Package dev.frostlake.executor

Class StarArgument

java.lang.Object

dev.frostlake.executor.StarArgument

public final class StarArgument
extends Object

A star written as a function ARGUMENT — COUNT(*), HASH_AGG(t.*), COUNT(* EXCLUDE (a)), COUNT(* ILIKE 'a%') — and what it stands for: the in-scope columns it expands to, so that the call is then an ordinary multi-argument one (live-verified: a qualified star expands to that relation's columns only, an EXCLUDE drops the named columns, an ILIKE keeps the matching ones, and HASH_AGG(t.*) equals HASH_AGG(t.a, t.b, t.c)).

The three refusals are the account's: a qualifier naming no relation in scope is "Object 'X' does not exist or not authorized.", an EXCLUDE naming no column is "column 'X' does not exist", and one naming a column twice is "duplicate column name 'X'". A star that expands to nothing is left to the caller's arity rule, which spells "not enough arguments for function [COUNT()], expected 1, got 0".

The one star this does NOT expand is the bare, unqualified, unmodified * under COUNT, which counts rows; every other shape — a qualifier, an EXCLUDE, an ILIKE, another aggregate — is the written-out list, and a COUNT over that list counts the rows in which every column is non-NULL.

Constructor Summary

Constructors

Constructor	Description
StarArgument(String qualifier, List<String> excludes, String ilike)

Method Summary

Modifier and Type	Method	Description
List<String>	expand(Table table, Map<String,Table> aliasToTable, List<Table> allTables, boolean qualified)	The columns this star stands for, as argument texts.
List<ColumnReferenceExpression>	expandReferences(Table table, Map<String,Table> aliasToTable, List<Table> allTables, boolean qualified)	The columns this star names, as references — see expand(dev.frostlake.metastore.model.Table, java.util.Map<java.lang.String, dev.frostlake.metastore.model.Table>, java.util.List<dev.frostlake.metastore.model.Table>, boolean) — qualified by the relation each belongs to when qualified, which a join needs to tell its sides apart.
String	getQualifier()
boolean	isBare()	Whether this is the bare * — no qualifier and no filter — that COUNT counts rows by.
static StarArgument	of(FunctionCallExpression call)	The star a star-shaped call node carries.
static StarArgument	of(FrostlakeParser.FunctionArgContext arg)	The star of a star function argument, or null when the argument is not a star.
static StarArgument	of(FrostlakeParser.FunctionCallStarExprContext starCall)	The star of a star-call parse tree (COUNT(t.* EXCLUDE (a))).
static StarArgument	ofWindowCall(FrostlakeParser.FunctionCallExprContext call)	The star a window call's sole argument is, or null when the call's argument is not a star.

Methods inherited from class java.lang.Object

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

Constructor Details

StarArgument

public StarArgument(String qualifier,
 List<String> excludes,
 String ilike)

Parameters:

qualifier - the relation a qualified star names, canonical upper-cased, or null

excludes - the EXCLUDE names, canonical upper-cased, in written order (duplicates kept)

ilike - the ILIKE pattern between its quotes, or null

Method Details

of

public static StarArgument of(FrostlakeParser.FunctionCallStarExprContext starCall)

The star of a star-call parse tree (COUNT(t.* EXCLUDE (a))).

of

public static StarArgument of(FrostlakeParser.FunctionArgContext arg)

The star of a star function argument, or null when the argument is not a star.

of

public static StarArgument of(FunctionCallExpression call)

The star a star-shaped call node carries.

ofWindowCall

public static StarArgument ofWindowCall(FrostlakeParser.FunctionCallExprContext call)

The star a window call's sole argument is, or null when the call's argument is not a star.

getQualifier

public String getQualifier()

isBare

public boolean isBare()

Whether this is the bare * — no qualifier and no filter — that COUNT counts rows by.

expand

public List<String> expand(Table table,
 Map<String,Table> aliasToTable,
 List<Table> allTables,
 boolean qualified)

The columns this star stands for, as argument texts.

Parameters:

table - the source relation

aliasToTable - the FROM clause's alias map, or null for a single relation

allTables - every relation in scope in FROM order, or null for a single relation

qualified - whether to spell each column as RELATION.COLUMN (the plain path's texts and every echo) or as the bare column name (a single relation's row)

Returns:

the argument texts, in relation order then column order

expandReferences

public List<ColumnReferenceExpression> expandReferences(Table table,
 Map<String,Table> aliasToTable,
 List<Table> allTables,
 boolean qualified)

The columns this star names, as references — see expand(dev.frostlake.metastore.model.Table, java.util.Map<java.lang.String, dev.frostlake.metastore.model.Table>, java.util.List<dev.frostlake.metastore.model.Table>, boolean) — qualified by the relation each belongs to when qualified, which a join needs to tell its sides apart.