oracle.toplink.essentials.internal.expressions.ObjectExpression Maven / Gradle / Ivy
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package oracle.toplink.essentials.internal.expressions;
import java.util.*;
import oracle.toplink.essentials.exceptions.*;
import oracle.toplink.essentials.querykeys.*;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.internal.helper.*;
import oracle.toplink.essentials.descriptors.ClassDescriptor;
/**
* Superclass for any object type expressions.
*/
public abstract class ObjectExpression extends DataExpression {
transient public ClassDescriptor descriptor;
public Vector derivedExpressions;
/** indicates whether subclasses should be joined */
protected boolean shouldUseOuterJoinForMultitableInheritance;
/** Is this query key to be resolved using an outer join or not. Does not apply to attributes. */
protected boolean shouldUseOuterJoin;
public ObjectExpression() {
this.shouldUseOuterJoin = false;
}
public void addDerivedExpression(Expression addThis) {
if (derivedExpressions == null) {
derivedExpressions = oracle.toplink.essentials.internal.helper.NonSynchronizedVector.newInstance();
}
derivedExpressions.addElement(addThis);
}
/**
* INTERNAL:
* Return the expression to join the main table of this node to any auxiliary tables.
*/
public Expression additionalExpressionCriteria() {
if (getDescriptor() == null) {
return null;
}
Expression criteria = getDescriptor().getQueryManager().getAdditionalJoinExpression();
if(getSession().getPlatform().shouldPrintOuterJoinInWhereClause()) {
if(isUsingOuterJoinForMultitableInheritance()) {
Expression childrenCriteria = getDescriptor().getInheritancePolicy().getChildrenJoinExpression();
childrenCriteria = getBaseExpression().twist(childrenCriteria, this);
childrenCriteria.convertToUseOuterJoin();
if(criteria == null) {
criteria = childrenCriteria;
} else {
criteria = criteria.and(childrenCriteria);
}
}
}
return criteria;
}
/**
* INTERNAL:
* Used in case outer joins should be printed in FROM clause.
* Each of the additional tables mapped to expressions that joins it.
*/
public Map additionalExpressionCriteriaMap() {
if (getDescriptor() == null) {
return null;
}
HashMap tablesJoinExpressions = null;
if(isUsingOuterJoinForMultitableInheritance()) {
Vector tables = getDescriptor().getTables();
tablesJoinExpressions = new HashMap();
List childrenTables = getDescriptor().getInheritancePolicy().getChildrenTables();
for( int i=0; i < childrenTables.size(); i++) {
DatabaseTable table = (DatabaseTable)childrenTables.get(i);
Expression joinExpression = (Expression)getDescriptor().getInheritancePolicy().getChildrenTablesJoinExpressions().get(table);
if (getBaseExpression() != null){
joinExpression = getBaseExpression().twist(joinExpression, this);
} else {
joinExpression = twist(joinExpression, this);
}
tablesJoinExpressions.put(table, joinExpression);
}
}
return tablesJoinExpressions;
}
/**
* PUBLIC:
* Return an expression representing traversal of a 1:many or many:many relationship.
* This allows you to query whether any of the "many" side of the relationship satisfies the remaining criteria.
* Example:
*
* TopLink: employee.anyOf("managedEmployees").get("firstName").equal("Bob")
* Java: no direct equivalent
* SQL: SELECT DISTINCT ... WHERE (t2.MGR_ID = t1.ID) AND (t2.F_NAME = 'Bob')
*
*/
public Expression anyOf(String attributeName) {
QueryKeyExpression queryKey = (QueryKeyExpression)newDerivedExpressionNamed(attributeName);
queryKey.doQueryToManyRelationship();
return queryKey;
}
public QueryKeyExpression derivedExpressionNamed(String attributeName) {
QueryKeyExpression existing = existingDerivedExpressionNamed(attributeName);
if (existing != null) {
return existing;
}
return newDerivedExpressionNamed(attributeName);
}
public Expression derivedManualExpressionNamed(String attributeName, ClassDescriptor aDescriptor) {
Expression existing = existingDerivedExpressionNamed(attributeName);
if (existing != null) {
return existing;
}
return newManualDerivedExpressionNamed(attributeName, aDescriptor);
}
protected void doNotUseOuterJoin() {
shouldUseOuterJoin = false;
}
protected void doUseOuterJoin() {
shouldUseOuterJoin = true;
}
public QueryKeyExpression existingDerivedExpressionNamed(String attributeName) {
if (derivedExpressions == null) {
return null;
}
for (Enumeration e = derivedExpressions.elements(); e.hasMoreElements();) {
QueryKeyExpression exp = (QueryKeyExpression)e.nextElement();
if (exp.getName().equals(attributeName)) {
return exp;
}
}
return null;
}
public Expression get(String attributeName, Vector arguments) {
Expression operatorExpression = super.get(attributeName, arguments);
if (operatorExpression != null) {
return operatorExpression;
}
QueryKeyExpression result = derivedExpressionNamed(attributeName);
result.doNotUseOuterJoin();
return result;
}
public Expression getAllowingNull(String attributeName, Vector arguments) {
ObjectExpression exp = (ObjectExpression)existingDerivedExpressionNamed(attributeName);
// The same (aliased) table cannot participate in a normal join and an outer join.
// To help enforce this, if the node already exists
if (exp != null) {
return exp;
}
exp = (ObjectExpression)derivedExpressionNamed(attributeName);
exp.doUseOuterJoin();
return exp;
}
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().getReferenceDescriptor();
if (getMapping().isVariableOneToOneMapping()) {
throw QueryException.cannotQueryAcrossAVariableOneToOneMapping(getMapping(), descriptor);
}
}
return descriptor;
}
/**
* 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.
*/
public Vector getFields() {
if (getDescriptor() == null) {
return new Vector(1);
}
if ((descriptor.hasInheritance() && ! descriptor.getInheritancePolicy().hasMultipleTableChild()) || (shouldUseOuterJoinForMultitableInheritance())){
// return all fields because we can.
return descriptor.getAllFields();
}else{
return descriptor.getFields();
}
}
/**
* INTERNAL:
* Returns the first field from each of the owned tables, used for
* fine-grained pessimistic locking.
*/
protected Vector getForUpdateOfFields() {
Vector allFields = getFields();
int expected = getTableAliases().size();
Vector firstFields = new Vector(expected);
DatabaseTable lastTable = null;
DatabaseField field = null;
int i = 0;
// The following loop takes O(n*m) time. n=# of fields. m=#tables.
// However, in the m=1 case this will take one pass only.
// Also assuming that fields are generally sorted by table, this will
// take O(n) time.
// An even faster way may be to go getDescriptor().getAdditionalPrimaryKeyFields.
while ((i < allFields.size()) && (firstFields.size() < expected)) {
field = (DatabaseField)allFields.elementAt(i++);
if ((lastTable == null) || !field.getTable().equals(lastTable)) {
lastTable = field.getTable();
int j = 0;
while (j < firstFields.size()) {
if (lastTable.equals(((DatabaseField)firstFields.elementAt(j)).getTable())) {
break;
}
j++;
}
if (j == firstFields.size()) {
firstFields.addElement(field);
}
}
}
return firstFields;
}
public Expression getManualQueryKey(String attributeName, ClassDescriptor aDescriptor) {
return derivedManualExpressionNamed(attributeName, aDescriptor);
}
/**
* INTERNAL:
*/
public Vector getOwnedTables() {
if(isUsingOuterJoinForMultitableInheritance()) {
return getDescriptor().getInheritancePolicy().getAllTables();
} else {
return super.getOwnedTables();
}
}
protected boolean hasDerivedExpressions() {
return derivedExpressions != null;
}
public boolean isObjectExpression() {
return true;
}
/**
* INTERNAL:
* indicates whether additional expressions for multitable inheritance should be used and are available
*/
public boolean isUsingOuterJoinForMultitableInheritance() {
return shouldUseOuterJoinForMultitableInheritance() &&
getDescriptor() != null && getDescriptor().hasInheritance() &&
getDescriptor().getInheritancePolicy().hasMultipleTableChild() &&
getDescriptor().getInheritancePolicy().shouldReadSubclasses();
}
public QueryKeyExpression newDerivedExpressionNamed(String attributeName) {
QueryKeyExpression result = new QueryKeyExpression(attributeName, this);
addDerivedExpression(result);
return result;
}
public Expression newManualDerivedExpressionNamed(String attributeName, ClassDescriptor aDescriptor) {
QueryKeyExpression result = new ManualQueryKeyExpression(attributeName, this, aDescriptor);
addDerivedExpression(result);
return result;
}
/**
* INTERNAL:
* Used for cloning.
*/
protected void postCopyIn(Dictionary alreadyDone) {
super.postCopyIn(alreadyDone);
derivedExpressions = copyCollection(derivedExpressions, alreadyDone);
}
/**
* INTERNAL:
* The method was added to circumvent derivedFields and derivedTables being
* protected.
* @see oracle.toplink.essentials.expressions.ExpressionBuilder#registerIn(Dictionary alreadyDone)
* @bug 2637484 INVALID QUERY KEY EXCEPTION THROWN USING BATCH READS AND PARALLEL EXPRESSIONS
*/
public void postCopyIn(Dictionary alreadyDone, Vector oldDerivedFields, Vector oldDerivedTables) {
if (oldDerivedFields != null) {
if (derivedFields == null) {
derivedFields = copyCollection(oldDerivedFields, alreadyDone);
} else {
derivedFields.addAll(copyCollection(oldDerivedFields, alreadyDone));
}
}
if (oldDerivedTables != null) {
if (derivedTables == null) {
derivedTables = copyCollection(oldDerivedTables, alreadyDone);
} else {
derivedTables.addAll(copyCollection(oldDerivedTables, alreadyDone));
}
}
}
/**
* INTERNAL:
* set the flag indicating whether subclasses should be joined
*/
public void setShouldUseOuterJoinForMultitableInheritance(boolean shouldUseOuterJoinForMultitableInheritance) {
this.shouldUseOuterJoinForMultitableInheritance = shouldUseOuterJoinForMultitableInheritance;
}
public boolean shouldUseOuterJoin() {
return shouldUseOuterJoin;
}
public boolean shouldUseOuterJoinForMultitableInheritance() {
return shouldUseOuterJoinForMultitableInheritance;
}
/**
* INTERNAL:
* writes the first field from each of the owned tables, used for
* fine-grained pessimistic locking.
*/
protected void writeForUpdateOfFields(ExpressionSQLPrinter printer, SQLSelectStatement statement) {
for (Enumeration fieldsEnum = getForUpdateOfFields().elements();
fieldsEnum.hasMoreElements();) {
DatabaseField field = (DatabaseField)fieldsEnum.nextElement();
writeField(printer, field, statement);
}
}
}