spark技术分享CodeGenerator
CodeGenerator is a base class for generators of JVM bytecode for expression evaluation.
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Guava’s LoadingCache with at most 100 pairs of |
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CodeGenerator Contract
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package org.apache.spark.sql.catalyst.expressions.codegen abstract class CodeGenerator[InType, OutType] { def create(in: InType): OutType def canonicalize(in: InType): InType def bind(in: InType, inputSchema: Seq[Attribute]): InType def generate(expressions: InType, inputSchema: Seq[Attribute]): OutType def generate(expressions: InType): OutType } |
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Generates an evaluator for expression(s) that may (optionally) have expression(s) bound to a schema (i.e. a collection of Attribute). Used in:
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create Method
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create(references: Seq[Expression]): UnsafeProjection |
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Caution
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FIXME |
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Note
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Creating CodegenContext — newCodeGenContext Method
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newCodeGenContext(): CodegenContext |
newCodeGenContext simply creates a new CodegenContext.
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