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* distributed with this work for additional information
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing,
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* KIND, either express or implied. See the License for the
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package org.apache.cayenne.lifecycle.id;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import org.apache.cayenne.ObjectContext;
import org.apache.cayenne.configuration.ConfigurationNodeVisitor;
import org.apache.cayenne.exp.Expression;
import org.apache.cayenne.exp.ExpressionFactory;
import org.apache.cayenne.map.DataMap;
import org.apache.cayenne.map.DbEntity;
import org.apache.cayenne.map.EntityResolver;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.map.Procedure;
import org.apache.cayenne.query.PrefetchTreeNode;
import org.apache.cayenne.query.Query;
import org.apache.cayenne.query.QueryCacheStrategy;
import org.apache.cayenne.query.QueryChain;
import org.apache.cayenne.query.QueryMetadata;
import org.apache.cayenne.query.QueryRouter;
import org.apache.cayenne.query.SQLAction;
import org.apache.cayenne.query.SQLActionVisitor;
import org.apache.cayenne.query.SelectQuery;
import org.apache.cayenne.reflect.ClassDescriptor;
/**
* A query that allows to fetch objects based on one or more String IDs. The returned
* objects do not have to be of the same type, be related via inheritance, or come from
* the same DB table. Note that if you expect multiple types of objects, use
* {@link ObjectContext#performGenericQuery(Query)}. The returned QueryResponse will
* contain separate lists of DataRows for each type in no particular order.
* <p>
* As of this writing, a limitation of this query is that it returns DataRows that need to
* be manually converted to objects if needed. In that it is similar to {@link QueryChain}.
*
* @since 3.1
*/
public class StringIdQuery implements Query {
private static Collection<String> toCollection(String... stringIds) {
if (stringIds == null) {
throw new NullPointerException("Null stringIds");
}
return Arrays.asList(stringIds);
}
protected String name;
protected DataMap dataMap;
protected Collection<String> stringIds;
protected transient Map<String, SelectQuery> idQueriesByEntity;
public StringIdQuery(String... stringIds) {
this(toCollection(stringIds));
}
public StringIdQuery(Collection<String> stringIds) {
// using a Set to ensure that duplicates do not result in a longer invariant
// qualifier
this.stringIds = new HashSet<String>(stringIds);
}
public Collection<String> getStringIds() {
return stringIds;
}
public void addStringIds(String... ids) {
if (ids == null) {
throw new NullPointerException("Null ids");
}
boolean changed = false;
for (String id : ids) {
if (stringIds.add(id)) {
changed = true;
}
}
if (changed) {
idQueriesByEntity = null;
}
}
protected Map<String, SelectQuery> getIdQueriesByEntity(EntityResolver resolver) {
if (this.idQueriesByEntity == null) {
Map<String, SelectQuery> idQueriesByEntity = new HashMap<String, SelectQuery>();
Map<String, EntityIdCoder> codersByEntity = new HashMap<String, EntityIdCoder>();
for (String id : stringIds) {
String entityName = EntityIdCoder.getEntityName(id);
EntityIdCoder coder = codersByEntity.get(entityName);
SelectQuery query;
if (coder == null) {
coder = new EntityIdCoder(resolver.getObjEntity(entityName));
query = new SelectQuery(entityName);
codersByEntity.put(entityName, coder);
idQueriesByEntity.put(entityName, query);
}
else {
query = idQueriesByEntity.get(entityName);
}
Expression idExp = ExpressionFactory.matchAllDbExp(coder
.toObjectId(id)
.getIdSnapshot(), Expression.EQUAL_TO);
query.orQualifier(idExp);
}
this.idQueriesByEntity = idQueriesByEntity;
}
return this.idQueriesByEntity;
}
public <T> T acceptVisitor(ConfigurationNodeVisitor<T> visitor) {
return visitor.visitQuery(this);
}
public QueryMetadata getMetaData(EntityResolver resolver) {
// Cayenne doesn't know how to handle multiple root entities, so this
// QueryMetadata, just like QueryChain's metadata is not very precise and won't
// result in correct PersistentObjects...
return new QueryMetadata() {
public DataMap getDataMap() {
return null;
}
public List<Object> getResultSetMapping() {
return null;
}
public Query getOrginatingQuery() {
return null;
}
public QueryCacheStrategy getCacheStrategy() {
return QueryCacheStrategy.getDefaultStrategy();
}
public DbEntity getDbEntity() {
return null;
}
public ObjEntity getObjEntity() {
return null;
}
public ClassDescriptor getClassDescriptor() {
return null;
}
public Procedure getProcedure() {
return null;
}
public String getCacheKey() {
return null;
}
public String[] getCacheGroups() {
return null;
}
public boolean isFetchingDataRows() {
// overriding this... Can't fetch objects until DataDomainQueryAction
// starts converting multiple ResultSets to object... Same as QueryChain
// essentially.
return true;
}
public boolean isRefreshingObjects() {
return true;
}
public int getPageSize() {
return QueryMetadata.PAGE_SIZE_DEFAULT;
}
public int getFetchOffset() {
return -1;
}
public int getFetchLimit() {
return QueryMetadata.FETCH_LIMIT_DEFAULT;
}
public PrefetchTreeNode getPrefetchTree() {
return null;
}
public Map<String, String> getPathSplitAliases() {
return Collections.emptyMap();
}
public int getStatementFetchSize() {
return QueryMetadata.STATEMENT_FETCH_SIZE_DEFAULT;
}
};
}
public void route(QueryRouter router, EntityResolver resolver, Query substitutedQuery) {
Map<String, SelectQuery> queries = getIdQueriesByEntity(resolver);
for (SelectQuery query : queries.values()) {
query.route(router, resolver, this);
}
}
public SQLAction createSQLAction(SQLActionVisitor visitor) {
throw new UnsupportedOperationException(
"This query was supposed to be replace with a set of SelectQueries during the route phase");
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public DataMap getDataMap() {
return dataMap;
}
public void setDataMap(DataMap dataMap) {
this.dataMap = dataMap;
}
}