[GitHub] [flink] hehuiyuan opened a new pull request #11870: [FLINK-17117][SQL-Blink]Remove useless cast class code for processElement method in SourceCon…

[GitBox]

hehuiyuan opened a new pull request #11870:
URL: https://github.com/apache/flink/pull/11870


   
   
![image](https://user-images.githubusercontent.com/18002496/80060767-f1024080-8561-11ea-9dcb-8925001577c1.png)
   
    
   
   This method `generateOneInputStreamOperator` when OperatorCodeGenerator  
generates SourceConversion:
   
   ```
   @Override
   public void processElement($STREAM_RECORD $ELEMENT) throws Exception {
     $inputTypeTerm $inputTerm = ($inputTypeTerm) 
${converter(s"$ELEMENT.getValue()")};
     ${ctx.reusePerRecordCode()}
     ${ctx.reuseLocalVariableCode()}
     ${if (lazyInputUnboxingCode) "" else ctx.reuseInputUnboxingCode()}
     $processCode
   }
    
   
    $inputTypeTerm $inputTerm = ($inputTypeTerm) 
${converter(s"$ELEMENT.getValue()")};
   ScanUtil calls generateOneInputStreamOperator
   
   
   val generatedOperator = 
OperatorCodeGenerator.generateOneInputStreamOperator[Any, BaseRow](
     ctx,
     convertName,
     processCode,
     outputRowType,
     converter = inputTermConverter)
   
   //inputTermConverter
   val (inputTermConverter, inputRowType) = {
     val convertFunc = CodeGenUtils.genToInternal(ctx, inputType)
     internalInType match {
       case rt: RowType => (convertFunc, rt)
       case _ => ((record: String) => 
s"$GENERIC_ROW.of(${convertFunc(record)})",
           RowType.of(internalInType))
     }
   }
   ```
   There is an useless cast class code:
   ```
   $inputTypeTerm $inputTerm = ($inputTypeTerm) 
${converter(s"$ELEMENT.getValue()")};
   ```
   CodeGenUtils.scala  :  genToInternal
   
   ```
   def genToInternal(ctx: CodeGeneratorContext, t: DataType): String => String 
= {
     val iTerm = boxedTypeTermForType(fromDataTypeToLogicalType(t))
     if (isConverterIdentity(t)) {
       term => s"($iTerm) $term"
     } else {
       val eTerm = boxedTypeTermForExternalType(t)
       val converter = ctx.addReusableObject(
         DataFormatConverters.getConverterForDataType(t),
         "converter")
       term => s"($iTerm) $converter.toInternal(($eTerm) $term)"
     }
   }
   ```
    
   The code `($iTerm) ` and `($inputTypeTerm)` are same.


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