使用Source Monitor檢測Java代碼的環複雜度

Today I found a useful free software called 「SourceMonitor」 which can help to calculate and monitor the java code ( and other programming language like C++, C# etc ) complexity.

For the definition and how to calculate cyclomatic complexity itself, please refer to detail in wikipedia.

In order to demonstrate the usage of this software, I use a very simple java class below for example:

package test;
import java.util.ArrayList;
public class monthTool {
 static ArrayList<String> monthCollection = new ArrayList<String>();
 public static void main(String[] args) {
  monthTool tool = new monthTool();
  tool.printV1(1);
  tool.printV2(2);
  tool.printV1(0);
  tool.printV2(-1);
  tool.printV3(3);
  tool.printV3(13);
 }
 public monthTool(){
  monthCollection.add("Invalid");
  monthCollection.add("January");
  monthCollection.add("Febrary");
  monthCollection.add("March");
  monthCollection.add("April");
  monthCollection.add("May");
  monthCollection.add("June");
  monthCollection.add("July");
  monthCollection.add("August");
  monthCollection.add("September");
  monthCollection.add("October");
  monthCollection.add("November");
  monthCollection.add("December");
 }
 public void printV1(int month){
  System.out.println("Month is: " + getMonthNameV1(month));
 }
 public void printV2(int month){
  if( month >= 1 && month <= 12)
   System.out.println("Month is: " + getMonthNameV2(month));
  else
   System.out.println("Please specify a valid month");
 }
 public void printV3(int month) {
  System.out.println("Month is: " + getMonthNameV3(month));
 }
 public String getMonthNameV2(int month){
  if( month == 1)
   return "January";
  else if( month == 2)
   return "Febrary";
  else if( month == 3)
   return "March";
  else if( month == 4)
   return "April";
  else if( month == 5)
   return "May";
  else if( month == 6)
   return "June";
  else if( month == 7)
   return "July";
  else if( month == 8)
   return "August";
  else if( month == 9)
   return "September";
  else if( month == 10)
   return "October";
  else if( month == 11)
   return "November";
  else if( month == 12)
   return "December";
  else
   return "Invalid";
 }
 public String getMonthNameV1(int month){
  switch (month){
  case 1:
   return "January";
  case 2:
   return "Febrary";
  case 3:
   return "March";
  case 4:
   return "April";
  case 5:
   return "May";
  case 6:
   return "June";
  case 7:
   return "July";
  case 8:
   return "August";
  case 9:
   return "September";
  case 10:
   return "October";
  case 11:
   return "November";
  case 12:
   return "December";
  default:
   return "Invalid";
  }
 }
 public String getMonthNameV3(int month){
  try {
   return monthCollection.get(month);
  }
  catch (java.lang.IndexOutOfBoundsException e){
   return "Invalid";
  }
 }
}

It has three different ways to convert an integer into a month name if possible, or else the string 「Invalid」 is returned.

(1) Create a new project:

Here you could find out all supported programming language:

(2) specify a project name and locate the directory of SourceMonitor project file. For me I choose to store it into the same path of my test java project.

(3) Specify which source files will be scanned by SourceMonitor:

(4) For the left steps in wizard, just use default settings and finish wizard. Click OK button to start scan.

And soon we get the analysis result. Since we are more interested with the detail of each method, we choose 「Display Method Metrics」 from context menu.

From the result list it is easily known that the third approach of month name retrieval is much better than the first two ones, no matter regarding complexity or statement number.

You could also view the result list via 「Chart Method Metrics」 from context menu:

Take the complex graph for example: X axis is the complexity value of each method, the Y axis is the total occurrence of each different complex value.

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