Package org.apache.calcite.plan.hep

Enum HepMatchOrder

java.lang.Object

java.lang.Enum<HepMatchOrder>

org.apache.calcite.plan.hep.HepMatchOrder

All Implemented Interfaces:

Serializable, Comparable<HepMatchOrder>, Constable

public enum HepMatchOrder
extends Enum<HepMatchOrder>

HepMatchOrder specifies the order of graph traversal when looking for rule matches.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
ARBITRARY	Match in arbitrary order.
BOTTOM_UP	Match from leaves up.
DEPTH_FIRST	Match in depth-first order.
TOP_DOWN	Match from root down.

Method Summary

Modifier and Type	Method	Description
static HepMatchOrder	valueOf(String name)	Returns the enum constant of this type with the specified name.
static HepMatchOrder[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

ARBITRARY

public static final HepMatchOrder ARBITRARY

Match in arbitrary order. This is the default because it is efficient, and most rules don't care about order.

BOTTOM_UP

public static final HepMatchOrder BOTTOM_UP

Match from leaves up. A match attempt at a descendant precedes all match attempts at its ancestors.

TOP_DOWN

public static final HepMatchOrder TOP_DOWN

Match from root down. A match attempt at an ancestor always precedes all match attempts at its descendants.

DEPTH_FIRST

public static final HepMatchOrder DEPTH_FIRST

Match in depth-first order.

It avoids applying a rule to the previous RelNode repeatedly after new vertex is generated in one rule application. It can therefore be more efficient than ARBITRARY in cases such as Union with large fan-out.

Method Details

values

public static HepMatchOrder[] values()

Returns an array containing the constants of this enum type, in the order they are declared.

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static HepMatchOrder valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null