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* 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
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package org.apache.cayenne.access;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
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.ObjEntity;
import org.apache.cayenne.map.ObjRelationship;
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.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.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
* @author Andrus Adamchik
*/
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 queriesByNode;
Map 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) {
if (interceptMappedConversion() != DONE) {
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 (!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;
}
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 = (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;
}
// a hack to prevent passing partial snapshots to ObjectResolver ... See
// CAY-724 for details.
else if (context != null
&& domain.getEntityResolver().lookupInheritanceTree(
(ObjEntity) relationship.getTargetEntity()) == null) {
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
domain.getSharedSnapshotCache().clear();
context.getQueryCache().clear();
GenericResponse response = new GenericResponse();
response.addUpdateCount(1);
this.response = response;
return DONE;
}
Collection objects = refreshQuery.getObjects();
if (objects != null && !objects.isEmpty()) {
Collection ids = new ArrayList(objects.size());
Iterator it = objects.iterator();
while (it.hasNext()) {
Persistent object = (Persistent) it.next();
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 (int i = 0; i < groups.length; i++) {
domain.getQueryCache().removeGroup(groups[i]);
}
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 = QueryMetadata.SHARED_CACHE.equals(metadata.getCachePolicy());
boolean cacheOrCacheRefresh = cache
|| QueryMetadata.SHARED_CACHE_REFRESH.equals(metadata.getCachePolicy());
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) {
Iterator nodeIt = queriesByNode.entrySet().iterator();
while (nodeIt.hasNext()) {
Map.Entry entry = (Map.Entry) nodeIt.next();
QueryEngine nextNode = (QueryEngine) entry.getKey();
Collection nodeQueries = (Collection) entry.getValue();
nextNode.performQueries(nodeQueries, this);
}
}
}
private void interceptObjectConversion() {
if (context != null && !metadata.isFetchingDataRows()) {
List mainRows = response.firstList();
if (mainRows != null && !mainRows.isEmpty()) {
List objects;
ClassDescriptor descriptor = metadata.getClassDescriptor();
PrefetchTreeNode prefetchTree = metadata.getPrefetchTree();
// take a shortcut when no prefetches exist...
if (prefetchTree == null) {
objects = new ObjectResolver(context, descriptor, metadata
.isRefreshingObjects(), metadata.isResolvingInherited())
.synchronizedObjectsFromDataRows(mainRows);
}
else {
ObjectTreeResolver resolver = new ObjectTreeResolver(
context,
metadata);
objects = resolver.synchronizedObjectsFromDataRows(
prefetchTree,
mainRows,
prefetchResultsByPath);
}
if (response instanceof GenericResponse) {
((GenericResponse) response).replaceResult(mainRows, objects);
}
else if (response instanceof ListResponse) {
this.response = new ListResponse(objects);
}
else {
throw new IllegalStateException("Unknown response object: "
+ this.response);
}
}
}
}
private boolean interceptMappedConversion() {
SQLResultSetMapping rsMapping = metadata.getResultSetMapping();
if (rsMapping == null) {
return !DONE;
}
List mainRows = response.firstList();
if (mainRows != null && !mainRows.isEmpty()) {
Collection columns = rsMapping.getColumnResults();
if (columns.isEmpty()) {
throw new CayenneRuntimeException(
"Invalid result set mapping, no columns mapped.");
}
Object[] columnsArray = columns.toArray();
int rowsLen = mainRows.size();
int rowWidth = columnsArray.length;
List objects = new ArrayList(rowsLen);
// add scalars to the result
if (rowWidth == 1) {
for (int i = 0; i < rowsLen; i++) {
Map row = (Map) mainRows.get(i);
objects.add(row.get(columnsArray[0]));
}
}
// add Object[]'s to the result
else {
for (int i = 0; i < rowsLen; i++) {
Map row = (Map) mainRows.get(i);
Object[] rowDecoded = new Object[rowWidth];
for (int j = 0; j < rowWidth; j++) {
rowDecoded[j] = row.get(columnsArray[j]);
}
objects.add(rowDecoded);
}
}
if (response instanceof GenericResponse) {
((GenericResponse) response).replaceResult(mainRows, objects);
}
else if (response instanceof ListResponse) {
this.response = new ListResponse(objects);
}
else {
throw new IllegalStateException("Unknown response object: "
+ this.response);
}
}
return DONE;
}
public void route(QueryEngine engine, Query query, Query substitutedQuery) {
List queries = null;
if (queriesByNode == null) {
queriesByNode = new HashMap();
}
else {
queries = (List) queriesByNode.get(engine);
}
if (queries == null) {
queries = new ArrayList(5);
queriesByNode.put(engine, queries);
}
queries.add(query);
// handle case when routing resuled in an "exectable" query different from the
// original query.
if (substitutedQuery != null && substitutedQuery != query) {
if (queriesByExecutedQueries == null) {
queriesByExecutedQueries = new HashMap();
}
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 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;
}
}