org.apache.druid.segment.filter.cnf

Class CalciteCnfHelper

java.lang.Object

org.apache.druid.segment.filter.cnf.CalciteCnfHelper

public class CalciteCnfHelper
extends Object

All functions in this class were basically adopted from Apache Calcite and modified to use them in Druid. See https://github.com/apache/calcite/blob/branch-1.21/core/src/main/java/org/apache/calcite/rex/RexUtil.java#L1615 for original implementation.

Method Summary

Modifier and Type	Method and Description
static Filter	composeConjunction(Iterable<? extends Filter> nodes) As composeConjunction(Iterable, boolean) but never returns null.
static Filter	composeConjunction(Iterable<? extends Filter> nodes, boolean nullOnEmpty) Converts a collection of expressions into an AND.
static Filter	composeDisjunction(Iterable<? extends Filter> nodes) Converts a collection of expressions into an OR.
static Filter	composeDisjunction(Iterable<? extends Filter> nodes, boolean nullOnEmpty) Converts a collection of expressions into an OR, optionally returning null if the list is empty.
static List<Filter>	conjunctions(Filter rexPredicate) Returns a condition decomposed by AND.
static void	decomposeConjunction(Filter rexPredicate, List<Filter> rexList) Decomposes a predicate into a list of expressions that are AND'ed together.
static com.google.common.collect.ImmutableList<Filter>	flattenAnd(Iterable<? extends Filter> nodes) Flattens a list of AND nodes.
static com.google.common.collect.ImmutableList<Filter>	flattenOr(Iterable<? extends Filter> nodes) Flattens a list of OR nodes.
static Filter	pull(Filter rex)

Methods inherited from class java.lang.Object

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

Method Detail

pull

public static Filter pull(Filter rex)

composeConjunction

@Nonnull
public static Filter composeConjunction(Iterable<? extends Filter> nodes)

As composeConjunction(Iterable, boolean) but never returns null.

composeConjunction

public static Filter composeConjunction(Iterable<? extends Filter> nodes,
                                        boolean nullOnEmpty)

Converts a collection of expressions into an AND. If there are zero expressions, returns TRUE. If there is one expression, returns just that expression. If any of the expressions are FALSE, returns FALSE. Removes expressions that always evaluate to TRUE. Returns null only if nullOnEmpty and expression is TRUE.

flattenAnd

public static com.google.common.collect.ImmutableList<Filter> flattenAnd(Iterable<? extends Filter> nodes)

Flattens a list of AND nodes.

Treats null nodes as literal TRUE (i.e. ignores them).

composeDisjunction

@Nonnull
public static Filter composeDisjunction(Iterable<? extends Filter> nodes)

Converts a collection of expressions into an OR. If there are zero expressions, returns FALSE. If there is one expression, returns just that expression. If any of the expressions are TRUE, returns TRUE. Removes expressions that always evaluate to FALSE. Flattens expressions that are ORs.

composeDisjunction

public static Filter composeDisjunction(Iterable<? extends Filter> nodes,
                                        boolean nullOnEmpty)

Converts a collection of expressions into an OR, optionally returning null if the list is empty.

flattenOr

public static com.google.common.collect.ImmutableList<Filter> flattenOr(Iterable<? extends Filter> nodes)

Flattens a list of OR nodes.

conjunctions

public static List<Filter> conjunctions(Filter rexPredicate)

Returns a condition decomposed by AND.

For example, conjunctions(TRUE) returns the empty list; conjunctions(FALSE) returns list {FALSE}.

decomposeConjunction

public static void decomposeConjunction(Filter rexPredicate,
                                        List<Filter> rexList)

Decomposes a predicate into a list of expressions that are AND'ed together.

Parameters:

rexPredicate - predicate to be analyzed

rexList - list of decomposed RexNodes