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EclipseLink build based upon Git transaction f2b9fc5
/*
* Copyright (c) 1998, 2022 Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2019, 2022 IBM Corporation. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0,
* or the Eclipse Distribution License v. 1.0 which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
*/
// Contributors:
// Oracle - initial API and implementation from Oracle TopLink
// IBM - Bug 537795: CASE THEN and ELSE scalar expression Constants should not be casted to CASE operand type
package org.eclipse.persistence.internal.expressions;
import java.io.BufferedWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
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.expressions.ExpressionBuilder;
import org.eclipse.persistence.expressions.ExpressionOperator;
import org.eclipse.persistence.history.AsOfClause;
import org.eclipse.persistence.internal.databaseaccess.DatabasePlatform;
import org.eclipse.persistence.internal.helper.ClassConstants;
import org.eclipse.persistence.internal.helper.DatabaseField;
import org.eclipse.persistence.internal.helper.DatabaseTable;
import org.eclipse.persistence.internal.helper.NonSynchronizedVector;
import org.eclipse.persistence.internal.queries.ReportItem;
import org.eclipse.persistence.internal.sessions.AbstractRecord;
import org.eclipse.persistence.internal.sessions.AbstractSession;
import org.eclipse.persistence.mappings.DatabaseMapping;
import org.eclipse.persistence.mappings.OneToOneMapping;
import org.eclipse.persistence.mappings.querykeys.ForeignReferenceQueryKey;
import org.eclipse.persistence.mappings.querykeys.QueryKey;
import org.eclipse.persistence.queries.DatabaseQuery;
import org.eclipse.persistence.queries.ReadQuery;
import org.eclipse.persistence.queries.ReportQuery;
/**
* Used for expressions that have 0 to n children.
* These include not, between and all functions.
*/
public class FunctionExpression extends BaseExpression {
protected Vector children;
protected ExpressionOperator operator;
protected transient ExpressionOperator platformOperator;
protected Class resultType;
public FunctionExpression() {
this.children = org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance(2);
this.resultType = null;
}
/**
* INTERNAL:
* Return if the expression is equal to the other.
* This is used to allow dynamic expression's SQL to be cached.
* This must be over written by each subclass.
*/
@Override
public boolean equals(Object object) {
if (this == object) {
return true;
}
if (!super.equals(object)) {
return false;
}
FunctionExpression expression = (FunctionExpression) object;
if ((this.operator != expression.getOperator()) && ((this.operator == null) || (!this.operator.equals(expression.getOperator())))) {
return false;
}
List children = getChildren();
List otherChildren = expression.getChildren();
int size = children.size();
if (size != otherChildren.size()) {
return false;
}
for (int index = 0; index < size; index++) {
if (!children.get(index).equals(otherChildren.get(index))) {
return false;
}
}
return true;
}
/**
* INTERNAL:
* Compute a consistent hash-code for the expression.
* This is used to allow dynamic expression's SQL to be cached.
*/
@Override
public int computeHashCode() {
int hashCode = super.computeHashCode();
if (this.operator != null) {
hashCode = hashCode + this.operator.hashCode();
}
List children = getChildren();
int size = children.size();
for (int index = 0; index < size; index++) {
hashCode = hashCode + children.get(index).hashCode();
}
return hashCode;
}
public void addChild(Expression child) {
getChildren().addElement(child);
}
/**
* INTERNAL:
* Find the alias for a given table
*/
@Override
public DatabaseTable aliasForTable(DatabaseTable table) {
return getBaseExpression().aliasForTable(table);
}
@Override
public Expression asOf(AsOfClause clause) {
final AsOfClause finalClause = clause;
ExpressionIterator iterator = new ExpressionIterator() {
@Override
public void iterate(Expression each) {
if (each.isDataExpression()) {
each.asOf(finalClause);
}
}
@Override
public boolean shouldIterateOverSubSelects() {
return true;
}
};
iterator.iterateOn(this);
return this;
}
/**
* INTERNAL:
*/
@Override
public Expression create(Expression base, Object singleArgument, ExpressionOperator anOperator) {
baseExpression = base;
addChild(base);
Expression localBase = base;
if(anOperator.isFunctionOperator()) {
ExpressionBuilder builder = getBuilder();
if(builder != null) {
localBase = builder;
}
}
Expression arg = Expression.from(singleArgument, localBase);
addChild(arg);
setOperator(anOperator);
return this;
}
/**
* INTERNAL:
* added for Trim support. TRIM([trim_character FROM] string_primary)
*/
@Override
public Expression createWithBaseLast(Expression base, Object singleArgument, ExpressionOperator anOperator) {
baseExpression = base;
Expression localBase = base;
if(anOperator.isFunctionOperator()) {
ExpressionBuilder builder = getBuilder();
if(builder != null) {
localBase = builder;
}
}
Expression arg = Expression.from(singleArgument, localBase);
addChild(arg);
addChild(base);
setOperator(anOperator);
return this;
}
/**
* INTERNAL:
*/
@Override
public Expression create(Expression base, List arguments, ExpressionOperator anOperator) {
this.baseExpression = base;
setOperator(anOperator);
addChild(base);
Expression localBase = base;
if (anOperator.isFunctionOperator()) {
ExpressionBuilder builder = getBuilder();
if (builder != null) {
localBase = builder;
}
}
for (Object argument : arguments) {
Expression arg = Expression.from(argument, localBase);
addChild(arg);
}
return this;
}
/**
* INTERNAL:
* Used for debug printing.
*/
@Override
public String descriptionOfNodeType() {
return "Function";
}
/**
* INTERNAL:
* Check if the object conforms to the expression in memory.
* This is used for in-memory querying.
* If the expression in not able to determine if the object conform throw a not supported exception.
*/
@Override
public boolean doesConform(Object object, AbstractSession session, AbstractRecord translationRow, int valueHolderPolicy, boolean isObjectUnregistered) {
int selector = this.operator.getSelector();
// Must check for NOT and negate entire base expression.
if (selector == ExpressionOperator.Not) {
return !getBaseExpression().doesConform(object, session, translationRow, valueHolderPolicy, isObjectUnregistered);
}
// Conform between or in function.
if ((selector == ExpressionOperator.Between) || (selector == ExpressionOperator.NotBetween)
|| (selector == ExpressionOperator.In) || (selector == ExpressionOperator.NotIn)
|| (selector == ExpressionOperator.Like) || (selector == ExpressionOperator.Regexp)
|| (selector == ExpressionOperator.NotLike)) {
// Extract the value from the left side.
Object leftValue = getBaseExpression().valueFromObject(object, session, translationRow, valueHolderPolicy, isObjectUnregistered);
// Extract the value from the arguments, skip the first child which is the base.
int size = this.children.size();
Vector rightValue = new Vector(size);
for (int index = 1; index < size; index++) {
Object valueFromRight;
Expression child = this.children.get(index);
if (child instanceof Expression) {
valueFromRight = child.valueFromObject(object, session, translationRow, valueHolderPolicy, isObjectUnregistered);
} else {
valueFromRight = child;
}
//If valueFromRight is a Vector, then there is only one child other than the base, e.g. valueFromRight is a collection of constants.
//Then it should be the vector to be compared with. Don't add it to another collection.
if (valueFromRight instanceof Vector) {
rightValue = (Vector)valueFromRight;
//Single values should be added to the rightValue, which will be compared with leftValue.
} else {
rightValue.add(valueFromRight);
}
}
// If left is anyof collection of values, check each one.
// If the right had an anyof not supported will be thrown from the operator.
if (leftValue instanceof Vector) {
for (Object tempLeft : (Vector)leftValue) {
if (this.operator.doesRelationConform(tempLeft, rightValue)) {
return true;
}
}
// Only return false if none of the values match.
return false;
} else {
return this.operator.doesRelationConform(leftValue, rightValue);
}
} else if ((selector == ExpressionOperator.IsNull) || (selector == ExpressionOperator.NotNull)) {
// Extract the value from the left side.
Object leftValue = getBaseExpression().valueFromObject(object, session, translationRow, valueHolderPolicy, isObjectUnregistered);
// If left is anyof collection of values, check each one.
if (leftValue instanceof Vector) {
for (Object tempLeft : (Vector)leftValue) {
if (this.operator.doesRelationConform(tempLeft, null)) {
return true;
}
}
// Only return false if none of the values match.
return false;
} else {
return this.operator.doesRelationConform(leftValue, null);
}
}
// No other relation functions are supported.
// Non-relation functions are supported through valueFromObject().
throw QueryException.cannotConformExpression();
}
public Vector getChildren() {
return this.children;
}
/**
* INTERNAL: Not to be confused with the public getField(String)
* This returns a collection of all fields associated with this object. Really
* only applies to query keys representing an object or to expression builders.
*
*/
@Override
public Vector getFields() {
return getBaseExpression().getFields();
}
/**
* INTERNAL:
*/
@Override
public List getSelectionFields(ReadQuery query) {
return getBaseExpression().getSelectionFields(query);
}
@Override
public ExpressionOperator getOperator() {
return operator;
}
public ExpressionOperator getPlatformOperator(DatabasePlatform platform) {
if (platformOperator == null) {
initializePlatformOperator(platform);
}
return platformOperator;
}
public Class getResultType() {
return resultType;
}
public boolean hasResultType() {
return resultType != null;
}
/**
* INTERNAL:
*/
public void initializePlatformOperator(DatabasePlatform platform) {
// First, check that the platform operator doesn't override the operator behavior
platformOperator = platform.getOperator(this.operator.getSelector());
if (platformOperator == null) {
// If the platform doesn't specifically override, fallback on the internal operator
// This operator should be either user-defined or one from ExpressionOperator.initializeInternalOperators.
platformOperator = this.operator;
if (platformOperator == null) {
throw QueryException.invalidOperator(this.operator);
}
}
}
@Override
public boolean isFunctionExpression() {
return true;
}
/**
* INTERNAL:
* Return if the represents an object comparison.
*/
protected boolean isObjectComparison() {
int selector = this.operator.getSelector();
if (((selector != ExpressionOperator.IsNull) && (selector != ExpressionOperator.NotNull)) || (this.children.size() != 1)) {
if (((selector != ExpressionOperator.InSubQuery) && (selector != ExpressionOperator.NotInSubQuery))
|| (this.children.size() != 2)) {
return false;
}
}
Expression base = getBaseExpression();
//bug 384641 - check that directCollections are not treated as object comparisons
return (base.isObjectExpression() && (!((ObjectExpression)base).isAttribute()) &&
!((ObjectExpression)base).isDirectCollection() );
}
/**
* INTERNAL:
* For iterating using an inner class
*/
@Override
public void iterateOn(ExpressionIterator iterator) {
super.iterateOn(iterator);
for (Enumeration childrenEnum = this.children.elements(); childrenEnum.hasMoreElements();) {
Expression child = childrenEnum.nextElement();
child.iterateOn(iterator);
}
}
/**
* INTERNAL:
* Normalize into a structure that is printable.
* Also compute printing information such as outer joins.
* This checks for object isNull, notNull, in and notIn comparisons.
*/
@Override
public Expression normalize(ExpressionNormalizer normalizer) {
//This method has no validation but we should still make the method call for consistency
//bug # 2956674
//validation is moved into normalize to ensure that expressions are valid before we attempt to work with them
validateNode();
if (this.children.isEmpty()) {
return this;
}
// Ensure session has been set.
ExpressionBuilder builder = getBuilder();
if ((builder != null) && (builder.getSession() == null)) {
builder.setSession(normalizer.getSession().getRootSession(null));
}
if (this.operator.getSelector() == ExpressionOperator.Count) {
// Attempting to count an Entity and not an attribute. Need to augment this expression.
// This is normally normalized in ReportQuery, but can get to here in a having clause.
prepareObjectAttributeCount(normalizer, null, null, null);
}
if (!isObjectComparison()) {
for (int index = 0; index < this.children.size(); index++) {
this.children.set(index, this.children.get(index).normalize(normalizer));
}
return this;
} else {
//if not normalizing we must still validate the corresponding node to make sure that they are valid
//bug # 2956674
for (int index = 0; index < this.children.size(); index++) {
this.children.get(index).validateNode();
}
}
// This code is executed only in the case of an is[not]Null, or [not]in on an
// object attribute.
ObjectExpression base = (ObjectExpression)getBaseExpression();
// For cr2334, fix code so that normalize is first called on base expressions.
// I.e. if base itself had a base expression this expression would not be normalized.
if (base.getBaseExpression() != null) {
base.getBaseExpression().normalize(normalizer);
}
// Check for IN with objects, "e IN (Select e2 from Employee e2)".
if ((this.operator.getSelector() == ExpressionOperator.InSubQuery)
|| (this.operator.getSelector() == ExpressionOperator.NotInSubQuery)) {
// Switch object comparison to compare on primary key.
if (this.children.size() != 2) {
throw QueryException.invalidExpression(this);
}
// Check if the left is for a 1-1 mapping, then optimize to compare on foreign key to avoid join.
DatabaseMapping mapping = null;
if (base.isQueryKeyExpression()) {
mapping = base.getMapping();
}
List sourceFields = null;
List targetFields = null;
if ((mapping != null) && mapping.isOneToOneMapping()
&& (!((OneToOneMapping)mapping).hasRelationTableMechanism())
&& (!((OneToOneMapping)mapping).hasCustomSelectionQuery())) {
base = (ObjectExpression)base.getBaseExpression();
Map targetToSourceKeyFields = ((OneToOneMapping)mapping).getTargetToSourceKeyFields();
sourceFields = new ArrayList(targetToSourceKeyFields.size());
targetFields = new ArrayList(targetToSourceKeyFields.size());
for (Map.Entry entry : targetToSourceKeyFields.entrySet()) {
sourceFields.add(entry.getValue());
targetFields.add(entry.getKey());
}
} else {
mapping = null;
sourceFields = base.getDescriptor().getPrimaryKeyFields();
targetFields = sourceFields;
}
if (sourceFields.size() != 1) {
base = (ObjectExpression)getBaseExpression();
// For composite ids an exists and subselect is used.
SubSelectExpression subSelectExp = (SubSelectExpression)this.children.get(1);
ReportQuery subQuery = subSelectExp.getSubQuery();
// some db (derby) require that in EXIST(SELECT...) subquery returns a single column
subQuery.getItems().clear();
subQuery.addItem("one", new ConstantExpression(Integer.valueOf(1), subQuery.getExpressionBuilder()));
Expression subSelectCriteria = subQuery.getSelectionCriteria();
ExpressionBuilder subBuilder = subQuery.getExpressionBuilder();
Expression newExp;
// Any or Some
if (this.operator.getSelector() == ExpressionOperator.InSubQuery) {
subSelectCriteria = subBuilder.equal(base).and(subSelectCriteria);
} else {
subSelectCriteria = subBuilder.notEqual(base).and(subSelectCriteria);
}
subQuery.setSelectionCriteria(subSelectCriteria);
newExp = builder.exists(subQuery);
return newExp.normalize(normalizer);
}
Expression newBase = base.getField(sourceFields.get(0));
setBaseExpression(newBase);
this.children.set(0, newBase);
Expression right = this.children.get(1);
if (right.isSubSelectExpression()) {
// Check for sub-select, need to replace sub-selects on object to select its id.
ReportQuery query = ((SubSelectExpression)right).getSubQuery();
if (query.getItems().size() != 1) {
throw QueryException.invalidExpression(this);
}
ReportItem item = query.getItems().get(0);
item.setAttributeExpression(item.getAttributeExpression().getField(targetFields.get(0)));
} else {
throw QueryException.invalidExpression(this);
}
// Still need to normalize the children.
for (int index = 0; index < this.children.size(); index++) {
this.children.set(index, this.children.get(index).normalize(normalizer));
}
return this;
}
// else isNull/notNull
Expression foreignKeyJoin = null;
if (base.getMapping() == null) {
// Is an expression builder, transform to a null primary key expression.
foreignKeyJoin = base.getDescriptor().getObjectBuilder().buildPrimaryKeyExpressionFromKeys(null, getSession());
foreignKeyJoin = foreignKeyJoin.rebuildOn(base);
} else {
// Switch to null foreign key comparison (i.e. get('c').isNull() to getField('C_ID').isNull()).
// For bug 3105559 also must handle aggregates: get("period").isNull();
foreignKeyJoin = base.getMapping().buildObjectJoinExpression(base, (Object)null, getSession());
}
if (this.operator.getSelector() == ExpressionOperator.NotNull) {
foreignKeyJoin = foreignKeyJoin.not();
}
return foreignKeyJoin.normalize(normalizer);
}
/**
* INTERNAL:
* Used for cloning.
*/
@Override
protected void postCopyIn(Map alreadyDone) {
super.postCopyIn(alreadyDone);
Vector oldChildren = this.children;
this.children = org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance();
for (int i = 0; i < oldChildren.size(); i++) {
addChild((oldChildren.elementAt(i).copiedVersionFrom(alreadyDone)));
}
}
/**
* INTERNAL:
* Print SQL using the operator.
*/
@Override
public void printSQL(ExpressionSQLPrinter printer) {
/*
* If this ExpressionOperator does not support binding, and the platform allows,
* then disable binding for the whole query
*/
if (printer.getPlatform().isDynamicSQLRequiredForFunctions() && !this.children.isEmpty()) {
boolean allParams = true;
for (Iterator iterator = this.children.iterator(); iterator.hasNext(); ) {
Expression child = iterator.next();
if (!(child.isParameterExpression() || child.isConstantExpression())) {
allParams = false;
}
}
if (allParams) {
printer.getCall().setUsesBinding(false);
}
}
ExpressionOperator realOperator;
realOperator = getPlatformOperator(printer.getPlatform());
realOperator.printCollection(this.children, printer);
}
/**
* INTERNAL:
* Print java for project class generation
*/
@Override
public void printJava(ExpressionJavaPrinter printer) {
ExpressionOperator realOperator = getPlatformOperator(printer.getPlatform());
realOperator.printJavaCollection(this.children, printer);
}
/**
* 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);
Vector newChildren = org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance(this.children.size());
for (int i = 1; i < this.children.size(); i++) {// Skip the first one, since it's also the base
newChildren.addElement(this.children.elementAt(i).rebuildOn(newBase));
}
newLocalBase.setSelectIfOrderedBy(getBaseExpression().selectIfOrderedBy());
FunctionExpression rebuilt = (FunctionExpression) newLocalBase.performOperator(this.operator, newChildren);
rebuilt.setResultType(this.getResultType()); //copy over result type.
return rebuilt;
}
/**
* INTERNAL:
* Search the tree for any expressions (like SubSelectExpressions) that have been
* built using a builder that is not attached to the query. This happens in case of an Exists
* call using a new ExpressionBuilder(). This builder needs to be replaced with one from the query.
*/
@Override
public void resetPlaceHolderBuilder(ExpressionBuilder queryBuilder){
getBaseExpression().resetPlaceHolderBuilder(queryBuilder);
for (int i = this.children.size()-1; i > 0; i--) {// Skip the first one, since it's also the base
this.children.elementAt(i).resetPlaceHolderBuilder(queryBuilder);
}
}
// Set the local base expression, ie the one on the other side of the operator
// Most types will ignore this, since they don't need it.
@Override
public void setLocalBase(Expression exp) {
getBaseExpression().setLocalBase(exp);
}
public void setOperator(ExpressionOperator theOperator) {
operator = theOperator;
}
public void setResultType(Class resultType) {
this.resultType = resultType;
}
/**
* INTERNAL:
* Rebuild myself against the base, with the values of parameters supplied by the context
* expression. This is used for transforming a standalone expression (e.g. the join criteria of a mapping)
* into part of some larger expression. You normally would not call this directly, instead calling twist
* See the comment there for more details"
*/
@Override
public Expression twistedForBaseAndContext(Expression newBase, Expression context, Expression oldBase) {
if (this.children.isEmpty()) {
return (Expression)clone();
}
Vector newChildren = org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance(this.children.size());
// For functions the base is the first child, we only want the arguments so start at the second.
for (int index = 1; index < this.children.size(); index++) {
newChildren.addElement(this.children.elementAt(index).twistedForBaseAndContext(newBase, context, oldBase));
}
// Aply the function to the twisted old base.
Expression oldBaseExp = this.children.elementAt(0);
return oldBaseExp.twistedForBaseAndContext(newBase, context, oldBase).performOperator(this.operator, newChildren);
}
/**
* INTERNAL:
* Return the value for in memory comparison.
* This is only valid for valueable expressions.
*/
@Override
public Object valueFromObject(Object object, AbstractSession session, AbstractRecord translationRow, int valueHolderPolicy, boolean isObjectUnregistered) {
Object baseValue = getBaseExpression().valueFromObject(object, session, translationRow, valueHolderPolicy, isObjectUnregistered);
Vector arguments = org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance(this.children.size());
for (int index = 1; index < this.children.size(); index++) {
if (this.children.elementAt(index) instanceof Expression) {
arguments.addElement((this.children.elementAt(index)).valueFromObject(object, session, translationRow, valueHolderPolicy, isObjectUnregistered));
} else {
arguments.addElement(this.children.elementAt(index));
}
}
if (baseValue instanceof Vector) {// baseValue might be a vector, so the individual values must be extracted before applying the function call to them
Vector baseVector = new Vector();
for (Enumeration valuesToCompare = ((Vector)baseValue).elements();
valuesToCompare.hasMoreElements();) {
Object baseObject = valuesToCompare.nextElement();
if (baseObject == null) {
baseVector.addElement(null);
} else {
baseVector.addElement(this.operator.applyFunction(baseObject, arguments));
}
}
return baseVector;
} else {
// Do not apply functions to null, just leave as null.
if (baseValue == null) {
return null;
} else {
return this.operator.applyFunction(baseValue, arguments);
}
}
}
/**
* INTERNAL:
* Used to print a debug form of the expression tree.
*/
@Override
public void writeDescriptionOn(BufferedWriter writer) throws IOException {
writer.write(operator.toString());
}
/**
* INTERNAL: called from SQLSelectStatement.writeFieldsFromExpression(...)
*/
@Override
public void writeFields(ExpressionSQLPrinter printer, Vector newFields, SQLSelectStatement statement) {
//print ", " before each selected field except the first one
if (printer.isFirstElementPrinted()) {
printer.printString(", ");
} else {
printer.setIsFirstElementPrinted(true);
}
if (getBaseExpression().isDataExpression()) {
DatabaseField field = ((DataExpression)getBaseExpression()).getField();
if (field == null) {
// This means the select wants a *.
field = new DatabaseField("*");
} else {
// Clone the field since we will change its type.
field = field.clone();
}
// If the result type is set, use it.
field.setSqlType(DatabaseField.NULL_SQL_TYPE);
//we also cache the JDBC type now so reset it as well.
if (hasResultType()) {
field.setType(getResultType());
} else {
// If the function is anything but min or max, null out the
// field type. The type will be calculated based on the
// function.
int selector = this.operator.getSelector();
if (selector != ExpressionOperator.Maximum && selector != ExpressionOperator.Minimum) {
field.setType(null);
}
}
newFields.addElement(field);
} else {
// This field is a complex function value so any name can be used.
DatabaseField field = new DatabaseField("*");
// If the result type is set, use it.
field.setSqlType(DatabaseField.NULL_SQL_TYPE);
field.setType(getResultType());
newFields.addElement(field);
}
printSQL(printer);
}
/**
* INTERNAL:
* Used in SQL printing.
*/
@Override
public void writeSubexpressionsTo(BufferedWriter writer, int indent) throws IOException {
if (baseExpression != null) {
baseExpression.toString(writer, indent);
}
}
/**
* INTERNAL:
* JPQL allows count([distinct] e), where e can be an object, not just a single field,
* however the database only allows a single field, so object needs to be translated to a single field.
* If the descriptor has a single pk, it is used, otherwise any pk is used if distinct, otherwise a subselect is used.
* If the object was obtained through an outer join, then the subselect also will not work, so an error is thrown.
*/
public void prepareObjectAttributeCount(ExpressionNormalizer normalizer, ReportItem item, ReportQuery query, Map clonedExpressions) {
// ** Note that any of the arguments may be null depending on the caller.
if (getOperator().getSelector() == ExpressionOperator.Count) {
Expression baseExp = getBaseExpression();
boolean distinctUsed = false;
if (baseExp.isFunctionExpression() && (((FunctionExpression)baseExp).getOperator().getSelector() == ExpressionOperator.Distinct)) {
distinctUsed = true;
baseExp = ((FunctionExpression)baseExp).getBaseExpression();
}
boolean outerJoin = false;
ClassDescriptor newDescriptor = null;
AbstractSession session = null;
if (query != null) {
session = query.getSession();
} else {
session = normalizer.getSession();
}
if (baseExp.isQueryKeyExpression()) {
// now need to find out if it is a direct to field or something else.
ClassDescriptor descriptor = null;
if (query == null) {
descriptor = ((QueryKeyExpression) baseExp).getDescriptor();
} else {
descriptor = query.getDescriptor();
}
DatabaseMapping mapping = baseExp.getLeafMapping(query, descriptor, session);
if ((mapping != null) && !mapping.isAbstractDirectMapping()) {
outerJoin = ((QueryKeyExpression)baseExp).shouldUseOuterJoin();
if (mapping.isAggregateMapping()){
newDescriptor = mapping.getDescriptor();
baseExp = ((QueryKeyExpression)baseExp).getBaseExpression();
} else {
newDescriptor = mapping.getReferenceDescriptor();
}
} else {
QueryKey queryKey = getLeafQueryKeyFor(query, baseExp, descriptor, session);
if ((queryKey != null) && queryKey.isForeignReferenceQueryKey()){
outerJoin = ((QueryKeyExpression) baseExp).shouldUseOuterJoin();
newDescriptor = session.getDescriptor(((ForeignReferenceQueryKey)queryKey).getReferenceClass());
}
}
} else if (baseExp.isExpressionBuilder()) {
if (((ExpressionBuilder)baseExp).getQueryClass() == null) {
if (item != null) {
item.setResultType(ClassConstants.INTEGER);
}
} else {
newDescriptor = session.getDescriptor(((ExpressionBuilder)baseExp).getQueryClass());
}
}
if (newDescriptor != null) {
// At this point we are committed to rewriting the query.
if ((newDescriptor.getPrimaryKeyFields().size() == 1) || !distinctUsed) {
// case 1: single PK =>
// treat COUNT(entity) as COUNT(entity.pk)
Expression countArg = baseExp.getField(newDescriptor.getPrimaryKeyFields().get(0));
if (distinctUsed) {
countArg = countArg.distinct();
}
setBaseExpression(countArg);
getChildren().set(0, countArg);
} else if (((DatabasePlatform)session.getPlatform(newDescriptor.getJavaClass())).supportsCountDistinctWithMultipleFields()) {
// case 3, is database allows multiple fields, then just print them
// treat COUNT(distinct entity) as COUNT(distinct entity.pk1, entity.pk2)
List args = new ArrayList(newDescriptor.getPrimaryKeyFields().size());
Expression firstField = null;
for (DatabaseField field : newDescriptor.getPrimaryKeyFields()) {
if (firstField == null) {
firstField = baseExp.getField(field);
} else {
args.add(baseExp.getField(field));
}
}
ExpressionOperator anOperator = new ExpressionOperator();
anOperator.setType(ExpressionOperator.FunctionOperator);
Vector v = NonSynchronizedVector.newInstance(args.size());
v.addElement("DISTINCT ");
for (int index = 0; index < args.size(); index++) {
v.add(", ");
}
v.add("");
anOperator.printsAs(v);
anOperator.bePrefix();
anOperator.setNodeClass(ClassConstants.FunctionExpression_Class);
Expression distinctFunction = anOperator.expressionForArguments(firstField, args);
setBaseExpression(distinctFunction);
getChildren().set(0, distinctFunction);
} else if (!outerJoin && (query != null)) {
// case 4: composite PK and DISTINCT, but no
// outer join => previous solution using
// COUNT(*) and EXISTS subquery
// TODO, this doesn't really work for most cases (joins, other things selected, group by),
// this should probably be removed and throw an error,
// or changed to just concat all the pks together.
// If this is a subselect baseExp is yet uncloned,
// and will miss out if moved now from items into a selection criteria.
if (clonedExpressions != null) {
if (clonedExpressions.get(baseExp.getBuilder()) != null) {
baseExp = baseExp.copiedVersionFrom(clonedExpressions);
} else {
baseExp = baseExp.rebuildOn(query.getExpressionBuilder());
}
}
// Now the reference class of the query needs to be reversed.
// See the bug description for an explanation.
ExpressionBuilder countBuilder = baseExp.getBuilder();
ExpressionBuilder outerBuilder ;
ReportQuery subSelect = new ReportQuery(query.getReferenceClass(), countBuilder);
query.getSession().getPlatform().retrieveFirstPrimaryKeyOrOne(subSelect);
// Make sure the outerBuilder does not appear on the left of the subselect.
// Putting a builder on the left is desirable to trigger an optimization.
if (query.getSelectionCriteria() != null) {
outerBuilder = new ExpressionBuilder(newDescriptor.getJavaClass());
query.setExpressionBuilder(outerBuilder);
subSelect.setSelectionCriteria(baseExp.equal(outerBuilder).and(query.getSelectionCriteria()));
} else {
outerBuilder = new ExpressionBuilder(newDescriptor.getJavaClass());
query.setExpressionBuilder(outerBuilder);
subSelect.setSelectionCriteria(baseExp.equal(outerBuilder));
}
query.setNonFetchJoinAttributeExpressions(null);
query.setSelectionCriteria(outerBuilder.exists(subSelect));
setBaseExpression(outerBuilder);
getChildren().set(0, outerBuilder);
query.setReferenceClass(newDescriptor.getJavaClass());
query.changeDescriptor(session);
} else {
// case 4: composite PK, DISTINCT, outer join =>
// not supported, throw exception
DatabaseQuery reportQuery = query;
if (query == null) {
reportQuery = normalizer.getStatement().getQuery();
}
throw QueryException.distinctCountOnOuterJoinedCompositePK(newDescriptor, reportQuery);
}
}
}
}
/**
* INTERNAL:
* Lookup the query key for this item.
* If an aggregate of foreign mapping is found it is traversed.
*/
protected QueryKey getLeafQueryKeyFor(DatabaseQuery query, Expression expression, ClassDescriptor rootDescriptor, AbstractSession session) throws QueryException {
// Check for database field expressions or place holder
if ((expression == null) || (expression.isFieldExpression())) {
return null;
}
if (!(expression.isQueryKeyExpression())) {
return null;
}
QueryKeyExpression qkExpression = (QueryKeyExpression)expression;
Expression baseExpression = qkExpression.getBaseExpression();
ClassDescriptor descriptor = baseExpression.getLeafDescriptor(query, rootDescriptor, session);
return descriptor.getQueryKeyNamed(qkExpression.getName());
}
protected DatabaseMapping getMappingOfFirstPrimaryKey(ClassDescriptor descriptor) {
if (descriptor != null) {
for (Iterator i = descriptor.getMappings().iterator(); i.hasNext(); ) {
DatabaseMapping m = (DatabaseMapping)i.next();
if (m.isPrimaryKeyMapping()) {
return m;
}
}
}
return null;
}
/**
* INTERNAL:
* Lookup the mapping for this item by traversing its expression recursively.
*/
@Override
public DatabaseMapping getLeafMapping(DatabaseQuery query, ClassDescriptor rootDescriptor, AbstractSession session) {
int selector = this.operator.getSelector();
//MAX and MIN functions require mappings for their result value. See JPA 2.1; section 4.8.5
if (this.baseExpression != null && ((selector == ExpressionOperator.Maximum) || (selector == ExpressionOperator.Minimum))) {
return this.baseExpression.getLeafMapping(query, rootDescriptor, session);
}
return super.getLeafMapping(query, rootDescriptor, session);
}
}