gudusoft.gsqlparser.dlineage.dataflow.model

Class LineageNodeKey

Object

gudusoft.gsqlparser.dlineage.dataflow.model.LineageNodeKey

public final class LineageNodeKey
extends Object

Structural identity of one lineage graph node — a single column slot inside one table or result set (stage S0 of docs/refactor/identifier_identity_display_separation_plan.md).

Why a name cannot do this job

The lineage walker currently keys nodes by (parent display name, column display name). Duplicate output names are legal SQL: SELECT a AS [x], b AS x on SQL Server has two projection slots, two distinct source dependencies — and one published name. Keying by name therefore conflates them, which is why ResultColumn today lowercases its alias and appends a (1) suffix to break the tie. That workaround mutates a published name to carry identity.

Note what is not the fix: making the name key case-sensitive. The two aliases [x] and x are genuinely the same identifier under SQL Server's rules, so a correct case-sensitive key still merges them. The slots are distinct for a structural reason — they are different positions in the projection — so identity must be structural.

What the ids are

Every analysis-model node (Table, ResultSet, TableColumn, ResultColumn) takes its id from one shared counter, ModelBindingManager.get().TABLE_COLUMN_ID, and none of them exposes a setter, so within one analysis an id is unique across kinds and immutable. A column id alone is therefore already unique; the parent id is carried as well so an index can bucket by container.

No value is treated as "unassigned". The counter starts from Option.getStartId(), which callers may set to zero or a negative number — with startId = -100 the published ids really are negative — so there is no sentinel this class could reject. That is also why the factories take model objects wherever possible: deriving both ids from one object is what prevents a mismatched pair, since no validation can.

Do not build this from the serialized model. The XML/JSON DTOs (dataflow.model.xml.table and friends) carry String ids that are renumbered at output time (see DataFlowAnalyzer's table-merge pass), so they are a presentation concern and are not stable identity.

There are therefore TWO identity domains and this type covers only the first:

• internal analysis model — immutable long ids from one shared counter. This class.
• post-serialization graph — XML String parent_id and column id. Walkers that run on the serialized model, such as RoutineSummaryExtractor, live there and cannot use this type. They need SerializedNodeKey, whose whole point is that it keys on the column ID and never on the column NAME.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o)
long	getColumnId()
long	getParentId()
int	hashCode()
static LineageNodeKey	of(ResultColumn column) Key for a result-set projection slot.
static LineageNodeKey	of(ResultSetRelationRows rows) Key for a RelationRows pseudo-node — whole-row flow through a result set.
static LineageNodeKey	of(TableColumn column) Key for a column of a table endpoint.
static LineageNodeKey	of(TableRelationRows rows) Key for a table's RelationRows pseudo-node.
String	toString()

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

of

public static LineageNodeKey of(ResultColumn column)

Key for a result-set projection slot. The container is read from the column itself, so the pair cannot be mismatched.

Throws:

IllegalArgumentException - if the column is null or has no result set

of

public static LineageNodeKey of(TableColumn column)

Key for a column of a table endpoint. The container is read from the column itself.

Throws:

IllegalArgumentException - if the column is null or has no table

of

public static LineageNodeKey of(ResultSetRelationRows rows)

Key for a RelationRows pseudo-node — whole-row flow through a result set. It is a real graph node with its own id from the same counter, so it needs a node key; the text label "RelationRows" is a different thing and belongs to ModelLabelKey.

of

public static LineageNodeKey of(TableRelationRows rows)

Key for a table's RelationRows pseudo-node.

getParentId

public long getParentId()

getColumnId

public long getColumnId()

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object