org.apache.spark.sql.catalyst.expressions.codegen.GeneratePredicate.scala Maven / Gradle / Ivy
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* 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
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package org.apache.spark.sql.catalyst.expressions.codegen
import org.apache.spark.sql.catalyst.InternalRow
import org.apache.spark.sql.catalyst.expressions._
/**
* Interface for generated predicate
*/
abstract class Predicate {
def eval(r: InternalRow): Boolean
/**
* Initializes internal states given the current partition index.
* This is used by nondeterministic expressions to set initial states.
* The default implementation does nothing.
*/
def initialize(partitionIndex: Int): Unit = {}
}
/**
* Generates bytecode that evaluates a boolean [[Expression]] on a given input [[InternalRow]].
*/
object GeneratePredicate extends CodeGenerator[Expression, Predicate] {
protected def canonicalize(in: Expression): Expression = ExpressionCanonicalizer.execute(in)
protected def bind(in: Expression, inputSchema: Seq[Attribute]): Expression =
BindReferences.bindReference(in, inputSchema)
protected def create(predicate: Expression): Predicate = {
val ctx = newCodeGenContext()
val eval = predicate.genCode(ctx)
val codeBody = s"""
public SpecificPredicate generate(Object[] references) {
return new SpecificPredicate(references);
}
class SpecificPredicate extends ${classOf[Predicate].getName} {
private final Object[] references;
${ctx.declareMutableStates()}
public SpecificPredicate(Object[] references) {
this.references = references;
${ctx.initMutableStates()}
}
public void initialize(int partitionIndex) {
${ctx.initPartition()}
}
public boolean eval(InternalRow ${ctx.INPUT_ROW}) {
${eval.code}
return !${eval.isNull} && ${eval.value};
}
${ctx.declareAddedFunctions()}
}"""
val code = CodeFormatter.stripOverlappingComments(
new CodeAndComment(codeBody, ctx.getPlaceHolderToComments()))
logDebug(s"Generated predicate '$predicate':\n${CodeFormatter.format(code)}")
val (clazz, _) = CodeGenerator.compile(code)
clazz.generate(ctx.references.toArray).asInstanceOf[Predicate]
}
}