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From "Satendra Kumar (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (KAFKA-3768) Replace all pattern match on boolean value by if/elase block.
Date Sat, 28 May 2016 15:53:12 GMT

     [ https://issues.apache.org/jira/browse/KAFKA-3768?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Satendra Kumar updated KAFKA-3768:
----------------------------------
    Issue Type: Improvement  (was: Bug)

> Replace all pattern match on boolean value by if/elase block.
> -------------------------------------------------------------
>
>                 Key: KAFKA-3768
>                 URL: https://issues.apache.org/jira/browse/KAFKA-3768
>             Project: Kafka
>          Issue Type: Improvement
>            Reporter: Satendra Kumar
>            Priority: Minor
>   Original Estimate: 1h
>  Remaining Estimate: 1h
>
> Scala recommend  use if/else clock instead of  pattern match on boolean values.
> For example:
> class Comparasion {
>     def method1(flag: Boolean): String = {
>           flag match {
>              case true => "TRUE"
>              case false => "FALSE"
>            }
>     }
>   def method2(flag: Boolean): String = {
>           if(flag) {
>                    "TRUE"
>              }else {
>                "FALSE"
>              }
>           }
> }
> Byte code comparison between method1 and method2:
> scala>javap -cp Comparasion
> Compiled from "<console>"
> public class Comparasion {
>   public java.lang.String method1(boolean);
>     Code:
>        0: iload_1
>        1: istore_2
>        2: iconst_1
>        3: iload_2
>        4: if_icmpne     13
>        7: ldc           #9                  // String TRUE
>        9: astore_3
>       10: goto          21
>       13: iconst_0
>       14: iload_2
>       15: if_icmpne     23
>       18: ldc           #11                 // String FALSE
>       20: astore_3
>       21: aload_3
>       22: areturn
>       23: new           #13                 // class scala/MatchError
>       26: dup
>       27: iload_2
>       28: invokestatic  #19                 // Method scala/runtime/BoxesRunTime.boxToBoolean:(Z)Ljava/lang/Boolean;
>       31: invokespecial #23                 // Method scala/MatchError."<init>":(Ljava/lang/Object;)V
>       34: athrow
>   public java.lang.String method2(boolean);
>     Code:
>        0: iload_1
>        1: ifeq          9
>        4: ldc           #9                  // String TRUE
>        6: goto          11
>        9: ldc           #11                 // String FALSE
>       11: areturn
>   public Comparasion();
>     Code:
>        0: aload_0
>        1: invokespecial #33                 // Method java/lang/Object."<init>":()V
>        4: return
> }
> method1 have 23 line of byte code and 6 line  byte code. Pattern match are more expensive
comparison to if/else block.



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