io.druid.sql.calcite.expression

Class Expressions

java.lang.Object

io.druid.sql.calcite.expression.Expressions

public class Expressions
extends Object

A collection of functions for translating from Calcite expressions into Druid objects.

Method Summary

Modifier and Type	Method and Description
static TimestampFloorExprMacro.TimestampFloorExpr	asTimestampFloorExpr(DruidExpression expression, ExprMacroTable macroTable)
static ExprType	exprTypeForValueType(ValueType valueType)
static org.apache.calcite.rex.RexNode	fromFieldAccess(RowSignature rowSignature, org.apache.calcite.rel.core.Project project, int fieldNumber) Translate a field access, possibly through a projection, to an underlying Druid dataSource.
static DruidExpression	toDruidExpression(PlannerContext plannerContext, RowSignature rowSignature, org.apache.calcite.rex.RexNode rexNode) Translate a Calcite RexNode to a Druid expressions.
static List<DruidExpression>	toDruidExpressions(PlannerContext plannerContext, RowSignature rowSignature, List<org.apache.calcite.rex.RexNode> rexNodes) Translate a list of Calcite RexNode to Druid expressions.
static DimFilter	toFilter(PlannerContext plannerContext, RowSignature rowSignature, org.apache.calcite.rex.RexNode expression) Translates "condition" to a Druid filter, or returns null if we cannot translate the condition.
static Granularity	toQueryGranularity(DruidExpression expression, ExprMacroTable macroTable) Converts an expression to a Granularity, if possible.

Methods inherited from class java.lang.Object

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

Method Detail

fromFieldAccess

public static org.apache.calcite.rex.RexNode fromFieldAccess(RowSignature rowSignature,
                                                             org.apache.calcite.rel.core.Project project,
                                                             int fieldNumber)

Translate a field access, possibly through a projection, to an underlying Druid dataSource.

Parameters:

rowSignature - row signature of underlying Druid dataSource

project - projection, or null

fieldNumber - number of the field to access

Returns:

row expression

toDruidExpressions

@Nullable
public static List<DruidExpression> toDruidExpressions(PlannerContext plannerContext,
                                                                 RowSignature rowSignature,
                                                                 List<org.apache.calcite.rex.RexNode> rexNodes)

Translate a list of Calcite RexNode to Druid expressions.

Parameters:

plannerContext - SQL planner context

rowSignature - signature of the rows to be extracted from

rexNodes - list of Calcite expressions meant to be applied on top of the rows

Returns:

list of Druid expressions in the same order as rexNodes, or null if not possible. If a non-null list is returned, all elements will be non-null.

toDruidExpression

@Nullable
public static DruidExpression toDruidExpression(PlannerContext plannerContext,
                                                          RowSignature rowSignature,
                                                          org.apache.calcite.rex.RexNode rexNode)

Translate a Calcite RexNode to a Druid expressions.

Parameters:

plannerContext - SQL planner context

rowSignature - signature of the rows to be extracted from

rexNode - expression meant to be applied on top of the rows

Returns:

rexNode referring to fields in rowOrder, or null if not possible

toFilter

@Nullable
public static DimFilter toFilter(PlannerContext plannerContext,
                                           RowSignature rowSignature,
                                           org.apache.calcite.rex.RexNode expression)

Translates "condition" to a Druid filter, or returns null if we cannot translate the condition.

Parameters:

plannerContext - planner context

rowSignature - row signature of the dataSource to be filtered

expression - Calcite row expression

exprTypeForValueType

public static ExprType exprTypeForValueType(ValueType valueType)

toQueryGranularity

@Nullable
public static Granularity toQueryGranularity(DruidExpression expression,
                                                       ExprMacroTable macroTable)

Converts an expression to a Granularity, if possible. This is possible if, and only if, the expression is a timestamp_floor function on the __time column with literal parameters for period, origin, and timeZone.

Returns:

granularity or null if not possible

asTimestampFloorExpr

@Nullable
public static TimestampFloorExprMacro.TimestampFloorExpr asTimestampFloorExpr(DruidExpression expression,
                                                                                        ExprMacroTable macroTable)