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

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Extracting and generalizing “repeated” methods with similar functionality

Let's say we have a class with many methods that do something different but can be grouped together as one "kind of functionality". For example, adding a configuration o setting rules up. Let's go ...
3
votes
1answer
232 views

Help in writing more generic code

I'm doing a php MVC project using code igniter. I have two models, a and b. Each class contains four functions (insert, delete, update and view) and their implementations are almost the same with ...
0
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1answer
99 views

Best practices/patterns for generation PDF reports

I have PDF generation feature in my app. I am using iTextPDF for generating reports, so it works well. The problem is not exactly in pdf generation but in approach. Currently PDF generation code looks ...
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0answers
29 views

Develop an API within ESB to access a database

I am working with a service provider where I need to get data from their service. The service provider wants to give me access to their database to get the data I need. My question is should I ...
13
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4answers
1k views

How specific should the Single Responsibility pattern be for classes?

For example, suppose you have a console game program, which has all kinds of input/output methods to and from the console. Would it be smart to keep them all in a single inputOutput class or break ...
6
votes
1answer
706 views

What is priming the pump? Sometimes called a priming read

I was taught this expression and pattern way back in the day. Sure, the name comes from old pumps that needed to be filled with water before they could pump water, but who cares? We're talking about ...
2
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1answer
84 views

Getting posts from users that are being followed: two different implementations

I have two different implementations for retrieving posts from the users someone is following and I want to know which one you would recommend using. First I'l show you the tables, and then the two ...
3
votes
1answer
80 views

Simple messaging pattern to replace shared DB? [closed]

There are two modules A and B using the same DB. A imports B as a JAR. I read that messaging patterns can replace the tightly coupled solution of using a shared DB but I am not sure which message ...
7
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5answers
185 views

Open Closed principle in design patterns

I am bit confused about how Open Closed principle can be applied in real life. Requirement in any business changes over the time. According to Open-Closed principle you should extend the class instead ...
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2answers
2k views

Principle of least astonishment (POLA) and interfaces

A good quarter of a century ago when I was learning C++, I was taught that interfaces should be forgiving and as far as possible not care about the order that methods were called since the consumer ...
6
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1answer
163 views

Relaxed architecture DAL or anemic BLL?

Particularly for the sake of unit testing, I'm trying to implement an application with a layered architecture. I'm coding in C# and using ASP.NET Web API for the service layer. I'm aiming at a 3-layer ...
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1answer
134 views

Getting data from a database with the MVC model

I am creating an application which will have a very large database to draw it's information from (a student registration system to be exact). The database is created with Microsoft SQL Server if that ...
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2answers
131 views

MVC - Database search logic in View or Model

Special Note: I asked a very similar question on Stack Overflow, but I have since decided the problem should be solved from a design standpoint rather than an implementation standpoint. I have ...
0
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1answer
76 views

How to use link tables in backend code?

This is more of an open ended question regarding design best practice. Say I have two classes; one is a Vehicle, and the other is an InformationSource (for maintenance/repair information). An ...
0
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1answer
85 views

Design Pattern for Object Updates

I have a "Product" class that has some ID, and multiple other fields, and a function updateProduct(id, Product update). The intention is that "update" only contains the changed information - other ...
0
votes
1answer
42 views

Full data history, current values can be rebuilt ignoring provisional or invalidated changes

I would like to create a website for a local school and then offer it to others. The school's main headache at the moment is capturing student marks and comments at the end of each school term. The ...
2
votes
5answers
240 views

Constructor overloading or allow null?

Which is the preferred design to use, one constructor that allows null, or two constructors where one throws an ArgumentNullException on null? Two constructors with exception throwing public class ...
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2answers
95 views

What design patterns exist for large dataset manipulation within MVC for a rich client data grid?

I want to feed an HTML5 data grid with large data sets that the client will want to manipulate in different ways, e.g. aggregation, grouping, pivoting. The data comes from different web services and ...
22
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8answers
4k views

How can I promote the use of the Builder pattern in my team?

Our codebase is old and new programmers, like myself, quickly learn to do it the way it's done for the sake of uniformity. Thinking that we have to start somewhere, I took it upon myself to refactor a ...
0
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3answers
196 views

What kind of development am I doing?

I am doing a webapp for the internals in my company, it has been 8 months and now I want to become more professional about it, and to know precisely what I am doing. My workflow is to make little ...
6
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2answers
195 views

MVP (Supervising Controller) Does the view update the model?

I've been reading about MVP, specifically Supervising Controller. One thing I'm having difficulty wrapping my head around is how the View interacts with the Model. It was my understanding that the ...
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votes
2answers
60 views

How to allow Object creation of a class on only particular classes in PHP? [closed]

In PHP, let there be four classes A, B, C, and D. None of them inherits the other. They are all independent classes. Now, I want only B and C to be able to create Objects of the class A. D Should not ...
6
votes
1answer
100 views

How to allow for custom Rules in a Entity Component System designed game engine?

So I've been doing a lot of research into game engines, and Entity Component System (ECS) seems to be the most flexible and extendable design to use. Just to summarize, in ECS the basic idea is that ...
0
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1answer
83 views

Design patterns for ERP software with clients and web service

I'll will make ERP software for managing data for business activities. The solution must have two big parts: a WPF application for all the clients and an ASP MVC Web API application for all the ...
6
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3answers
363 views

Best practices for using public, protected, private?

Is it fair to say that it is good practice to default everything to private up front when coding something? And then only upgrade it to protected if a subclass needs it, or public if another class ...
1
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1answer
59 views

Better way to organize query methods in Android?

In my Android app I have a SQLiteHelper class that extends SQLIteOpenHelper, and takes care of things like table-creation and upgrades. SQLiteDatasource class that performs CRUD operations on the ...
2
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1answer
61 views

Invoking Methods of another component in Observer Pattern

Question: Are there any techniques for communicating with methods of other components but still keep a "pure" Observer pattern ? If yes are they indicated/regularly-used or am I just ...
3
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2answers
201 views

Using MVC style, where is the best place to put SQL functionality?

I am wondering about best practices here. MVC (Model - View - Controller) patterns involve separating components of your program that model the data, manipulate those models, and display those ...
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Is the observer pattern suitable when the observers are not independent of each other?

I have a class Car which has 2 properties: int price and boolean inStock. It also holds a List of abstract class State (empty class). There are 2 states which can be applied on the car and each is ...
4
votes
1answer
53 views

What is the best pattern to define own type with definitive collection of values?

I want to define own data type, say a Digit, which would have definite type of values ( 0 to 9 ) and I'm struggling with defining this in a way it's practical. What's the best way (design pattern) to ...
5
votes
2answers
102 views

Design pattern for too many ctor parameters within class hierarchy

Is there some design pattern for handling situation where class hierarchy constructors parameters force the most bottom classes to have too many parameters? Ideally this would be in C++, if language ...
2
votes
2answers
148 views

Reversible Functions

Currently writing a JSON Importer and creating some POJOs based on the data. I also have a requirement to write an JSON Exporter which take the information in the POJOs and exports a JSON doc. To me ...
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votes
1answer
99 views

Is there an official name for the “one object disease” anti-pattern (iterative single object operations on databases, services etc.)?

It is caused by the naive programming paradigm: focus on just a single object, do something with it, and if you have to work with many objects, you loop, iterate and traverse, repeating the operation ...
5
votes
1answer
105 views

Partially parallel producer-consumer pattern with internal state

I need to implement a producer-consumer pattern for reading, processing and saving electrical values. I have to implement this in C# .NET 4.6.1. I try to describe this in great detail, so that there ...
2
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1answer
134 views

Developing a calculator using the command pattern

In an attempt to solidify my understanding of the command pattern, I decided to write a calculator application that utilised it. After making some progress, I realised that my choice of application ...
4
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1answer
159 views

Am I using the factory method design pattern correctly, or which creational pattern should I use?

I've been studying creational design patterns for the past week or so because I have a common use case that keeps coming up, and I can't figure out which pattern fits the bill. Here is a simplified ...
0
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2answers
135 views

C++ class vs function header file

I'm using C++ for implementing a project that requires to import a file once. All the data in this file needs to brought in memory as key value pairs, but only when the file is imported. Since this ...
2
votes
4answers
120 views

Are names like OrderCreation and UserRegistration suitable names for business logic / domain classes

We have moved to a more SRP model and found coming up with class names challenging. Previously we had a Order class that looked something like this: public class Order { public void Create() ...
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4answers
230 views

Is Template Pattern a good way to implement DRY?

Here is my problem: I have and class structure like this: class Base { private: SomeType something; bool isSomeValue; public: virtual void myMethod() = 0; ...
2
votes
2answers
109 views

Should we add an extra class to this code sample

I have a shopping website which allows users to place orders. In my web application when the users click 'Create Order' i call an OrderService class which looks like the below: public class ...
3
votes
4answers
245 views

Defining logic without nested if-else statements

I'm working on a somewhat simple game. Currently trying to implement the game logic for moving the pieces around. Logic is something like this: does player have pieces in inventory? if yes: ...
5
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2answers
177 views

DDD: Creating reusable modules and service type distinctions (Domain, Infrastructure, Application)

So after reading "Implementing Domain-Driven Design by Vaughn Vernon" I've decided to refactor my code for better re usability by isolating what I believe to be core domain concepts into separate ...
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3answers
111 views

What should be in my business logic class

We are currently having an internal debate on how our business logic classes should be structured. At the moment we structure our business classes like this: public class OrderBL { public void ...
1
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1answer
162 views

What could be the better c# design for following requirement? [closed]

I am working on creating a c# design for following requirement. I am creating this for a fitness website. I have an article (as Text) and a exercise (as Image or Videos) as the base entity. Now i ...
0
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0answers
73 views

SQL/HQL in a Play framework controller and Service Layer pattern

I started using the Play Framework a couple of months ago. It "redefines" many conventions from the traditional Java world (like the way of using static methods among other things). I was browsing the ...
2
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1answer
121 views

Are nested private classes considered composition?

Background I am considering a design that includes a public API class containing many nested private classes. I am doing this for the following reasons: Why private nesting? They will have no use ...
0
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2answers
199 views

Per my design requirements, does this design hierarchy seem reasonable?

Background Construction Note that I am using C# here, but it may not be necessary to provide input to my conceptual questions about design. Consider the following design methodology... I work at a ...
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2answers
104 views

How to implement application that will connect to server allowing the server to request data

I'm not sure what to title this question or if this is the right place to ask it. After Googling and continually coming up empty, I'm turning here as a last resort. I've developed a SAAS web ...
19
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5answers
4k views

Is it okay for a class to use its own public method?

Background I currently have a situation where I have an object that is both transmitted and received by a device. This message has several constructs, as follows: public void ReverseData() public ...
0
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1answer
60 views

Change stock calculation depending on warehouse

I have a currently-existing stock management dashboard. The user selects a warehouse, and it displays the current stock in this warehouse. The stock management teams wants to display a date, ...