private RelationPlan processAndCoerceIfNecessary(Relation node, Void context) {
Type[] coerceToTypes = analysis.getRelationCoercion(node);
RelationPlan plan = node.accept(this, context);
if (coerceToTypes == null) {
return plan;
}
List<Symbol> oldSymbols = plan.getOutputSymbols();
TupleDescriptor oldDescriptor = plan.getDescriptor().withOnlyVisibleFields();
verify(coerceToTypes.length == oldSymbols.size());
ImmutableList.Builder<Symbol> newSymbols = new ImmutableList.Builder<>();
Field[] newFields = new Field[coerceToTypes.length];
ImmutableMap.Builder<Symbol, Expression> assignments = new ImmutableMap.Builder<>();
for (int i = 0; i < coerceToTypes.length; i++) {
Symbol inputSymbol = oldSymbols.get(i);
Type inputType = symbolAllocator.getTypes().get(inputSymbol);
Type outputType = coerceToTypes[i];
if (outputType != inputType) {
Cast cast =
new Cast(
new QualifiedNameReference(inputSymbol.toQualifiedName()),
outputType.getTypeSignature().toString());
Symbol outputSymbol = symbolAllocator.newSymbol(cast, outputType);
assignments.put(outputSymbol, cast);
newSymbols.add(outputSymbol);
} else {
assignments.put(inputSymbol, new QualifiedNameReference(inputSymbol.toQualifiedName()));
newSymbols.add(inputSymbol);
}
Field oldField = oldDescriptor.getFieldByIndex(i);
newFields[i] =
new Field(
oldField.getRelationAlias(),
oldField.getName(),
coerceToTypes[i],
oldField.isHidden());
}
ProjectNode projectNode =
new ProjectNode(idAllocator.getNextId(), plan.getRoot(), assignments.build());
return new RelationPlan(
projectNode, new TupleDescriptor(newFields), newSymbols.build(), plan.getSampleWeight());
}
