Module com.darkcollective.relix.ast

Package com.darkcollective.relix.ast

Record Class ProjectionNode

java.lang.Object

java.lang.Record

com.darkcollective.relix.ast.ProjectionNode

Record Components:

attributes - the projected attributes; must not be empty

input - the source relation; must not be null

location - the source location of this node; never null

All Implemented Interfaces:

RelNode

public record ProjectionNode(List<ProjectedAttribute> attributes, RelNode input, SourceLocation location)
extends Record
implements RelNode

Projection (π) — selects a subset of attributes from input, optionally computing new expressions or renaming columns.

Example: π id, price * 1.1 → adjusted (Products)

Constructor Summary

Constructors

Constructor	Description
ProjectionNode(List<ProjectedAttribute> attributes, RelNode input)	Convenience constructor for tests; uses SourceLocation.UNKNOWN.
ProjectionNode(List<ProjectedAttribute> attributes, RelNode input, SourceLocation location)	Creates an instance of a ProjectionNode record class.

Method Summary

Modifier and Type	Method	Description
<R> R	accept(RelNodeVisitor<R> visitor)
List<ProjectedAttribute>	attributes()	Returns the value of the attributes record component.
final boolean	equals(Object o)	Indicates whether some other object is "equal to" this one.
final int	hashCode()	Returns a hash code value for this object.
RelNode	input()	Returns the value of the input record component.
boolean	isColumnPruning()	Whether this projection only drops columns — every attribute is a bare column reference with no alias and no computation, so the output columns are a sub-list of the input's under their own names.
SourceLocation	location()	Returns the value of the location record component.
final String	toString()	Returns a string representation of this record class.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.darkcollective.relix.ast.RelNode

children, mapChildren, materializationMode, prettyPrint

Constructor Details

ProjectionNode

public ProjectionNode(List<ProjectedAttribute> attributes,
 RelNode input,
 SourceLocation location)

Creates an instance of a ProjectionNode record class.

Parameters:

attributes - the value for the attributes record component

input - the value for the input record component

location - the value for the location record component

ProjectionNode

public ProjectionNode(List<ProjectedAttribute> attributes,
 RelNode input)

Convenience constructor for tests; uses SourceLocation.UNKNOWN.

Method Details

isColumnPruning

public boolean isColumnPruning()

Whether this projection only drops columns — every attribute is a bare column reference with no alias and no computation, so the output columns are a sub-list of the input's under their own names.

This is the shape the optimizer's column pruning (PROJ-004) inserts, and it is the one π a pushdown renderer can fold without fixing the select list: because it introduces no new name, an operator above it still refers to real source columns, so a WHERE/GROUP BY/ORDER BY can still be folded on top. A computed or aliased projection cannot make that claim.

Returns:

true when every projected attribute is an unaliased AttributeOperand

accept

public <R> R accept(RelNodeVisitor<R> visitor)

Specified by:

accept in interface RelNode

toString

public final String toString()

Returns a string representation of this record class. The representation contains the name of the class, followed by the name and value of each of the record components.

Specified by:

toString in class Record

Returns:

a string representation of this object

hashCode

public final int hashCode()

Returns a hash code value for this object. The value is derived from the hash code of each of the record components.

Specified by:

hashCode in class Record

Returns:

a hash code value for this object

equals

public final boolean equals(Object o)

Indicates whether some other object is "equal to" this one. The objects are equal if the other object is of the same class and if all the record components are equal. All components in this record class are compared with Objects::equals(Object,Object).

Specified by:

equals in class Record

Parameters:

o - the object with which to compare

Returns:

true if this object is the same as the o argument; false otherwise.

attributes

public List<ProjectedAttribute> attributes()

Returns the value of the attributes record component.

Returns:

the value of the attributes record component

input

public RelNode input()

Returns the value of the input record component.

Returns:

the value of the input record component

location

public SourceLocation location()

Returns the value of the location record component.

Specified by:

location in interface RelNode

Returns:

the value of the location record component