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

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How do I write an API that makes use of many smaller APIs?

I have a solid set of classes that do the following build tables from data and templates advanced form serialization build forms from data and templates launch overlays with forms/wizards short poll ...
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77 views

Polymorphic constants in Java

I am designing some polymorphic code to perform mathematical operations. The idea is to abstract out the underlying representation of the data, as different use cases require different representations....
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112 views

How to authentication user in REST API (domain driven design)

I am using REST API as a presentation layer of a DDD project. In order to secure API calls I am using token based security. http://www.codeproject.com/Articles/1005485/RESTful-Day-sharp-Security-in-...
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124 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 ...
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77 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 ...
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163 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 ...
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73 views

Guaranteed message sending for messages of different priority for different modules

We have created a message que system using priority messages. The idea behind this is as follows: We have a list of clients. All clients know if (and what kind of priority) messages they have ...
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137 views

OOP - Modeling a Chat Design Review [closed]

Seeking thoughts on the following design. I know the design could be lot simpler if use Sockets. But I wanted to think of a design with pure POJO classes. User string id; string displayname; ...
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99 views

Data Mapper pattern vs. model encapsulation

I am currently developing my first custom data mapper layer but have run into a conceptual problem that seems to be glossed over all books and guides I have read. My problem is as follows. My data ...
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62 views

is Command appropriate software pattern for this?

I have following task: I need to send several instructions after each other to the hardware. Next instruction is never sent before either answer to previous instruction comes (valid answer or error) ...
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164 views

Repositories, Gateways, Models and Architecture Questions

I am working with a Laravel project and I am looking for a way to solve the issue of bloated models and cross referencing between them. I had started extracting higher level methods to a repository ...
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115 views

Option<T> functional type implementation and scenarios

Have you ever being implementing Option<T> functional type? It is discussed here: https://app.pluralsight.com/library/courses/tactical-design-patterns-dot-net-control-flow/table-of-contents ...
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Can this be used to implement Post Redirect Get pattern?

I am trying to implement proper a Post Redirect Get on a PHP site (question is language agnostic in nature however). I thought about it, and realized that running this code on every request seems to ...
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83 views

Possible design patterns for a service that synchronizes two third party services [closed]

I am currently in the process of refactoring a web service that synchronizes two third party services. The two services do not really interact well with each other, and there is quite a bit of ...
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71 views

Function behavior dependent on the calling class [closed]

I have a base class B and several children classes of it. Every children B1, B2, B3... has a method that calls a method M of another class C. Class C has a component D (implementing an interface, ...
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2answers
189 views

Design of an online book reader

I want to design an online book reader system as a programming exercise. I wrote down the following requirements: Searching a book by title. Bookmarking a book. Mark a book as favorite. Give rating. ...
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58 views

Storing reference to a model obtained using DataMapper to be able to call save on it

When using the DataMapper pattern, which involves modeling classes containing business logic and knowing absolutely nothing about persistence, caching,... I usually want the models to represent real-...
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1answer
39 views

Deploying and maintaining a script on customer's domains

I am trying to figure the best way (or just the pros and cons of various options) for delivering a service via a script which runs on the customer's site (think Google Analytics). Unlike Google ...
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Fill widget with data retrieved from internet

I want to retrieve data from internet and show them into a widget. In particular, I've a widget with a QComboBox containing some service from which I can retrieve a list of exchange markets. When I ...
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383 views

Abstract Alert Dialog Builders (Same Method Calls, Different Objects)

Currently I'm working on an Android library that creates a dialog which allows to select colors from a palette (examples at the end) and I've stumbled upon an interesting design problem. To create ...
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Pattern for passing in a field as a parameter

I'm writing a Rails app which uses ActiveRecord ORM and a Postgres DB. I've got two attributes which are similar but are separate fields in the database. The assignment and saving of these is kinda ...
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289 views

How should one model an ExchangeService object (in ews-java-api) for sharing MS Exchange connections?

I am creating an application which uses ews-java-api to connect to an MS Exchange server. Once the connection is authenticated, the api dictates use of ExchangeService object for searching mailboxes, ...
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Adding fields a good use case for EAV? [duplicate]

Is being able to add fields quickly to a system a good use case for EAV? What would be the frequency or number that would justify using an EAV model?
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Is MVC controller an use case controller?

In GRASP (http://en.wikipedia.org/wiki/GRASP_(object-oriented_design) ), a controller (use case controller) is defined as: A use case controller should be used to deal with all system events of ...
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227 views

Partially Fulfilled Specification Pattern

We have a model (IPayableModel) with a boolean property indicating that a user may or may not pay for the item. A set of specifications defining criteria that would disqualify the model from payment ...
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121 views

How to to log clicks for a Pay-Per-Click software?

Let say you have a Website with advertising, and each time a user clicks on it, you want to charge an advertiser the amount he bids (basically, a pay-per-click system, like Adswords, with a different ...
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What is the best way to create DTOs from entities and update entities from DTOs in a layered architecture?

Option 1: At first I would make a call to my service layer, which served as an API for my core domain, to get a domain object or a list of domain objects and then pass them into the assembler which ...
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542 views

Pattern for validating rules having different signatures

I have a class in charge of responding to an input event and maybe triggering another event. To decide, it has several rules to check. I'm trying to get away from a class looking like this: public ...
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Strategies for maintaining backwards compatibility when persisting objects to XML [duplicate]

I am using XStream to persist Java objects to files. This works fine and so far I have had no problems. However, in the course of development, the objects have changed. Some new properties have been ...
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226 views

Choosing the right design pattern/architecture for a scenario

I have a situation, in which I would like your opinion about the best approach that I should take. Let's consider 10 classes (obj001, obj002 etc.) all which represent some business entities, and are ...
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2answers
334 views

Design pattern for multiple companies in AngularJS

We are on the verge of launching v3 of our in-house product. v2 was written completely in AngularJS and V3 will be the same, but written completely in Typescript. We have a few customers that have ...
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Concurrent directory-tree search

I am trying to get familiar with concurrent programming, and have picked up an excercise to use a fixed number of threads that search through a directory structure. This is pretty much the way it is ...
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207 views

Mailbox Pattern with Variable Arguments in C++

In a game I'm developing, the GUI thread is catching user actions, and the simulation thread is responsible of handling and responding to them. To minimize complexity and delay, I predefined all ...
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306 views

Transaction Management in Hibernate with DAO Design Pattern

I have many Tables, For every Table,we have DAO Interface and DAOImplementation class. Example DAO Interface public interface CancelPolicyDAO { public CancelPolicy insertCancelPolicy(CancelPolicy ...
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Need to refactor file downloader and post processing utility [duplicate]

Not sure whether this is the right forum to ask this but here goes. Using this solution - http://stackoverflow.com/questions/26571351/replacing-if-else-logic-with-state-strategy-pattern I was able to ...
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Generalization of phase based systems for card and board games

In an exercise of futility I'm trying to abstract and generalize a framework where to build any turn/rule based system. I've had a head start but after decompiling HearthStone I'm second-guessing that ...
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62 views

Choosing a pattern for domain logic on top of ORM model

I am using Python and ORM, particular SQLAlchmey. I have an ORM model which implements data mapper pattern. The model has a field state, which can take one of several states, let's say NEW, CANCELLED, ...
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67 views

How to clean composition root from anything other than object construction?

I'm doing poor man's DI (manual injection) in my application. My (pseudo-) composition root looks something like this: var connectionSettings = new Settings(SqlParameters) var dataLoader = new ...
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206 views

Am I following a good design thought process? Is the Abp framework overkill?

As I finish one project and start another, I have a small time window to come up with an architecture for the new. I am coming from the following design: Web applicationReceives domain models & ...
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154 views

The finer points of HMVC

I'm new to HMVC and whilst tutorials are great about dealing with the overall details of keeping modules separate and only letting controllers communicate, they aren't so great at explaining the ...
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276 views

What is a good way to structure my UI classes?

So, I have a program which has a swing GUI. (Java - duh!) I really, really don't think the way I'm structuring my classes now is good, so I am reorganizing from the ground up to follow best practices. ...
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168 views

How to validate information on server without using database or session

Each user has multiple sites they can access reporting data for in an application I am working on. To prevent having to go to the database on every single request, I validate that they have access to ...
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Passing configuration to a handler

I'm building my own JET Parser and one of the things I am trying to do as per the JET specifications is to allow changing of the start and end tags from the default <% and %>. Right now I have ...
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337 views

NCurses, scrolling of multiline items, “current item” pointer and “selected items”

I am looking for hints/ideas for the best (most effective) way on how to scroll multi-line items as well as emphasizing of the "current item" and "selected items" such as: 1 FOO ITEM 1 Foo sub-item ...
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1answer
183 views

Is this considered an implementation of the Template Method design pattern? [closed]

Please consider a StringBank class. This class holds a list of Strings and can return them to the client. It's code (irrelevant stuff omitted): abstract class StringBank{ List<String> ...
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885 views

Correct way to inject dependencies in Business logic service?

Currently the structure of my application is as below Web App --> WCF Service (just a facade) --> Business Logic Services --> Repository -> Entity Framework Datacontext Now each of my Business logic ...
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72 views

Modelling network and persistent entity representations

I have an app where I need to synchronize some entities (simply download latest versions of entities from server to client). Entity has bunch of text properties and bunch of resource links (referenced ...
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2answers
294 views

Can this argument be enough?

We have two C++ classes named Important and Small The class Small use a few methods and attributes from the class Important, but not all. Since our application is performance critical, instead of ...
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786 views

Implementing a strategy pattern with dependency injection

Okay, so the goal here is to implement a strategy pattern that can be tested using any sort of automated testing tool. I've been struggling with this problem conceptually for a few weeks now and I ...
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129 views

Looking for design pattern to represent shared state in music sequencer

I like to give lots of context, but also to state the basic question up top as concisely as possible. Feel free to read a little or a lot. I'm working on a music sequencer, and have been happy so far ...