A design pattern is a general reusable solution to a commonly occurring problem in software design.

learn more… | top users | synonyms (1)

0
votes
1answer
134 views

Observing progress of a distributed system

For a distributed system, there is a requirement of observing the progress of smaller applications on distributed computers (runtime 5 - 20 minutes). There is a web fronted, which right now only ...
1
vote
2answers
128 views

Should an abstract class always abstract its methods to an interface?

I had learned sometime ago that abstract classes should always abstract their functions to an interface. So instead of having something like this - abstract class a{ public int i; public int ...
1
vote
3answers
319 views

Passing data between hundreds of objects in java [closed]

Currently, I'm working with a group on building a model. This model simulates interactions between many "agents" in a region. Agents can be any entity such as a city, a farmer, a business etc. Each ...
4
votes
1answer
78 views

Mapping multiple differing taxonomies to each other

At work we have a varied number of websites selling second-hand products. The bosses have noticed that there's often some overlap between the products sold on some of the websites and would like to ...
0
votes
2answers
221 views

Is there a design pattern for dynamically applying transformations or filters to a model?

For example, there is a model of an event with certain attributes that can be adjusted by existing processes: maybe one that looks at a geo-location stamp and determines a nearby city; another that ...
2
votes
1answer
185 views

ASP.NET MVC - Dynamic Views with many similar controls

I have a main View which has several sections and a main dropdown at the top which defines how the rest of the view looks like. All these sections have some data that is visible all the time, and some ...
0
votes
1answer
365 views

Onion Architecture Structure

I am looking to understand and implement the Onion Architecture and have a vague idea on how to structure everything but need help to clear up some of my confusion. Based on different examples and ...
2
votes
2answers
216 views

Best patterns for variable-scope disposables

I have Client which uses a disposable Connection for talking to a remote service. A Connection is somewhat expensive to set up and needs to be Dispose()d properly. I want to allow multiple methods ...
3
votes
4answers
197 views

How to identify and run the most relevant automated tests?

Suppose you have a reasonably large codebase (0.5 - 1 msloc) with a large test-suite (6-7hr single-threaded runtime; with a mix of unit-tests and integration-tests built with different tools). You ...
31
votes
9answers
4k views

Should we avoid using design patterns in constantly changing projects?

A friend of mine is working for a small company on a project every developer would hate: he's pressured to release as quickly as possible, he's the only one who seem to care about technical debt, the ...
0
votes
1answer
133 views

What design pattern should I use for import, update, export

I need to create a simple payments validator. On the following class diagram, I tried to present the model of payments. As you can see, each payment type inherits from Payments class. Now I want ...
1
vote
2answers
207 views

Sanity check for design pattern used with an intricate calculation model

I am working on a project that generates technical brochures in batch. The 3rd party API that is being used expects POCOs with property names that match field names used in each of the brochure ...
3
votes
1answer
796 views

does this model-pattern have a name?

A few years back, I wrote this answer to a question from which the following idea emerged. I call these "Type Descriptors", as I have never been able to find this pattern documented or formally ...
3
votes
1answer
325 views

Is there a term for this coding practice?

One of the incidental complexities of introducing features to an existing system is that the programmer often has to touch several areas of code that are not immediately adjacent. Over the long haul ...
2
votes
4answers
165 views

Subclass only have methods without variables

Is it ok to have subclass which does not declare its own variables (instance variables) and inherits from super class or base class? It has methods and there are some common methods which it overides ...
2
votes
1answer
316 views

Builder pattern inside interface. Bad design decision?

I am having trouble evaluating an implementation of the builder pattern I just came up with. The context is an API library, so I am trying not to expose any implementations in order to have a stable ...
0
votes
1answer
159 views

Where and how to reference composite MVP components?

I am learning about the MVP (Model-View-Presenter) Passive View flavour of MVC. I intend to expose events from view interfaces rather than using the observer pattern to remove explicit coupling with ...
0
votes
1answer
193 views

Is testability and mockability really that important in web development?

I'm reading this series on Laravel, and it's in great depth dealing with making everything testable, using Repository instead of just using the Models, using Dependency Injection and other obscure ...
0
votes
2answers
128 views

Is there a better way to load objects?

I have always kept the code to load an object within the object itself. That way no matter what method is creating the object, it always has access to the method to load the object. However this does ...
2
votes
1answer
147 views

Choosing between the view and the controller for my code

I'm aware there are a lot of topics about MVC design but it's hard to find good explanations: what I should do, what are the consequences of the different possibilities... So I'm working on an ASP ...
4
votes
5answers
2k views

Is this a good practice or not?

I have a colleague who has come up with a way of 'genericizing' information from a database so that all his web application's drop-down lists can share the same object in his MVC.NET C# code and ...
2
votes
2answers
82 views

subclass reference to another subclass

Imagine I have the following code: class A: pass class B(A): pass class C(A): def __init__(self): self.b = B() Is the above code correct in terms of correct inheritance? I ...
2
votes
1answer
93 views

What is a good strategy to develop apps that run in console and as API?

I develop quite often scripts that are primary used as a console application but later they are used in other scripts, webservices and other things where it is very convenient, to just import the ...
1
vote
5answers
225 views

Coupling business logic with class definitions

Perhaps it is my scripting background, but my perspective is that the purpose of an object should be to contain data. Classes are necessary in that they provide templates and standard ways to classify ...
4
votes
3answers
665 views

What is a helper? Is it a design pattern? Is it an algorithm? [closed]

Maybe a little tongue-in-cheek, but as I can't find this answer anywhere through Google, so to ensure Programmers Stackexchange has the answer: What is a helper? I see the name being used everywhere ...
2
votes
2answers
361 views

Repository pattern implementation that knows nothing about the database table and column names

I've seen around the Internet and Github, implementations for the design pattern Repository that knows about database table and column names. I was think, if I want to work with the database as a ...
1
vote
1answer
421 views

Confused on how to properly employ a Repository Pattern with Service/Business Layer on top

I'm building a ASP.NET Web Api 2 solution for learning purposes, and I've hit a snag. I was wondering if anyone could tell me what exactly it is that I'm missing. My Web Api solution has 4 Layers: ...
1
vote
1answer
77 views

Adding new functionality to all of shelve.Shelf's subclasses in Python

In order to avoid the overhead associated with the shelve module's writeback option I'm interested in putting together a shelf class that only accepts hashable values, with hashability being a proxy ...
4
votes
3answers
98 views

Returning results of method on batch list?

The title is a bit vague so I'll try to elaborate. I have a function makeFoo(int bar) -> returns Foo or throws Exception. I also have a batch version of this makeFoos(int[] bars) -> ...
1
vote
1answer
106 views

Freeing Memory: Observer Pattern?

I am building a scientific application in matlab which handles several hundred large matrices (large as in 'very few of these will fit into ram'). Each matrix is contained within a dedicated object to ...
1
vote
0answers
375 views

MVC content management framework with an admin panel

I've lately been developing my own MVC content management system using PHP and, at least in my mind, am a little stuck with the system design. I believe this would apply to building a content ...
1
vote
1answer
209 views

Implement Generic DataSet Builder with C#

I want to create a data access library that can build a DataSets with relations which can easily be written to XML with dataset.WriteXML(). This is a get to know C# endeavor that will hopefully gain ...
1
vote
1answer
217 views

How to design extension mechanism for java app

I have an application where I have a set of core features. The application itself HAS to work in core only mode. I would also want to make the application extensible such that, when certain ...
0
votes
2answers
93 views

Select design pattern - user stage

I'm struggling to point a finger into the right design pattern. I have a web site which user can register and interact with the system. I want to add the following abilities to a user: Each user ...
0
votes
0answers
11 views

Select design pattern - user stage [duplicate]

I'm struggling to point a finger into the right design pattern. I have a web site which user can register and interact with the system. I want to add the following abilities to a user: Each user ...
0
votes
1answer
53 views

Store Arbitrary values related to mysql record

I have created an app that manages a Data cleansing workflow. Each row imported needs to store an arbitrary number of key value pairs in addition to our standard mysql schema. The key values need to ...
4
votes
3answers
524 views

Functional programming strategies in imperative languages

I've been convinced for awhile now that some strategies in functional programming are better suited to a number of computations (i.e immutability of data structures). However, due to the popularity of ...
0
votes
2answers
385 views

DTO - service layer - statelessness best practices interfering with each other

I am designing a REST API coupled with a service layer that takes DTOs as input and produces them as output. This works fine for most service calls where the DTO is used to access an underlying ...
2
votes
1answer
224 views

Design Patterns for creating tasks

I am developing software where each action in my entities need create tasks that will be execute in my infrastructure. When I create a task it is only records in the database. Afterwards, a windows ...
0
votes
2answers
168 views

Good architecture for passing data to multiple APIs

I have a hypothetical scenario where I need to pass data to APIs from multiple different providers, depending on the 'vendor identity' provided by one of the pieces of data. If I have the data as ...
0
votes
1answer
86 views

Implement RPC via SIP

Look at the following use case. I have a client (Java) application, which wants to get/set the state of another, remote application (C). The communication between them is done via SIP, which is run ...
0
votes
0answers
30 views

API providing function to be run in a thread vs. thread that runs this function

I'm writing a Python library which exposes a certain event listener interface. The user can register callbacks to handle different types of events. There is also a function which handles the actual ...
3
votes
2answers
276 views

Is the Java Integer cache a realization of the object pool pattern?

One of the best-known examples of a full-fledged object pool is the JDBC connection pool. Main reasons: objects in the pool are expensive to create and relate with external resources each object in ...
0
votes
0answers
32 views

update methods in simple factories

I have simple factory class with differently named methods which create the same object but differently. These created objects are persisted to db. These are then retrieved from the db elsewhere and ...
-1
votes
1answer
168 views

All programming functions always return to the If or If/Else statement? [closed]

After learning, coding, and coding even more than ever now, I have noticed a trend in a lot of programming which I do. The trend is that the majority of my functions are if{} or if{} else{} statements ...
3
votes
1answer
177 views

Pattern to use to relate multiple data sources to different user data widgets

I have an client x server intranet application the basically gets data from the server, format it and send that data to the client for display. At the server we are using ASP.NET C# running on IIS ...
2
votes
1answer
169 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 ...
2
votes
2answers
327 views

Reduce number of if statements through design pattern

I had a loop through object Process, each process instance can be of a different type, derived from Process base class (e.g.: Process1, Process2,...). Each derived type of Process has different ...
-2
votes
4answers
261 views

What is the name of this design pattern? [closed]

I have been using this "design pattern" (may or may not be an "official" design pattern) for a while and I wanted to know if it had a name (so that I could name my classes after it). Example in PHP ...
0
votes
1answer
151 views

Why is the “app” folder now a (more) common pattern in web projects?

It might be related to the Yeoman project, or they might have adopted this from somewhere else, but it seems to be the default for all of their generators. Aside from Yeoman generators I've also ...