com.mysema.query.group.GroupByMap Maven / Gradle / Ivy
/*
* Copyright 2013, Mysema Ltd
*
* Licensed 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 com.mysema.query.group;
import java.util.LinkedHashMap;
import java.util.Map;
import com.mysema.commons.lang.CloseableIterator;
import com.mysema.query.Projectable;
import com.mysema.query.Tuple;
import com.mysema.query.types.Expression;
import com.mysema.query.types.FactoryExpression;
import com.mysema.query.types.FactoryExpressionUtils;
import com.mysema.query.types.QTuple;
/**
* Provides aggregated results as a map
*
* @author tiwe
*
* @param
* @param
*/
public class GroupByMap extends AbstractGroupByTransformer> {
GroupByMap(Expression key, Expression... expressions) {
super(key, expressions);
}
@Override
public Map transform(Projectable projectable) {
Map groups = new LinkedHashMap();
// create groups
FactoryExpression expr = FactoryExpressionUtils.wrap(new QTuple(expressions));
boolean hasGroups = false;
for (Expression e : expr.getArgs()) {
hasGroups |= e instanceof GroupExpression;
}
if (hasGroups) {
expr = withoutGroupExpressions(expr);
}
CloseableIterator iter = projectable.iterate(expr);
try {
while (iter.hasNext()) {
Object[] row = iter.next().toArray();
K groupId = (K) row[0];
GroupImpl group = (GroupImpl)groups.get(groupId);
if (group == null) {
group = new GroupImpl(groupExpressions, maps);
groups.put(groupId, group);
}
group.add(row);
}
} finally {
iter.close();
}
// transform groups
return transform(groups);
}
protected Map transform(Map groups) {
return (Map)groups;
}
}