@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 =
            convertToCastDescriptor(
                getSession().getDescriptor(queryKey.getReferenceClass()), getSession());
        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);
      }
      descriptor = convertToCastDescriptor(descriptor, getSession());
    }
    return descriptor;
  }
  /**
   * INTERNAL Return the descriptor which contains this query key, look in the inheritance hierarchy
   * of rootDescriptor for the descriptor.
   */
  public ClassDescriptor convertToCastDescriptor(
      ClassDescriptor rootDescriptor, AbstractSession session) {
    if (castClass == null || rootDescriptor == null || rootDescriptor.getJavaClass() == castClass) {
      return rootDescriptor;
    }

    ClassDescriptor castDescriptor = session.getClassDescriptor(castClass);

    if (castDescriptor == null) {
      throw QueryException.couldNotFindCastDescriptor(castClass, getBaseExpression());
    }
    if (!castDescriptor.hasInheritance()) {
      throw QueryException.castMustUseInheritance(getBaseExpression());
    }
    ClassDescriptor parentDescriptor = castDescriptor.getInheritancePolicy().getParentDescriptor();
    while (parentDescriptor != null) {
      if (parentDescriptor == rootDescriptor) {
        return castDescriptor;
      }
      parentDescriptor = parentDescriptor.getInheritancePolicy().getParentDescriptor();
    }

    ClassDescriptor childDescriptor = rootDescriptor;
    while (childDescriptor != null) {
      if (childDescriptor == castDescriptor) {
        return rootDescriptor;
      }
      childDescriptor = childDescriptor.getInheritancePolicy().getParentDescriptor();
    }

    throw QueryException.couldNotFindCastDescriptor(castClass, getBaseExpression());
  }
  /**
   * INTERNAL Return true if it uses a cast class and query is downcasting. It will look into
   * inheritance hierarchy of the root descriptor.
   */
  public boolean isDowncast(ClassDescriptor rootDescriptor, AbstractSession session) {
    if (castClass == null) {
      return false;
    }

    if (rootDescriptor.getJavaClass() == castClass) {
      return false;
    }

    ClassDescriptor castDescriptor = session.getClassDescriptor(castClass);

    if (castDescriptor == null) {
      throw QueryException.couldNotFindCastDescriptor(castClass, getBaseExpression());
    }
    if (castDescriptor.getInheritancePolicy() == null) {
      throw QueryException.castMustUseInheritance(getBaseExpression());
    }
    ClassDescriptor parentDescriptor = castDescriptor.getInheritancePolicy().getParentDescriptor();
    while (parentDescriptor != null) {
      if (parentDescriptor == rootDescriptor) {
        return true;
      }
      parentDescriptor = parentDescriptor.getInheritancePolicy().getParentDescriptor();
    }

    throw QueryException.couldNotFindCastDescriptor(castClass, getBaseExpression());
  }
 public DatabaseMapping getMappingFromQueryKey() {
   QueryKey queryKey = getQueryKeyOrNull();
   if ((queryKey == null) || (!(queryKey instanceof DirectQueryKey))) {
     throw QueryException.cannotConformExpression();
   }
   mapping =
       queryKey
           .getDescriptor()
           .getObjectBuilder()
           .getMappingForField(((DirectQueryKey) queryKey).getField());
   if (mapping == null) {
     throw QueryException.cannotConformExpression();
   }
   return mapping;
 }
 /** INTERNAL: Return if the expression is for a direct mapped attribute. */
 public boolean isAttribute() {
   if (isAttributeExpression == null) {
     if (getSession() == null) {
       // We can't tell, so say no.
       return false;
     }
     QueryKey queryKey = getQueryKeyOrNull();
     if (queryKey != null) {
       isAttributeExpression = Boolean.valueOf(queryKey.isDirectQueryKey());
     } else {
       DatabaseMapping mapping = getMapping();
       if (mapping != null) {
         if (mapping.isVariableOneToOneMapping()) {
           throw QueryException.cannotQueryAcrossAVariableOneToOneMapping(
               mapping, mapping.getDescriptor());
         } else {
           isAttributeExpression = Boolean.valueOf(mapping.isDirectToFieldMapping());
         }
       } else {
         isAttributeExpression = Boolean.FALSE;
       }
     }
   }
   return isAttributeExpression.booleanValue();
 }
 /**
  * PUBLIC: Configure the query to use an instance of the specified container class to hold the
  * result objects. The key used to index the value in the Map is the value returned by a call to
  * the specified zero-argument method. The method must be implemented by the class (or a
  * superclass) of the value to be inserted into the Map.
  *
  * <p>jdk1.2.x: The container class must implement (directly or indirectly) the Map interface.
  *
  * <p>jdk1.1.x: The container class must be a subclass of Hashtable.
  *
  * <p>The referenceClass must set before calling this method.
  */
 public void useMapClass(Class concreteClass, String methodName) {
   // the reference class has to be specified before coming here
   if (getReferenceClass() == null) {
     throw QueryException.referenceClassMissing(this);
   }
   ContainerPolicy policy = ContainerPolicy.buildPolicyFor(concreteClass);
   policy.setKeyName(methodName, getReferenceClass().getName());
   setContainerPolicy(policy);
 }
  /** Do any required validation for this node. Throw an exception if it's incorrect. */
  public void validateNode() {
    if ((getQueryKeyOrNull() == null) && (getMapping() == null)) {
      throw QueryException.invalidQueryKeyInExpression(getName());
    }

    QueryKey queryKey = getQueryKeyOrNull();
    DatabaseMapping mapping = getMapping();

    Object theOneThatsNotNull = null;
    boolean qkIsToMany = false;
    if (queryKey != null) {
      theOneThatsNotNull = queryKey;
      qkIsToMany = queryKey.isManyToManyQueryKey() || queryKey.isOneToManyQueryKey();
    }
    boolean isNestedMapping = false;
    if (mapping != null) {
      // Bug 2847621 - Add Aggregate Collection to the list of valid items for outer join.
      if (shouldUseOuterJoin
          && (!(mapping.isOneToOneMapping()
              || mapping.isOneToManyMapping()
              || mapping.isManyToManyMapping()
              || mapping.isAggregateCollectionMapping()
              || mapping.isDirectCollectionMapping()))) {
        throw QueryException.outerJoinIsOnlyValidForOneToOneMappings(getMapping());
      }
      qkIsToMany = mapping.isCollectionMapping();
      if (index != null) {
        if (qkIsToMany) {
          CollectionMapping collectionMapping = (CollectionMapping) getMapping();
          if (collectionMapping.getListOrderField() != null) {
            index.setField(collectionMapping.getListOrderField());
            if (collectionMapping.shouldUseListOrderFieldTableExpression()) {
              Expression newBase = getTable(collectionMapping.getListOrderField().getTable());
              index.setBaseExpression(newBase);
            } else {
              addDerivedField(index);
            }
          } else {
            throw QueryException.indexRequiresCollectionMappingWithListOrderField(
                this, collectionMapping);
          }
        } else {
          throw QueryException.indexRequiresCollectionMappingWithListOrderField(this, mapping);
        }
      }
      isNestedMapping = mapping.isNestedTableMapping();
      theOneThatsNotNull = mapping;
    } else {
      if (index != null) {
        throw QueryException.indexRequiresCollectionMappingWithListOrderField(this, null);
      }
    }
    if ((!shouldQueryToManyRelationship()) && qkIsToMany && (!isNestedMapping)) {
      throw QueryException.invalidUseOfToManyQueryKeyInExpression(theOneThatsNotNull);
    }
    if (shouldQueryToManyRelationship() && !qkIsToMany) {
      throw QueryException.invalidUseOfAnyOfInExpression(theOneThatsNotNull);
    }
  }
 /**
  * INTERNAL: Execute the query. If there are cached results return those. This must override the
  * super to support result caching.
  *
  * @param session - the session in which the receiver will be executed.
  * @return An object or vector, the result of executing the query.
  * @exception DatabaseException - an error has occurred on the database
  */
 public Object execute(AbstractSession session, AbstractRecord row) throws DatabaseException {
   if (shouldCacheQueryResults()) {
     if (getContainerPolicy().overridesRead()) {
       throw QueryException.cannotCacheCursorResultsOnQuery(this);
     }
     if (shouldConformResultsInUnitOfWork()) {
       throw QueryException.cannotConformAndCacheQueryResults(this);
     }
     if (isPrepared()) { // only prepared queries can have cached results.
       Object queryResults = getQueryResults(session, row, true);
       if (queryResults != null) {
         if (QueryMonitor.shouldMonitor()) {
           QueryMonitor.incrementReadAllHits(this);
         }
         // bug6138532 - check for "cached no results" (InvalidObject singleton) in query
         // results, and return an empty container instance as configured
         if (queryResults == InvalidObject.instance) {
           return getContainerPolicy().containerInstance(0);
         }
         Collection results = (Collection) queryResults;
         if (session.isUnitOfWork()) {
           ContainerPolicy policy = getContainerPolicy();
           Object resultCollection = policy.containerInstance(results.size());
           Object iterator = policy.iteratorFor(results);
           while (policy.hasNext(iterator)) {
             Object result =
                 ((UnitOfWorkImpl) session)
                     .registerExistingObject(policy.next(iterator, session), this.descriptor);
             policy.addInto(result, resultCollection, session);
           }
           return resultCollection;
         }
         return results;
       }
     }
   }
   if (QueryMonitor.shouldMonitor()) {
     QueryMonitor.incrementReadAllMisses(this);
   }
   return super.execute(session, row);
 }
  public QueryKey getQueryKeyOrNull() {
    if (!hasQueryKey) {
      return null;
    }

    // Oct 19, 2000 JED
    // Added try/catch. This was throwing a NPE in the following case
    // expresssionBuilder.get("firstName").get("bob")
    // moved by Gordon Yorke to cover validate and normalize
    if (getContainingDescriptor() == null) {
      throw QueryException.invalidQueryKeyInExpression(getName());
    }
    if (queryKey == null) {
      queryKey = getContainingDescriptor().getQueryKeyNamed(getName());
      if (queryKey == null) {
        hasQueryKey = false;
      }
    }
    return queryKey;
  }
  /**
   * INTERNAL This method iterates through a collection and gets the values from the objects to
   * conform in an in-memory query. Creation date: (1/19/01 1:18:27 PM)
   */
  public Object valuesFromCollection(
      Object object, AbstractSession session, int valueHolderPolicy, boolean isObjectUnregistered) {
    // in case the mapping is null - this can happen if a query key is being used
    // In this case, check for the query key and find it's mapping.
    boolean readMappingFromQueryKey = false;
    if (getMapping() == null) {
      getMappingFromQueryKey();
      readMappingFromQueryKey = true;
    }

    // For bug 2780817 get the mapping directly from the object.  In EJB 2.0
    // inheritance, each child must override mappings defined in an abstract
    // class with its own.
    DatabaseMapping mapping = this.mapping;
    ClassDescriptor descriptor = mapping.getDescriptor();
    if (descriptor.hasInheritance() && (descriptor.getJavaClass() != object.getClass())) {
      mapping =
          session
              .getDescriptor(object.getClass())
              .getObjectBuilder()
              .getMappingForAttributeName(getName());
      descriptor = mapping.getDescriptor();
    }

    // fetch group support
    if (descriptor.hasFetchGroupManager()) {
      FetchGroupManager fetchGroupManager = descriptor.getFetchGroupManager();
      if (fetchGroupManager.isPartialObject(object)
          && (!fetchGroupManager.isAttributeFetched(object, mapping.getAttributeName()))) {
        // the conforming attribute is not fetched, simply throw exception
        throw QueryException.cannotConformUnfetchedAttribute(mapping.getAttributeName());
      }
    }

    if (mapping.isDirectToFieldMapping()) {
      return ((AbstractDirectMapping) mapping).valueFromObject(object, mapping.getField(), session);
    } else if (mapping.isForeignReferenceMapping()) {
      // CR 3677 integration of a ValueHolderPolicy
      Object valueFromMapping = mapping.getAttributeValueFromObject(object);
      if (!((ForeignReferenceMapping) mapping)
          .getIndirectionPolicy()
          .objectIsInstantiated(valueFromMapping)) {
        if (valueHolderPolicy != InMemoryQueryIndirectionPolicy.SHOULD_TRIGGER_INDIRECTION) {
          // If the client wishes us to trigger the indirection then we should do so,
          // Other wise throw the exception
          throw QueryException
              .mustInstantiateValueholders(); // you should instantiate the valueholder for this to
                                              // work
        }

        // maybe we should throw this exception from the start, to save time
      }
      Object valueToIterate = mapping.getRealAttributeValueFromObject(object, session);
      UnitOfWorkImpl uow = isObjectUnregistered ? (UnitOfWorkImpl) session : null;

      // First check that object in fact is unregistered.
      // toDo: ?? Why is this commented out? Why are we supporting the unregistered thing at all?
      // Does not seem to be any public API for this, nor every used internally?
      // if (isObjectUnregistered) {
      //	isObjectUnregistered = !uow.getCloneMapping().containsKey(object);
      // }
      if (mapping.isCollectionMapping() && (valueToIterate != null)) {
        // For bug 2766379 must use the correct version of vectorFor to
        // unwrap the result same time.
        valueToIterate = mapping.getContainerPolicy().vectorFor(valueToIterate, session);

        // toDo: If the value is empty, need to support correct inner/outer join filtering
        // symantics.
        // For CR 2612601, try to partially replace the result with already
        // registered objects.
        if (isObjectUnregistered && (uow.getCloneMapping().get(object) == null)) {
          Vector objectValues = (Vector) valueToIterate;
          for (int i = 0; i < objectValues.size(); i++) {
            Object original = objectValues.elementAt(i);
            Object clone =
                uow.getIdentityMapAccessorInstance()
                    .getIdentityMapManager()
                    .getFromIdentityMap(original);
            if (clone != null) {
              objectValues.setElementAt(clone, i);
            }
          }
        }

        // For CR 2612601, conforming without registering, a query could be
        // bob.get("address").get("city").equal("Ottawa"); where the address
        // has been registered and modified in the UOW, but bob has not.  Thus
        // even though bob does not point to the modified address now, it will
        // as soon as it is registered, so should point to it here.
      } else if (isObjectUnregistered && (uow.getCloneMapping().get(object) == null)) {
        Object clone =
            uow.getIdentityMapAccessorInstance()
                .getIdentityMapManager()
                .getFromIdentityMap(valueToIterate);
        if (clone != null) {
          valueToIterate = clone;
        }
      }
      return valueToIterate;
    } else if (mapping.isAggregateMapping()) {
      Object aggregateValue = mapping.getAttributeValueFromObject(object);
      // Bug 3995468 - if this query key is to a mapping in an aggregate object, get the object from
      // actual mapping rather than the aggregate mapping
      while (readMappingFromQueryKey
          && mapping.isAggregateObjectMapping()
          && !((AggregateObjectMapping) mapping)
              .getReferenceClass()
              .equals(queryKey.getDescriptor().getJavaClass())) {
        mapping =
            mapping
                .getReferenceDescriptor()
                .getObjectBuilder()
                .getMappingForField(((DirectQueryKey) queryKey).getField());
        aggregateValue = mapping.getRealAttributeValueFromObject(aggregateValue, session);
      }
      return aggregateValue;
    } else {
      throw QueryException.cannotConformExpression();
    }
  }
 /**
  * PUBLIC: Specify the foreign-reference mapped attribute to be optimized in this query. The query
  * will execute normally, however when any of the batched parts is accessed, the parts will all be
  * read in a single query, this allows all of the data required for the parts to be read in a
  * single query instead of (n) queries. This should be used when the application knows that it
  * requires the part for all of the objects being read. This can be used for one-to-one,
  * one-to-many, many-to-many and direct collection mappings.
  *
  * <p>The use of the expression allows for nested batch reading to be expressed.
  *
  * <p>Example: query.addBatchReadAttribute("phoneNumbers")
  *
  * @see #addBatchReadAttribute(Expression)
  * @see ObjectLevelReadQuery#addJoinedAttribute(String)
  */
 public void addBatchReadAttribute(String attributeName) {
   if (!getQueryMechanism().isExpressionQueryMechanism()) {
     throw QueryException.batchReadingNotSupported(this);
   }
   getBatchReadAttributeExpressions().add(getExpressionBuilder().get(attributeName));
 }
 /**
  * INTERNAL: Possible for future development, not currently supported.
  *
  * <p>Retrieve the value through using batch reading. This executes a single query to read the
  * target for all of the objects and stores the result of the batch query in the original query to
  * allow the other objects to share the results.
  */
 @Override
 protected Object batchedValueFromRow(AbstractRecord row, ReadAllQuery query) {
   throw QueryException.batchReadingNotSupported(this, query);
 }