/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.hydromatic.optiq.rules.java;
import net.hydromatic.avatica.ByteString;
import net.hydromatic.linq4j.expressions.*;
import net.hydromatic.optiq.BuiltinMethod;
import net.hydromatic.optiq.DataContext;
import net.hydromatic.optiq.impl.java.JavaTypeFactory;
import net.hydromatic.optiq.runtime.SqlFunctions;
import org.eigenbase.reltype.RelDataType;
import org.eigenbase.reltype.RelDataTypeFactoryImpl;
import org.eigenbase.rex.*;
import org.eigenbase.sql.*;
import org.eigenbase.util.*;
import org.eigenbase.util14.DateTimeUtil;
import java.lang.reflect.*;
import java.math.BigDecimal;
import java.util.*;
import static org.eigenbase.sql.fun.SqlStdOperatorTable.*;
/**
* Translates {@link org.eigenbase.rex.RexNode REX expressions} to
* {@link Expression linq4j expressions}.
*/
public class RexToLixTranslator {
public static final Map<Method, SqlOperator> JAVA_TO_SQL_METHOD_MAP =
Util.<Method, SqlOperator>mapOf(
findMethod(String.class, "toUpperCase"), UPPER,
findMethod(
SqlFunctions.class, "substring", String.class, Integer.TYPE,
Integer.TYPE), SUBSTRING,
findMethod(SqlFunctions.class, "charLength", String.class),
CHARACTER_LENGTH,
findMethod(SqlFunctions.class, "charLength", String.class),
CHAR_LENGTH);
final JavaTypeFactory typeFactory;
final RexBuilder builder;
private final RexProgram program;
private final RexToLixTranslator.InputGetter inputGetter;
private final BlockBuilder list;
private final Map<? extends RexNode, Boolean> exprNullableMap;
private final RexToLixTranslator parent;
private static Method findMethod(
Class<?> clazz, String name, Class... parameterTypes) {
try {
return clazz.getMethod(name, parameterTypes);
} catch (NoSuchMethodException e) {
throw new RuntimeException(e);
}
}
private RexToLixTranslator(
RexProgram program,
JavaTypeFactory typeFactory,
InputGetter inputGetter,
BlockBuilder list) {
this(
program, typeFactory, inputGetter, list,
Collections.<RexNode, Boolean>emptyMap(),
new RexBuilder(typeFactory));
}
private RexToLixTranslator(
RexProgram program,
JavaTypeFactory typeFactory,
InputGetter inputGetter,
BlockBuilder list,
Map<RexNode, Boolean> exprNullableMap,
RexBuilder builder) {
this(program, typeFactory, inputGetter, list, exprNullableMap, builder,
null);
}
private RexToLixTranslator(
RexProgram program,
JavaTypeFactory typeFactory,
InputGetter inputGetter,
BlockBuilder list,
Map<? extends RexNode, Boolean> exprNullableMap,
RexBuilder builder,
RexToLixTranslator parent) {
this.program = program;
this.typeFactory = typeFactory;
this.inputGetter = inputGetter;
this.list = list;
this.exprNullableMap = exprNullableMap;
this.builder = builder;
this.parent = parent;
}
/**
* Translates a {@link RexProgram} to a sequence of expressions and
* declarations.
*
* @param program Program to be translated
* @param typeFactory Type factory
* @param list List of statements, populated with declarations
* @param outputPhysType Output type, or null
* @param inputGetter Generates expressions for inputs
* @return Sequence of expressions, optional condition
*/
public static List<Expression> translateProjects(
RexProgram program,
JavaTypeFactory typeFactory,
BlockBuilder list,
PhysType outputPhysType,
InputGetter inputGetter) {
List<Type> storageTypes = null;
if (outputPhysType != null) {
final RelDataType rowType = outputPhysType.getRowType();
storageTypes = new ArrayList<Type>(rowType.getFieldCount());
for (int i = 0; i < rowType.getFieldCount(); i++) {
storageTypes.add(outputPhysType.getJavaFieldType(i));
}
}
return new RexToLixTranslator(program, typeFactory, inputGetter, list)
.translateList(program.getProjectList(), storageTypes);
}
/** Creates a translator for translating aggregate functions. */
public static RexToLixTranslator forAggregation(JavaTypeFactory typeFactory,
BlockBuilder list, InputGetter inputGetter) {
return new RexToLixTranslator(null, typeFactory, inputGetter, list);
}
Expression translate(RexNode expr) {
final RexImpTable.NullAs nullAs =
RexImpTable.NullAs.of(isNullable(expr));
return translate(expr, nullAs);
}
Expression translate(RexNode expr, RexImpTable.NullAs nullAs) {
return translate(expr, nullAs, null);
}
Expression translate(RexNode expr, Type storageType) {
final RexImpTable.NullAs nullAs =
RexImpTable.NullAs.of(isNullable(expr));
return translate(expr, nullAs, storageType);
}
Expression translate(RexNode expr, RexImpTable.NullAs nullAs,
Type storageType) {
Expression expression = translate0(expr, nullAs, storageType);
assert expression != null;
return list.append("v", expression);
}
Expression translateCast(
RelDataType sourceType,
RelDataType targetType,
Expression operand) {
Expression convert = null;
switch (targetType.getSqlTypeName()) {
case ANY:
convert = operand;
break;
case DATE:
switch (sourceType.getSqlTypeName()) {
case CHAR:
case VARCHAR:
convert =
Expressions.call(BuiltinMethod.STRING_TO_DATE.method, operand);
}
break;
case TIME:
switch (sourceType.getSqlTypeName()) {
case CHAR:
case VARCHAR:
convert =
Expressions.call(BuiltinMethod.STRING_TO_TIME.method, operand);
}
break;
case TIMESTAMP:
switch (sourceType.getSqlTypeName()) {
case CHAR:
case VARCHAR:
convert =
Expressions.call(BuiltinMethod.STRING_TO_TIMESTAMP.method, operand);
}
break;
case BOOLEAN:
switch (sourceType.getSqlTypeName()) {
case CHAR:
case VARCHAR:
convert = Expressions.call(
BuiltinMethod.STRING_TO_BOOLEAN.method,
operand);
}
break;
case CHAR:
case VARCHAR:
final SqlIntervalQualifier interval =
sourceType.getIntervalQualifier();
switch (sourceType.getSqlTypeName()) {
case DATE:
convert = RexImpTable.optimize2(
operand,
Expressions.call(
BuiltinMethod.UNIX_DATE_TO_STRING.method,
operand));
break;
case TIME:
convert = RexImpTable.optimize2(
operand,
Expressions.call(
BuiltinMethod.UNIX_TIME_TO_STRING.method,
operand));
break;
case TIMESTAMP:
convert = RexImpTable.optimize2(
operand,
Expressions.call(
BuiltinMethod.UNIX_TIMESTAMP_TO_STRING.method,
operand));
break;
case INTERVAL_YEAR_MONTH:
convert = RexImpTable.optimize2(
operand,
Expressions.call(
BuiltinMethod.INTERVAL_YEAR_MONTH_TO_STRING.method,
operand,
Expressions.constant(interval.foo())));
break;
case INTERVAL_DAY_TIME:
convert = RexImpTable.optimize2(
operand,
Expressions.call(
BuiltinMethod.INTERVAL_DAY_TIME_TO_STRING.method,
operand,
Expressions.constant(interval.foo()),
Expressions.constant(
interval.getFractionalSecondPrecision(
typeFactory.getTypeSystem()))));
break;
case BOOLEAN:
convert = RexImpTable.optimize2(
operand,
Expressions.call(
BuiltinMethod.BOOLEAN_TO_STRING.method,
operand));
break;
}
}
if (convert == null) {
convert = convert(operand, typeFactory.getJavaClass(targetType));
}
// Going from CHAR(n), trim.
switch (sourceType.getSqlTypeName()) {
case CHAR:
switch (targetType.getSqlTypeName()) {
case VARCHAR:
convert = Expressions.call(
BuiltinMethod.RTRIM.method, convert);
}
break;
case BINARY:
switch (targetType.getSqlTypeName()) {
case VARBINARY:
convert = Expressions.call(
BuiltinMethod.RTRIM.method, convert);
}
break;
}
// Going from anything to CHAR(n) or VARCHAR(n), make sure value is no
// longer than n.
truncate:
switch (targetType.getSqlTypeName()) {
case CHAR:
case VARCHAR:
case BINARY:
case VARBINARY:
final int targetPrecision = targetType.getPrecision();
if (targetPrecision >= 0) {
switch (sourceType.getSqlTypeName()) {
case CHAR:
case VARCHAR:
case BINARY:
case VARBINARY:
// If this is a widening cast, no need to truncate.
final int sourcePrecision = sourceType.getPrecision();
if (sourcePrecision < 0
|| sourcePrecision >= 0
&& sourcePrecision <= targetPrecision) {
break truncate;
}
default:
convert =
Expressions.call(
BuiltinMethod.TRUNCATE.method,
convert,
Expressions.constant(targetPrecision));
}
}
break;
case TIMESTAMP:
int targetScale = targetType.getScale();
if (targetScale == RelDataType.SCALE_NOT_SPECIFIED) {
targetScale = 0;
}
if (targetScale < sourceType.getScale()) {
convert =
Expressions.call(
BuiltinMethod.ROUND_LONG.method,
convert,
Expressions.constant(
(long) Math.pow(10, 3 - targetScale)));
}
break;
}
return convert;
}
/** Translates an expression that is not in the cache.
*
* @param expr Expression
* @param nullAs If false, if expression is definitely not null at
* runtime. Therefore we can optimize. For example, we can cast to int
* using x.intValue().
* @return Translated expression
*/
private Expression translate0(RexNode expr, RexImpTable.NullAs nullAs,
Type storageType) {
if (nullAs == RexImpTable.NullAs.NULL && !expr.getType().isNullable()) {
nullAs = RexImpTable.NullAs.NOT_POSSIBLE;
}
switch (expr.getKind()) {
case INPUT_REF:
final int index = ((RexInputRef) expr).getIndex();
Expression x = inputGetter.field(list, index, storageType);
Expression input = list.append("inp" + index + "_", x); // safe to share
if (nullAs == RexImpTable.NullAs.NOT_POSSIBLE
&& input.type.equals(storageType)) {
// When we asked for not null input that would be stored as box, avoid
// unboxing via nullAs.handle below.
return input;
}
Expression nullHandled = nullAs.handle(input);
// If we get ConstantExpression, just return it (i.e. primitive false)
if (nullHandled instanceof ConstantExpression) {
return nullHandled;
}
// if nullHandled expression is the same as "input",
// then we can just reuse it
if (nullHandled == input) {
return input;
}
// If nullHandled is different, then it might be unsafe to compute
// early (i.e. unbox of null value should not happen _before_ ternary).
// Thus we wrap it into brand-new ParameterExpression,
// and we are guaranteed that ParameterExpression will not be shared
String unboxVarName = "v_unboxed";
if (input instanceof ParameterExpression) {
unboxVarName = ((ParameterExpression) input).name + "_unboxed";
}
ParameterExpression unboxed = Expressions.parameter(nullHandled.getType(),
list.newName(unboxVarName));
list.add(Expressions.declare(Modifier.FINAL, unboxed, nullHandled));
return unboxed;
case LOCAL_REF:
return translate(
deref(expr),
nullAs,
storageType);
case LITERAL:
return translateLiteral(
(RexLiteral) expr,
nullifyType(
expr.getType(),
isNullable(expr)
&& nullAs != RexImpTable.NullAs.NOT_POSSIBLE),
typeFactory,
nullAs);
case DYNAMIC_PARAM:
return translateParameter((RexDynamicParam) expr, nullAs, storageType);
default:
if (expr instanceof RexCall) {
return translateCall((RexCall) expr, nullAs);
}
throw new RuntimeException(
"cannot translate expression " + expr);
}
}
/** Dereferences an expression if it is a
* {@link org.eigenbase.rex.RexLocalRef}. */
public RexNode deref(RexNode expr) {
if (expr instanceof RexLocalRef) {
RexLocalRef ref = (RexLocalRef) expr;
final RexNode e2 = program.getExprList().get(ref.getIndex());
assert ref.getType().equals(e2.getType());
return e2;
} else {
return expr;
}
}
/** Translates a call to an operator or function. */
private Expression translateCall(RexCall call, RexImpTable.NullAs nullAs) {
final SqlOperator operator = call.getOperator();
CallImplementor implementor =
RexImpTable.INSTANCE.get(operator);
if (implementor == null) {
throw new RuntimeException("cannot translate call " + call);
}
return implementor.implement(this, call, nullAs);
}
/** Translates a parameter. */
private Expression translateParameter(RexDynamicParam expr,
RexImpTable.NullAs nullAs, Type storageType) {
if (storageType == null) {
storageType = typeFactory.getJavaClass(expr.getType());
}
return nullAs.handle(
convert(
Expressions.call(
DataContext.ROOT,
BuiltinMethod.DATA_CONTEXT_GET.method,
Expressions.constant("?" + expr.getIndex())),
storageType));
}
/** Translates a literal.
*
* @throws AlwaysNull if literal is null but {@code nullAs} is
* {@link net.hydromatic.optiq.rules.java.RexImpTable.NullAs#NOT_POSSIBLE}.
*/
public static Expression translateLiteral(
RexLiteral literal,
RelDataType type,
JavaTypeFactory typeFactory,
RexImpTable.NullAs nullAs) {
final Comparable value = literal.getValue();
if (value == null) {
switch (nullAs) {
case TRUE:
case IS_NULL:
return RexImpTable.TRUE_EXPR;
case FALSE:
case IS_NOT_NULL:
return RexImpTable.FALSE_EXPR;
case NOT_POSSIBLE:
throw AlwaysNull.INSTANCE;
case NULL:
default:
return RexImpTable.NULL_EXPR;
}
} else {
switch (nullAs) {
case IS_NOT_NULL:
return RexImpTable.TRUE_EXPR;
case IS_NULL:
return RexImpTable.FALSE_EXPR;
}
}
Type javaClass = typeFactory.getJavaClass(type);
final Object value2;
switch (literal.getType().getSqlTypeName()) {
case DECIMAL:
assert javaClass == BigDecimal.class;
return Expressions.new_(BigDecimal.class,
Expressions.constant(value.toString()));
case DATE:
value2 = (int)
(((Calendar) value).getTimeInMillis() / DateTimeUtil.MILLIS_PER_DAY);
javaClass = int.class;
break;
case TIME:
value2 = (int)
(((Calendar) value).getTimeInMillis() % DateTimeUtil.MILLIS_PER_DAY);
javaClass = int.class;
break;
case TIMESTAMP:
value2 = ((Calendar) value).getTimeInMillis();
javaClass = long.class;
break;
case INTERVAL_DAY_TIME:
value2 = ((BigDecimal) value).longValue();
javaClass = long.class;
break;
case INTERVAL_YEAR_MONTH:
value2 = ((BigDecimal) value).intValue();
javaClass = int.class;
break;
case CHAR:
case VARCHAR:
value2 = ((NlsString) value).getValue();
break;
case BINARY:
case VARBINARY:
return Expressions.new_(
ByteString.class,
Expressions.constant(
((ByteString) value).getBytes(),
byte[].class));
case SYMBOL:
value2 = value;
javaClass = value.getClass();
break;
default:
final Primitive primitive = Primitive.ofBoxOr(javaClass);
if (primitive != null && value instanceof Number) {
value2 = primitive.number((Number) value);
} else {
value2 = value;
}
}
return Expressions.constant(value2, javaClass);
}
public List<Expression> translateList(
List<RexNode> operandList,
RexImpTable.NullAs nullAs) {
final List<Expression> list = new ArrayList<Expression>();
for (RexNode rex : operandList) {
list.add(translate(rex, nullAs));
}
return list;
}
/**
* Translates the list of {@code 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 {@link net.hydromatic.optiq.rules.java.RexToLixTranslator#translateList(java.util.List, java.util.List)}
* version.
*
* @param operandList list of RexNodes to translate
*
* @return translated expressions
*/
public List<Expression> translateList(List<? extends RexNode> operandList) {
return translateList(operandList, null);
}
/**
* Translates the list of {@code RexNode}, while optimizing for output
* storage.
* For instance, if the result of translation is going to be stored in
* {@code Object[]}, and the input is {@code Object[]} as well,
* then translator will avoid casting, boxing, etc.
*
* @param operandList list of RexNodes to translate
* @param storageTypes hints of the java classes that will be used
* to store translation results. Use null to use
* default storage type
*
* @return translated expressions
*/
public List<Expression> translateList(List<? extends RexNode> operandList,
List<? extends Type> storageTypes) {
final List<Expression> list = new ArrayList<Expression>(operandList.size());
for (int i = 0; i < operandList.size(); i++) {
RexNode rex = operandList.get(i);
Type desiredType = null;
if (storageTypes != null) {
desiredType = storageTypes.get(i);
}
final Expression translate = translate(rex, desiredType);
list.add(translate);
// desiredType is still a hint, thus we might get any kind of output
// (boxed or not) when hint was provided.
// It is favourable to get the type matching desired type
if (desiredType == null && !isNullable(rex)) {
assert !Primitive.isBox(translate.getType())
: "Not-null boxed primitive should come back as primitive: "
+ rex + ", " + translate.getType();
}
}
return list;
}
public static Expression translateCondition(
RexProgram program,
JavaTypeFactory typeFactory,
BlockBuilder list,
InputGetter inputGetter) {
if (program.getCondition() == null) {
return RexImpTable.TRUE_EXPR;
}
final RexToLixTranslator translator =
new RexToLixTranslator(program, typeFactory, inputGetter, list);
return translator.translate(
program.getCondition(),
RexImpTable.NullAs.FALSE);
}
public static Expression convert(Expression operand, Type toType) {
final Type fromType = operand.getType();
if (fromType.equals(toType)) {
return operand;
}
// E.g. from "Short" to "int".
// Generate "x.intValue()".
final Primitive toPrimitive = Primitive.of(toType);
final Primitive toBox = Primitive.ofBox(toType);
final Primitive fromBox = Primitive.ofBox(fromType);
final Primitive fromPrimitive = Primitive.of(fromType);
final boolean fromNumber = fromType instanceof Class
&& Number.class.isAssignableFrom((Class) fromType);
if (fromType == String.class) {
if (toPrimitive != null) {
switch (toPrimitive) {
case CHAR:
case SHORT:
case INT:
case LONG:
case FLOAT:
case DOUBLE:
// Generate "SqlFunctions.toShort(x)".
return Expressions.call(
SqlFunctions.class,
"to" + SqlFunctions.initcap(toPrimitive.primitiveName),
operand);
default:
// Generate "Short.parseShort(x)".
return Expressions.call(
toPrimitive.boxClass,
"parse" + SqlFunctions.initcap(toPrimitive.primitiveName),
operand);
}
}
if (toBox != null) {
switch (toBox) {
case CHAR:
// Generate "SqlFunctions.toCharBoxed(x)".
return Expressions.call(
SqlFunctions.class,
"to" + SqlFunctions.initcap(toBox.primitiveName) + "Boxed",
operand);
default:
// Generate "Short.valueOf(x)".
return Expressions.call(
toBox.boxClass,
"valueOf",
operand);
}
}
}
if (toPrimitive != null) {
if (fromPrimitive != null) {
// E.g. from "float" to "double"
return Expressions.convert_(
operand, toPrimitive.primitiveClass);
}
if (fromNumber) {
// Generate "x.shortValue()".
return Expressions.unbox(operand, toPrimitive);
} else {
// E.g. from "Object" to "short".
// Generate "SqlFunctions.toShort(x)"
return Expressions.call(
SqlFunctions.class,
"to" + SqlFunctions.initcap(toPrimitive.primitiveName),
operand);
}
} else if (fromNumber && toBox != null) {
// E.g. from "Short" to "Integer"
// Generate "x == null ? null : Integer.valueOf(x.intValue())"
return Expressions.condition(
Expressions.equal(operand, RexImpTable.NULL_EXPR),
RexImpTable.NULL_EXPR,
Expressions.box(
Expressions.unbox(operand, toBox),
toBox));
} else if (fromPrimitive != null && toBox != null) {
// E.g. from "int" to "Long".
// Generate Long.valueOf(x)
// Eliminate primitive casts like Long.valueOf((long) x)
if (operand instanceof UnaryExpression) {
UnaryExpression una = (UnaryExpression) operand;
if (una.nodeType == ExpressionType.Convert
|| Primitive.of(una.getType()) == toBox) {
return Expressions.box(una.expression, toBox);
}
}
return Expressions.box(operand, toBox);
} else if (toType == BigDecimal.class) {
if (fromBox != null) {
// E.g. from "Integer" to "BigDecimal".
// Generate "x == null ? null : new BigDecimal(x.intValue())"
return Expressions.condition(
Expressions.equal(operand, RexImpTable.NULL_EXPR),
RexImpTable.NULL_EXPR,
Expressions.new_(
BigDecimal.class,
Expressions.unbox(operand, fromBox)));
}
if (fromPrimitive != null) {
// E.g. from "int" to "BigDecimal".
// Generate "new BigDecimal(x)"
return Expressions.new_(
BigDecimal.class, operand);
}
// E.g. from "Object" to "BigDecimal".
// Generate "x == null ? null : SqlFunctions.toBigDecimal(x)"
return Expressions.condition(
Expressions.equal(operand, RexImpTable.NULL_EXPR),
RexImpTable.NULL_EXPR,
Expressions.call(
SqlFunctions.class,
"toBigDecimal",
operand));
} else if (toType == String.class) {
if (fromPrimitive != null) {
switch (fromPrimitive) {
case DOUBLE:
case FLOAT:
// E.g. from "double" to "String"
// Generate "SqlFunctions.toString(x)"
return Expressions.call(
SqlFunctions.class,
"toString",
operand);
default:
// E.g. from "int" to "String"
// Generate "Integer.toString(x)"
return Expressions.call(
fromPrimitive.boxClass,
"toString",
operand);
}
} else if (fromType == BigDecimal.class) {
// E.g. from "BigDecimal" to "String"
// Generate "x.toString()"
return Expressions.condition(
Expressions.equal(operand, RexImpTable.NULL_EXPR),
RexImpTable.NULL_EXPR,
Expressions.call(
SqlFunctions.class,
"toString",
operand));
} else {
// E.g. from "BigDecimal" to "String"
// Generate "x == null ? null : x.toString()"
return Expressions.condition(
Expressions.equal(operand, RexImpTable.NULL_EXPR),
RexImpTable.NULL_EXPR,
Expressions.call(
operand,
"toString"));
}
}
return Expressions.convert_(operand, toType);
}
private static <T> T elvis(T t0, T t1) {
return t0 != null ? t0 : t1;
}
private static <T> T elvis(T t0, T t1, T t2) {
return t0 != null ? t0 : t1 != null ? t1 : t2;
}
public Expression translateConstructor(
List<RexNode> operandList, SqlKind kind) {
switch (kind) {
case MAP_VALUE_CONSTRUCTOR:
Expression map =
list.append(
"map",
Expressions.new_(LinkedHashMap.class),
false);
for (int i = 0; i < operandList.size(); i++) {
RexNode key = operandList.get(i++);
RexNode value = operandList.get(i);
list.add(
Expressions.statement(
Expressions.call(
map,
BuiltinMethod.MAP_PUT.method,
Expressions.box(translate(key)),
Expressions.box(translate(value)))));
}
return map;
case ARRAY_VALUE_CONSTRUCTOR:
Expression lyst =
list.append(
"list",
Expressions.new_(ArrayList.class),
false);
for (RexNode value : operandList) {
list.add(
Expressions.statement(
Expressions.call(
lyst,
BuiltinMethod.COLLECTION_ADD.method,
Expressions.box(translate(value)))));
}
return lyst;
default:
throw new AssertionError("unexpected: " + kind);
}
}
/** 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.
*
* <p>For example, {@code WHERE a == b} translates to
* {@code a != null && b != null && a.equals(b)}. When translating the
* 3rd part of the disjunction, we already know a and b are not null.</p>
*
* @param e Expression
* @return Whether expression is nullable in the current translation context
*/
public boolean isNullable(RexNode e) {
if (!e.getType().isNullable()) {
return false;
}
final Boolean b = isKnownNullable(e);
return b == null || b;
}
/**
* Walks parent translator chain and verifies if the expression is nullable.
*
* @param node RexNode to check if it is nullable or not
* @return null when nullability is not known, true or false otherwise
*/
protected Boolean isKnownNullable(RexNode node) {
if (!exprNullableMap.isEmpty()) {
Boolean nullable = exprNullableMap.get(node);
if (nullable != null) {
return nullable;
}
}
return parent == null ? null : parent.isKnownNullable(node);
}
/** Creates a read-only copy of this translator that records that a given
* expression is nullable. */
public RexToLixTranslator setNullable(RexNode e, boolean nullable) {
return setNullable(Collections.singletonMap(e, nullable));
}
/** Creates a read-only copy of this translator that records that a given
* expression is nullable. */
public RexToLixTranslator setNullable(Map<? extends RexNode,
Boolean> nullable) {
if (nullable == null || nullable.isEmpty()) {
return this;
}
return new RexToLixTranslator(
program, typeFactory, inputGetter, list, nullable, builder, this);
}
public RexToLixTranslator setBlock(BlockBuilder block) {
if (block == list) {
return this;
}
return new RexToLixTranslator(
program, typeFactory, inputGetter, block,
Collections.<RexNode, Boolean>emptyMap(), builder, this);
}
public RelDataType nullifyType(RelDataType type, boolean nullable) {
if (!nullable) {
final Primitive primitive = javaPrimitive(type);
if (primitive != null) {
return typeFactory.createJavaType(primitive.primitiveClass);
}
}
return typeFactory.createTypeWithNullability(type, nullable);
}
private Primitive javaPrimitive(RelDataType type) {
if (type instanceof RelDataTypeFactoryImpl.JavaType) {
return Primitive.ofBox(
((RelDataTypeFactoryImpl.JavaType) type).getJavaClass());
}
return null;
}
/** Translates a field of an input to an expression. */
public interface InputGetter {
Expression field(BlockBuilder list, int index, Type storageType);
}
/** Implementation of {@link InputGetter} that calls
* {@link PhysType#fieldReference}. */
public static class InputGetterImpl implements InputGetter {
private List<Pair<Expression, PhysType>> inputs;
public InputGetterImpl(List<Pair<Expression, PhysType>> inputs) {
this.inputs = inputs;
}
public Expression field(BlockBuilder list, int index, Type storageType) {
int offset = 0;
for (Pair<Expression, PhysType> input : inputs) {
final PhysType physType = input.right;
int fieldCount = physType.getRowType().getFieldCount();
if (index >= offset + fieldCount) {
offset += fieldCount;
continue;
}
final Expression left = list.append("current", input.left);
return physType.fieldReference(left, index - offset, storageType);
}
throw new IllegalArgumentException("Unable to find field #" + index);
}
}
/** Thrown in the unusual (but not erroneous) situation where the expression
* we are translating is the null literal but we have already checked that
* it is not null. It is easier to throw (and caller will always handle)
* than to check exhaustively beforehand. */
static class AlwaysNull extends ControlFlowException {
public static final AlwaysNull INSTANCE = new AlwaysNull();
private AlwaysNull() {}
}
}
// End RexToLixTranslator.java