cayenne-server/src/main/java/org/apache/cayenne/access/ObjectResolver.java - cayenne - Git at Google

 /*****************************************************************
  *   Licensed to the Apache Software Foundation (ASF) under one
  *  or more contributor license agreements.  See the NOTICE file
  *  distributed with this work for additional information
  *  regarding copyright ownership.  The ASF licenses this file
  *  to you under the Apache License, Version 2.0 (the
  *  "License"); you may not use this file except in compliance
  *  with the License.  You may obtain a copy of the License at
  *
  *    https://www.apache.org/licenses/LICENSE-2.0
  *
  *  Unless required by applicable law or agreed to in writing,
  *  software distributed under the License is distributed on an
  *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  *  KIND, either express or implied.  See the License for the
  *  specific language governing permissions and limitations
  *  under the License.
  ****************************************************************/

 package org.apache.cayenne.access;

 import org.apache.cayenne.CayenneRuntimeException;
 import org.apache.cayenne.DataObject;
 import org.apache.cayenne.DataRow;
 import org.apache.cayenne.ObjectContext;
 import org.apache.cayenne.ObjectId;
 import org.apache.cayenne.PersistenceState;
 import org.apache.cayenne.Persistent;
 import org.apache.cayenne.map.DbAttribute;
 import org.apache.cayenne.map.DbEntity;
 import org.apache.cayenne.map.EntityResolver;
 import org.apache.cayenne.map.ObjEntity;
 import org.apache.cayenne.reflect.ClassDescriptor;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 /**
  * DataRows-to-objects converter for a specific ObjEntity.
  *
  * @since 1.2
  */
 class ObjectResolver {

 	private static final Logger LOGGER = LoggerFactory.getLogger(ObjectResolver.class);

 	DataContext context;
 	ClassDescriptor descriptor;
 	Collection<DbAttribute> primaryKey;

 	boolean refreshObjects;
 	DataRowStore cache;
 	DescriptorResolutionStrategy descriptorResolutionStrategy;

 	ObjectResolver(DataContext context, ClassDescriptor descriptor, boolean refresh) {

 		// sanity check
 		if (descriptor == null || descriptor.getEntity() == null) {
 			// possible cause: query that is not expected to have result set somehow got it..
 			throw new CayenneRuntimeException("No ClassDescriptor. Maybe DataRows should be fetched instead of objects.");
 		}

 		DbEntity dbEntity = descriptor.getEntity().getDbEntity();
 		if (dbEntity == null) {
 			throw new CayenneRuntimeException("ObjEntity '%s' has no DbEntity.", descriptor.getEntity().getName());
 		}

 		this.primaryKey = dbEntity.getPrimaryKeys();
 		if (primaryKey.size() == 0) {
 			throw new CayenneRuntimeException("Won't be able to create ObjectId for '%s'. Reason: DbEntity " +
 					"'%s' has no Primary Key defined.", descriptor.getEntity().getName(), dbEntity.getName());
 		}

 		this.context = context;
 		this.cache = context.getObjectStore().getDataRowCache();
 		this.refreshObjects = refresh;
 		this.descriptor = descriptor;

 		this.descriptorResolutionStrategy = descriptor.hasSubclasses() ? new InheritanceStrategy()
 				: new NoInheritanceStrategy();
 	}

 	PrefetchProcessorNode synchronizedRootResultNodeFromDataRows(List<? extends DataRow> rows) {
 		PrefetchProcessorNode rootNode = new PrefetchProcessorNode(null, null);
 		rootNode.setObjects(synchronizedObjectsFromDataRows(rows));
 		return rootNode;
 	}

 	/**
 	 * Properly synchronized version of 'objectsFromDataRows'.
 	 */
 	List<Persistent> synchronizedObjectsFromDataRows(List<? extends DataRow> rows) {
 		synchronized (context.getObjectStore()) {
 			return objectsFromDataRows(rows);
 		}
 	}

 	/**
 	 * Converts rows to objects.
 	 * <p>
 	 * Synchronization note. This method requires EXTERNAL synchronization on
 	 * ObjectStore and DataRowStore.
 	 * </p>
 	 */
 	List<Persistent> objectsFromDataRows(List<? extends DataRow> rows) {
 		if (rows == null || rows.size() == 0) {
 			return new ArrayList<>(1);
 		}

 		List<Persistent> results = new ArrayList<>(rows.size());
 		for (DataRow row : rows) {
 			// nulls are possible here since 3.0 for some varieties of EJBQL,
 			// simple example of this: "select p.toGallery+ from Painting p" where toGallery is null.
 			results.add(objectFromDataRow(row));
 		}

 		// now deal with snapshots
 		cache.snapshotsUpdatedForObjects(results, rows, refreshObjects);
 		return results;
 	}

 	Persistent objectFromDataRow(DataRow row) {
 		// determine entity to use
 		ClassDescriptor classDescriptor = descriptorResolutionStrategy.descriptorForRow(row);

 		// not using DataRow.createObjectId for performance reasons -
 		// ObjectResolver has all needed metadata already cached.
 		ObjectId anId = createObjectId(row, classDescriptor.getEntity(), null);
 		return objectFromDataRow(row, anId, classDescriptor);
 	}

 	Persistent objectFromDataRow(DataRow row, ObjectId anId, ClassDescriptor classDescriptor) {

 		// this condition is valid - see comments on 'createObjectId' for
 		// details
 		if (anId == null) {
 			return null;
 		}

 		// this will create a HOLLOW object if it is not registered yet
 		Persistent object = context.findOrCreateObject(anId);

 		// resolve additional Object IDs for flattened attributes
 		resolveAdditionalIds(row, object, classDescriptor);

 		// deal with object state
 		int state = object.getPersistenceState();
 		switch (state) {
 		case PersistenceState.COMMITTED:
 		case PersistenceState.MODIFIED:
 		case PersistenceState.DELETED:
 			// process the above only if refresh is requested...
 			if (refreshObjects) {
 				DataRowUtils.mergeObjectWithSnapshot(context, classDescriptor, object, row);

 				if (object instanceof DataObject) {
 					((DataObject) object).setSnapshotVersion(row.getVersion());
 				}
 			}
 			break;
 		case PersistenceState.HOLLOW:
 			if (!refreshObjects) {
 				DataRow cachedRow = cache.getCachedSnapshot(anId);
 				if (cachedRow != null) {
 					row = cachedRow;
 				}
 			}
 			DataRowUtils.mergeObjectWithSnapshot(context, classDescriptor, object, row);
 			if (object instanceof DataObject) {
 				((DataObject) object).setSnapshotVersion(row.getVersion());
 			}
 			break;
 		default:
 			break;
 		}

 		return object;
 	}

     private void resolveAdditionalIds(DataRow row, Persistent object, ClassDescriptor classDescriptor) {
 	    if(classDescriptor.getAdditionalDbEntities().isEmpty()) {
 	        return;
         }

 	    for(Map.Entry<String, DbEntity> entry : classDescriptor.getAdditionalDbEntities().entrySet()) {
             DbEntity dbEntity = entry.getValue();
             String path = entry.getKey();
             int lastDot = path.lastIndexOf('.');
             String prefix = lastDot == -1 ? path : path.substring(lastDot + 1);
             ObjectId objectId = createObjectId(row, "db:" + dbEntity.getName(), dbEntity.getPrimaryKeys(), prefix + '.', false);
             if(objectId != null) {
 				context.getObjectStore().markFlattenedPath(object.getObjectId(), path, objectId);
             }
         }
     }

     ObjEntity getEntity() {
 		return descriptor.getEntity();
 	}

 	ClassDescriptor getDescriptor() {
 		return descriptor;
 	}

 	EntityResolver getEntityResolver() {
 		return context.getEntityResolver();
 	}

 	ObjectContext getContext() {
 		return context;
 	}

 	ObjectId createObjectId(DataRow dataRow, ObjEntity objEntity, String namePrefix) {
         Collection<DbAttribute> pk = objEntity == this.descriptor.getEntity()
                 ? this.primaryKey
                 : objEntity.getDbEntity().getPrimaryKeys();
         return createObjectId(dataRow, objEntity.getName(), pk, namePrefix, true);
     }

     ObjectId createObjectId(DataRow dataRow, String name, Collection<DbAttribute> pk, String namePrefix, boolean strict) {
 		boolean prefix = namePrefix != null && namePrefix.length() > 0;

 		// ... handle special case - PK.size == 1
 		// use some not-so-significant optimizations...

 		if (pk.size() == 1) {
 			DbAttribute attribute = pk.iterator().next();

 			String key = (prefix) ? namePrefix + attribute.getName() : attribute.getName();

 			Object val = dataRow.get(key);

 			// this is possible when processing left outer joint prefetches
 			if (val == null) {
 				if(strict && !dataRow.containsKey(key)) {
 					throw new CayenneRuntimeException("No PK column '%s' found in data row.", key);
 				}
 				return null;
 			}

 			// PUT without a prefix
 			return ObjectId.of(name, attribute.getName(), val);
 		}

 		// ... handle generic case - PK.size > 1

 		Map<String, Object> idMap = new HashMap<>(pk.size() * 2);
 		for (final DbAttribute attribute : pk) {

 			String key = (prefix) ? namePrefix + attribute.getName() : attribute.getName();

 			Object val = dataRow.get(key);

 			// this is possible when processing left outer joint prefetches
 			if (val == null) {
 				if(strict && !dataRow.containsKey(key)) {
 					throw new CayenneRuntimeException("No PK column '%s' found in data row.", key);
 				}
 				return null;
 			}

 			// PUT without a prefix
 			idMap.put(attribute.getName(), val);
 		}

 		return ObjectId.of(name, idMap);
 	}

 	interface DescriptorResolutionStrategy {

 		ClassDescriptor descriptorForRow(DataRow row);
 	}

 	class NoInheritanceStrategy implements DescriptorResolutionStrategy {

 		public final ClassDescriptor descriptorForRow(DataRow row) {
 			return descriptor;
 		}
 	}

 	class InheritanceStrategy implements DescriptorResolutionStrategy {

 		public final ClassDescriptor descriptorForRow(DataRow row) {
 			String entityName = row.getEntityName();

 			// null either means a bug in Cayenne (e.g. CAY-2101) or the inheritance qualifiers are messed up
 			if(entityName == null) {
 				if(LOGGER.isWarnEnabled()) {
 					LOGGER.warn("** Null entity name for DataRow, can't resolve sub descriptor for {}",
 							descriptor.getEntity().getName());
 				}
 				return descriptor;
 			}

 			return context.getEntityResolver().getClassDescriptor(entityName);
 		}
 	}
 }
	/*****************************************************************
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* https://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	****************************************************************/

	package org.apache.cayenne.access;

	import org.apache.cayenne.CayenneRuntimeException;
	import org.apache.cayenne.DataObject;
	import org.apache.cayenne.DataRow;
	import org.apache.cayenne.ObjectContext;
	import org.apache.cayenne.ObjectId;
	import org.apache.cayenne.PersistenceState;
	import org.apache.cayenne.Persistent;
	import org.apache.cayenne.map.DbAttribute;
	import org.apache.cayenne.map.DbEntity;
	import org.apache.cayenne.map.EntityResolver;
	import org.apache.cayenne.map.ObjEntity;
	import org.apache.cayenne.reflect.ClassDescriptor;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;

	/**
	* DataRows-to-objects converter for a specific ObjEntity.
	*
	* @since 1.2
	*/
	class ObjectResolver {

	private static final Logger LOGGER = LoggerFactory.getLogger(ObjectResolver.class);

	DataContext context;
	ClassDescriptor descriptor;
	Collection<DbAttribute> primaryKey;

	boolean refreshObjects;
	DataRowStore cache;
	DescriptorResolutionStrategy descriptorResolutionStrategy;

	ObjectResolver(DataContext context, ClassDescriptor descriptor, boolean refresh) {

	// sanity check
	if (descriptor == null \|\| descriptor.getEntity() == null) {
	// possible cause: query that is not expected to have result set somehow got it..
	throw new CayenneRuntimeException("No ClassDescriptor. Maybe DataRows should be fetched instead of objects.");
	}

	DbEntity dbEntity = descriptor.getEntity().getDbEntity();
	if (dbEntity == null) {
	throw new CayenneRuntimeException("ObjEntity '%s' has no DbEntity.", descriptor.getEntity().getName());
	}

	this.primaryKey = dbEntity.getPrimaryKeys();
	if (primaryKey.size() == 0) {
	throw new CayenneRuntimeException("Won't be able to create ObjectId for '%s'. Reason: DbEntity " +
	"'%s' has no Primary Key defined.", descriptor.getEntity().getName(), dbEntity.getName());
	}

	this.context = context;
	this.cache = context.getObjectStore().getDataRowCache();
	this.refreshObjects = refresh;
	this.descriptor = descriptor;

	this.descriptorResolutionStrategy = descriptor.hasSubclasses() ? new InheritanceStrategy()
	: new NoInheritanceStrategy();
	}

	PrefetchProcessorNode synchronizedRootResultNodeFromDataRows(List<? extends DataRow> rows) {
	PrefetchProcessorNode rootNode = new PrefetchProcessorNode(null, null);
	rootNode.setObjects(synchronizedObjectsFromDataRows(rows));
	return rootNode;
	}

	/**
	* Properly synchronized version of 'objectsFromDataRows'.
	*/
	List<Persistent> synchronizedObjectsFromDataRows(List<? extends DataRow> rows) {
	synchronized (context.getObjectStore()) {
	return objectsFromDataRows(rows);
	}
	}

	/**
	* Converts rows to objects.
	* <p>
	* Synchronization note. This method requires EXTERNAL synchronization on
	* ObjectStore and DataRowStore.
	* </p>
	*/
	List<Persistent> objectsFromDataRows(List<? extends DataRow> rows) {
	if (rows == null \|\| rows.size() == 0) {
	return new ArrayList<>(1);
	}

	List<Persistent> results = new ArrayList<>(rows.size());
	for (DataRow row : rows) {
	// nulls are possible here since 3.0 for some varieties of EJBQL,
	// simple example of this: "select p.toGallery+ from Painting p" where toGallery is null.
	results.add(objectFromDataRow(row));
	}

	// now deal with snapshots
	cache.snapshotsUpdatedForObjects(results, rows, refreshObjects);
	return results;
	}

	Persistent objectFromDataRow(DataRow row) {
	// determine entity to use
	ClassDescriptor classDescriptor = descriptorResolutionStrategy.descriptorForRow(row);

	// not using DataRow.createObjectId for performance reasons -
	// ObjectResolver has all needed metadata already cached.
	ObjectId anId = createObjectId(row, classDescriptor.getEntity(), null);
	return objectFromDataRow(row, anId, classDescriptor);
	}

	Persistent objectFromDataRow(DataRow row, ObjectId anId, ClassDescriptor classDescriptor) {

	// this condition is valid - see comments on 'createObjectId' for
	// details
	if (anId == null) {
	return null;
	}

	// this will create a HOLLOW object if it is not registered yet
	Persistent object = context.findOrCreateObject(anId);

	// resolve additional Object IDs for flattened attributes
	resolveAdditionalIds(row, object, classDescriptor);

	// deal with object state
	int state = object.getPersistenceState();
	switch (state) {
	case PersistenceState.COMMITTED:
	case PersistenceState.MODIFIED:
	case PersistenceState.DELETED:
	// process the above only if refresh is requested...
	if (refreshObjects) {
	DataRowUtils.mergeObjectWithSnapshot(context, classDescriptor, object, row);

	if (object instanceof DataObject) {
	((DataObject) object).setSnapshotVersion(row.getVersion());
	}
	}
	break;
	case PersistenceState.HOLLOW:
	if (!refreshObjects) {
	DataRow cachedRow = cache.getCachedSnapshot(anId);
	if (cachedRow != null) {
	row = cachedRow;
	}
	}
	DataRowUtils.mergeObjectWithSnapshot(context, classDescriptor, object, row);
	if (object instanceof DataObject) {
	((DataObject) object).setSnapshotVersion(row.getVersion());
	}
	break;
	default:
	break;
	}

	return object;
	}

	private void resolveAdditionalIds(DataRow row, Persistent object, ClassDescriptor classDescriptor) {
	if(classDescriptor.getAdditionalDbEntities().isEmpty()) {
	return;
	}

	for(Map.Entry<String, DbEntity> entry : classDescriptor.getAdditionalDbEntities().entrySet()) {
	DbEntity dbEntity = entry.getValue();
	String path = entry.getKey();
	int lastDot = path.lastIndexOf('.');
	String prefix = lastDot == -1 ? path : path.substring(lastDot + 1);
	ObjectId objectId = createObjectId(row, "db:" + dbEntity.getName(), dbEntity.getPrimaryKeys(), prefix + '.', false);
	if(objectId != null) {
	context.getObjectStore().markFlattenedPath(object.getObjectId(), path, objectId);
	}
	}
	}

	ObjEntity getEntity() {
	return descriptor.getEntity();
	}

	ClassDescriptor getDescriptor() {
	return descriptor;
	}

	EntityResolver getEntityResolver() {
	return context.getEntityResolver();
	}

	ObjectContext getContext() {
	return context;
	}

	ObjectId createObjectId(DataRow dataRow, ObjEntity objEntity, String namePrefix) {
	Collection<DbAttribute> pk = objEntity == this.descriptor.getEntity()
	? this.primaryKey
	: objEntity.getDbEntity().getPrimaryKeys();
	return createObjectId(dataRow, objEntity.getName(), pk, namePrefix, true);
	}

	ObjectId createObjectId(DataRow dataRow, String name, Collection<DbAttribute> pk, String namePrefix, boolean strict) {
	boolean prefix = namePrefix != null && namePrefix.length() > 0;

	// ... handle special case - PK.size == 1
	// use some not-so-significant optimizations...

	if (pk.size() == 1) {
	DbAttribute attribute = pk.iterator().next();

	String key = (prefix) ? namePrefix + attribute.getName() : attribute.getName();

	Object val = dataRow.get(key);

	// this is possible when processing left outer joint prefetches
	if (val == null) {
	if(strict && !dataRow.containsKey(key)) {
	throw new CayenneRuntimeException("No PK column '%s' found in data row.", key);
	}
	return null;
	}

	// PUT without a prefix
	return ObjectId.of(name, attribute.getName(), val);
	}

	// ... handle generic case - PK.size > 1

	Map<String, Object> idMap = new HashMap<>(pk.size() * 2);
	for (final DbAttribute attribute : pk) {

	String key = (prefix) ? namePrefix + attribute.getName() : attribute.getName();

	Object val = dataRow.get(key);

	// this is possible when processing left outer joint prefetches
	if (val == null) {
	if(strict && !dataRow.containsKey(key)) {
	throw new CayenneRuntimeException("No PK column '%s' found in data row.", key);
	}
	return null;
	}

	// PUT without a prefix
	idMap.put(attribute.getName(), val);
	}

	return ObjectId.of(name, idMap);
	}

	interface DescriptorResolutionStrategy {

	ClassDescriptor descriptorForRow(DataRow row);
	}

	class NoInheritanceStrategy implements DescriptorResolutionStrategy {

	public final ClassDescriptor descriptorForRow(DataRow row) {
	return descriptor;
	}
	}

	class InheritanceStrategy implements DescriptorResolutionStrategy {

	public final ClassDescriptor descriptorForRow(DataRow row) {
	String entityName = row.getEntityName();

	// null either means a bug in Cayenne (e.g. CAY-2101) or the inheritance qualifiers are messed up
	if(entityName == null) {
	if(LOGGER.isWarnEnabled()) {
	LOGGER.warn("** Null entity name for DataRow, can't resolve sub descriptor for {}",
	descriptor.getEntity().getName());
	}
	return descriptor;
	}

	return context.getEntityResolver().getClassDescriptor(entityName);
	}
	}
	}