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* 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
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package org.apache.cayenne.access.jdbc;
import java.util.Collection;
import java.util.Iterator;
import org.apache.cayenne.ejbql.EJBQLBaseVisitor;
import org.apache.cayenne.ejbql.EJBQLException;
import org.apache.cayenne.ejbql.EJBQLExpression;
import org.apache.cayenne.ejbql.EJBQLExpressionVisitor;
import org.apache.cayenne.map.DbAttribute;
import org.apache.cayenne.map.DbEntity;
import org.apache.cayenne.map.DbRelationship;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.map.ObjRelationship;
import org.apache.cayenne.reflect.ClassDescriptor;
/**
* @since 3.0
*/
class EJBQLGroupByTranslator extends EJBQLBaseVisitor {
private EJBQLTranslationContext context;
private int itemCount;
EJBQLGroupByTranslator(EJBQLTranslationContext context) {
this.context = context;
}
@Override
public boolean visitIdentifier(EJBQLExpression expression) {
if (itemCount++ > 0) {
context.append(',');
}
expression.visit(context.getTranslatorFactory().getIdentifierColumnsTranslator(
context));
return false;
}
@Override
public boolean visitPath(EJBQLExpression expression, int finishedChildIndex) {
if (itemCount++ > 0) {
context.append(',');
}
EJBQLExpressionVisitor childVisitor = new EJBQLPathTranslator(context) {
@Override
protected void appendMultiColumnPath(EJBQLMultiColumnOperand operand) {
throw new EJBQLException(
"Can't GROUP BY on multi-column paths or objects");
}
@Override
public boolean visitIdentificationVariable(EJBQLExpression expression) {
String idVariableAbsolutePath = fullPath + "." + expression.getText();
ClassDescriptor descriptor = context.getEntityDescriptor(idVariableAbsolutePath);
if (descriptor != null) {
this.lastAlias = context.getTableAlias(idVariableAbsolutePath, descriptor.getEntity().getDbEntity().getFullyQualifiedName());
}
this.lastPathComponent = expression.getText();
this.fullPath = fullPath + '.' + lastPathComponent;
return true;
}
@Override
protected void processTerminatingRelationship(ObjRelationship relationship) {
Collection<DbAttribute> dbAttr = ((ObjEntity) relationship
.getTargetEntity()).getDbEntity().getAttributes();
DbRelationship dbRelationship = relationship.getDbRelationships().get(0);
DbEntity table = (DbEntity) dbRelationship.getTargetEntity();
Iterator<DbAttribute> it = dbAttr.iterator();
String alias = this.lastAlias != null ? lastAlias : context
.getTableAlias(idPath, table.getFullyQualifiedName());
boolean first = true;
while (it.hasNext()) {
context.append(!first ? ", " : " ");
DbAttribute dbAttribute = it.next();
context.append(alias).append('.').append(dbAttribute.getName());
first = false;
}
}
};
expression.visit(childVisitor);
return false;
}
}