[KAFKA-3768] Replace all pattern match on boolean value by if/elase block.

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.10.1.0
• Assignee: Satendra Kumar
• Reporter: Satendra Kumar
• Created: 28/May/16 15:47
• Updated: 04/Jun/16 20:26
• Resolved: 04/Jun/16 20:25

Description

Scala recommend use if/else block instead of pattern match on boolean values.

For example:

Comparasion.scala

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

Comparasion.class

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 method2 have only 6 line byte code. Pattern match are more expensive comparison to if/else block.

Issue Links

• links to: GitHub Pull Request #1444
• links to: GitHub Pull Request #1445