Code Size Rules

The Code Size Ruleset contains a collection of rules that find code size related problems.

ExcessiveMethodLength

Excessive Method Length usually means that the method is doing too much. There is usually quite a bit of Cut and Paste there as well. Try to reduce the method size by creating helper methods, and removing cut and paste. Default value is 2.5 sigma greater than the mean. There are three parameters available: minimum - Minimum Length before reporting. sigma - Std Deviations away from the mean before reporting. topscore - The Maximum Number of reports to generate. At this time, only one can be used at a time.

This rule is defined by the following Java class: net.sourceforge.pmd.rules.design.LongMethodRule

Here's an example of code that would trigger this rule:

			

public void doSomething() {
  System.out.println("I am a fish.");
  System.out.println("I am a fish.");
  System.out.println("I am a fish.");
  System.out.println("I am a fish.");
  System.out.println("I am a fish.");
  // 495 copies omitted for brevity.
}

ExcessiveParameterList

This checks to make sure that the Parameter Lists in the project aren't getting too long. If there are long parameter lists, then that is generally indicative that another object is hiding around there. Basically, try to group the parameters together. Default value is 2.5 sigma greater than the mean. NOTE: In version 0.9 and higher, their are three parameters available: minimum - Minimum Length before reporting. sigma - Std Deviations away from the mean before reporting. topscore - The Maximum Number of reports to generate. At this time, only one can be used at a time.

This rule is defined by the following Java class: net.sourceforge.pmd.rules.design.LongParameterListRule

Here's an example of code that would trigger this rule:

			

public void addData(
  int p00, int p01, int p02, int p03, int p04, int p05,
  int p05, int p06, int p07, int p08, int p09, int p10) {

  }
}

ExcessiveClassLength

Long Class files are indications that the class may be trying to do too much. Try to break it down, and reduce the size to something managable. Default value is 2.5 sigma greater than the mean. NOTE: In version 0.9 and higher, their are three parameters available: minimum - Minimum Length before reporting. sigma - Std Deviations away from the mean before reporting. topscore - The Maximum Number of reports to generate. At this time, only one can be used at a time.

This rule is defined by the following Java class: net.sourceforge.pmd.rules.design.LongClassRule

Here's an example of code that would trigger this rule:

			

public class Foo {
  public void bar() {
    // 500 lines of code
  }

  public void baz() {
    // 500 more lines of code
  }
}

CyclomaticComplexity

Complexity is determined by the number of decision points in a method plus one for the method entry. The decision points are 'if', 'while', 'for', and 'case labels'. Scale: 1-4 (low complexity) 5-7 (moderate complexity) 8-10 (high complexity) 10+ (very high complexity)

This rule is defined by the following Java class: net.sourceforge.pmd.rules.CyclomaticComplexity

Here's an example of code that would trigger this rule:

			

Cyclomatic Complexity = 12

public class Foo
{
1   public void example()
    {
2       if (a == b)
        {
3           if (a1 == b1)
            {
                do something;
            }
4           else if a2 == b2)
            {
                do something;
            }
            else
            {
                do something;
            }
        }
5       else if (c == d)
        {
6           while (c == d)
            {
                do something;
            }
        }
7       else if (e == f)
        {
8           for (int n = 0; n < h; n++)
            {
                do something;
            }
        }
        else
        {
            switch (z)
            {
9               case 1:
                    do something;
                    break;

10              case 2:
                    do something;
                    break;

11              case 3:
                    do something;
                    break;

12              default:
                    do something;
                    break;
            }
        }
    }
}

ExcessivePublicCount

A large amount of public methods and attributes declared in an object can indicate the class may need to be broken up as increased effort will be required to thoroughly test such a class.

This rule is defined by the following Java class: net.sourceforge.pmd.rules.ExcessivePublicCount

Here's an example of code that would trigger this rule:

			
    

    public class Foo {
    public String value;
    public Bar something;
    public Variable var;
    //more public attributes
    public void doWork() {}
    public void doMoreWork() {}
    public void doWorkAgain() {}
    public void doWorking() {}
    public void doWorkIt() {}
    public void doWorkingAgain() {}
    public void doWorkAgainAgain() {}
    public void doWorked() {}

    }

TooManyFields

Classes that have too many fields could be redesigned to have less fields and some nested object grouping some of the information collected on the many fields.

This rule is defined by the following Java class: net.sourceforge.pmd.rules.design.TooManyFields

Here's an example of code that would trigger this rule:

			
   
   public Class Person {
       String street;
       int number;
       int floor;
       String postal;
       String street;
       long phone;
       String city;
       String state;
       String Country;
       // fields above should be in a class for Address or something similar
       // that information does not really belong to a person, but to a place
       // fields below are really from person
       String firstname;
       String lastname;
       Date born;
       Person father;
       Person mother;
   }