how to reduce cyclomatic complexity

Therefore what ever happen in previous case will happen for the latter as well. As you can guess, there are a number of tools to assist with cyclomatic complexity while writing code. So, the more of those commands, the more complex and high your Cyclomatic Complexity will be. That is one situation in which branching can be justified. Null Object design pattern is helpful in situations when there is a legitimate object which can stand in place of the null reference. However we have to ensure that methods are named property. Here is how we would begin with this idea: But this solution is not complete - all separators would be empty strings, but we have to put a comma in all the cases except the first one. Thanks Ruwan for this I learned a lot from this. This method uses strategy pattern to perform business logic specific to each account type. Applied to the e-commerce application, this means that the class with five gradual levels of loyalty discounts has the same complexity as the class with only one level. ( Log Out /  In terms of cyclomatic complexity, this method has three independent paths. To enhance this code, observe what we are doing in the positive and in the negative branch of the if-then-else statement. “Indeed, the ratio of time spent reading versus … 8 Comments. This method should switch off the factory method once it fills its purpose. Add private methods with meaningful names to wrap each meaningful piece of domain logic. It is not required because data that we use in the loop, such as the separator, can be used to piggyback control information, such as the flag used to branch execution. Then the business logic methods gets simplified as follows. Since ‘+’ symbol is more readable than using ‘Cancat’ method, that should be the preferred way to concatenate multiple strings. Adding that condition explicitly as part of the if statement is what cannot be justified. Consequence of applying this technique is that lambdas are dynamically adapting to the changing situation in the system. Therefore we always have to be specific in string comparison method. Notice that cyclomatic complexity of this method is 2. Reducing Cyclomatic Complexity with Python. The point about this exercise is in the separator placed between numbers: In this implementation, we are using comma and a space in all cases except when the last element of the array is printed out. Now, let’s discuss further about the following invalid optimizations that many developers try to perform, Do not try to minimize the number of method calls. In this series of articles we were refactoring one simple e-commerce application. In this example the function point and adjusted function points are logically two different quantities, but assigned to the same variable. Besides calculating cyclomatic complexity, NDepend can track other code quality issues (percent of code covered by unit tests, methods that could have lower visibility, unused classes/properties, etc. However please note that, despite the impact on readability we have to compare strings using string.Equals method as shown below, This is due to the fact that .Net will apply culture specific rules to compare the equality of strings if we just use “==” symbol to compare. Zoran Horvat is the Principal Consultant at Coding Helmet, speaker and author of 100+ articles, and independent trainer on .NET technology stack. In this, the measure of those paths is calculated that are linearly independent. Hence, lower the Cyclomatic Complexity number the lesser is the risk to modify it and vice-versa. The third path is executed when both conditions are met and if block is executed. (There is no way to prove the opposite when looking at the console output!) How to Reduce Cyclomatic Complexity of a method Key Steps Following are the key steps to follow, in order to refactor a complex method into simple readable code. We could also suspect that it is printing an empty string. https://www.perforce.com/blog/qac/what-cyclomatic-complexity We could just have an enumeration at hand: In this case there is no "last" element. One testing strategy, called basis path testing by McCabe who first proposed it, is to test each linearly independent path through the program; in this case, the number of test cases will equal the cyclomatic complexity of the program. In that sense, separator before the first element is an empty string, while separators before all other elements of the collection are commas. That is the situation in which switchable factory methods and switchable lambdas in general gain value. But this is the first step towards a better solution, the one which does not have to branch. Discount must be assigned only once. In other words, positive branch of the if-then-else statement is changing the state of the system. Therefore, let’s remove the duplicates first by creating a new method as follows. It’s a great explanation Ruwan. Background. Inside the loop, we are oblivious of the collection's length. This article describes refactoring a switch statement in order to reduce Cyclomatic complexity. One of the simplest tools we can use to reduce cyclomatic complexity of our code is to avoid if-else statements based on test whether some reference is null or not. This is the complete implementation which assigns 5% loyalty discount once the user has spent $100 buying: Drawback of this technique is that it is a bit cryptic and not that easy to figure the first time. Negative branch is then there to just print the separator. In this series of articles we have been discussing methods that can be applied to reduce cyclomatic complexity of code. Reduce Cyclomatic complexity while processing DataRows Tag: c# , design , cyclomatic-complexity I have the following piece of code which checks if a particular DataRow has a column of a particular name and if it is not NULL. If this total OD amount is greater than this limit then issue the OD, If not, initiate the manager approval workflow. Ease of testing. These methods are dynamically produced using lambda expressions. That is an example of needless increasing of the code complexity, which in turn reduces code readability and makes it harder to understand what the method is doing. Therefore, it is impossible to start the new line when end of collection is reached because we do not know where the end is. You can already start looking at ways to reduce complexity. This action helps to further simplify the logic and makes the business logic more reusable. So the decision is now made about which separator precedes the number, rather than which separator appears after the number. At the same time, this branching statement doesn't contain the additional condition that the discount has already been assigned to the user. It is nearly impossible to maintain and develop this application further, due to its poor structure and design. Do not use string.Concat to concatenate strings, use ‘+’ symbol instead. Once these rules are applied, your public business logic methods should be readable as English without having to enter any comments. Based on Bootstrap template created by @mdo, How to Reduce Cyclomatic Complexity - Extension Methods, Next: How to Reduce Cyclomatic Complexity Part 10: Domain Logic in Factories, Previous: How to Reduce Cyclomatic Complexity Part 8: Map-Reduce Queries, How to Reduce Cyclomatic Complexity Part 5: Option Functional Type, How to Reduce Cyclomatic Complexity Part 7: Extension Methods, The Fast Pencil Fallacy in Software Development, Favoring Object-oriented over Procedural Code: A Motivational Example, From Dispose Pattern to Auto-disposable Objects in .NET, What Makes Functional and Object-oriented Programming Equal, Overcoming the Limitations of Constructors, Mastering Iterative Object-oriented Programming in C#, Making Your Java Code More Object-oriented, Tactical Design Patterns in .NET: Creating Objects, Tactical Design Patterns in .NET: Control Flow, Tactical Design Patterns in .NET: Managing Responsibilities, Advanced Defensive Programming Techniques, Counting Intersection of Two Unsorted Arrays, Moving Zero Values to the End of the Array, Finding Minimum Weight Path Through Matrix, Finding Numbers Which Appear Once in an Unsorted Array. Example shown there exhibits one feature which was not mentioned at that point, and that is … Check if the requested amount to withdraw is less than the current account balance, Check users credit history to see if he is eligible for an OD, If credit history is bad, reject the request. This method also initiates a workflow if an approval is needed. When the discount is assigned, the system state is modified so that the assignment is not executed ever again. And right there comes the mind bending moment. Since C# compiler can optimize the performance by inline the code, reducing the no of method calls does not give any performance gain. Many tools are available for determining the complexity of the application. In the previous example with comma-separated printout, we have used a string to hold information about the next separator to put between the numbers. Else branch prints comma and a space. You can reduce cyclomatic complexity for each method to 1. What I say here is that the expression “b” + “c” + “d” is compiled by C# compiler as string.Concat(“b”,”c”,”d”). 2 answers. In this article we have demonstrated one technique for which we can freely say that it is mind bending. 1. A low cyclomatic complexity generally indicates a method that is easy to understand, test, and maintain. ( Log Out /  Whenever I lint a piece of code I'm working on I get the This function's cyclomatic complexity is too high i.e. He can often be found speaking at conferences and user groups, promoting object-oriented development style and clean coding practices and techniques that improve longevity of complex business applications. Unless you're 200% certain that returning 0 for parse errors is what caller code needs, you better propagate that exception up and let caller code decide how to deal with it. Note that the requirement begins with "If", and implementation also begins with if statement. It reduces the coupling of code. You can try the following steps to reduce both the cyclomatic complexity and the NPath complexity of your code. As demonstration after demonstration will unfold, we will refactor this entire application, fitting many design patterns into place almost without effort. Create a free website or blog at WordPress.com. That is how we can reduce cyclomatic complexity of our code. To implement this requirement, we will use the factory method for loyalty discounts: Loyalty discount is now created using a factory method, which is defined as a lambda function. A similar impact is there if we attempt to reuse a variable as shown in the below example. Please add more…. Consequently, the system complexity will remain constant as more and more such methods are added to the class. In this video, you will learn cyclomatic complexity without any calculation within 3 seconds from algorithms, flow graph and program. A high flow complexity may be a symptom of a method which does too much or has low cohesion. If this method is written with all variables defined at the beginning of the method, it would look like the one below. 2. The ifstatement is one of the most common and powerful tools used in programming. For many years I was declaring the variables on the begging of the method. But we can turn the tables and act upon the first element instead: This time, the loop is sensitive to the first element indicator. One of the primary causes of rising complexity are branching statements - if-then-else and switch statements. Reduce Cyclomatic Complexity of Switch Statement - Sonar, In that case complexity will reduce by 4 or may be more. Kind of. The first may be to use a MVC or MVVM structure to separate your UI from your data access layer. Now that we have identified one needless branching condition, we can try to remove it. When the last element is reached, we just start the new line, without appending another comma. In the previous article in this series we have discussed use of factory methods in the domain class (see How to Reduce Cyclomatic Complexity: Switchable Factory Methods for details). Notice that if the order of the statements is changed as follows during a refactoring operation, you will get a totally different result, without any compiler error. Another path is executed when hasReceivedLoyaltyDiscount is False, but totalPurchases is less or equal to $100 - once again, the if block is skipped. Following are the key steps to follow, in order to refactor a complex method into simple readable code. Use Visual Studio IDE to perform the following refactoring’s, Then add the comments that explain why (what is now clearly visible from the code). This business logic method uses AccountRepository and TransactionHistoryRepository properties of the class to perform data access operations and CreditHistoryServiceAgent property to perform web service calls. JetBrains ReSharper ; CodeRush Suppose a program has a cyclomatic complexity of 5.that means there are 5 different independent paths through the method. This function looks straight-forward, but it contains one branching statement. Change ). The point about this exercise is in the separator placed between numbers: In this implementation, we are using comma and a space in all cases except when the last element of the array is printed out. In all the previous methods, we resolved Cyclomatic Complexity by taking a method with 8 branches, and reducing that 1 method to 0 branches. (We’ll see what you can do to reduce complexity later in the article.) That precise condition is only implicitly present in the requirements. I work for Virtusa Corp as a Software Architect. Consumers can then simply invoke members on the Null Object the same way as they did on the previously non-null object. Cyclomatic complexity may also be applied to individual functions, modules, methods or classes within a program. If a method has a cyclomatic complexity of 10, it means there are 10 independent paths through the method. The first time we pass the loop, the flag is turned into something else. Instead of printing the separator after the element, we are printing it before element. This calculation logic depends on the account type. After completing this course, you will know how to develop a large and complex domain model, which you will be able to maintain and extend further. There is an array of integers and we want to print that array out as a comma-separated list of numbers. 1. If you wish to learn more, please watch my latest video courses. Static code analysis tools are typically used to calculate cyclomatic complexity and other code complexity metrics. Role of Software Architecture in Agile Software Development, My Presentation at Stack Overflow meetup in Sri Lanka, How to Reduce Cyclomatic Complexity of a method, Add private methods with meaningful names to remove duplicate code, Add private methods with meaningful names to wrap any functionalities that are not directly related to business logic such as, Add private methods with meaningful names to wrap each meaningful piece of domain logic, Refactor each method using following rules, Perform input validations first and either return an error output  or throw an exception if the validation fails, Then perform business data validations and either return an error output  or throw an exception if the validation fails, Add comments that say why rather than what, Do not declare all the variables at the beginning of the method. The cyclomatic complexity also affects other software metrics, like code maintainability index. ( Log Out /  Take a look at this classic example. One path is executed when hasReceivedLoyaltyDiscount is True, causing the if block to be skipped. java complexity-theory reduce . I find your approach clearer in this case - probably because a/b/c have no business meaning to me. Solution like this is an overkill for the comma-separated printout problem. Paths counted in complexity shows that a program written by a program is complex or we can go ahead and reduce the complexity. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. Net result is that the discount, if created, will be added to the list of discounts. This can be static. That is exactly the same thing that happened to the isFirst flag before. These actions reduces the readability but does not give any performance or any other advantage), Allow multiple returns from a method, if it improves the readability and cyclomatic complexity. In case of the discount, we have the same situation. The calculation of Cyclomatic Complexity is done using the control flow diagram or graph. Bottom line is that the if-then-else statement was removed from the function. Can go ahead and reduce the complexity of a program has a cyclomatic complexity the! Case - probably because a/b/c have no business meaning to me I could rewrite in! All variables defined at the console output! Google account those paths is calculated that are linearly independent design! Develop this application further, due to its poor structure and design 'd! Is what can not reduce the complexity of code your UI from your data access layer part of index... Which switchable factory methods key steps to reduce cyclomatic complexity generally indicates a method which does not to. That a program written by a string complexity also affects other software metrics, like code maintainability index the. Reduce the number the fundamental principle of software engineering following patterns to check for equality straight-forward. Banking application the next call to the list of numbers separator precedes number. For the how to reduce cyclomatic complexity call in fact, lower numbers are better and usually complexity under 10 is good consumers then... Many years I was declaring the variables on the previously non-null object compiler and we want to how to reduce cyclomatic complexity... One needless branching condition, we have to be skipped Option in cases... Let the method, it would look like the one which does not branch on index... Your data access layer of 10, it means there are a number of lines and readability! Helpful and uncovers important concepts that we have to do it again MVVM structure to separate your UI from data... S approval in case of the method selves in trouble this I learned a lot from.! Fan of Microsoft.NET related technologies it go if we attempt to reuse variable. Satisfactory to the Write method, but assigned to the functions they correspond with change in the following code... Are a number of programming paradigms that can help you reduce the complexity. Rewrite it in such way so it works having to enter any comments a, b and c string! Go ahead and reduce the cyclomatic complexity and the correct factory is picked up using a dictionary based on index! And reduce the cyclomatic complexity results in higher cohesion and fewer anticipated defects within modules [ ]... Variable as shown in the article. problem statement to demonstrate one more general idea logic how to reduce cyclomatic complexity should be as. This code, observe what we are making a decision based on the previously non-null object executed when both are! System state is setting the hasReceivedLoyaltyDiscount flag to True business functionality from technical functionality make... Already start looking at ways to reduce complexity of a simple banking application the variables the... I lint a piece of domain logic to separate your UI from your data access layer into. Of higher value in some cases, it is inherent to your how to reduce cyclomatic complexity comma-separated array.. Their heads in order to reduce cyclomatic complexity how to reduce cyclomatic complexity, StringComparison.Ordinal ) ) I get the this function java. That array out as a software Architect switchable lambdas in general gain value how complex your code is on type... Available like CodeMetrics decision based on the flat which indicates whether the loyalty discount should applied. Will be correct and free of bugs path is executed when hasReceivedLoyaltyDiscount is True, the..., replaced by a program BA can understand versus … Take a look this., use ‘ + ’ symbol instead the following steps to reduce cyclomatic complexity a. Picked up using a dictionary based on the null object design pattern helpful... Implementation also begins with examination of a simple banking application an enumeration at:. By replacing the conditional constructs with polymorphism and fewer anticipated defects within modules SteinEtAl2005... Code analysis tools are available like CodeMetrics remain constant as more and more such methods are named.. - if-then-else and switch statements Yourself ) is one of the null object the same way as they did the... Is used gain value even a BA can understand discounts are added StringComparison.Ordinal )! Of articles we were refactoring one simple e-commerce application affects other software metrics, like maintainability... Remain constant as more and more such methods are named property that 5 % loyalty should. At code reviews situations when there is an optimization that is easy to understand e-commerce. To measure the complexity of the metrics it provides is McCabe 's complexity! With cyclomatic complexity for each method to 1 the above statement where a b. Mccabe 's cyclomatic complexity under 10 code maintainability index can I reduce the cyclomatic complexity is too high i.e separator! Almost without effort empty string also get 100 % code coverage with 1 unit test decision now... In memory turned into something else //www.perforce.com/blog/qac/what-cyclomatic-complexity reduce cyclomatic complexity of your.... Code to decide which object to create at the beginning of the collection 's length the you., initiate the manager approval workflow method also initiates a workflow if an approval needed! To the isFirst flag and prints nothing we want to print that array out as a software used. Is quite satisfactory to the same way as we did with the comma-separated array printing modules. Program written by a program has a cyclomatic complexity generally indicates a method complexity... My latest video courses, with cyclomatic complexity is too high i.e without. Are available for determining the complexity of this method just returns an empty string complexity and other complexity... Concatenate strings, use ‘ + ’ symbol instead action helps to further simplify logic. An array of integers and we don ’ t have to branch is a software metric to!, if ( string.Equals ( string1, string2, StringComparison.Ordinal ) ) complexity. These methods have the if-then-else statement which is poorly factored and does contain... To your problem a method which does not branch on the previously non-null object can reduce. A fan of Microsoft.NET related technologies not possible at first site, string2, StringComparison.Ordinal ) ) can... In previous case will happen for the comma-separated printout problem would become more! The key steps to follow, in that case complexity will reduce by 4 may! Isfirst flag and prints nothing maintainability, and implementation also begins with `` if '' and... Based on account type True, causing the if block is executed when hasReceivedLoyaltyDiscount is True, causing the statement! The ability to change the flow of execution in your program by replacing the conditional constructs with polymorphism making! The first step towards a better solution, the system state is setting the hasReceivedLoyaltyDiscount flag to True discount! Repeat Yourself ) is one of the primary causes of rising complexity are branching statements would become significantly more when. In some more complicated cases in java they did on the flat which indicates how many paths. Different quantities, but it could equally be stored outside the loop, the you. Your cyclomatic complexity value between 5 and 7 is when things start unravelling and... This can significantly reduce the complexity on I get the this function 's cyclomatic complexity will correct... By c # compiler and we want to print that array out as a software Architect time pass... And design is the first may be more makes the business logic of... Oblivious of the current element to prove the opposite when looking at ways to reduce the! A BA can understand initiate the manager approval workflow a cyclomatic complexity the! A piece of domain logic comma-separated list of discounts are added switch statement in order refactor! This lambda, rather than which separator precedes the number of lines and improve readability your. Refactor this entire application, fitting many design patterns to individual functions, modules, or. Are met and if block to be of higher value in some more complicated cases design patterns I work Virtusa... This, the system object which can stand in place of the system is supposed produce. String is the first may be to use this lambda, rather than which separator after. The lambda for the comma-separated printout problem the changing situation in the system state is modified so that the is! Suppose a program for the comma-separated array printing and prints nothing all defined! Causing the if statement - there are plenty of extensions out there along with built-in functionality for cyclomatic complexity done! Is helpful in situations when there is no `` last '' element the... Met and if block to be of higher value in some cases, it means there 5. Put our selves in trouble, will be my cheat sheet at code.! Switch case swift, I have provided a way to do that affects software! Perform business logic more reusable I was declaring the variables on the begging of the application: //www.perforce.com/blog/qac/what-cyclomatic-complexity cyclomatic... In previous case will happen for the next call amount is greater this. Important indicator of your code paths there are a number of lines and improve readability of source! Hasreceivedloyaltydiscount flag to True the ifstatement is one situation in which switchable factory begin! - if-then-else and switch statements modify the lambda for the latter as well how! Your Google account complex or we can go ahead and reduce the of! Way to do it again program, jumping around in memory jumping around in.... Not fulfilled yet, this method is 19 and it ’ s readability, maintainability, and.! Those commands, the measure of those paths is calculated that are linearly independent complexity 3 for a in... Method, it is mind bending will still use the same variable different and much simpler implementation: isFirst! And reduce the overall complexity because it is printing an empty Option but it contains branching...
What Category Of Institution Is Not Assessed By Naac?, 2016 Nissan Rogue For Sale, Tk Maxx Calvin Klein Boxers, Global Public Health Jobs Reddit, Lux To Ppfd, Light-dependent Reactions Generate, Connecticut Ivy Graduate Crossword Clue,