Questions tagged [legacy]

Questions about legacy languages, code, or applications.

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Microservice integration with an external legacy system

We are decomposing a monolithic legacy system into microservices. As we do so, we can't completely remove reliance on some of the data in the legacy system that's required for each microservice. ...
2
votes
1answer
98 views

Wrapping a legacy project in a test framework

I am working on wrapping an old project written in C# in a test framework. The largest problem I have is that I have a bunch of classes that are all VERY tightly coupled with other classes. All of ...
-3
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1answer
33 views

Best Practices for Building An API and SDK for a Legacy Application

I have been given a task to take on a legacy application (which has a very poor API in terms of user experience, is undocumented largely, and performs slowly) and build a new API and SDK to improve ...
3
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5answers
322 views

How do you assess the damage in a system that has been using floats or doubles for money?

I've been assigned to a code base responsible for millions of dollars of transactions, per quarter, and has been in use for over a decade. Sifting through the solution, I see doubles used everywhere ...
3
votes
1answer
186 views

How to modernize large legacy Fortran program? [duplicate]

Problem Background Recently, I joined a government agency as a software engineer/scientist/analyst. Previously, worked in software industry - gained 3 years of software engineering experience at ...
4
votes
1answer
216 views

Is stateless mode necessary before containerizing a monolithic application?

In my team, we are maintaining a monolithic application that was started in 2003. It is written in Java and has seen several successive layers of technical changes, growing to a hefty 400k-line ...
8
votes
3answers
849 views

How do I write unit tests for legacy code (that I don't understand)?

Forward I've read a lot of things before asking this question, including many relevant questions right here on SE: (Software Engineering SE) Writing tests for code whose purpose I don't understand (...
2
votes
1answer
188 views

Is it possible to layer an API (REST, GraphQL, etc.) in front of data that is currently only accessible via an enterprise desktop GUI?

Currently, my thoughts are that GET requests would be feasible by using the concept of screen scraping combined with a cron job that runs at a set interval to scrape data from the GUI and sync to my ...
1
vote
1answer
853 views

Should I Microkernel or Microservice my legacy ERP?

I have been working on an n-tier monolith application for a couple of years, and want to build a plan to transform this big ball of mud to a more maintainable system. I came across Software ...
1
vote
1answer
249 views

Strategies for managing legacy data for a medium sized enterprise

I work for a mid market manufacturing company with around 1700 internal employees and about 7000 external users (employees of our customers). We grew through acquisition which means we have many ...
2
votes
1answer
363 views

With source code lost, can the binary be released as MIT without it? [closed]

I preserve old software by asking copyright owners (often one author) to release the source code under an Open Source License, GPL or MIT. In many cases the source is gone, but the binaries still ...
3
votes
2answers
136 views

How to convert multiple Git repositories for related code into proper branches/tags

Background I've recently become the technical lead/senior developer for a small R&D/data science team. I've got a decent amount of non-lead experience in bigger development teams, but I've not ...
14
votes
3answers
6k views

Is Poor Man's Dependency Injection a good way to introduce testability to a legacy application?

In the past year, I created a new system using Dependency Injection and an IOC container. This taught me a lot about DI! However, even after learning the concepts and proper patterns, I consider it ...
14
votes
6answers
3k views

What are the best practices around retiring obsolete database columns? [closed]

I'm designing an application which will in an early stage collect data A, B, and C from clients, but later on will instead collect data A, B, and D. A, B, C, and D are very related and right now ...
5
votes
2answers
539 views

How to approach this legacy Java project? [duplicate]

Edit: Assume that I will stay on this project until "the end". The Problem I'm currently working on a legacy interesting Java project(s).  A full rewrite is currently out of the question, as I am ...
2
votes
2answers
124 views

Make sense out of automatic information gathered from legacy system

I have a legacy system I need to plan a migration for. It's mainly developed in Ingres+4GL (an old Ingres based form system). I have the following information: Data Structures (data base relations ...
1
vote
2answers
2k views

What pattern for implementing multiple interfaces on the same type?

Description of the environment: I am implementing a (hobbyist) modern engine for (an old) PlayStation 1 video game Graphical data is represented as packets where it can represent either a polygon or ...
3
votes
3answers
369 views

Designing new system to replace legacy: Would you start with a new database and maintain both independently until the switch? [closed]

We have a legacy system which will eventually be deprecated, at which point we will switch to using a new system. What are the pros and cons of maintaining separate databases for the old and new ...
4
votes
2answers
820 views

Introducing TDD in a legacy product

I'd like to introduce test-driven development practices in an established legacy product. As with most legacy products, we could use quality improvement via safe gradual refactoring/code coverage and ...
3
votes
3answers
696 views

Questions to ask a developer about legacy code before they leave? [duplicate]

We currently have over 300 web projects that are legacy code, that is kind of spaghetti like based on a modified version of an old framework. Our one developer that knows these systems best is ...
0
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2answers
172 views

Advice on using middleware to phase out legacy ERP system

I would like to know if any of you have any experiences and advice you'd like to share about middleware systems? A little background first: the company I work for is based entirely on a closed ...
14
votes
3answers
316 views

Supporting development for older OS

I am maintaining a large portion of legacy code, written in C. This code was initially written to be comiled against Windows 3 for Workgroups, and later a version for NT was created. This legacy ...
3
votes
2answers
746 views

Repository pattern and Dependency Injection without an ORM

I want to implement the repository pattern in an old legacy project. I already did some research, and found that, without an ORM, it's completely acceptable to have methods like "GetBySpecialProperty"...
13
votes
5answers
693 views

Broken Old/Legacy Unit Tests

I work for a big company and I'm responsible for a large java application with thousands of junit tests. Since I moved to this role, there have been 200-300 broken tests (likely broken for years). ...
4
votes
0answers
97 views

Architecting an account system for oauth that bridges a new and legacy system

So this question is specific to implementing auth in our system but I'm looking for high-level (just the architecture) solution or advice on which direction to head towards. Overview (TL;DR) Our ...
3
votes
2answers
4k views

Converting static utility class into singleton

In company where I work we have lots of "utility" classes, each has lots of code inside (thousands of lines), and they are all static. And one static methods call anothers. The problem here is that ...
0
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0answers
186 views

Integrating legacy application with new functionality

We have a legacy application with, among other things, the ability to create instances classes within VB6 DLLs dynamically and call methods with varying signatures. We have no way of accessing the ...
0
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1answer
120 views

Access Database Migration: Sharepoint or Custom solution [closed]

In order to migrate a local Access database and make it available on-line I'm considering two solutions: Migrate the database to SQL and build a custom ASP application in order to add/edit/delete ...
7
votes
2answers
830 views

Going TDD in the middle of the project

They want us to develop new features of a product with TDD. I know that they don't usually write tests for legacy code of already developed modules. But yet, what if new features have to be added to ...
5
votes
5answers
2k views

How are financial organizations planning for the degradation of old programming languages such as COBOL? [closed]

I know that some financial organizations still use "dead" languages such as COBOL. I'm wondering what will happen in the future, when almost no one will program in those languages, and the maintenance ...
6
votes
3answers
1k views

Working with legacy code - introducing an external BDD integration test harness

Here's the scenario. There's a large, organically grown application written in some language and manner that makes it difficult to test. It works but is hard to maintain. Specifications are woolly, ...
3
votes
2answers
1k views

How to Keep Track of Thread Safe Code in a mostly Thread Unsafe Legacy Rich C++ Code Base

For large legacy C++ code bases, notions like Herb Sutter's "const means threadsafe" don't seem to help much, because there can be an overwhelming amount of code in const functions which are modifying ...
2
votes
1answer
346 views

Best practice for accessing data from an external legacy ERP system

I have an architectural problem, and would be glad to receive some consultancy :). The application I am developing (let's call it system A) is responsible for management of work groups, where these ...
-1
votes
1answer
228 views

Best solution for future maintenance of a website with hardcoded ids, custom CMS using bad database design [duplicate]

Recently I was put into a position of a tech-lead on a very interesting project that I have been partially working for two years. This project carries a lot of legacy stuff with it even though we try ...
2
votes
1answer
250 views

Working with a large, messy object [duplicate]

I have been handed a very cluttered, "One Ring" object (one object to rule them all). The OR class has 40 fields. These fields map to 16 different objects (the OR has all the fields from the 16 ...
5
votes
3answers
2k views

Inheritance vs containment while extending a large legacy project

I have got a legacy Java project with a lot of code. The code uses MVC pattern and is well structured and well written. It also has a lot of unit tests and it is still actively maintained (bug fixing, ...
1
vote
1answer
420 views

What is the most efficient method in converting AutoLISP legacy code to C#?

I am engaged in a project that works mainly in AutoCAD to design and manufacture prefabricated building components such as roofing trusses. One of our goals is to redesign a program that was written ...
0
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3answers
420 views

New and old technologies coexist in legacy system [closed]

New technologies can accomplish existing tasks in more efficient and powerful way. But sometimes old technologies cannot be discarded unfortunately, so more numbers of technologies in one system make ...
0
votes
1answer
83 views

testing: which code layers should I aim to test?

Say I have this code: Design { public function load() { $this->loadProduct(); $this->loadService(); ... } public function loadProduct() { ...
-1
votes
1answer
396 views

How to reuse spaghetti code

We're working on a new firmware for our new V2 device. The company has an older V1 firmware (and hardware). Hardwares are similar to each other (but there are some differences) so basically we could ...
9
votes
2answers
610 views

Too many CS files in a single project [duplicate]

I am working on a ‘brown-field’ project, with a team of programmers. I understand each programmer will have different styles. I am running into some criticism with my coding style, specifically ...
3
votes
1answer
360 views

When not to move a “C style” code to “C++ or Object Oriented” code?

Context I am (part of team A) developing a piece of functionality which depends on new APIs provided by team B. Old APIs (also provided by Team B) are there and this is how they are being used in our ...
5
votes
4answers
1k views

How do I handle merging code that hasn't been merged in ~3 years in an agile manner? [closed]

Our team has recently adopted agile practices and most of the team is new to agile. In our product, we use some code developed by another team and only they maintain that code. For the last 4-5 years,...
28
votes
8answers
4k views

What are the advantages to developing with outdated technologies? [closed]

A little background: I am working at a large company, using Windows XP and coding Winforms in VB6/VB.Net and some WebForms in VB.Net (95% maintenance code). I have one 4:3 19" screen. A more modern ...
2
votes
4answers
723 views

Considerations before rewriting a software component from scratch? [duplicate]

A piece of software is a patchwork of old and undocumented efforts. There are no comments, no documentation, and the code is hairy -- it involves Unix shell scripts that check for dummy files and then ...
13
votes
3answers
560 views

How should a non-IT manager secure the long-term maintenance and development of essential legacy software?

We are a small, very specialized, benefits administration firm with an extremely useful, robust collection of software, some written in COBOL but most in BASIC. Two full-time consultants have ably ...
1
vote
1answer
203 views

When should one use composition instead of re-writing the functionality?

Say, I have a class A which has methods m1,m2,m3,m4,m5.... m100. I am making another simpler class B and I require only m2,m3 and m5 in B. Should I be ideally using compositions and put a reference ...
2
votes
3answers
407 views

How to insert a database layer in PHP

I maintain and add features on a freelance basis to a website written in PHP. The application was started in PHP4 by a junior programmer back in 2006, and features some very insecure and ...
-1
votes
2answers
311 views

What's a good way to manage long piece of code in files? [duplicate]

I am a web developer and at the moment am finding it hard to cope with long un-documented code written by previous developers in an organisation I work for. With the deadline gun always pointed at my ...
1
vote
5answers
1k views

Is it sometimes reasonable to cut corners and expect to re-write software in a couple of years? [duplicate]

I work for an organization with one developer (me) and one DBA. When I started, the previous developer had developed applications that had bad architectural practices and it was getting and more time ...