Software re-engineering and re-engineering process | Agilie

Software reengineering is the process of creating new functionality or eliminating bugs by making a revolutionary change, but using software that is already in use. The reengineering process is described by Chikofsky and Cross in their 1990 paper as "The examination and alteration of a system to reconstitute it in a new form". In less formal terms, reengineering is the modification of a software system after it has been reverse-engineered.

Key Takeaways
Software reengineering is a critical process that involves improving and modernizing legacy systems to meet current and future needs. It is a complex process that requires a comprehensive understanding of the software system's architecture, design, and functionality. This understanding is necessary to identify the system's strengths and weaknesses, and to develop a plan for improvement.

The key steps involved in software reengineering, include reverse engineering, restructuring, and forward engineering. These steps enable developers to identify and fix issues in the legacy system and modernize it to meet current and future needs.

Software reengineering brings numerous benefits, such as improved system performance, increased system reliability, and reduced maintenance costs. These benefits make software reengineering a valuable investment for companies that rely on legacy systems to conduct their business operations.

By investing in software reengineering, companies can modernize their legacy systems, improve system performance, and reduce maintenance costs, ultimately leading to improved business outcomes. It is a critical process that should not be overlooked in modern software development practices.

By prioritizing software reengineering, companies can ensure that their legacy systems meet current and future needs, ultimately leading to improved business outcomes and success.

Stages of Software Re-engineering

Re-engineering can be divided into seven stages, and the work involved, starting from the initial stage of determining the feasibility, effectiveness and cost of re-engineering and construction of a functional model.

  • Initial phase. The reengineering process should begin with determining what is in the existing system (initial tests, databases, descriptions, etc.). This fixes the current state of the inherited system (all changes made to it after this moment are not taken into account when performing reengineering).

  • Definition of system architectures. Work on the description of architectures actually begins at the initial stage, when the composition of the equipment and standard software (SW) necessary for the installation and launch of an existing fixed system are determined. Thus, the architectures of the database, hardware and standard software, and telecommunications are actually determined. All architecture is presented in UML notation and, if necessary, supplemented with textual descriptions. The sharpened architectural models in the process of reengineering will be refined and supplemented.

  • Automatic reengineering. Automatic reengineering is carried out using visual modeling tools. Its implementation allows you to build models that can be taken as initial ones. Both business logic (if there are
    Where can I find people to work on Software Reengineering projects? source codes in an object-oriented or object-based language) and the database is subject to automatic reengineering.

    Automatic reengineering of business logic can be performed only if there is (in whole or in part) the source code of the programs. Automatic code reengineering produces class diagrams and UML component diagrams.

  • Database reengineering is done using database design tools. The result is a relational data model that can be graphically displayed by this tool. The resulting relational model can, at the discretion of the developers, be translated into a UML class diagram by using the applied database development tool or software bridges with visual modeling tools.

  • Editing model diagrams. Automated models are very difficult to read and analyze because model elements are placed without consideration for diagram visibility. Therefore, the constructed models must be edited. During editing, you should not perform meaningful transformations (delete or add model elements). The main goal of editing at this stage is to achieve clarity of diagrams. For this, the movement of chart elements is used. During editing, comments can be added to model elements. For example, you can comment on the purpose of individual classes. Comments are entered in the specification fields of model elements.

    If the diagram contains too many elements, then it is difficult to analyze it. Try to analyze a diagram containing over 100 classes! Therefore, it is advisable to break such a diagram into several separate diagrams, leaving approximately 7-10 elements in each.

  • The method of increasing the visibility of diagrams is well known. This is a hierarchical restructuring. The means of its implementation in the UML are packages. Complex software systems usually include several subsystems with different purposes and functionality. Therefore, at the top level of the hierarchy, you can show packages - subsystems. Each of these packages should be given a name that reflects the essence of the corresponding subsystem. At this level, you can also show class packages that are common to the entire system and used by subsystems. At the initial stage of restructuring the logical model, you can introduce a top-level package, where classes are placed that are difficult to attribute to any other package. Any PS has a user interface, communication with the database, management, and processing. This type of package can be introduced into each subsystem at the next level of the hierarchy.

  • Construction of a functional model. The functioning model is described using diagrams and detailed diagrams of sequences and activities. The source for its construction is a working inherited system and experiments carried out with it. At this stage, it is especially effective to involve an expert in the customer's organization in the reengineering work. It is possible to quickly and accurately determine the composition of the actors of the inherited system. The customer's expert can verbally describe who uses the system and what it should do for each type of user.

Team of Software Reengineering Experts

The team represents the heart of the project. It mainly consists of stakeholders such as IT project pilot, analyst, IT architect, developer, security specialist, system administrator, database administrator, application integrator.

Also, Service Oriented Architects, Modelers, Service Designers, Process Designers, Service Developers, Integration Specialists, Interoperability Testers, SOA Pilots, SOA System Administrators, Software Operators

The application user, on the other hand, is part of a team of software operators, and the success of a reengineering project depends to a large extent on their agreement with the application transformation they are trying to achieve.

Software statements, but outside the structure in which the RL will be executed

They provide good objectivity regarding the selected changes.

Reverse Engineering

Reverse Engineering is a method of disassembling an object that helps to understand how a previously created device, process, system, or piece of software is constructed. An engineer takes a product apart to understand how it works and then recreates a similar or identical solution. The developer answers the question: “What processes provoke this behavior of the product?”.

In this way, it won't be possible to obtain the exact source code, but engineers will be able to understand the general logic of work and repeat the functionality.

Reverse engineering is used in computer engineering, game development, mechanical engineering, design, electronic engineering, software development, chemical engineering, and even systems biology.

Companies often reverse engineer old, discontinued electronic components. If a piece of computer hardware has features lost due to changes in technology, reverse engineering allows manufacturers to discover and update those formulas. The method also helps to develop components that connect new and old, in order to connect obsolete equipment to new.

In IT, reverse engineering is used to study software and hardware, their elements, and principles of operation.

Objects can be:

  • files - to find out exactly how the application works;

  • part of the operating system - to use undocumented features;

  • data format - to get the structure of the file format;

  • network protocol - to restore the format of data packets and the sequence of data exchange.

What is reverse engineering used for?

  • search and correction of errors in programs, to the source code of which the developers do not have access;

  • analysis of viruses to create anti-virus software;

  • improving the functionality of the application when it is impossible to contact the previous developer - for example, the developer company has ceased to exist;

  • a description of the mechanics of the game. When the developer takes an existing game as an example, observes its development, analyzes the scenario, and offers his own version;

  • learning: if a developer does not understand some part of his product, he can analyze someone else's and draw conclusions about its functioning.

Reverse engineering is also used for illegal purposes - stealing code, bypassing technical copyright protection, and endless use of free versions of the application.


Restructuring is the transformation of software into other software in order to preserve its external behavior in terms of functionality and semantics. The code-to-code transformation name is also used to describe the restructuring.

Software restructuring changes source code and/or data to make it amenable to future changes. Restructuring doesn't modify the overall program architecture. It focuses on the design details of individual modules and on local data structures. If the restructuring effort is beyond module boundaries and surrounds the software architecture, it becomes forward engineering.

There are a number of benefits:

  • Programs will have high quality - better documentation, less complexity, and accordance with current software engineering practices and standards.

  • Irritability among engineers who have to work on the program is reduced, so productivity is improved.

  • Reduced efforts required to perform maintenance activities

  • The software will be easy to test and debug.

If the basic architecture of an app is solid, even though technical components need work, software restructuring occurs. It is possible when major parts of the software are serviceable and only a subset of modules and data needs modification.

Code Restructuring

Code restructuring is used for a design that produces the same function but with higher quality than the original program. 

A resource exchange diagram maps each program module and the resources that are exchanged between it and other modules. By building representations of resource flow, the program architecture can be restructured.

Data Restructuring

Before the start of data restructuring, the analysis of the source code must be included. A programming language statement that contains data definition, file description, I/O, and interface description is evaluated. The purpose is to extract data items and objects, and get information on data flow, to understand the data structures that have been implemented. 

After data analysis has been completed, data redesign (data name rationalization) starts. A data record standardization step makes clear data definitions to achieve consistency among data item names or physical record formats. Data name rationalization ensures that all data naming conventions conform to local standards.

Forward Engineering

Forward Engineering (Renovation and Reclamation) is an approach to building an app with the help of the given requirements. 

It requires high proficiency skills. Forward Engineering takes more time to create an application. It is a technique of creating high-level models or designs to build complexity and low-level information. The software engineering process which includes SDLC to recreate the associated existing applications is a forward. 

Main features of forward engineering:

  1. It is a variety of engineering that has a variety of principles in the amount of packaging and information processes.

  2. It represents a ‘normal’ development process.

  3. Deals with the conversion of business services, processes, and functions into applications.

  4. In this approach, the first is to develop a business model. Then the package from the model was developed.

  5. Forward engineering tools are moving from implementation styles and logic to the event of supply code. The user can develop a business model that can be translated into data system components.

Re-engineering is an important part of software evolution 

Do you have a system that is already built but needs improvement? The previous developer abandoned the project, "locking" your investment in unfinished software. We can help!

We have seen many cases where a client already had a solution or piece of code but needed to update or continue working on the program. The most typical situations:

  • Need new opportunities

The software works great, but new features are needed and the previous command is not available.

  • Operation speed has become slow

The software is functional, but the number of users has grown, or the database has become larger. The speed of work has become unacceptably low.

  • There are bugs in the software

The software mostly works, but there are bugs that the previous command cannot fix.

  • An old version of CMS

The software is built on an old version of CMS. The user wants to take advantage of new features, but custom modules are written in such a way that they cannot be easily updated.

  • Development not completed

The software is partially functional. The team that started the work cannot continue or the client decides to replace the developers.

  • Complex interface

The software works, but users complain about the complicated interface, spend too much time doing trivial things, or can't find the functionality they need.

  • The current software is self-made

The software is a self-made prototype and there was a need to develop a professional version.

 In most cases, it is convenient for us to work with someone else's code, as we understand the limitations and needs of our clients. But there are certain risks that must be taken by all parties, as well as a number of mandatory steps.

Where can I find people to work on Software Reengineering projects?

In Agilie we can help you with re-engineering projects. But the main obstacle is that we can't make any judgments before we explore the existing solution and analyze the code. Even after that, there is still the risk of the appearance of previously unnoticed solutions by previous developers. This is also part of our work and the risk that exists.

The rest of the process is similar to standard software development methods. We are working on what needs to be done and comparing it to the current or expected version. Then we create a backlog of the necessary features and implement them in accordance with the customer's priorities.

In many cases, we will use an existing solution as a prototype. In this case, we reproduce the capabilities of the system, looking at how they should work.

Sometimes we will be able to build a system on top of an existing solution and use the existing code. Sometimes it is necessary to do code refactoring to make the system easier to maintain. In the most complex cases, the software is developed from scratch.


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