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* 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
*
* http://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 java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.cayenne.CayenneException;
import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.DataRow;
import org.apache.cayenne.ObjectContext;
import org.apache.cayenne.ObjectId;
import org.apache.cayenne.Persistent;
import org.apache.cayenne.QueryResponse;
import org.apache.cayenne.cache.QueryCache;
import org.apache.cayenne.cache.QueryCacheEntryFactory;
import org.apache.cayenne.map.DataMap;
import org.apache.cayenne.map.DbRelationship;
import org.apache.cayenne.map.LifecycleEvent;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.map.ObjRelationship;
import org.apache.cayenne.query.EntityResult;
import org.apache.cayenne.query.ObjectIdQuery;
import org.apache.cayenne.query.PrefetchSelectQuery;
import org.apache.cayenne.query.PrefetchTreeNode;
import org.apache.cayenne.query.Query;
import org.apache.cayenne.query.QueryCacheStrategy;
import org.apache.cayenne.query.QueryMetadata;
import org.apache.cayenne.query.QueryRouter;
import org.apache.cayenne.query.RefreshQuery;
import org.apache.cayenne.query.RelationshipQuery;
import org.apache.cayenne.query.SQLResultSetMapping;
import org.apache.cayenne.reflect.ClassDescriptor;
import org.apache.cayenne.reflect.LifecycleCallbackRegistry;
import org.apache.cayenne.util.GenericResponse;
import org.apache.cayenne.util.ListResponse;
import org.apache.cayenne.util.Util;
import org.apache.commons.collections.Transformer;
/**
* Performs query routing and execution. During execution phase intercepts callbacks to
* the OperationObserver, remapping results to the original pre-routed queries.
*
* @since 1.2
*/
class DataDomainQueryAction implements QueryRouter, OperationObserver {
static final boolean DONE = true;
DataContext context;
DataDomain domain;
DataRowStore cache;
Query query;
QueryMetadata metadata;
QueryResponse response;
GenericResponse fullResponse;
Map prefetchResultsByPath;
Map<QueryEngine, Collection<Query>> queriesByNode;
Map<Query, Query> queriesByExecutedQueries;
boolean noObjectConversion;
/*
* A constructor for the "new" way of performing a query via 'execute' with
* QueryResponse created internally.
*/
DataDomainQueryAction(ObjectContext context, DataDomain domain, Query query) {
if (context != null && !(context instanceof DataContext)) {
throw new IllegalArgumentException(
"DataDomain can only work with DataContext. "
+ "Unsupported context type: "
+ context);
}
this.domain = domain;
this.query = query;
this.metadata = query.getMetaData(domain.getEntityResolver());
this.context = (DataContext) context;
// cache may be shared or unique for the ObjectContext
if (context != null) {
this.cache = this.context.getObjectStore().getDataRowCache();
}
if (this.cache == null) {
this.cache = domain.getSharedSnapshotCache();
}
}
QueryResponse execute() {
// run chain...
if (interceptOIDQuery() != DONE) {
if (interceptRelationshipQuery() != DONE) {
if (interceptRefreshQuery() != DONE) {
if (interceptSharedCache() != DONE) {
if (interceptDataDomainQuery() != DONE) {
runQueryInTransaction();
}
}
}
}
}
if (!noObjectConversion) {
interceptObjectConversion();
}
return response;
}
private boolean interceptDataDomainQuery() {
if (query instanceof DataDomainQuery) {
response = new ListResponse(domain);
return DONE;
}
return !DONE;
}
private boolean interceptOIDQuery() {
if (query instanceof ObjectIdQuery) {
ObjectIdQuery oidQuery = (ObjectIdQuery) query;
DataRow row = null;
if (cache != null && !oidQuery.isFetchMandatory()) {
row = cache.getCachedSnapshot(oidQuery.getObjectId());
}
// refresh is forced or not found in cache
if (row == null) {
if (oidQuery.isFetchAllowed()) {
runQueryInTransaction();
}
else {
response = new ListResponse();
}
}
else {
response = new ListResponse(row);
}
return DONE;
}
return !DONE;
}
private boolean interceptRelationshipQuery() {
if (query instanceof RelationshipQuery) {
RelationshipQuery relationshipQuery = (RelationshipQuery) query;
if (relationshipQuery.isRefreshing()) {
return !DONE;
}
ObjRelationship relationship = relationshipQuery.getRelationship(domain
.getEntityResolver());
// check if we can derive target PK from FK... this implies that the
// relationship is to-one
if (relationship.isSourceIndependentFromTargetChange()) {
return !DONE;
}
if (cache == null) {
return !DONE;
}
DataRow sourceRow = cache.getCachedSnapshot(relationshipQuery.getObjectId());
if (sourceRow == null) {
return !DONE;
}
// we can assume that there is one and only one DbRelationship as
// we previously checked that
// "!isSourceIndependentFromTargetChange"
DbRelationship dbRelationship = relationship.getDbRelationships().get(0);
ObjectId targetId = sourceRow.createTargetObjectId(relationship
.getTargetEntityName(), dbRelationship);
// null id means that FK is null...
if (targetId == null) {
this.response = new GenericResponse(Collections.EMPTY_LIST);
return DONE;
}
DataRow targetRow = cache.getCachedSnapshot(targetId);
if (targetRow != null) {
this.response = new GenericResponse(Collections.singletonList(targetRow));
return DONE;
}
ObjEntity targetEntity = (ObjEntity) relationship.getTargetEntity();
// do not create a target hollow object for qualified entities or entities
// involved in inheritance, as the target object may be null even for non-null
// FK.
if (context != null
&& !isQualifiedEntity(targetEntity)
&& domain.getEntityResolver().lookupInheritanceTree(targetEntity) == null) {
// prevent passing partial snapshots to ObjectResolver per CAY-724. Create
// a hollow object right here and skip object conversion downstream
this.noObjectConversion = true;
Object object = context.localObject(targetId, null);
this.response = new GenericResponse(Collections.singletonList(object));
return DONE;
}
}
return !DONE;
}
/**
* @since 3.0
*/
private boolean interceptRefreshQuery() {
if (query instanceof RefreshQuery) {
RefreshQuery refreshQuery = (RefreshQuery) query;
if (refreshQuery.isRefreshAll()) {
// not sending any events - peer contexts will not get refreshed
if (domain.getSharedSnapshotCache() != null) {
domain.getSharedSnapshotCache().clear();
}
context.getQueryCache().clear();
GenericResponse response = new GenericResponse();
response.addUpdateCount(1);
this.response = response;
return DONE;
}
Collection<Persistent> objects = (Collection<Persistent>) refreshQuery
.getObjects();
if (objects != null && !objects.isEmpty()) {
Collection<ObjectId> ids = new ArrayList<ObjectId>(objects.size());
for (final Persistent object : objects) {
ids.add(object.getObjectId());
}
if (domain.getSharedSnapshotCache() != null) {
// send an event for removed snapshots
domain.getSharedSnapshotCache().processSnapshotChanges(
context.getObjectStore(),
Collections.EMPTY_MAP,
Collections.EMPTY_LIST,
ids,
Collections.EMPTY_LIST);
}
GenericResponse response = new GenericResponse();
response.addUpdateCount(1);
this.response = response;
return DONE;
}
// 3. refresh query - this shouldn't normally happen as child datacontext
// usually does a cascading refresh
if (refreshQuery.getQuery() != null) {
Query cachedQuery = refreshQuery.getQuery();
String cacheKey = cachedQuery
.getMetaData(context.getEntityResolver())
.getCacheKey();
context.getQueryCache().remove(cacheKey);
this.response = domain.onQuery(context, cachedQuery);
return DONE;
}
// 4. refresh groups...
if (refreshQuery.getGroupKeys() != null
&& refreshQuery.getGroupKeys().length > 0) {
String[] groups = refreshQuery.getGroupKeys();
for (String group : groups) {
domain.getQueryCache().removeGroup(group);
}
GenericResponse response = new GenericResponse();
response.addUpdateCount(1);
this.response = response;
return DONE;
}
}
return !DONE;
}
/*
* Wraps execution in shared cache checks
*/
private final boolean interceptSharedCache() {
if (metadata.getCacheKey() == null) {
return !DONE;
}
boolean cache = QueryCacheStrategy.SHARED_CACHE == metadata.getCacheStrategy();
boolean cacheOrCacheRefresh = cache
|| QueryCacheStrategy.SHARED_CACHE_REFRESH == metadata.getCacheStrategy();
if (!cacheOrCacheRefresh) {
return !DONE;
}
QueryCache queryCache = domain.getQueryCache();
QueryCacheEntryFactory factory = getCacheObjectFactory();
if (cache) {
List cachedResults = queryCache.get(metadata, factory);
// response may already be initialized by the factory above ... it is null if
// there was a preexisting cache entry
if (response == null) {
response = new ListResponse(cachedResults);
}
if (cachedResults instanceof ListWithPrefetches) {
this.prefetchResultsByPath = ((ListWithPrefetches) cachedResults)
.getPrefetchResultsByPath();
}
}
else {
// on cache-refresh request, fetch without blocking and fill the cache
queryCache.put(metadata, (List) factory.createObject());
}
return DONE;
}
private QueryCacheEntryFactory getCacheObjectFactory() {
return new QueryCacheEntryFactory() {
public Object createObject() {
runQueryInTransaction();
List list = response.firstList();
if (list != null) {
// make an immutable list to make sure callers don't mess it up
list = Collections.unmodifiableList(list);
// include prefetches in the cached result
if (prefetchResultsByPath != null) {
list = new ListWithPrefetches(list, prefetchResultsByPath);
}
}
return list;
}
};
}
/*
* Gets response from the underlying DataNodes.
*/
void runQueryInTransaction() {
domain.runInTransaction(new Transformer() {
public Object transform(Object input) {
runQuery();
return null;
}
});
}
private void runQuery() {
// reset
this.fullResponse = new GenericResponse();
this.response = this.fullResponse;
this.queriesByNode = null;
this.queriesByExecutedQueries = null;
// whether this is null or not will driver further decisions on how to process
// prefetched rows
this.prefetchResultsByPath = metadata.getPrefetchTree() != null
&& !metadata.isFetchingDataRows() ? new HashMap() : null;
// categorize queries by node and by "executable" query...
query.route(this, domain.getEntityResolver(), null);
// run categorized queries
if (queriesByNode != null) {
for (Map.Entry<QueryEngine, Collection<Query>> entry : queriesByNode
.entrySet()) {
QueryEngine nextNode = entry.getKey();
Collection<Query> nodeQueries = entry.getValue();
nextNode.performQueries(nodeQueries, this);
}
}
}
private void interceptObjectConversion() {
if (context != null && !metadata.isFetchingDataRows()) {
List<DataRow> mainRows = response.firstList();
if (mainRows != null && !mainRows.isEmpty()) {
ObjectConversionStrategy converter;
SQLResultSetMapping rsMapping = metadata.getResultSetMapping();
if (rsMapping == null) {
converter = new SingleObjectConversionStrategy();
}
else {
int entityResultCount = 0;
int columnResultCount = 0;
for (Object result : rsMapping.getResultDescriptors()) {
if (result instanceof String) {
columnResultCount++;
}
else {
entityResultCount++;
}
}
if (entityResultCount == 1 && columnResultCount == 0) {
converter = new SingleObjectConversionStrategy();
}
else if (entityResultCount == 0 && columnResultCount == 1) {
converter = new SingleScalarConversionStrategy();
}
else {
converter = new MixedConversionStrategy();
}
}
converter.convert(mainRows);
}
}
}
public void route(QueryEngine engine, Query query, Query substitutedQuery) {
Collection<Query> queries = null;
if (queriesByNode == null) {
queriesByNode = new HashMap<QueryEngine, Collection<Query>>();
}
else {
queries = queriesByNode.get(engine);
}
if (queries == null) {
queries = new ArrayList<Query>(5);
queriesByNode.put(engine, queries);
}
queries.add(query);
// handle case when routing resulted in an "executable" query different from the
// original query.
if (substitutedQuery != null && substitutedQuery != query) {
if (queriesByExecutedQueries == null) {
queriesByExecutedQueries = new HashMap<Query, Query>();
}
queriesByExecutedQueries.put(query, substitutedQuery);
}
}
public QueryEngine engineForDataMap(DataMap map) {
if (map == null) {
throw new NullPointerException("Null DataMap, can't determine DataNode.");
}
QueryEngine node = domain.lookupDataNode(map);
if (node == null) {
throw new CayenneRuntimeException("No DataNode exists for DataMap " + map);
}
return node;
}
public void nextCount(Query query, int resultCount) {
fullResponse.addUpdateCount(resultCount);
}
public void nextBatchCount(Query query, int[] resultCount) {
fullResponse.addBatchUpdateCount(resultCount);
}
public void nextDataRows(Query query, List<DataRow> dataRows) {
// exclude prefetched rows in the main result
if (prefetchResultsByPath != null && query instanceof PrefetchSelectQuery) {
PrefetchSelectQuery prefetchQuery = (PrefetchSelectQuery) query;
prefetchResultsByPath.put(prefetchQuery.getPrefetchPath(), dataRows);
}
else {
fullResponse.addResultList(dataRows);
}
}
public void nextDataRows(Query q, ResultIterator it) {
throw new CayenneRuntimeException("Invalid attempt to fetch a cursor.");
}
public void nextGeneratedDataRows(Query query, ResultIterator keysIterator) {
if (keysIterator != null) {
try {
nextDataRows(query, keysIterator.dataRows(true));
}
catch (CayenneException ex) {
// don't throw here....
nextQueryException(query, ex);
}
}
}
public void nextQueryException(Query query, Exception ex) {
throw new CayenneRuntimeException("Query exception.", Util.unwindException(ex));
}
public void nextGlobalException(Exception e) {
throw new CayenneRuntimeException("Global exception.", Util.unwindException(e));
}
public boolean isIteratedResult() {
return false;
}
/**
* Returns true if the entity or its super entities have a limiting qualifier.
*/
private boolean isQualifiedEntity(ObjEntity entity) {
if (entity.getDeclaredQualifier() != null) {
return true;
}
entity = entity.getSuperEntity();
if (entity == null) {
return false;
}
return isQualifiedEntity(entity);
}
abstract class ObjectConversionStrategy {
abstract void convert(List<DataRow> mainRows);
protected List<Persistent> toObjects(
ClassDescriptor descriptor,
PrefetchTreeNode prefetchTree,
List<DataRow> normalizedRows) {
List<Persistent> objects;
// take a shortcut when no prefetches exist...
if (prefetchTree == null) {
objects = new ObjectResolver(context, descriptor, metadata
.isRefreshingObjects())
.synchronizedObjectsFromDataRows(normalizedRows);
}
else {
ObjectTreeResolver resolver = new ObjectTreeResolver(context, metadata);
objects = resolver.synchronizedObjectsFromDataRows(
prefetchTree,
normalizedRows,
prefetchResultsByPath);
}
return objects;
}
protected List<DataRow> toNormalizedDataRows(
EntityResult entityMapping,
List<DataRow> dataRows) {
List<DataRow> normalized = new ArrayList<DataRow>(dataRows.size());
Map<String, String> fields = entityMapping.getDbFields(domain
.getEntityResolver());
int rowCapacity = (int) Math.ceil(fields.size() / 0.75);
for (DataRow src : dataRows) {
DataRow target = new DataRow(rowCapacity);
for (Map.Entry<String, String> field : fields.entrySet()) {
target.put(field.getKey(), src.get(field.getValue()));
}
normalized.add(target);
}
return normalized;
}
protected void updateResponse(List sourceObjects, List targetObjects) {
if (response instanceof GenericResponse) {
((GenericResponse) response).replaceResult(sourceObjects, targetObjects);
}
else if (response instanceof ListResponse) {
response = new ListResponse(targetObjects);
}
else {
throw new IllegalStateException("Unknown response object: " + response);
}
}
}
class SingleObjectConversionStrategy extends ObjectConversionStrategy {
@Override
void convert(List<DataRow> mainRows) {
List<DataRow> normalized;
// convert data rows to standardized format...
SQLResultSetMapping rsMapping = metadata.getResultSetMapping();
if (rsMapping != null) {
// expect 1 and only 1 entityMapping...
EntityResult entityMapping = rsMapping.getEntityResult(0);
normalized = toNormalizedDataRows(entityMapping, mainRows);
}
else {
normalized = mainRows;
}
ClassDescriptor descriptor = metadata.getClassDescriptor();
PrefetchTreeNode prefetchTree = metadata.getPrefetchTree();
List<Persistent> objects = toObjects(descriptor, prefetchTree, normalized);
updateResponse(mainRows, objects);
// apply POST_LOAD callback
LifecycleCallbackRegistry callbackRegistry = context
.getEntityResolver()
.getCallbackRegistry();
if (!callbackRegistry.isEmpty(LifecycleEvent.POST_LOAD)) {
callbackRegistry.performCallbacks(LifecycleEvent.POST_LOAD, objects);
}
}
}
class SingleScalarConversionStrategy extends ObjectConversionStrategy {
@Override
void convert(List<DataRow> mainRows) {
SQLResultSetMapping rsMapping = metadata.getResultSetMapping();
int rowsLen = mainRows.size();
List objects = new ArrayList(rowsLen);
String column = rsMapping.getColumnResult(0);
// add scalars to the result
for (DataRow row : mainRows) {
objects.add(row.get(column));
}
updateResponse(mainRows, objects);
}
}
class MixedConversionStrategy extends ObjectConversionStrategy {
@Override
void convert(List<DataRow> mainRows) {
int rowsLen = mainRows.size();
List<Object[]> objects = new ArrayList<Object[]>(rowsLen);
SQLResultSetMapping rsMapping = metadata.getResultSetMapping();
// pass 1 - init Object[]'s and resolve scalars for each row
int resultWidth = rsMapping.getResultDescriptors().size();
int[] entityPositions = rsMapping.getEntityResultPositions();
int[] columnPositions = rsMapping.getColumnResultPositions();
for (DataRow row : mainRows) {
Object[] resultRow = new Object[resultWidth];
for (int i = 0; i < columnPositions.length; i++) {
int pos = columnPositions[i];
resultRow[pos] = row.get(rsMapping.getColumnResult(pos));
}
objects.add(resultRow);
}
// pass 2 - resolve individual object columns, and then update the rows...
List[] resultLists = new List[entityPositions.length];
for (int i = 0; i < entityPositions.length; i++) {
int pos = entityPositions[i];
EntityResult entityMapping = rsMapping.getEntityResult(pos);
List<DataRow> normalized = toNormalizedDataRows(entityMapping, mainRows);
List<Persistent> nextResult = toObjects(entityMapping
.getClassDescriptor(domain.getEntityResolver()), null, normalized);
for (int j = 0; j < rowsLen; j++) {
objects.get(j)[pos] = nextResult.get(j);
}
resultLists[i] = nextResult;
}
updateResponse(mainRows, objects);
// invoke callbacks now that all objects are resolved...
LifecycleCallbackRegistry callbackRegistry = context
.getEntityResolver()
.getCallbackRegistry();
if (!callbackRegistry.isEmpty(LifecycleEvent.POST_LOAD)) {
for (int i = 0; i < entityPositions.length; i++) {
callbackRegistry.performCallbacks(
LifecycleEvent.POST_LOAD,
resultLists[i]);
}
}
}
}
}