JPA equivalent

         protected ClassDescriptor getClassDescriptor(Class persistableClass) {

                 if (persistableClass == null) {

                         throw new IllegalArgumentException("invalid (null) object");

                 }

                 ClassDescriptor classDescriptor = null;

                 DescriptorRepository globalRepository = getDescriptorRepository();

                 try {

                         classDescriptor = globalRepository.getDescriptorFor(persistableClass);

                 } catch (ClassNotPersistenceCapableException e) {

                         throw new ClassNotPersistableException("class '" + persistableClass.getName() + "' is not persistable", e);

                 }

                 return classDescriptor;

         }

         /**

          * Determines if JPA is enabled for the KNS and for the given class

          * 

          * @param clazz the class to check for JPA enabling of

          * @return true if JPA is enabled for the class, false otherwise

          */

         public boolean isJpaEnabledForKradClass(Class clazz) {

                 final boolean jpaAnnotated = OrmUtils.isJpaAnnotated(clazz);

                 final boolean jpaEnabled = OrmUtils.isJpaEnabled();

                 final boolean prefixJpaEnabled = OrmUtils.isJpaEnabled("rice.krad");

                 return jpaAnnotated && (jpaEnabled || prefixJpaEnabled);

         }

         /**

          * @see org.kuali.rice.krad.service.PersistenceStructureService#getBusinessObjectAttributeClass(java.lang.Class,

          *      java.lang.String)

          */

         @CacheNoCopy

         public Class<? extends PersistableBusinessObjectExtension> getBusinessObjectAttributeClass(Class<? extends PersistableBusinessObject> clazz, String attributeName) {

                 String baseAttributeName = attributeName;

                 String subAttributeString = null;

                 if (attributeName.contains(".")) {

                         baseAttributeName = attributeName.substring(0, attributeName.indexOf('.'));

                         subAttributeString = attributeName.substring(attributeName.indexOf('.') + 1);

                 }

             // Rice JPA MetadataManager

                 if (isJpaEnabledForKradClass(clazz)) {

                         Class attributeClass = null;

                     EntityDescriptor descriptor = MetadataManager.getEntityDescriptor(clazz);

                     ObjectDescriptor objectDescriptor = descriptor.getObjectDescriptorByName(baseAttributeName);

                         if (objectDescriptor != null) {

                                 attributeClass = objectDescriptor.getTargetEntity();

                         }

                         // recurse if necessary

                         if (subAttributeString != null) {

                                 attributeClass = getBusinessObjectAttributeClass(attributeClass, subAttributeString);

                         }

                         return attributeClass;

                 } else {

                     // Legacy OJB

                         Class attributeClassLegacy = null;

                         ClassDescriptor classDescriptor = this.getClassDescriptor(clazz);

                         ObjectReferenceDescriptor refDescriptor = classDescriptor.getObjectReferenceDescriptorByName(baseAttributeName);

                         if (refDescriptor != null) {

                                 attributeClassLegacy = refDescriptor.getItemClass();

                         }

                         // recurse if necessary

                         if (subAttributeString != null) {

                                 attributeClassLegacy = getBusinessObjectAttributeClass(attributeClassLegacy, subAttributeString);

                         }

                         return attributeClassLegacy;

                 }

         }

 }