/*******************************************************************************
* Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* tware - initial implementation
******************************************************************************/
package org.eclipse.persistence.internal.expressions;
import java.io.BufferedWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Vector;
import org.eclipse.persistence.descriptors.ClassDescriptor;
import org.eclipse.persistence.exceptions.QueryException;
import org.eclipse.persistence.expressions.Expression;
import org.eclipse.persistence.internal.helper.DatabaseField;
import org.eclipse.persistence.internal.helper.DatabaseTable;
import org.eclipse.persistence.internal.queries.ContainerPolicy;
import org.eclipse.persistence.internal.queries.InterfaceContainerPolicy;
import org.eclipse.persistence.mappings.CollectionMapping;
import org.eclipse.persistence.mappings.DatabaseMapping;
import org.eclipse.persistence.mappings.querykeys.ForeignReferenceQueryKey;
import org.eclipse.persistence.mappings.querykeys.QueryKey;
import org.eclipse.persistence.queries.ReadQuery;
public class MapEntryExpression extends QueryKeyExpression {
protected boolean returnMapEntry = false;
public MapEntryExpression(Expression base) {
this();
this.baseExpression = base;
}
public MapEntryExpression() {
this.shouldQueryToManyRelationship = true;
this.hasQueryKey = true;
this.hasMapping = false;
}
/**
* INTERNAL:
* Find the alias for a given table. A TableEntry is a place holder and its base expression holds
* all the relevant information. Get the alias from the baseExpression
*/
@Override
public DatabaseTable aliasForTable(DatabaseTable table) {
return ((DataExpression)getBaseExpression()).aliasForTable(table);
}
/**
* Set this expression to represent a Map.Entry rather than the Map's key
*/
public void returnMapEntry(){
returnMapEntry = true;
}
/**
* INTERNAL:
* This expression is built on a different base than the one we want. Rebuild it and
* return the root of the new tree
*/
@Override
public Expression rebuildOn(Expression newBase) {
Expression newLocalBase = getBaseExpression().rebuildOn(newBase);
Expression result = null;
if (returnMapEntry){
result = newLocalBase.mapEntry();
} else {
result = newLocalBase.mapKey();
}
result.setSelectIfOrderedBy(selectIfOrderedBy());
return result;
}
/**
* INTERNAL:
* A special version of rebuildOn where the newBase need not be a new
* ExpressionBuilder but any expression.
* <p>
* For nested joined attributes, the joined attribute query must have
* its joined attributes rebuilt relative to it.
*/
@Override
public Expression rebuildOn(Expression oldBase, Expression newBase) {
if (this == oldBase) {
return newBase;
}
Expression newLocalBase = ((QueryKeyExpression)getBaseExpression()).rebuildOn(oldBase, newBase);
Expression result = null;
if (returnMapEntry){
result = newLocalBase.mapEntry();
} else {
result = newLocalBase.mapKey();
}
result.setSelectIfOrderedBy(selectIfOrderedBy());
return result;
}
/**
* INTERNAL:
* Used for debug printing.
*/
@Override
public String descriptionOfNodeType() {
if (returnMapEntry){
return "MapEntry";
} else {
return "MapKey";
}
}
/**
* INTERNAL:
*/
@Override
public Expression existingDerivedTable(DatabaseTable table) {
if (baseExpression.isDataExpression()){
return ((DataExpression)baseExpression).existingDerivedTable(table);
}
return super.existingDerivedTable(table);
}
/**
* Exclude any tables defined by base.
*/
@Override
public List<DatabaseTable> getOwnedTables() {
return null;
}
@Override
public ClassDescriptor getDescriptor() {
if (isAttribute()) {
return null;
}
if (descriptor == null) {
// Look first for query keys, then mappings. Ultimately we should have query keys
// for everything and can dispense with the mapping part.
ForeignReferenceQueryKey queryKey = (ForeignReferenceQueryKey)getQueryKeyOrNull();
if (queryKey != null) {
descriptor = getSession().getDescriptor(queryKey.getReferenceClass());
return descriptor;
}
if (getMapping() == null) {
throw QueryException.invalidQueryKeyInExpression(this);
}
// We assume this is either a foreign reference or an aggregate mapping
descriptor = getMapping().getContainerPolicy().getDescriptorForMapKey();
if (getMapping().isVariableOneToOneMapping()) {
throw QueryException.cannotQueryAcrossAVariableOneToOneMapping(getMapping(), descriptor);
}
}
return descriptor;
}
/**
* INTERNAL:
*/
@Override
public DatabaseField getField() {
if (!isAttribute()) {
return null;
}
DatabaseField field = getInterfaceContainerPolicy().getDirectKeyField(getMapping());
return field;
}
/**
* INTERNAL:
* Return all the fields
*/
@Override
public Vector getFields() {
Vector result = new Vector();
InterfaceContainerPolicy icp = getInterfaceContainerPolicy();
// if this is a map entry get all the fields for both the key and the value
if (returnMapEntry || !icp.isMappedKeyMapPolicy()){
result.addAll(getBaseExpression().getFields());
} else if (isAttribute()) {
DatabaseField field = getField();
if (field != null) {
result.add(field);
}
} else {
result.addAll(getInterfaceContainerPolicy().getAdditionalFieldsForJoin(getMapping()));
}
return result;
}
/**
* INTERNAL:
*/
@Override
public List<DatabaseField> getSelectionFields(ReadQuery query) {
ArrayList<DatabaseField> result = new ArrayList<DatabaseField>();
InterfaceContainerPolicy icp = getInterfaceContainerPolicy();
// if this is a map entry get all the fields for both the key and the value
if (returnMapEntry || !icp.isMappedKeyMapPolicy()){
result.addAll(getBaseExpression().getSelectionFields(query));
} else if (isAttribute()) {
DatabaseField field = getField();
if (field != null) {
result.add(field);
}
} else {
result.addAll(getInterfaceContainerPolicy().getAdditionalFieldsForJoin(getMapping()));
}
return result;
}
@Override
public CollectionMapping getMapping() {
return (CollectionMapping)((QueryKeyExpression)getBaseExpression()).getMapping();
}
@Override
public QueryKey getQueryKeyOrNull() {
if (!hasQueryKey) {
return null;
}
InterfaceContainerPolicy cp = getInterfaceContainerPolicy();
if (queryKey == null) {
if (returnMapEntry){
return null;
} else {
queryKey = cp.createQueryKeyForMapKey();
}
}
return queryKey;
}
/**
* INTERNAL:
* Return if the expression is for a direct mapped attribute.
*/
@Override
public boolean isAttribute() {
if (isAttributeExpression == null) {
if (returnMapEntry){
return false;
}
InterfaceContainerPolicy containerPolicy = getInterfaceContainerPolicy();
return containerPolicy.isMapKeyAttribute();
}
return isAttributeExpression.booleanValue();
}
/**
* INTERNAL:
*/
@Override
public boolean isMapEntryExpression(){
return true;
}
private InterfaceContainerPolicy getInterfaceContainerPolicy(){
DatabaseMapping mapping = getMapping();
if (mapping == null) {
throw QueryException.noMappingForMapEntryExpression(getBaseExpression());
}
if (!mapping.isCollectionMapping()){
throw QueryException.mapEntryExpressionForNonCollection(getBaseExpression(), getMapping());
}
InterfaceContainerPolicy cp = null;
try{
cp = (InterfaceContainerPolicy)getMapping().getContainerPolicy();
} catch (ClassCastException e){
throw QueryException.mapEntryExpressionForNonMap(getBaseExpression(), getMapping());
}
return cp;
}
/**
* INTERNAL:
* Mapping criteria will be provided by the base expression
*/
@Override
public Expression mappingCriteria(Expression base) {
return null;
}
public boolean shouldReturnMapEntry(){
return returnMapEntry;
}
/**
* Do any required validation for this node. Throw an exception if it's incorrect.
*/
@Override
public void validateNode() {
if ((getQueryKeyOrNull() == null) && (getMapping() == null)) {
throw QueryException.invalidQueryKeyInExpression(getName());
}
if (!getMapping().isCollectionMapping()) {
throw QueryException.mapEntryExpressionForNonCollection(getBaseExpression(), getMapping());
}
ContainerPolicy cp = getMapping().getContainerPolicy();
if ((cp == null) || !cp.isMapPolicy()) {
throw QueryException.mapEntryExpressionForNonMap(getBaseExpression(), getMapping());
}
}
/**
* INTERNAL:
* Used to print a debug form of the expression tree.
*/
@Override
public void writeDescriptionOn(BufferedWriter writer) throws IOException {
writer.write(descriptionOfNodeType());
}
}