org.apache.calcite.adapter.enumerable

Class RexToLixTranslator

java.lang.Object

org.apache.calcite.adapter.enumerable.RexToLixTranslator

public class RexToLixTranslator
extends Object

Translates REX expressions to linq4j expressions.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	RexToLixTranslator.InputGetter Translates a field of an input to an expression.
static class	RexToLixTranslator.InputGetterImpl Implementation of RexToLixTranslator.InputGetter that calls PhysType.fieldReference(org.apache.calcite.linq4j.tree.Expression, int).

Field Summary

Fields

Modifier and Type	Field and Description
static Map<Method,SqlOperator>	JAVA_TO_SQL_METHOD_MAP

Method Summary

Methods

Modifier and Type	Method and Description
static Expression	convert(Expression operand, Type toType)
RexNode	deref(RexNode expr) Dereferences an expression if it is a RexLocalRef.
static RexToLixTranslator	forAggregation(JavaTypeFactory typeFactory, BlockBuilder list, RexToLixTranslator.InputGetter inputGetter) Creates a translator for translating aggregate functions.
Expression	getRoot()
protected Boolean	isKnownNullable(RexNode node) Walks parent translator chain and verifies if the expression is nullable.
boolean	isNullable(RexNode e) Returns whether an expression is nullable.
RelDataType	nullifyType(RelDataType type, boolean nullable)
RexToLixTranslator	setBlock(BlockBuilder block)
RexToLixTranslator	setCorrelates(Function1<String,RexToLixTranslator.InputGetter> correlates)
RexToLixTranslator	setNullable(Map<? extends RexNode,Boolean> nullable) Creates a read-only copy of this translator that records that a given expression is nullable.
RexToLixTranslator	setNullable(RexNode e, boolean nullable) Creates a read-only copy of this translator that records that a given expression is nullable.
static Expression	translateCondition(RexProgram program, JavaTypeFactory typeFactory, BlockBuilder list, RexToLixTranslator.InputGetter inputGetter, Function1<String,RexToLixTranslator.InputGetter> correlates)
Expression	translateConstructor(List<RexNode> operandList, SqlKind kind)
List<Expression>	translateList(List<? extends RexNode> operandList) Translates the list of RexNode, using the default output types.
List<Expression>	translateList(List<? extends RexNode> operandList, List<? extends Type> storageTypes) Translates the list of RexNode, while optimizing for output storage.
List<Expression>	translateList(List<RexNode> operandList, RexImpTable.NullAs nullAs)
static Expression	translateLiteral(RexLiteral literal, RelDataType type, JavaTypeFactory typeFactory, RexImpTable.NullAs nullAs) Translates a literal.
static List<Expression>	translateProjects(RexProgram program, JavaTypeFactory typeFactory, BlockBuilder list, PhysType outputPhysType, Expression root, RexToLixTranslator.InputGetter inputGetter, Function1<String,RexToLixTranslator.InputGetter> correlates) Translates a RexProgram to a sequence of expressions and declarations.

Methods inherited from class java.lang.Object

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

Field Detail

JAVA_TO_SQL_METHOD_MAP

public static final Map<Method,SqlOperator> JAVA_TO_SQL_METHOD_MAP

Method Detail

translateProjects

public static List<Expression> translateProjects(RexProgram program,
                                 JavaTypeFactory typeFactory,
                                 BlockBuilder list,
                                 PhysType outputPhysType,
                                 Expression root,
                                 RexToLixTranslator.InputGetter inputGetter,
                                 Function1<String,RexToLixTranslator.InputGetter> correlates)

Translates a RexProgram to a sequence of expressions and declarations.

Parameters:

program - Program to be translated

typeFactory - Type factory

list - List of statements, populated with declarations

outputPhysType - Output type, or null

root - Root expression

inputGetter - Generates expressions for inputs

correlates - Provider of references to the values of correlated variables

Returns:

Sequence of expressions, optional condition

forAggregation

public static RexToLixTranslator forAggregation(JavaTypeFactory typeFactory,
                                BlockBuilder list,
                                RexToLixTranslator.InputGetter inputGetter)

Creates a translator for translating aggregate functions.

deref

public RexNode deref(RexNode expr)

Dereferences an expression if it is a RexLocalRef.

translateLiteral

public static Expression translateLiteral(RexLiteral literal,
                          RelDataType type,
                          JavaTypeFactory typeFactory,
                          RexImpTable.NullAs nullAs)

Translates a literal.

Throws:

AlwaysNull - if literal is null but nullAs is RexImpTable.NullAs.NOT_POSSIBLE.

translateList

public List<Expression> translateList(List<RexNode> operandList,
                             RexImpTable.NullAs nullAs)

translateList

public List<Expression> translateList(List<? extends RexNode> operandList)

Translates the list of RexNode, using the default output types. This might be suboptimal in terms of additional box-unbox when you use the translation later. If you know the java class that will be used to store the results, use translateList(java.util.List, java.util.List) version.

Parameters:

operandList - list of RexNodes to translate

Returns:

translated expressions

translateList

public List<Expression> translateList(List<? extends RexNode> operandList,
                             List<? extends Type> storageTypes)

Translates the list of RexNode, while optimizing for output storage. For instance, if the result of translation is going to be stored in Object[], and the input is Object[] as well, then translator will avoid casting, boxing, etc.

Parameters:

operandList - list of RexNodes to translate

storageTypes - hints of the java classes that will be used to store translation results. Use null to use default storage type

Returns:

translated expressions

translateCondition

public static Expression translateCondition(RexProgram program,
                            JavaTypeFactory typeFactory,
                            BlockBuilder list,
                            RexToLixTranslator.InputGetter inputGetter,
                            Function1<String,RexToLixTranslator.InputGetter> correlates)

convert

public static Expression convert(Expression operand,
                 Type toType)

translateConstructor

public Expression translateConstructor(List<RexNode> operandList,
                              SqlKind kind)

isNullable

public boolean isNullable(RexNode e)

Returns whether an expression is nullable. Even if its type says it is nullable, if we have previously generated a check to make sure that it is not null, we will say so.

For example, WHERE a == b translates to a != null && b != null && a.equals(b). When translating the 3rd part of the disjunction, we already know a and b are not null.

Parameters:

e - Expression

Returns:

Whether expression is nullable in the current translation context

isKnownNullable

protected Boolean isKnownNullable(RexNode node)

Walks parent translator chain and verifies if the expression is nullable.

Parameters:

node - RexNode to check if it is nullable or not

Returns:

null when nullability is not known, true or false otherwise

setNullable

public RexToLixTranslator setNullable(RexNode e,
                             boolean nullable)

Creates a read-only copy of this translator that records that a given expression is nullable.

setNullable

public RexToLixTranslator setNullable(Map<? extends RexNode,Boolean> nullable)

Creates a read-only copy of this translator that records that a given expression is nullable.

setBlock

public RexToLixTranslator setBlock(BlockBuilder block)

setCorrelates

public RexToLixTranslator setCorrelates(Function1<String,RexToLixTranslator.InputGetter> correlates)

nullifyType

public RelDataType nullifyType(RelDataType type,
                      boolean nullable)

getRoot

public Expression getRoot()