Package io.prestosql.sql.planner

Class ScopeAware<T extends Node>

java.lang.Object

io.prestosql.sql.planner.ScopeAware<T>

public class ScopeAware<T extends Node>
extends Object

A wrapper for Expressions that can be used as a key in maps and sets.

Expressions are considered equal if they are structurally equal and column references refer to the same logical fields.

For example, given

SELECT t.a, a FROM (VALUES 1) t(a)

"t.a" and "a" are considered equal because they reference the same field of "t"

Limitation: the expressions in the following query are currently not considered equal to each other, even though they refer to the same field from the same table or named query "t". This is because we currently don't assign identity to table references. (TODO: implement this)

SELECT (SELECT t.a FROM t), (SELECT a FROM t)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
T	getNode()
int	hashCode()
static <T extends Node> ScopeAware<T>	scopeAwareKey(T node, Analysis analysis, Scope scope)
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

scopeAwareKey

public static <T extends Node> ScopeAware<T> scopeAwareKey(T node,
                                                           Analysis analysis,
                                                           Scope scope)

getNode

public T getNode()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object