INTRODUCTION:
Refactoring is basically restructuring or altering the internal code of a program. It tends to improve the overall quality of the code base so that it can become easier to maintain, improves its readability, and can extend over time. It is done without posing any effect on the external behavior of the program. Refactoring is a crucial part of any software development cycle. Basically, it is a process to improve internal code with external results remains the same.
Its primary objective is to make such modifications in code that will evolve and make it easier to use in the future by keeping the same output of the system. Refactoring techniques are a must have for adding new features, fixing a bug/smell or for better understanding.
REFACTORING VS REWRITE/REDESIGN:
It is possible to continue todeliver updates to the user other than just fixing bugs in case of refactoring along with improvement in system’s code base. However, it is most of the time impossible to improve or change technologies /framework of the system. Also, a significant challenge is to make system work in the same way as it did before along with doing desired modifications. Because of this reason, refactoring involves a large amount of testing and debugging.The figure below clearly illustrates how it does.
While rewriting is the opportunity to develop everything from scratch. One can easily choose its desired technology or framework in case of rewriting without any legacy limitation which is almost impossible in case of refactoring. Everything can be altered, accordingly to what is desired at that time; from language to the pattern, from framework to even the type of application, like the desktop to mobile or from mobile to web,etc. But there are also major problems involved with rewrites like less productivity and poor design of the system. Also, to transport some function from one system to another is also not as simple as it expected to be. Sometimes, there are dark parts of the code that are too hard to transport and debug. So, doing a whole rewrite of the system is a complete risk. The figure below will describe rewrite and refactoring more precisely.
Hence, refactoring provides incremental changes, less time, increased productivity, better evolution over time and inspection of results along with fewer risks involved.
TYPES OF REFACTORING:
Refactoring is commonly applied to codes,but it can also be applied to other development artifacts like;
1. App refactoring
2. Database refactoring
3. Architecture refactoring
4. Design Refactoring
App Refactoring is the type of refactoring developers used to improve lifecycle, support for multiple platforms, market reach and usability of their apps. Refactoring can also reduce development time while extending capabilities in an app. App refactoring also makes it easier and possible to transport an app from one operating system to another like from android to iOS.
Database refactoring refers to a simple change in a database schematic. It will retain both its information as well as behavior along with an improvement in its design. This type of refactoring is tougher than a simple code refactoring because it needs to retain both information and behavior while a code is refactoring only needs to maintain the behavior. Code refactoring has no concern with the information.
Architecture refactoring plays a vital role because,during development, architecture is the main part which is continuously expanding and changing. This refactoring is a standardactivity to reduce risks, costly errors and schedule delays during any development process.
Design Refactoring is mainly done to remove any design smells in the software design. Design smells refers to certain structure in design that includes a violation of fundamental design,and it impacts negatively on design quality. With the evolution of the worldon a daily basis, requirements changes continually, and the software needs to be maintained with those requirements. So, a design refactoring is crucial for fulfilling those changing requirements.
REFACTORING TECHNIQUES:
1. Rename Method:
This method is implemented when we want to rename anything. The need to change the name arises from the fact that some element,e.g. a variable name does not depict the purpose for which it is being used in the code so by replacing its name with a suitable name that will reflect its purpose. Hence, the rename method will, in turn, reduce the need for comments in the code.
2. Extract Method:
Extract method is implemented to extract useful statements and expressions from the previously written code and diminishes the extra-long fragments and complicated code. This method is usually employed where the original one is too long to be handled. This method creates a new method that describes the purpose of the original one but in more precise and short code. It selects long fragments and then replaces them concerning the new one. It is a clean-up method to save both time and space.
3. Move Method:
Move method is the refactoring technique which is used for moving static methods, static fields and many other elements from one class to another class. The need for this movement arises from the fact that sometimes a method is currently located in one class,butit is more frequently used by some other class. So, it is more suitable to move that method to the class where it is used frequently.
4. Pull up Method:
This refactoring technique is used to “pulling up” some method in its inheritance class chain procedure. This technique is implemented where some method is needed to be used by many implementers. It is used where some sub-classes uses the same field,so they are “Pulled up” to a single superclass. It moves fields or methods to that superclass where they appear to be as an abstract.
REFACTORING TOOLS:
Refactoring involves various tools which can be usedlike;
1. Refactoring Browser
2. Eclipse
3. Idea
Refactoring Browser was the first tool which was widely implemented for refactoring. It involves refactoring for a singlelanguage like its field refactoring, class refactoring or method refactoring. This tool sets the basis for all modern refactoring tools.
Eclipse tool is most widely used because it does not focus on a single language; instead, it aims to be providing a general development environment. It provides a “universal tool platform.” It offers many refactoring features,e.g. parameter, pull-up method, moves method etc. it is the most powerful tool regarding refactoring techniques.
An idea is a tool created by Intellij. It provides an integrated commercial development environment in Java. The idea has a limited number of refactoring techniques,and it does not implement many of them. Hence, experts could not describe it as refactoring browser. The idea has refactoring features like rename method; introduce variable, method parameter,etc.
Concluding Application refactoring plays a vital role for the maintenance of the appby the latest trends and developments along with introducing updates and improving the user interface. It is an important part of the development cycle. As refactoring app will save time, improves quality with the removal of bugs/smells in the system while assuring same output of the system. So, App refactoring is the most suitable platform to improve apps and work by future requirements.