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/*
* 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 org.apache.spark.sql.catalyst.expressions.codegen
import org.apache.spark.sql.catalyst.expressions._
import org.apache.spark.sql.catalyst.expressions.aggregate.NoOp
// MutableProjection is not accessible in Java
abstract class BaseMutableProjection extends MutableProjection
/**
* Generates byte code that produces a [[MutableRow]] object that can update itself based on a new
* input [[InternalRow]] for a fixed set of [[Expression Expressions]].
* It exposes a `target` method, which is used to set the row that will be updated.
* The internal [[MutableRow]] object created internally is used only when `target` is not used.
*/
object GenerateMutableProjection extends CodeGenerator[Seq[Expression], MutableProjection] {
protected def canonicalize(in: Seq[Expression]): Seq[Expression] =
in.map(ExpressionCanonicalizer.execute)
protected def bind(in: Seq[Expression], inputSchema: Seq[Attribute]): Seq[Expression] =
in.map(BindReferences.bindReference(_, inputSchema))
def generate(
expressions: Seq[Expression],
inputSchema: Seq[Attribute],
useSubexprElimination: Boolean): MutableProjection = {
create(canonicalize(bind(expressions, inputSchema)), useSubexprElimination)
}
protected def create(expressions: Seq[Expression]): MutableProjection = {
create(expressions, false)
}
private def create(
expressions: Seq[Expression],
useSubexprElimination: Boolean): MutableProjection = {
val ctx = newCodeGenContext()
val (validExpr, index) = expressions.zipWithIndex.filter {
case (NoOp, _) => false
case _ => true
}.unzip
val exprVals = ctx.generateExpressions(validExpr, useSubexprElimination)
val projectionCodes = exprVals.zip(index).map {
case (ev, i) =>
val e = expressions(i)
if (e.nullable) {
val isNull = s"isNull_$i"
val value = s"value_$i"
ctx.addMutableState("boolean", isNull, s"this.$isNull = true;")
ctx.addMutableState(ctx.javaType(e.dataType), value,
s"this.$value = ${ctx.defaultValue(e.dataType)};")
s"""
${ev.code}
this.$isNull = ${ev.isNull};
this.$value = ${ev.value};
"""
} else {
val value = s"value_$i"
ctx.addMutableState(ctx.javaType(e.dataType), value,
s"this.$value = ${ctx.defaultValue(e.dataType)};")
s"""
${ev.code}
this.$value = ${ev.value};
"""
}
}
// Evaluate all the subexpressions.
val evalSubexpr = ctx.subexprFunctions.mkString("\n")
val updates = validExpr.zip(index).map {
case (e, i) =>
val ev = ExprCode("", s"this.isNull_$i", s"this.value_$i")
ctx.updateColumn("mutableRow", e.dataType, i, ev, e.nullable)
}
val allProjections = ctx.splitExpressions(ctx.INPUT_ROW, projectionCodes)
val allUpdates = ctx.splitExpressions(ctx.INPUT_ROW, updates)
val codeBody = s"""
public java.lang.Object generate(Object[] references) {
return new SpecificMutableProjection(references);
}
class SpecificMutableProjection extends ${classOf[BaseMutableProjection].getName} {
private Object[] references;
private MutableRow mutableRow;
${ctx.declareMutableStates()}
public SpecificMutableProjection(Object[] references) {
this.references = references;
mutableRow = new $genericMutableRowType(${expressions.size});
${ctx.initMutableStates()}
}
${ctx.declareAddedFunctions()}
public ${classOf[BaseMutableProjection].getName} target(MutableRow row) {
mutableRow = row;
return this;
}
/* Provide immutable access to the last projected row. */
public InternalRow currentValue() {
return (InternalRow) mutableRow;
}
public java.lang.Object apply(java.lang.Object _i) {
InternalRow ${ctx.INPUT_ROW} = (InternalRow) _i;
$evalSubexpr
$allProjections
// copy all the results into MutableRow
$allUpdates
return mutableRow;
}
}
"""
val code = CodeFormatter.stripOverlappingComments(
new CodeAndComment(codeBody, ctx.getPlaceHolderToComments()))
logDebug(s"code for ${expressions.mkString(",")}:\n${CodeFormatter.format(code)}")
val c = CodeGenerator.compile(code)
c.generate(ctx.references.toArray).asInstanceOf[MutableProjection]
}
}
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