Package org.apache.flink.table.codesplit

Class BlockStatementGrouper

java.lang.Object

org.apache.flink.table.codesplit.BlockStatementGrouper

@Internal
public class BlockStatementGrouper
extends Object

Groups end extract single line statements such as operations on fields/local variables, IF and WHILE statements and extract new method for each group making them smaller.

BlockStatementGrouper does not recognize if statement operates on local of class member variable. Because of that, code must be preprocessed by DeclarationRewriter which converts all local variables extracted as to member variables.

Before

 {
     a[0] += b[1];
     b[1] += a[1];
     while (counter > 0) {
         myFun_whileBody0_0(a, b);
         if (a[0] > 0) {
             myFun_whileBody0_0_ifBody0(a, b);
         } else {
             myFun_whileBody0_0_ifBody1(a, b);
         }
         counter--;
     }

     a[2] += b[2];
     b[3] += a[3];
 }

 

After

 {
     myFun_rewriteGroup4(a, b);
     myFun_rewriteGroup5(a, b);
 }
 

Where bodies of extracted "methods" are:

     myFun_rewriteGroup4 ->
         a[0] += b[1];
         b[1] += a[1];
         while (counter > 0) {
             myFun_rewriteGroup0_1_rewriteGroup3(a, b);
             counter--;
         }
 

     myFun_rewriteGroup5 ->
         a[2] += b[2];
         b[3] += a[3];
 

     myFun_rewriteGroup0_1_rewriteGroup3 ->
         myFun_whileBody0_0(a, b);
         if (a[0] > 0) {
             myFun_whileBody0_0_ifBody0(a, b);
         } else {
             myFun_whileBody0_0_ifBody1(a, b);
         }
 

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	BlockStatementGrouper.RewriteGroupedCode	This object represents a rewritten code block.

Constructor Summary

Constructors

Constructor	Description
BlockStatementGrouper(String code, long maxMethodLength, String parameters)	Initialize new BlockStatementGrouper.

Method Summary

Modifier and Type	Method	Description
BlockStatementGrouper.RewriteGroupedCode	rewrite(String context)	Rewrite code block used for initialization of this object.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BlockStatementGrouper

public BlockStatementGrouper(String code,
                             long maxMethodLength,
                             String parameters)

Initialize new BlockStatementGrouper.

Parameters:

code - code block that should be rewritten for statement grouping.

maxMethodLength - maximal length of the extracted code block.

parameters - parameters definition that should be used for extracted methods.

Method Detail

rewrite

public BlockStatementGrouper.RewriteGroupedCode rewrite(String context)

Rewrite code block used for initialization of this object. The code block is grouped into new methods.

Parameters:

context - prefix used for extracted group names.

Returns:

BlockStatementGrouper.RewriteGroupedCode representing rewritten code block and containing extracted groups with their names and content.