paul-rogers commented on a change in pull request #1429: DRILL-6676: Add Union,
List and Repeated List types to Result Set Loader
URL: https://github.com/apache/drill/pull/1429#discussion_r211113272
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/rowSet/impl/BuildFromSchema.java
##########
@@ -96,4 +132,67 @@ private void expandMap(ObjectWriter colWriter,
ColumnMetadata colSchema) {
buildTuple(colWriter.tuple(), colSchema.mapSchema());
}
}
+
+ private void buildVariant(ParentShim parent, ColumnMetadata colSchema) {
+ final ObjectWriter colWriter = parent.add(colSchema.cloneEmpty());
+ expandVariant(colWriter, colSchema);
+ }
+
+ private void expandVariant(ObjectWriter colWriter, ColumnMetadata colSchema)
{
+ if (colSchema.isArray()) {
+ buildUnion(colWriter.array().variant(), colSchema.variantSchema());
+ } else {
+ buildUnion(colWriter.variant(), colSchema.variantSchema());
+ }
+ }
+
+ public void buildUnion(VariantWriter writer, VariantMetadata schema) {
+ final UnionShim unionShim = new UnionShim(writer);
+ for (final ColumnMetadata member : schema.members()) {
+ buildColumn(unionShim, member);
+ }
+ }
+
+ private void buildSingleList(ParentShim parent, ColumnMetadata colSchema) {
+ final ColumnMetadata seed = colSchema.cloneEmpty();
+ final ColumnMetadata subtype = colSchema.variantSchema().listSubtype();
+ seed.variantSchema().addType(subtype.cloneEmpty());
+ seed.variantSchema().becomeSimple();
+ final ObjectWriter listWriter = parent.add(seed);
+ expandColumn(listWriter, subtype);
+ }
+
+ /**
+ * Expand a repeated list. The list may be multi-dimensional, meaning that
+ * it may have may layers of other repeated lists before we get to the
element
+ * (inner-most) array.
+ *
+ * @param writer tuple writer for the tuple that holds the array
+ * @param colSchema schema definition of the array
+ */
+
+ private void buildRepeatedList(ParentShim parent, ColumnMetadata colSchema) {
+ final ColumnMetadata seed = colSchema.cloneEmpty();
+ final RepeatedListWriter listWriter = (RepeatedListWriter)
parent.add(seed).array();
+ final ColumnMetadata elements = colSchema.childSchema();
+ if (elements != null) {
+ final RepeatedListShim listShim = new RepeatedListShim(listWriter);
+ buildColumn(listShim, elements);
+ }
+ }
+
+ private void expandColumn(ObjectWriter colWriter, ColumnMetadata colSchema) {
+
+ if (colSchema.structureType() == StructureType.MULTI_ARRAY) {
+ assert false;
+ } else if (colSchema.isMap()) {
+ expandMap(colWriter, colSchema);
+ } else if (isSingleList(colSchema)) {
+ assert false;
+ } else if (colSchema.isVariant()) {
+ expandVariant(colWriter, colSchema);
+ } else {
+ // Nothing to expand for primitives
Review comment:
Fixed. Also, revisiting this file after many months, I saw opportunities to
add a few more explanations, so did that also.
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