Examples with ArrayExpression com.blazebit.persistence.parser.expression.ArrayExpression used on opensource projects

Example 16 with ArrayExpression

use of com.blazebit.persistence.parser.expression.ArrayExpression in project blaze-persistence by Blazebit.

the class JoinManager method implicitJoin.

@SuppressWarnings("checkstyle:methodlength")
public void implicitJoin(Expression expression, boolean joinAllowed, boolean singularJoinAllowed, boolean objectLeafAllowed, String targetTypeName, ClauseType fromClause, JoinType joinType, JoinNode currentJoinNode, Set<String> currentlyResolvingAliases, boolean fromSubquery, boolean fromSelectAlias, boolean joinRequired, boolean idRemovable, boolean fetch, boolean reuseExisting) {
    PathExpression pathExpression;
    if (expression instanceof PathExpression) {
        pathExpression = (PathExpression) expression;
        List<PathElementExpression> pathElements = pathExpression.getExpressions();
        int pathElementSize = pathElements.size();
        PathElementExpression elementExpr = pathElements.get(pathElements.size() - 1);
        int singleValuedAssociationNameStartIndex = -1;
        int singleValuedAssociationNameEndIndex = -1;
        JoinNode current = null;
        List<String> resultFields = new ArrayList<>();
        JoinResult currentResult;
        JoinNode possibleRoot;
        int startIndex = 0;
        Expression aliasedExpression;
        String alias;
        // If joinable select alias, it is guaranteed to have only a single element
        if (pathExpression.getExpressions().size() == 1 && currentlyResolvingAliases != null && !currentlyResolvingAliases.contains(alias = pathExpression.toString()) && (aliasedExpression = getJoinableSelectAlias(pathExpression, fromClause == ClauseType.SELECT, fromSubquery)) != null) {
            // this check is necessary to prevent infinite recursion in the case of e.g. SELECT name AS name
            if (!fromSelectAlias) {
                try {
                    currentlyResolvingAliases.add(alias);
                    // we have to do this implicit join because we might have to adjust the selectOnly flag in the referenced join nodes
                    implicitJoin(aliasedExpression, joinAllowed, singularJoinAllowed, true, null, fromClause, currentlyResolvingAliases, fromSubquery, true, joinRequired, false);
                } finally {
                    currentlyResolvingAliases.remove(alias);
                }
            }
            return;
        } else if (isExternal(pathExpression)) {
            // try to correlate the path expression and use the correlation alias here instead
            String correlatedAlias = addRoot(null, pathExpression, null, false, true);
            if (correlatedAlias != null) {
                pathElements.clear();
                pathElements.addAll(expressionFactory.createPathExpression(correlatedAlias).getExpressions());
                pathElementSize = pathElements.size();
                elementExpr = pathExpression.getExpressions().get(pathExpression.getExpressions().size() - 1);
            }
            PathElementExpression firstElement = pathElements.get(0);
            if (firstElement instanceof PropertyExpression) {
                AliasInfo aliasInfo = aliasManager.getAliasInfo(((PropertyExpression) firstElement).getProperty());
                if (pathElements.size() == 1) {
                    JoinManager manager;
                    if (aliasInfo.getAliasOwner() == aliasManager) {
                        manager = this;
                    } else {
                        manager = parent;
                    }
                    manager.implicitJoin(pathExpression, true, true, true, targetTypeName, fromClause, currentlyResolvingAliases, true, fromSelectAlias, joinRequired, false);
                    return;
                } else {
                    current = ((JoinAliasInfo) aliasInfo).getJoinNode();
                    startIndex = 1;
                }
            } else if (firstElement instanceof TreatExpression) {
                current = implicitJoinTreatExpression((TreatExpression) firstElement, true, true, fromClause, JoinType.LEFT, null, currentlyResolvingAliases, fromSubquery, fromSelectAlias, true, false, false, true);
                startIndex = 1;
                if (pathElements.size() == 1) {
                    return;
                }
            } else {
                throw new IllegalArgumentException("Unsupported correlation with expression: " + pathExpression);
            }
        }
        // Skip root speculation if this is just a single element path
        if (current == null && pathElements.size() > 1 && (possibleRoot = getRootNode(pathElements.get(0))) != null) {
            startIndex = 1;
            current = possibleRoot;
        }
        if (pathElements.size() > startIndex + 1) {
            currentResult = implicitJoin(current, pathExpression, fromClause, joinType, currentJoinNode, currentlyResolvingAliases, startIndex, pathElements.size() - 1, false, joinAllowed, singularJoinAllowed, idRemovable);
            current = currentResult.baseNode;
            resultFields = currentResult.addToList(resultFields);
            // It can never be a single valued association id reference if the join type is INNER i.e. it is required
            singleValuedAssociationNameStartIndex = currentResult.singleValuedAssociationNameIndex;
            singleValuedAssociationNameEndIndex = currentResult.singleValuedAssociationNameEndIndex;
            if (singleValuedAssociationNameStartIndex != -1) {
                if (!mainQuery.jpaProvider.supportsSingleValuedAssociationIdExpressions()) {
                    if (idRemovable) {
                        // remove the id part only if we come from a predicate
                        elementExpr = null;
                        if (current == null) {
                            // This is the case when we use a join alias like "alias.id"
                            // We need to resolve the base since it might not be the root node
                            AliasInfo a = aliasManager.getAliasInfo(pathElements.get(currentResult.singleValuedAssociationNameIndex).toString());
                            // We know this can only be a join node alias
                            current = ((JoinAliasInfo) a).getJoinNode();
                            resultFields = Collections.emptyList();
                        }
                    } else {
                        // Need a normal join
                        elementExpr = null;
                        resultFields.clear();
                        currentResult = implicitJoin(current, resultFields, pathExpression, fromClause, joinType, currentJoinNode, currentlyResolvingAliases, currentResult.singleValuedAssociationNameIndex, pathElements.size(), false, joinAllowed, singularJoinAllowed, idRemovable);
                        current = currentResult.baseNode;
                        resultFields = currentResult.addToList(resultFields);
                        singleValuedAssociationNameStartIndex = -1;
                    }
                }
            }
        } else {
            // Single element expression like "alias", "relation", "property" or "alias.relation"
            currentResult = implicitJoin(current, pathExpression, fromClause, joinType, currentJoinNode, currentlyResolvingAliases, startIndex, pathElements.size() - 1, false, joinAllowed, singularJoinAllowed, idRemovable);
            current = currentResult.baseNode;
            resultFields = currentResult.addToList(resultFields);
            if (idRemovable) {
                if (current != null) {
                    // If there is a "base node" i.e. a current, the expression has 2 elements
                    if (isSingleValuedAssociationId(current.getNodeType(), elementExpr)) {
                        // We remove the "id" part
                        elementExpr = null;
                        // Treat it like a single valued association id expression
                        singleValuedAssociationNameStartIndex = singleValuedAssociationNameEndIndex = startIndex - 1;
                    }
                } else {
                    // There is no base node, this is a expression with 1 element
                    // Either relative or a direct alias
                    String elementExpressionString;
                    if (elementExpr instanceof ArrayExpression) {
                        elementExpressionString = ((ArrayExpression) elementExpr).getBase().toString();
                    } else {
                        elementExpressionString = elementExpr.toString();
                    }
                    AliasInfo a = aliasManager.getAliasInfo(elementExpressionString);
                    if (a == null) {
                        // If the element expression is an alias, there is nothing to replace
                        current = getRootNodeOrFail("Could not join path [", expression, "] because it did not use an absolute path but multiple root nodes are available!");
                        if (isSingleValuedAssociationId(current.getNodeType(), elementExpr)) {
                            // We replace the "id" part with the alias
                            elementExpr = new PropertyExpression(current.getAlias());
                        }
                    }
                }
            }
        }
        JoinResult result;
        AliasInfo aliasInfo;
        // The case of a simple join alias usage
        if (pathElements.size() == 1 && !fromSelectAlias && currentlyResolvingAliases != null && !currentlyResolvingAliases.contains(alias = elementExpr.toString()) && (aliasInfo = aliasManager.getAliasInfoForBottomLevel(alias)) != null) {
            // No need to assert the resultFields here since they can't appear anyways if we enter this branch
            if (aliasInfo instanceof SelectInfo) {
                if (targetTypeName != null) {
                    throw new IllegalArgumentException("The select alias '" + aliasInfo.getAlias() + "' can not be used for a treat expression!.");
                }
                // We actually allow usage of select aliases in expressions, but JPA doesn't, so we have to resolve them here
                Expression selectExpr = ((SelectInfo) aliasInfo).getExpression();
                if (!(selectExpr instanceof PathExpression)) {
                    throw new RuntimeException("The select expression '" + selectExpr.toString() + "' is not a simple path expression! No idea how to implicit join that.");
                }
                // join the expression behind a select alias once when it is encountered the first time
                if (((PathExpression) selectExpr).getBaseNode() == null) {
                    implicitJoin(selectExpr, joinAllowed, singularJoinAllowed, objectLeafAllowed, null, fromClause, currentlyResolvingAliases, fromSubquery, true, joinRequired, false);
                }
                PathExpression selectPathExpr = (PathExpression) selectExpr;
                PathReference reference = selectPathExpr.getPathReference();
                result = new JoinResult((JoinNode) selectPathExpr.getBaseNode(), Arrays.asList(selectPathExpr.getField()), reference.getType(), -1, -1);
            } else {
                JoinNode pathJoinNode = ((JoinAliasInfo) aliasInfo).getJoinNode();
                if (targetTypeName != null) {
                    // Treated root path
                    ManagedType<?> targetType = metamodel.managedType(targetTypeName);
                    result = new JoinResult(pathJoinNode);
                } else {
                    // Naked join alias usage like in "KEY(joinAlias)"
                    result = new JoinResult(pathJoinNode);
                }
            }
        } else if (pathElements.size() == 1 && elementExpr instanceof QualifiedExpression) {
            QualifiedExpression qualifiedExpression = (QualifiedExpression) elementExpr;
            JoinNode baseNode;
            if (elementExpr instanceof MapKeyExpression) {
                baseNode = joinMapKey((MapKeyExpression) elementExpr, null, fromClause, currentlyResolvingAliases, fromSubquery, fromSelectAlias, true, fetch, true, true);
            } else if (elementExpr instanceof ListIndexExpression) {
                baseNode = joinListIndex((ListIndexExpression) elementExpr, null, fromClause, currentlyResolvingAliases, fromSubquery, fromSelectAlias, true, fetch, true, true);
            } else if (elementExpr instanceof MapEntryExpression) {
                baseNode = joinMapEntry((MapEntryExpression) elementExpr, null, fromClause, currentlyResolvingAliases, fromSubquery, fromSelectAlias, true, fetch, true, true);
            } else if (elementExpr instanceof MapValueExpression) {
                implicitJoin(qualifiedExpression.getPath(), true, singularJoinAllowed, objectLeafAllowed, targetTypeName, fromClause, joinType, null, currentlyResolvingAliases, fromSubquery, fromSelectAlias, joinRequired, false, fetch, false);
                baseNode = (JoinNode) qualifiedExpression.getPath().getBaseNode();
            } else {
                throw new IllegalArgumentException("Unknown qualified expression type: " + elementExpr);
            }
            result = new JoinResult(baseNode);
        } else {
            if (singleValuedAssociationNameStartIndex != -1) {
                String associationName = new PathExpression(pathElements.subList(singleValuedAssociationNameStartIndex, singleValuedAssociationNameEndIndex + 1)).toString();
                AliasInfo singleValuedAssociationRootAliasInfo = null;
                JoinTreeNode treeNode;
                // } else
                if (pathElements.size() == 2) {
                    // If this path is composed of only two elements, the association name could represent an alias
                    singleValuedAssociationRootAliasInfo = aliasManager.getAliasInfoForBottomLevel(associationName);
                }
                if (singleValuedAssociationRootAliasInfo != null) {
                    JoinNode singleValuedAssociationRoot = ((JoinAliasInfo) singleValuedAssociationRootAliasInfo).getJoinNode();
                    if (elementExpr != null) {
                        AttributeHolder attributeHolder = JpaUtils.getAttributeForJoining(metamodel, singleValuedAssociationRoot.getNodeType(), elementExpr, null);
                        Type<?> type = attributeHolder.getAttributeType();
                        result = new JoinResult(singleValuedAssociationRoot, Arrays.asList(elementExpr.toString()), type, -1, -1);
                    } else {
                        result = new JoinResult(singleValuedAssociationRoot);
                    }
                } else {
                    if (current == null) {
                        current = getRootNodeOrFail("Could not join path [", expression, "] because it did not use an absolute path but multiple root nodes are available!");
                    }
                    treeNode = current.getNodes().get(associationName);
                    if (reuseExisting && treeNode != null && treeNode.getDefaultNode() != null) {
                        if (elementExpr != null) {
                            Expression restExpression = new PathExpression(pathElements.subList(singleValuedAssociationNameEndIndex + 1, pathElementSize));
                            String elementString = restExpression.toString();
                            AttributeHolder attributeHolder = JpaUtils.getAttributeForJoining(metamodel, treeNode.getDefaultNode().getNodeType(), restExpression, null);
                            Type<?> type = attributeHolder.getAttributeType();
                            result = new JoinResult(treeNode.getDefaultNode(), Arrays.asList(elementString), type, -1, -1);
                        } else {
                            result = new JoinResult(treeNode.getDefaultNode());
                        }
                    } else {
                        if (elementExpr != null) {
                            Expression restExpression = new PathExpression(pathElements.subList(singleValuedAssociationNameStartIndex, pathElementSize));
                            String elementString = restExpression.toString();
                            AttributeHolder attributeHolder = JpaUtils.getAttributeForJoining(metamodel, currentResult.baseNode.getNodeType(), restExpression, null);
                            Type<?> type = attributeHolder.getAttributeType();
                            result = new JoinResult(currentResult.baseNode, Arrays.asList(elementString), type, -1, -1);
                        } else if (metamodel.getManagedType(ExtendedManagedType.class, current.getManagedType()).getAttributes().get(associationName) != null) {
                            Expression resultExpr = new PathExpression(new PropertyExpression(associationName));
                            AttributeHolder attributeHolder = JpaUtils.getAttributeForJoining(metamodel, current.getNodeType(), resultExpr, null);
                            Type<?> type = attributeHolder.getAttributeType();
                            result = new JoinResult(current, Arrays.asList(associationName), type, -1, -1);
                        } else {
                            result = new JoinResult(current);
                        }
                    }
                }
            } else if (elementExpr instanceof ArrayExpression) {
                // Element collection case
                ArrayExpression arrayExpr = (ArrayExpression) elementExpr;
                if (arrayExpr.getBase() instanceof PropertyExpression) {
                    if (current == null) {
                        current = getRootNodeOrFail("Could not join path [", expression, "] because it did not use an absolute path but multiple root nodes are available!");
                    }
                }
                String joinRelationName = arrayExpr.getBase().toString();
                implicitJoinIndex(arrayExpr);
                // Find a node by a predicate match
                JoinNode matchingNode;
                if (pathElements.size() == 1 && (aliasInfo = aliasManager.getAliasInfoForBottomLevel(joinRelationName)) != null) {
                    // The first node is allowed to be a join alias
                    if (aliasInfo instanceof SelectInfo) {
                        throw new IllegalArgumentException("Illegal reference to the select alias '" + joinRelationName + "'");
                    }
                    current = ((JoinAliasInfo) aliasInfo).getJoinNode();
                    generateAndApplyOnPredicate(current, arrayExpr);
                } else if ((matchingNode = findNode(current, joinRelationName, arrayExpr)) != null) {
                    // We found a join node for the same join relation with the same array expression predicate
                    current = matchingNode;
                } else {
                    String joinAlias = getJoinAlias(arrayExpr);
                    if (arrayExpr.getBase() instanceof PropertyExpression) {
                        resultFields.add(joinRelationName);
                        currentResult = createOrUpdateNode(current, resultFields, targetTypeName, joinAlias, joinType, currentJoinNode, true, false, joinAllowed, singularJoinAllowed);
                    } else {
                        joinAlias = aliasManager.generateJoinAlias(joinAlias);
                        Class<?> entityClass = ((EntityLiteral) arrayExpr.getBase()).getValue();
                        joinOn(null, rootNodes.get(0).getAlias(), entityClass, joinAlias, JoinType.LEFT, false).end();
                        currentResult = new JoinResult(((JoinAliasInfo) aliasManager.getAliasInfo(joinAlias)).getJoinNode());
                    }
                    current = currentResult.baseNode;
                    // TODO: Not sure if necessary
                    if (currentResult.hasField()) {
                        throw new IllegalArgumentException("The join path [" + pathExpression + "] has a non joinable part [" + currentResult.joinFields() + "]");
                    }
                    generateAndApplyOnPredicate(current, arrayExpr);
                }
                result = new JoinResult(current);
            } else if (!pathExpression.isUsedInCollectionFunction()) {
                if (current == null) {
                    current = getRootNodeOrFail("Could not join path [", expression, "] because it did not use an absolute path but multiple root nodes are available!");
                }
                if (resultFields.isEmpty()) {
                    result = implicitJoinSingle(current, elementExpr.toString(), targetTypeName, joinType, currentJoinNode, objectLeafAllowed, joinRequired, joinAllowed, singularJoinAllowed);
                } else {
                    resultFields.add(elementExpr.toString());
                    String attributeName = StringUtils.join(".", resultFields);
                    // Validates and gets the path type
                    getPathType(current.getNodeType(), attributeName, pathExpression);
                    result = implicitJoinSingle(current, attributeName, targetTypeName, joinType, currentJoinNode, objectLeafAllowed, joinRequired, joinAllowed, singularJoinAllowed);
                }
            } else {
                if (current == null) {
                    current = getRootNodeOrFail("Could not join path [", expression, "] because it did not use an absolute path but multiple root nodes are available!");
                }
                if (resultFields.isEmpty()) {
                    String attributeName = elementExpr.toString();
                    Type<?> type = getPathType(current.getNodeType(), attributeName, pathExpression);
                    result = new JoinResult(current, Arrays.asList(attributeName), type, -1, -1);
                } else {
                    resultFields.add(elementExpr.toString());
                    String attributeName = StringUtils.join(".", resultFields);
                    Type<?> type = getPathType(current.getNodeType(), attributeName, pathExpression);
                    result = new JoinResult(current, resultFields, type, -1, -1);
                }
            }
        }
        if (fetch) {
            fetchPath(result.baseNode);
        }
        // Don't forget to update the clause dependencies, but only for normal attribute accesses, that way paginated queries can prevent joins in certain cases
        if (fromClause != null) {
            try {
                result.baseNode.updateClauseDependencies(fromClause, new LinkedHashSet<JoinNode>());
            } catch (IllegalStateException ex) {
                throw new IllegalArgumentException("Implicit join in expression '" + expression + "' introduces cyclic join dependency!", ex);
            }
        }
        if (result.isLazy()) {
            pathExpression.setPathReference(new LazyPathReference(result.baseNode, result.joinFields(), result.type, joinAllowed));
        } else {
            pathExpression.setPathReference(new SimplePathReference(result.baseNode, result.joinFields(), result.type));
        }
    } else if (expression instanceof FunctionExpression) {
        FunctionExpression functionExpression = (FunctionExpression) expression;
        List<Expression> expressions = functionExpression.getExpressions();
        int size = expressions.size();
        for (int i = 0; i < size; i++) {
            implicitJoin(expressions.get(i), joinAllowed, singularJoinAllowed, objectLeafAllowed, null, fromClause, currentlyResolvingAliases, fromSubquery, fromSelectAlias, joinRequired, false);
        }
        List<OrderByItem> withinGroup = functionExpression.getWithinGroup();
        if (withinGroup != null) {
            size = withinGroup.size();
            for (int i = 0; i < size; i++) {
                implicitJoin(withinGroup.get(i).getExpression(), joinAllowed, singularJoinAllowed, objectLeafAllowed, null, fromClause, currentlyResolvingAliases, fromSubquery, fromSelectAlias, joinRequired, false);
            }
        }
    } else if (expression instanceof MapKeyExpression) {
        MapKeyExpression mapKeyExpression = (MapKeyExpression) expression;
        joinMapKey(mapKeyExpression, null, fromClause, currentlyResolvingAliases, fromSubquery, fromSelectAlias, joinRequired, fetch, true, true);
    } else if (expression instanceof QualifiedExpression) {
        implicitJoin(((QualifiedExpression) expression).getPath(), joinAllowed, singularJoinAllowed, objectLeafAllowed, null, fromClause, currentlyResolvingAliases, fromSubquery, fromSelectAlias, joinRequired, false);
    } else if (expression instanceof ArrayExpression || expression instanceof GeneralCaseExpression || expression instanceof TreatExpression) {
        // NOTE: I haven't found a use case for this yet, so I'd like to throw an exception instead of silently not supporting this
        throw new IllegalArgumentException("Unsupported expression for implicit joining found: " + expression);
    } else {
    // Other expressions don't need handling
    }
}

Example 17 with ArrayExpression

use of com.blazebit.persistence.parser.expression.ArrayExpression in project blaze-persistence by Blazebit.

the class JoinVisitor method visit.

private void visit(PathExpression expression, boolean idRemovable) {
    Expression aliasedExpression;
    String alias = expression.getExpressions().size() == 1 ? expression.toString() : null;
    if (alias != null && !currentlyResolvingAliases.contains(alias) && (aliasedExpression = joinManager.getJoinableSelectAlias(expression, fromClause == ClauseType.SELECT, false)) != null) {
        try {
            currentlyResolvingAliases.add(alias);
            aliasedExpression.accept(this);
            // We initialize the aliased PathExpression properly
            if (aliasedExpression instanceof PathExpression) {
                PathExpression aliasedPathExpression = (PathExpression) aliasedExpression;
                if (aliasedPathExpression.isCollectionQualifiedPath()) {
                    expression.setCollectionQualifiedPath(true);
                }
                if (aliasedPathExpression.isUsedInCollectionFunction()) {
                    expression.setUsedInCollectionFunction(true);
                }
            }
        } finally {
            currentlyResolvingAliases.remove(alias);
        }
    } else if (ArrayExpression.ELEMENT_NAME.equals(alias)) {
    // We will not resolve the ArrayExpression.ELEMENT_NAME alias, this must be done in the join manager and is only allowed within an ArrayExpression
    } else {
        if (relativeExpressionPrefix != null) {
            PathExpression leftMost = ExpressionUtils.getLeftMostPathExpression(expression);
            String leftMostAlias;
            if (leftMost.getExpressions().get(0) instanceof ArrayExpression) {
                leftMostAlias = ((ArrayExpression) leftMost.getExpressions().get(0)).getBase().toString();
            } else {
                leftMostAlias = ((PropertyExpression) leftMost.getExpressions().get(0)).getProperty();
            }
            if (ArrayExpression.ELEMENT_NAME.equals(leftMostAlias)) {
                return;
            }
            JoinAliasInfo aliasInfo = (JoinAliasInfo) joinManager.getAliasManager().getAliasInfo(leftMostAlias);
            if (aliasInfo == null) {
                leftMost.getExpressions().add(0, new PropertyExpression(ArrayExpression.ELEMENT_NAME));
                return;
            }
        }
        try {
            // But allow joins if this expression was joined before already to avoid possible side-effects of implicit joining multiple times
            if (expression.getBaseNode() != null) {
            }
            joinManager.implicitJoin(expression, joinAllowed, true, joinWithObjectLeafAllowed, null, fromClause, null, currentJoinNode, currentlyResolvingAliases, false, false, joinRequired, idRemovable, false, reuseExisting);
            if (parentVisitor != null) {
                JoinNode baseNode = (JoinNode) expression.getBaseNode();
                AliasManager aliasOwner = baseNode.getAliasInfo().getAliasOwner();
                if (aliasOwner != joinManager.getAliasManager()) {
                    addParentClauseDependencies(baseNode, aliasOwner);
                }
            }
        } catch (ImplicitJoinNotAllowedException ex) {
            if (conjunctionPathExpressionFindingVisitor == null) {
                conjunctionPathExpressionFindingVisitor = new ConjunctionPathExpressionFindingVisitor();
            }
            correlationPathReplacementVisitor.addPathExpression(expression, ex, conjunctionPathExpressionFindingVisitor.isInConjunction(currentJoinNode.getOnPredicate(), expression));
        }
    }
}

Example 18 with ArrayExpression

use of com.blazebit.persistence.parser.expression.ArrayExpression in project blaze-persistence by Blazebit.

the class JoinManager method isExternal.

private boolean isExternal(PathExpression path) {
    PathElementExpression firstElem = ExpressionUtils.getLeftMostPathExpression(path).getExpressions().get(0);
    String startAlias;
    if (firstElem instanceof ArrayExpression) {
        startAlias = ((ArrayExpression) firstElem).getBase().toString();
    } else if (firstElem instanceof PropertyExpression) {
        startAlias = ((PropertyExpression) firstElem).getProperty();
    } else {
        throw new IllegalArgumentException("Unexpected expression type[" + firstElem.getClass().getSimpleName() + "] in expression: " + path);
    }
    AliasInfo aliasInfo = aliasManager.getAliasInfo(startAlias);
    if (aliasInfo == null) {
        return false;
    }
    if (parent != null && aliasInfo.getAliasOwner() != aliasManager) {
        // an external select alias must not be de-referenced
        if (path.getExpressions().size() > 1) {
            // But if check if the expression really is just an alias reference or the
            if (aliasInfo instanceof SelectInfo) {
                throw new ExternalAliasDereferencingException("Start alias [" + startAlias + "] of path [" + path.toString() + "] is external and must not be dereferenced");
            }
        }
        // the alias is external so we do not have to treat it
        return true;
    } else if (aliasInfo.getAliasOwner() == aliasManager) {
        // the alias originates from the current query builder and is therefore not external
        return false;
    } else {
        throw new IllegalStateException("Alias [" + aliasInfo.getAlias() + "] originates from an unknown query");
    }
}