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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.
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package org.apache.cayenne.access;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
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.ObjRelationship;
import org.apache.cayenne.query.EntityResultSegment;
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.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;
}
// check whether a non-null FK is enough to assume non-null target, and if so,
// create a fault
if (context != null
&& relationship.isSourceDefiningTargetPrecenseAndType(domain
.getEntityResolver())) {
// 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<Object> mainRows = response.firstList();
if (mainRows != null && !mainRows.isEmpty()) {
ObjectConversionStrategy converter;
List<Object> rsMapping = metadata.getResultSetMapping();
if (rsMapping == null) {
converter = new SingleObjectConversionStrategy();
}
else {
if (rsMapping.size() == 1) {
if (rsMapping.get(0) instanceof EntityResultSegment) {
converter = new SingleObjectConversionStrategy();
}
else {
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 nextRows(Query query, List<?> 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 nextRows(Query q, ResultIterator it) {
throw new CayenneRuntimeException("Invalid attempt to fetch a cursor.");
}
public void nextGeneratedRows(Query query, ResultIterator keysIterator) {
if (keysIterator != null) {
try {
nextRows(query, keysIterator.allRows());
}
catch (CayenneException ex) {
// don't throw here....
nextQueryException(query, ex);
}
finally {
try {
keysIterator.close();
}
catch (CayenneException e) {
// don't throw here....
nextQueryException(query, e);
}
}
}
}
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;
}
abstract class ObjectConversionStrategy<T> {
abstract void convert(List<T> mainRows);
protected PrefetchProcessorNode toResultsTree(
ClassDescriptor descriptor,
PrefetchTreeNode prefetchTree,
List<DataRow> normalizedRows) {
// take a shortcut when no prefetches exist...
if (prefetchTree == null) {
return new ObjectResolver(context, descriptor, metadata
.isRefreshingObjects())
.synchronizedRootResultNodeFromDataRows(normalizedRows);
}
else {
HierarchicalObjectResolver resolver = new HierarchicalObjectResolver(
context,
metadata);
return resolver.synchronizedRootResultNodeFromDataRows(
prefetchTree,
normalizedRows,
prefetchResultsByPath);
}
}
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);
}
}
protected void performPostLoadCallbacks(
PrefetchProcessorNode node,
LifecycleCallbackRegistry callbackRegistry) {
if (node.hasChildren()) {
for (PrefetchTreeNode child : node.getChildren()) {
performPostLoadCallbacks(
(PrefetchProcessorNode) child,
callbackRegistry);
}
}
List<Persistent> objects = node.getObjects();
if (objects != null) {
callbackRegistry.performCallbacks(LifecycleEvent.POST_LOAD, objects);
}
}
}
class SingleObjectConversionStrategy extends ObjectConversionStrategy<DataRow> {
@Override
void convert(List<DataRow> mainRows) {
ClassDescriptor descriptor = metadata.getClassDescriptor();
PrefetchTreeNode prefetchTree = metadata.getPrefetchTree();
PrefetchProcessorNode node = toResultsTree(descriptor, prefetchTree, mainRows);
List<Persistent> objects = node.getObjects();
updateResponse(mainRows, objects != null
? objects
: new ArrayList<Persistent>(1));
// apply POST_LOAD callback
LifecycleCallbackRegistry callbackRegistry = context
.getEntityResolver()
.getCallbackRegistry();
if (!callbackRegistry.isEmpty(LifecycleEvent.POST_LOAD)) {
performPostLoadCallbacks(node, callbackRegistry);
}
}
}
class SingleScalarConversionStrategy extends ObjectConversionStrategy<Object> {
@Override
void convert(List<Object> mainRows) {
// noop... scalars require no further processing
}
}
class MixedConversionStrategy extends ObjectConversionStrategy<Object[]> {
protected PrefetchProcessorNode toResultsTree(
ClassDescriptor descriptor,
PrefetchTreeNode prefetchTree,
List<Object[]> rows,
int position) {
int len = rows.size();
List<DataRow> rowsColumn = new ArrayList<DataRow>(len);
for (int i = 0; i < len; i++) {
rowsColumn.add((DataRow) rows.get(i)[position]);
}
if (prefetchTree != null) {
PrefetchTreeNode prefetchTreeNode = null;
for (PrefetchTreeNode prefetch : prefetchTree.getChildren()) {
if (descriptor.getEntity().getName().equals(prefetch.getEntityName())) {
if (prefetchTreeNode == null) {
prefetchTreeNode = new PrefetchTreeNode();
}
PrefetchTreeNode addPath = prefetchTreeNode.addPath(prefetch
.getPath());
addPath.setSemantics(PrefetchTreeNode.JOINT_PREFETCH_SEMANTICS);
addPath.setPhantom(false);
}
}
prefetchTree = prefetchTreeNode;
}
if (prefetchTree == null) {
return new ObjectResolver(context, descriptor, metadata
.isRefreshingObjects())
.synchronizedRootResultNodeFromDataRows(rowsColumn);
}
else {
HierarchicalObjectResolver resolver = new HierarchicalObjectResolver(
context,
metadata,
descriptor,
true);
return resolver.synchronizedRootResultNodeFromDataRows(
prefetchTree,
rowsColumn,
prefetchResultsByPath);
}
}
@Override
void convert(List<Object[]> mainRows) {
int rowsLen = mainRows.size();
List<Object> rsMapping = metadata.getResultSetMapping();
int width = rsMapping.size();
// no conversions needed for scalar positions; reuse Object[]'s to fill them
// with resolved objects
List<PrefetchProcessorNode> segmentNodes = new ArrayList<PrefetchProcessorNode>(width);
for (int i = 0; i < width; i++) {
if (rsMapping.get(i) instanceof EntityResultSegment) {
EntityResultSegment entitySegment = (EntityResultSegment) rsMapping
.get(i);
PrefetchProcessorNode nextResult = toResultsTree(
entitySegment.getClassDescriptor(),
metadata.getPrefetchTree(),
mainRows,
i);
segmentNodes.add(nextResult);
List<Persistent> objects = nextResult.getObjects();
for (int j = 0; j < rowsLen; j++) {
Object[] row = mainRows.get(j);
row[i] = objects.get(j);
}
}
}
Set<List<?>> seen = new HashSet(mainRows.size());
Iterator<Object[]> it = mainRows.iterator();
while (it.hasNext()) {
if (!seen.add(Arrays.asList(it.next()))) {
it.remove();
}
}
// invoke callbacks now that all objects are resolved...
LifecycleCallbackRegistry callbackRegistry = context
.getEntityResolver()
.getCallbackRegistry();
if (!callbackRegistry.isEmpty(LifecycleEvent.POST_LOAD)) {
for (PrefetchProcessorNode node : segmentNodes) {
performPostLoadCallbacks(node, callbackRegistry);
}
}
}
}
}