gudusoft.gsqlparser.ir.semantic

Class OutputColumn

Object

gudusoft.gsqlparser.ir.semantic.OutputColumn

public final class OutputColumn
extends Object

One projected column in the SELECT list. sources is the list of input columns this output depends on; derived distinguishes a direct column reference (e.g. SELECT id) from a computed expression (e.g. SELECT salary*2 AS doubled or SELECT a.x + a.y); aggregate marks the output as the result of an aggregate function call (e.g. COUNT(*), SUM(salary)); windowSpec (slice 13) carries PARTITION BY / OVER ORDER BY refs when the projection is a window function.

Slice 4 introduced derived; slice 6 added aggregate and lifted the empty-sources restriction for aggregates only (e.g. COUNT(*) has no column refs); slice 13 added windowSpec and lifts the empty-sources restriction for window functions (e.g. ROW_NUMBER() OVER (...) has no column refs).

Note on flag propagation: derived, aggregate, and windowSpec are local to a single statement's output. They are not propagated transitively. If a CTE defines total = SUM(salary), that CTE's output has aggregate=true; an outer query that re-projects the CTE's total column (SELECT total FROM cte) is a direct reference and so the outer's output has aggregate=false (and derived=false). Consumers that need a transitive view should walk SemanticProgram.getLineage() and inspect each upstream OutputColumn.

Window-function invariant (slice 13): when windowSpec != null, aggregate MUST be false. Window functions are row-preserving (analytic), not row-collapsing, so the per-output aggregate flag stays false even when the window function is a name that overlaps with an aggregate (e.g. AVG(salary) OVER (...)). The constructor enforces this invariant.

Constructor Summary

Constructors

Constructor and Description
OutputColumn(String name, boolean derived, boolean aggregate, List<ColumnRef> sources) Backwards-compatible constructor delegating to the 5-arg form with windowSpec=null.
OutputColumn(String name, boolean derived, boolean aggregate, List<ColumnRef> sources, WindowSpec windowSpec)
OutputColumn(String name, boolean derived, boolean aggregate, List<ColumnRef> sources, WindowSpec windowSpec, String expressionText, SourceSpan expressionSpan) Full constructor (US-021a).

Method Summary

Modifier and Type	Method and Description
SourceSpan	getExpressionSpan() Source span of the projection expression (US-021a), half-open per SourceSpan.
String	getExpressionText() Original source text of the projection expression this output was built from (US-021a), reconstructed from the parser's token stream so multi-line expressions keep their newlines.
String	getName()
List<ColumnRef>	getSources()
WindowSpec	getWindowSpec() Per-output analytic dependencies (slice 13).
boolean	isAggregate() true when the projection is an aggregate function call (COUNT, SUM, AVG, MIN, MAX, etc.).
boolean	isDerived() true when the projection is an expression rather than a direct column reference.
OutputColumn	withExpression(String expressionText, SourceSpan expressionSpan) Copy of this output column with the projection-expression provenance attached (US-021a).

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OutputColumn

public OutputColumn(String name,
                    boolean derived,
                    boolean aggregate,
                    List<ColumnRef> sources)

Backwards-compatible constructor delegating to the 5-arg form with windowSpec=null. Slice 13 added the 5-arg constructor; this overload preserves source-compatibility for downstream callers that were already using OutputColumn from a published version of the library.

OutputColumn

public OutputColumn(String name,
                    boolean derived,
                    boolean aggregate,
                    List<ColumnRef> sources,
                    WindowSpec windowSpec)

OutputColumn

public OutputColumn(String name,
                    boolean derived,
                    boolean aggregate,
                    List<ColumnRef> sources,
                    WindowSpec windowSpec,
                    String expressionText,
                    SourceSpan expressionSpan)

Full constructor (US-021a). expressionText and expressionSpan are optional projection-expression provenance (see getExpressionText() / getExpressionSpan()); both default to null via the shorter overloads, preserving full behavioural compatibility for every existing caller.

Method Detail

withExpression

public OutputColumn withExpression(String expressionText,
                                   SourceSpan expressionSpan)

Copy of this output column with the projection-expression provenance attached (US-021a). Every other field is preserved verbatim. Returns this when both arguments are null (nothing to attach).

getName

public String getName()

isDerived

public boolean isDerived()

true when the projection is an expression rather than a direct column reference.

isAggregate

public boolean isAggregate()

true when the projection is an aggregate function call (COUNT, SUM, AVG, MIN, MAX, etc.). Always implies isDerived(). Always false when getWindowSpec() is non-null (window functions are row-preserving).

getSources

public List<ColumnRef> getSources()

getWindowSpec

public WindowSpec getWindowSpec()

Per-output analytic dependencies (slice 13). Non-null iff this projection is a window function (e.g. FUNC(arg) OVER (...)); null otherwise.

getExpressionText

public String getExpressionText()

Original source text of the projection expression this output was built from (US-021a), reconstructed from the parser's token stream so multi-line expressions keep their newlines. null when no single projection expression exists for this output — e.g. star expansion (one * produces many outputs), synthetic outputs (predicate-body scaffolding, UPDATE SET shells), or columns built by paths that have not been wired yet. Null-safe: never throws.

getExpressionSpan

public SourceSpan getExpressionSpan()

Source span of the projection expression (US-021a), half-open per SourceSpan. null under the same conditions as getExpressionText(), and additionally when the expression's boundary tokens cannot anchor a span. Null-safe: never throws.