/**********************************************************************
Copyright (c) 2005 Andy Jefferson and others. All rights reserved.
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.
Contributors:
...
**********************************************************************/
package org.jpox.store.rdbms.scostore;
import org.jpox.ClassLoaderResolver;
import org.jpox.StateManager;
import org.jpox.exceptions.JPOXUserException;
import org.jpox.metadata.AbstractClassMetaData;
import org.jpox.metadata.DiscriminatorStrategy;
import org.jpox.metadata.FieldRole;
import org.jpox.metadata.MetaDataUtils;
import org.jpox.store.mapped.DatastoreClass;
import org.jpox.store.mapped.DatastoreIdentifier;
import org.jpox.store.mapped.expression.LogicSetExpression;
import org.jpox.store.mapped.expression.QueryExpression;
import org.jpox.store.mapped.expression.ScalarExpression;
import org.jpox.store.mapped.mapping.JavaTypeMapping;
import org.jpox.store.mapped.mapping.ReferenceMapping;
import org.jpox.store.query.IncompatibleQueryElementTypeException;
import org.jpox.store.rdbms.query.DiscriminatorIteratorStatement;
import org.jpox.store.rdbms.query.UnionIteratorStatement;
import org.jpox.store.rdbms.table.ArrayTable;
import org.jpox.util.ClassUtils;
/**
* Backing store for an array stored using a join table.
* Can be used for all types of arrays :- PersistenceCapable arrays,
* non-PersistenceCapable arrays, reference arrays.
*
* @version $Revision: 1.18 $
*/
public class JoinArrayStore extends AbstractArrayStore
{
/**
* Constructor.
* @param joinTable Join table storing the relationship between owner and element
* @param clr ClassLoader resolver
*/
public JoinArrayStore(ArrayTable joinTable, ClassLoaderResolver clr)
{
super(joinTable.getStoreManager(), clr);
this.containerTable = joinTable;
setOwnerMemberMetaData(joinTable.getOwnerFieldMetaData());
ownerMapping = joinTable.getOwnerMapping();
elementMapping = joinTable.getElementMapping();
orderMapping = joinTable.getOrderMapping();
relationDiscriminatorMapping = joinTable.getRelationDiscriminatorMapping();
relationDiscriminatorValue = joinTable.getRelationDiscriminatorValue();
elementType = joinTable.getElementType();
elementsAreEmbedded = joinTable.isEmbeddedElement();
elementsAreSerialised = joinTable.isSerialisedElement();
if (elementsAreSerialised)
{
elementInfo = null;
}
else
{
Class element_class=clr.classForName(elementType);
if (storeMgr.getOMFContext().getTypeManager().isReferenceType(element_class))
{
// Array of reference types (interfaces/Objects)
String[] implNames = MetaDataUtils.getInstance().getImplementationNamesForReferenceField(ownerMemberMetaData,
FieldRole.ROLE_ARRAY_ELEMENT, clr);
elementInfo = new ElementInfo[implNames.length];
for (int i=0;i<implNames.length;i++)
{
DatastoreClass table = storeMgr.getDatastoreClass(implNames[i], clr);
AbstractClassMetaData cmd = storeMgr.getOMFContext().getMetaDataManager().getMetaDataForClass(implNames[i], clr);
elementInfo[i] = new ElementInfo(cmd, table);
}
}
else
{
// Collection of PC or non-PC
emd = storeMgr.getOMFContext().getMetaDataManager().getMetaDataForClass(element_class, clr);
if (emd != null)
{
elementType = emd.getFullClassName();
if (!elementsAreEmbedded && !elementsAreSerialised)
{
elementInfo = getElementInformationForClass();
if (elementInfo != null && elementInfo.length > 1)
{
throw new JPOXUserException(LOCALISER.msg("056045",
ownerMemberMetaData.getFullFieldName()));
}
}
else
{
elementInfo = null;
}
}
else
{
elementInfo = null;
}
}
}
}
/**
* Accessor for the iterator statement to retrieve the element(s) for the array.
* @param ownerSM The StateManager
* @return The Query Statement.
**/
protected QueryExpression getIteratorStatement(StateManager ownerSM)
{
QueryExpression stmt = null;
final ClassLoaderResolver clr = ownerSM.getObjectManager().getClassLoaderResolver();
if (elementsAreEmbedded || elementsAreSerialised)
{
// Element = Non-PC
stmt = dba.newQueryStatement(containerTable, clr);
stmt.select(elementMapping);
}
else if (elementMapping instanceof ReferenceMapping)
{
// Element = Reference type (interface/Object)
// Just select the join table since we're going to return the implementation id columns only
stmt = dba.newQueryStatement(containerTable, clr);
}
else if (elementInfo != null)
{
// Element = PC
// Join to the element table(s)
for (int i=0;i<elementInfo.length;i++)
{
// TODO This will only work if all element types have a discriminator
final int elementNo = i;
final Class elementCls = clr.classForName(elementInfo[elementNo].getClassName());
QueryExpression elementStmt = null;
if (elementInfo[elementNo].getDiscriminatorStrategy() != null &&
elementInfo[elementNo].getDiscriminatorStrategy() != DiscriminatorStrategy.NONE)
{
// The element uses a discriminator so just use that in the SELECT
if (storeMgr.getOMFContext().getTypeManager().isReferenceType(clr.classForName(ownerMemberMetaData.getCollection().getElementType())))
{
// Take the metadata for the first implementation of the reference type
String[] clsNames = storeMgr.getOMFContext().getMetaDataManager().getClassesImplementingInterface(ownerMemberMetaData.getCollection().getElementType(), clr);
Class[] cls = new Class[clsNames.length];
for( int j=0; j<clsNames.length; j++)
{
cls[j] = clr.classForName(clsNames[j]);
}
elementStmt = new DiscriminatorIteratorStatement(clr, cls,
true, this.storeMgr, true, allowsNull,
containerTable, elementMapping, elmIdentifier).getQueryStatement(null);
}
else
{
elementStmt = new DiscriminatorIteratorStatement(clr, new Class[] {elementCls},
true, this.storeMgr, true, allowsNull,
containerTable, elementMapping, elmIdentifier).getQueryStatement(null);
}
iterateUsingDiscriminator = true;
}
else
{
// The element has potential subclasses and no discrim so use UNIONs
elementStmt = new UnionIteratorStatement(clr, elementCls, true, this.storeMgr,
elementCls, elementMapping, containerTable, false, Boolean.TRUE,
true, allowsNull).getQueryStatement(null);
}
if (stmt == null)
{
stmt = elementStmt;
}
else
{
stmt.union(elementStmt);
}
}
}
else
{
// Should be impossible
throw new JPOXUserException("Attempt to get iterator for an array when insufficient information is available to perform the operation.");
}
// Apply condition on join-table owner field to filter by owner
ScalarExpression ownerExpr = ownerMapping.newScalarExpression(stmt, stmt.getMainTableExpression());
ScalarExpression ownerVal = ownerMapping.newLiteral(stmt, ownerSM.getObject());
stmt.andCondition(ownerExpr.eq(ownerVal), true);
// Apply condition on distinguisher field to filter by distinguisher (when present)
if (relationDiscriminatorMapping != null)
{
ScalarExpression distinguisherExpr = relationDiscriminatorMapping.newScalarExpression(stmt, stmt.getMainTableExpression());
ScalarExpression distinguisherVal = relationDiscriminatorMapping.newLiteral(stmt, relationDiscriminatorValue);
stmt.andCondition(distinguisherExpr.eq(distinguisherVal), true);
}
// Order by the position
ScalarExpression exprIndex[] = new ScalarExpression[orderMapping.getNumberOfDatastoreFields()];
boolean descendingOrder[] = new boolean[orderMapping.getNumberOfDatastoreFields()];
exprIndex = orderMapping.newScalarExpression(stmt, stmt.getMainTableExpression()).getExpressionList().toArray();
stmt.setOrdering(exprIndex, descendingOrder);
return stmt;
}
/**
* Method used in queries when contains() has been invoked.
* @param stmt The Query Statement
* @param parentStmt the parent Query Statement. If there is no parent, <code>parentStmt</code> must be equals to <code>stmt</code>
* @param ownerMapping the mapping for the owner.
* @param ownerTe Table Expression for the owner
* @param listTableAlias Alias for the "List" table.
* @param filteredElementType The Class Type for the filtered element
* @param elmExpr The Expression for the element
* @param elementTableAlias The SQL alias to assign to the expression or to the element table.
* @return expression to the join
**/
public ScalarExpression joinElementsTo(QueryExpression stmt,
QueryExpression parentStmt,
JavaTypeMapping ownerMapping,
LogicSetExpression ownerTe,
DatastoreIdentifier listTableAlias,
Class filteredElementType,
ScalarExpression elmExpr,
DatastoreIdentifier elementTableAlias)
{
ClassLoaderResolver clr=stmt.getClassLoaderResolver();
Class primitiveType = ClassUtils.getWrapperTypeForPrimitiveType(clr.classForName(elementType));
if (!clr.isAssignableFrom(elementType, filteredElementType) &&
!clr.isAssignableFrom(filteredElementType, elementType) &&
(primitiveType !=null && clr.isAssignableFrom(elementType,primitiveType.getName())))
{
throw new IncompatibleQueryElementTypeException(elementType, filteredElementType.getName());
}
LogicSetExpression ownTblExpr = stmt.newTableExpression(containerTable, listTableAlias);
ScalarExpression ownerExpr = ownerMapping.newScalarExpression(stmt, ownerTe);
ScalarExpression ownerSetExpr = this.ownerMapping.newScalarExpression(stmt, stmt.getTableExpression(listTableAlias));
if (!parentStmt.hasCrossJoin(ownTblExpr))
{
stmt.crossJoin(ownTblExpr, true);
}
stmt.andCondition(ownerExpr.eq(ownerSetExpr),true);
if (storeMgr.getOMFContext().getTypeManager().isSupportedType(filteredElementType.getName()))
{
// Element = Non-PC(embedded)
return elementMapping.newScalarExpression(stmt, stmt.getTableExpression(listTableAlias));
}
else if (elementsAreEmbedded || elementsAreSerialised)
{
// Element = PC(embedded), PC(serialised)
return elementMapping.newScalarExpression(stmt, stmt.getTableExpression(listTableAlias));
}
else
{
// Element = PC
// Join to element table on id column(s) of element
DatastoreClass elementTable = storeMgr.getDatastoreClass(filteredElementType.getName(), stmt.getClassLoaderResolver());
DatastoreClass joiningClass = (elmExpr.getLogicSetExpression() == null ? elementTable : (DatastoreClass)elmExpr.getLogicSetExpression().getMainTable());
JavaTypeMapping elementTableID = joiningClass.getIDMapping();
/* TODO this comment is no longer valid, since we use sub queries
* if elementType == filteredElementType
* INNER JOIN ELEMENT THIS_FILTER_ELEMENT_VARIABLE
* ON THIS_SETTABLE.ELEMENT_EID = THIS_FILTER_ELEMENT_VARIABLE.ELEMENT_ID
*
* else if elementType != filteredElementType but filteredElementType is a superclass of elementType
*
* INNER JOIN FILTER_ELEMENT_TYPE THIS_FILTER_ELEMENT_VARIABLE
* ON THIS_SETTABLE.ELEMENT_EID = THIS_FILTER_ELEMENT_VARIABLE.FILTER_ELEMENT_TYPE_ID */
LogicSetExpression elmTblExpr = stmt.getTableExpression(elementTableAlias);
if (elmTblExpr==null)
{
elmTblExpr = stmt.newTableExpression(elementTable,elementTableAlias);
}
ScalarExpression elmSetExpr = elementMapping.newScalarExpression(stmt, stmt.getTableExpression(listTableAlias));
if (!parentStmt.hasCrossJoin(elmTblExpr))
{
stmt.crossJoin(elmTblExpr, true);
}
if (elmExpr.getLogicSetExpression()!= null && !elementTable.equals(elmExpr.getLogicSetExpression().getMainTable()))
{
//elmExpr might express a FK in another to the ELEMENT table
stmt.andCondition(elmSetExpr.eq(elmExpr),true);
return this.elementMapping.newScalarExpression(stmt,stmt.getTableExpression(listTableAlias));
}
else
{
//elmExpr might be a PK of the ELEMENT table
ScalarExpression elementExpr = elementTableID.newScalarExpression(stmt, stmt.getTableExpression(elementTableAlias));
stmt.andCondition(elmSetExpr.eq(elementExpr),true);
return elementExpr;
}
}
}
}