/**
* INTERNAL: This method is used when computing the nested queries for batch read mappings. It
* recurses computing the nested mapping queries.
*/
protected void computeNestedQueriesForBatchReadExpressions(Vector batchReadExpressions) {
for (int index = 0; index < batchReadExpressions.size(); index++) {
ObjectExpression objectExpression = (ObjectExpression) batchReadExpressions.get(index);
// Expression may not have been initialized.
ExpressionBuilder builder = objectExpression.getBuilder();
builder.setSession(getSession().getRootSession(null));
builder.setQueryClass(getReferenceClass());
// PERF: Cache join attribute names.
ObjectExpression baseExpression = objectExpression;
while (!baseExpression.getBaseExpression().isExpressionBuilder()) {
baseExpression = (ObjectExpression) baseExpression.getBaseExpression();
}
this.batchReadAttributes.add(baseExpression.getName());
// Ignore nested
if (objectExpression.getBaseExpression().isExpressionBuilder()) {
DatabaseMapping mapping = objectExpression.getMapping();
if ((mapping != null) && mapping.isForeignReferenceMapping()) {
// A nested query must be built to pass to the descriptor that looks like the real query
// execution would.
ReadQuery nestedQuery = ((ForeignReferenceMapping) mapping).prepareNestedBatchQuery(this);
// Register the nested query to be used by the mapping for all the objects.
getBatchReadMappingQueries().put(mapping, nestedQuery);
}
}
}
}
/**
* INTERNAL: Selection criteria is created with source foreign keys and target keys. This criteria
* is then used to read target records from the table.
*/
public void initializeSelectionCriteria(AbstractSession session) {
Expression selectionCriteria = null;
Expression expression;
ExpressionBuilder expBuilder = new ExpressionBuilder();
Iterator sourceKeysEnum = getSourceToTargetQueryKeyNames().keySet().iterator();
while (sourceKeysEnum.hasNext()) {
DatabaseField sourceKey = (DatabaseField) sourceKeysEnum.next();
String target = (String) this.getSourceToTargetQueryKeyNames().get(sourceKey);
expression = expBuilder.getParameter(sourceKey).equal(expBuilder.get(target));
if (selectionCriteria == null) {
selectionCriteria = expression;
} else {
selectionCriteria = expression.and(selectionCriteria);
}
}
setSelectionCriteria(selectionCriteria);
}
/** INTERNAL: Conform the result if specified. */
protected Object conformResult(
Object result,
UnitOfWorkImpl unitOfWork,
AbstractRecord arguments,
boolean buildDirectlyFromRows) {
if (getSelectionCriteria() != null) {
ExpressionBuilder builder = getSelectionCriteria().getBuilder();
builder.setSession(unitOfWork.getRootSession(null));
builder.setQueryClass(getReferenceClass());
}
// If the query is redirected then the collection returned might no longer
// correspond to the original container policy. CR#2342-S.M.
ContainerPolicy cp;
if (getRedirector() != null) {
cp = ContainerPolicy.buildPolicyFor(result.getClass());
} else {
cp = getContainerPolicy();
}
// This code is now a great deal different... For one, registration is done
// as part of conforming. Also, this should only be called if one actually
// is conforming.
// First scan the UnitOfWork for conforming instances.
// This will walk through the entire cache of registered objects.
// Let p be objects from result not in the cache.
// Let c be objects from cache.
// Presently p intersect c = empty set, but later p subset c.
// By checking cache now doesConform will be called p fewer times.
Map indexedInterimResult =
unitOfWork.scanForConformingInstances(
getSelectionCriteria(), getReferenceClass(), arguments, this);
Cursor cursor = null;
// In the case of cursors just conform/register the initially read collection.
if (cp.isCursorPolicy()) {
cursor = (Cursor) result;
cp = ContainerPolicy.buildPolicyFor(ClassConstants.Vector_class);
// In nested UnitOfWork session might have been session of the parent.
cursor.setSession(unitOfWork);
result = cursor.getObjectCollection();
// for later incremental conforming...
cursor.setInitiallyConformingIndex(indexedInterimResult);
cursor.setSelectionCriteriaClone(getSelectionCriteria());
cursor.setTranslationRow(arguments);
}
// Now conform the result from the database.
// Remove any deleted or changed objects that no longer conform.
// Deletes will only work for simple queries, queries with or's or anyof's may not return
// correct results when untriggered indirection is in the model.
Vector fromDatabase = null;
// When building directly from rows, one of the performance benefits
// is that we no longer have to wrap and then unwrap the originals.
// result is just a vector, not a container of wrapped originals.
if (buildDirectlyFromRows) {
Vector rows = (Vector) result;
fromDatabase = new Vector(rows.size());
for (int i = 0; i < rows.size(); i++) {
Object object = rows.elementAt(i);
// null is placed in the row collection for 1-m joining to filter duplicate rows.
if (object != null) {
Object clone =
conformIndividualResult(
object,
unitOfWork,
arguments,
getSelectionCriteria(),
indexedInterimResult,
buildDirectlyFromRows);
if (clone != null) {
fromDatabase.addElement(clone);
}
}
}
} else {
fromDatabase = new Vector(cp.sizeFor(result));
AbstractSession sessionToUse = unitOfWork.getParent();
for (Object iter = cp.iteratorFor(result); cp.hasNext(iter); ) {
Object object = cp.next(iter, sessionToUse);
Object clone =
conformIndividualResult(
object,
unitOfWork,
arguments,
getSelectionCriteria(),
indexedInterimResult,
buildDirectlyFromRows);
if (clone != null) {
fromDatabase.addElement(clone);
}
}
}
// Now add the unwrapped conforming instances into an appropriate container.
// Wrapping is done automatically.
// Make sure a vector of exactly the right size is returned.
Object conformedResult =
cp.containerInstance(indexedInterimResult.size() + fromDatabase.size());
Object eachClone;
for (Iterator enumtr = indexedInterimResult.values().iterator(); enumtr.hasNext(); ) {
eachClone = enumtr.next();
cp.addInto(eachClone, conformedResult, unitOfWork);
}
for (Enumeration enumtr = fromDatabase.elements(); enumtr.hasMoreElements(); ) {
eachClone = enumtr.nextElement();
cp.addInto(eachClone, conformedResult, unitOfWork);
}
if (cursor != null) {
cursor.setObjectCollection((Vector) conformedResult);
// For nested UOW must copy all in object collection to
// initiallyConformingIndex, as some of these could have been from
// the parent UnitOfWork.
if (unitOfWork.isNestedUnitOfWork()) {
for (Enumeration enumtr = cursor.getObjectCollection().elements();
enumtr.hasMoreElements(); ) {
Object clone = enumtr.nextElement();
indexedInterimResult.put(clone, clone);
}
}
return cursor;
} else {
return conformedResult;
}
}