Exemplo n.º 1
0
  /**
   * 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);
  }
Exemplo n.º 3
0
  /** 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;
    }
  }