@Override
protected Type visitDereferenceExpression(DereferenceExpression node, AnalysisContext context) {
QualifiedName qualifiedName = DereferenceExpression.getQualifiedName(node);
// If this Dereference looks like column reference, try match it to column first.
if (qualifiedName != null) {
List<Field> matches = tupleDescriptor.resolveFields(qualifiedName);
if (matches.size() > 1) {
throw new SemanticException(AMBIGUOUS_ATTRIBUTE, node, "Column '%s' is ambiguous", node);
}
if (matches.size() == 1) {
Field field = Iterables.getOnlyElement(matches);
int fieldIndex = tupleDescriptor.indexOf(field);
resolvedNames.put(node, fieldIndex);
expressionTypes.put(node, field.getType());
columnReferences.add(node);
return field.getType();
}
}
Type baseType = process(node.getBase(), context);
if (!(baseType instanceof RowType)) {
throw new SemanticException(
SemanticErrorCode.TYPE_MISMATCH,
node.getBase(),
"Expression %s is not of type ROW",
node.getBase());
}
RowType rowType = (RowType) baseType;
Type rowFieldType = null;
for (RowField rowField : rowType.getFields()) {
if (rowField.getName().equals(Optional.of(node.getFieldName()))) {
rowFieldType = rowField.getType();
break;
}
}
if (rowFieldType == null) {
throw createMissingAttributeException(node);
}
expressionTypes.put(node, rowFieldType);
return rowFieldType;
}
private static QualifiedName asQualifiedName(Expression expression) {
QualifiedName name = null;
if (expression instanceof QualifiedNameReference) {
name = ((QualifiedNameReference) expression).getName();
} else if (expression instanceof DereferenceExpression) {
name = DereferenceExpression.getQualifiedName((DereferenceExpression) expression);
}
return name;
}