Refactoring:
We offer Refactoring services for your spaghetti legacy code.
Refactoring is the process of changing a software system in such a way that it does not alter the external behavior of the code yet improves its internal structure. Martin Fowler – Refactoring: Improving the Design of Existing Code
Over time and without effective counter measurements, as code is changed, it tends to deteriorate. Changes are often made on the fly, under time pressures, without regard for the overall structure of the code. This can lead to code entropy. Refactoring can help undo code entropy. Refactoring can make the code easier to understand and modify.
Refactoring is a specific, disciplined approach to restructuring and improving the design of an existing body of code while its observable functionality remains unchanged. At its heart is a series of small behavior-preserving transformations. Refactoring improves some aspects of program behavior such as readability, maintainability, or performance.
Once we have understood your requirements and have agreed to a suitable direction, the following steps are undertaken:
- Understand the specification and the code
- Create a comprehensive set of unit tests and integration tests
- Version control the code
- Refactor
- Create clear documentation of what has been done and why
- One of the preconditions of Refactoring is having solid tests. So before Refactoring is performed we ensure the availability of the tests and the testing environment.
What patterns of code are candidates for Refactoring?
- Same code structure in more than one place
- Too much code in a method
- Too many instance variables in a class
- A method has too many parameters
- When a class has more than one meaning to it
- When, every time, small changes need to be made to lot of classes
- When there are same data items in a lot of places
- Switch statements
- A particular class is not doing enough
- Temporary variables
- When too many methods are delegating to other classes
Why should you refactor?
Software maintenance usually has one of two goals. The first is to fix bugs, and the second is to add features. While the goal of refactoring is neither of these, it can greatly improve how easy it is to do either. At first it may seem a waste to refactor code without adding any new functionality, but trying to modify a poorly constructed program can take far more time and effort than first refactoring, and then modifying. Refactoring can reveal flaws in the structure of the existing code that are the underlying causes of bugs or incorrect behavior.
What are the benefits of Refactoring?
- Refactoring improves the design of software
- Refactoring makes software easier to understand
- Refactoring makes software easier to maintain
- Refactoring improves the performance of software
- Refactoring improves the modularity of software
- Refactoring improves the extensibility of software
- Refactoring helps find defects
- Refactoring helps program faster
When Should You Refactor?
- Refactor when you add function
- Refactor when you fix a defect
- Refactor while code review
When should you not refactor?
- When the existing code is really messy
- When the code is riddled with defects
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- When the project deadline is close
What does Refactoring result in?
- Fewer bugs
- Reduced time to market
- Savings in cost
- Stable product
Reengineering:
With a large number of legacy systems being used and as these systems can be mission critical, there is a need for reengineering.Reengineering can prevent accidents, reduce costs and increase efficiency. We understand the problem and that it exists. We believe that we can help solve this problem. As we have the relevant experience, we offer reengineering services to help customers to modernize and migrate from legacy systems to desired systems
In computing a legacy system is an old method, technology, computer system, or application program,"of, relating to, or being a previous or outdated computer system." – Merriam Webster
Legacy systems evolve over time. There are a large number of legacy systems being used and the number is growing. There is a lot of knowledge embedded in the legacy systems. This includes requirements, design decisions, and business rules. it is difficult to extract such knowledge. And also the legacy system maybe using archaic methodologies and may have undergone prolonged maintenance. The result is a legacy system that lacks the ability to evolve to meet ever-changing demands in a cost-effective manner. Reengineering offers an approach to migrating a legacy system towards an evolvable system.
Software reengineering is any activity that improves one’s understanding of software and/or improves the software itself. – R.S. Arnold, Software Reengineering
Reengineering is redoing existing legacy system and transforming them into desired systems. Legacy system, that has become expensive to maintain or obsolescent in terms of the architecture and inability to cater to the technological advancements.
Reengineering Process:
The reengineering process involves:
- Examination of the existing system
- Analysis of the existing system
- Alteration of the existing system to reconstitute it in a new form, and
- The subsequent implementation of the desired form
The reengineering process typically includes the following other processes:
- Analysis
- Reverse engineering
- Re-documentation
- Restructuring & Translation and
- Forward engineering
The goal is to understand the existing software (specification, design, implementation) and then to re-implement it to improve the system’s functionality, performance or implementation. The objective is to maintain the existing functionality and prepare for functionality to be added later.
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What are the challenges in reengineering?
- Lack of good design structure
- Lack of clear documentation
- Original developers not available
- Instilling good software development methods
- Generating a new system that maintains the existing functionality while applying new technologies
- Due to years of modifications, it is difficult to change
- No clear or logical structure and documentation
When do we need to reengineer?
- When the legacy system is no longer evolvable in a cost-effective manner
- When the legacy system enjoy properties worth preserving
- When the legacy system has already been deployed and has undergone significant scrutiny by their users
- When the legacy system has undergone a long history of maintenance
- When the legacy system has a wealth of test and validation capabilities
- When the legacy system has history recorded in the form of resources and documentation
What are the inputs needed for reengineering?
- Documentation
- Specifications
- Source code
What are the objectives of reengineering?
What are the factors for reengineering?
- Maintenance cost
- Higher performance demands.
- Usability
- Data storage requirements
- New trends
What are the categories of reengineering?
- Product Improvement
No new functionality is added. But the change was due to performance improvement, code restructuring, new platform support or due to data migration.
- Product enhancement