The patterns-and-practices tag has no usage guidance.
4
votes
2answers
84 views
Should I use the same object for individual instances and collections?
One of the functions of an application I manage is to operate a fleet of vehicles. I have an object vehicle with which I can do tasks that are vehicle-related; getMileage(), setDriver(), etc. I also ...
0
votes
1answer
60 views
Is it a bad practice to use external files for storing SQL templates?
I am working on a report system which aggregate a lot of data from multiple sources (databases and internal APIs).
Among other things I communicated with another departaments and told them I need some ...
5
votes
3answers
203 views
Design: How to avoid breaking backward compatibility because of database changes
This is my scenario, I have this interface:
public interface hitTheDataBase
{
public void insertMe(String [] values);
public void modifyMe(String [] values);
public DataTable selectMe();
...
1
vote
4answers
95 views
File-Directory Implementation: Does a a file have to own a reference to it's dir?
I am currently issuing a problem while forming the program-design, which is exact like a File-Directory relationship, and to ease it, I am using that as an example.
I think it is usual, that a ...
0
votes
1answer
41 views
How to design interface communication beween objects?
I'm stuck on a lightly philosophical question for me. I have three classes and I'm not sure how to make them related to each other. I have few competing approaches all of them standing on equal ground ...
1
vote
1answer
185 views
Is defining only one method against S in S.O.L.I.D
The first version of pseudo code I consider a code smell because of (I think) the Command Query Separation principle and/or the S in S.O.L.I.D. What I like to see is in the 2nd version.
Should I keep ...
1
vote
1answer
56 views
Best practices for working with public_html folders and git
Currently, everything that is in the public_html folder automatically gets published live. The git repository is also inited in this folder (though this can change if it's necessary).
What is a good ...
0
votes
1answer
63 views
Architecture of approval process
I want to design an approval process for my work flow but I wonder if there is an architecrural pattern or desing pattern for this solution.
For example an engineer will create a work. And program ...
1
vote
1answer
57 views
Is it a common pattern in Python to have instance variables assigned in a constructor start with an underscore?
I recently started using UtilSnips, a Vim plugin allowing for a certain level of automation while coding by using template-like code snippets for common code fragments (class and function definitions, ...
2
votes
4answers
84 views
Keeping a ratio column that's the division between two other columns
I'm about to build a SQL table where I want to store currency orders. That means that I need to store how much I paid for a certain quantity, and the ratio between both quantities. So for example:
...
0
votes
0answers
19 views
Relying on file hash for data synchronisation across mobile and server
Imagine a client-server app that lets user upload images/documents etc. to server and then lets users who have access, retrieve and view them later on their
respective mobile devices.
So the flow is ...
9
votes
8answers
795 views
Designs and practices to guard against erroneous null entries from database
One part of my program fetches data from many tables and columns in my database for processing. Some of the columns might be null, but in the current processing context that is an error.
This should ...
4
votes
2answers
119 views
Should a RESTful API be able to return files, or just a location
This has been puzzling me for a while.
For example, we have a REST API that provides basic content to a system, consuming and producing JSON. At this endpoint it produces a URL to a picture and a ...
2
votes
0answers
33 views
Should my application call statsd directly or should I call statsd based off logs?
I'm planning on incrementing counters in statsd based of various events within my application. I have logging in place for these events. So, from my viewpoint I have two options:
Update the ...
0
votes
1answer
58 views
Reusing array with static test data across test classes
I have a Map which takes in an a String key, and an array of custom objects as the value. the map usually contains two entries, and the arrays for both entries never change in terms of data; once they ...
5
votes
5answers
499 views
Advantages of Strategy Pattern
Why is it beneficial to use the strategy pattern if you can just write your code in if/then cases?
For example: I have a taxPayer class, and one of its methods calculates the taxes using different ...
2
votes
3answers
226 views
CRUD operations in DDD
I'm designing an application with DDD. I'm moving from flat POCO objects to strong domain models, so my question is:
Would I have to call my basic CRUD operations (located in my repository layer) ...
0
votes
1answer
267 views
MVC Best practice mixing Partial View and JavaScript
I searched the internet and really can't find a good answer to this question.
Imagine there is a View that contains a simple tab-element. Each tab-content is loaded dynamically (via ajax) when the ...
1
vote
2answers
94 views
Explaining concepts [closed]
How can I explain a concept when I don't know its name or any formal reason for it? The reason I ask is this...
A new programmer has entities with a property title in his system. He uses the title to ...
1
vote
0answers
77 views
Algorithm for evaluating line breaks efficiently [closed]
Consider following problem :
Given:
String input with the length n
Font(-metrics) - potentially slow in usage
Bounds of an abstract Textview which shall contain the text in a specific manner:
e.g ...
1
vote
1answer
90 views
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 ...
4
votes
1answer
341 views
How to make sure people call methods in the right order?
Situation
I'm designing a database abstraction layer for sql (mysql, sqlite) and mongoDb. The goal is to give the user/developer a library which is able to create queries for different databases. ...
3
votes
4answers
444 views
Where to store average value in db?
I have a restaurant review app which stores reviews in a db, MySql.
There's 2 tables. 1 for Restaurant. Another for reviews.
To increase the performance, I am considering to store the avg review of ...
8
votes
4answers
349 views
Is there a Haskell idiom for trying several functions and stop as soon as one succeeds?
In Haskell, I can use the type a -> Maybe b to model a function that either returns a value of type b, or returns nothing (it fails).
If I have types a1, ..., a(n+1) and functions f1, ..., fn, ...
1
vote
2answers
270 views
Is there a name for this pattern?
A while loop can be written as follows in C# (and many other languages):
int someValue;
int someTerminatingValue;
while ((someValue = GetSomeValue()) != someTerminatingValue)
{
// Do something ...
1
vote
2answers
341 views
Joshua Bloch Enum Singleton and Third Party APIs
In the book Effective Java he give the best Singleton pattern implementation in his, that is implement by a Enum. I have doubt to how to implement this pattern with a third party API.
I'm using an ...
2
votes
2answers
183 views
Does it break SRP to have concerns of data handling and object mapping inside a single class, as part of the DataMapper pattern?
Summary
I want to look into separating the concern of "creating a populated object from database", to use inside my application. DataMapper pattern seems to be doing just that for me.
DataMapper ...
9
votes
4answers
601 views
Reducing boilerplate in class that implements interfaces through composition
I have a class: A that is a composite of a number of smaller classes, B, Cand D.
B, C, and D implement interfaces IB, IC, and ID respectively.
Since A supports all the functionality of B, C and D, A ...
1
vote
1answer
54 views
Name pattern for quickly find descendents with SQL (PATH column with [TopId]…[DirectAncestorId].[OwnId]) NO nested sets
I read a long time ago about a pattern/technique for easily querying for all "descendants" of a record (no need to use CONNECT TO, which is not standard and not available with JPA).
I remembered the ...
3
votes
4answers
291 views
Function wrappers with no args: bad practice?
My colleague likes to write classes containing methods looking like this:
public function doTaskA()
{
return $this->doTask('A');
}
public function doTaskB()
{
return $this->doTask('B');
...
1
vote
2answers
748 views
Are the Repository Pattern and Active Record pattern compatible?
Currently I am developing a webapp where I have defined models implementing the Active Record pattern. Each model also is defined by an interface that specifies the Entity properties and makes it easy ...
1
vote
2answers
204 views
Is it a good idea to install more libraries than you need? [closed]
I decided to try Anaconda, it seems that too many large companies are using it. I was amazed by the number of libraries included by default
installing: python-2.7.9-2 ...
installing: ...
1
vote
1answer
462 views
JSP in Javascript file or multiple AJAX requests
I've been thinking about how I want to load my data for some checkboxes in an AngularJS app. I'm generating multiple checkboxes based on 2 JSON objects that are currenty hard-coded in the a Javascript ...
3
votes
2answers
179 views
Is it OK for an MVC view to request data from other sources than just the model?
I'm working in ASP.NET MVC, but this question is pretty much applicable to any MVC framework (and maybe even others).
In a typical MVC application a request arrives at the controller, which then ...
2
votes
1answer
56 views
Queue rescheduling naming convention (Command pattern)
For my project I'm creating a queueing mechanism based on the Command Pattern, which can execute one of a number of jobs. Jobs can add other jobs to the queue or can be added by a human. Most of the ...
7
votes
1answer
385 views
Should I build undo stack in model or its wrapper?
I am building an application (Python/PyQt). The first-order item will be a tree view/model with many helper functions to add new items, move them around in the tree, etc.. Then I will have a main ...
5
votes
3answers
500 views
How to solve the Lava flow anti-pattern?
In this blog post, the author describes an anti-pattern called the "lava flow"
In a nutshell, the lava flow anti-pattern happens when many programmers lead the development of an application, each of ...
5
votes
1answer
220 views
Is it poor decision making that using promises for GUI inputs?
So as you know the context: DOM with JavaScript, even though I think it is mostly a language agnostic issue (I know I put both language-agnostic and JavaScript tags, but it's only to let you see ...
0
votes
4answers
301 views
2 methods that are 75% the same? [closed]
I have code that violates the DRY principle and I would like to consolidate 2 methods as much as I can, but the problem I am facing is that they have some differences, I would say they are about 75% ...
0
votes
1answer
145 views
Why use the Singleton pattern over class functions and fields? [duplicate]
I'm going to start by saying that I understand that programming in mostly class functions and variables can be harmful to object-orientation, and that most of the time an instance is preferred. I'll ...
0
votes
3answers
250 views
Check a boolean before setting it in a loop, or just set it
I have a rather tight loop with the following check to see if balance had ever been positive:
balance_null = True
while (crazy_loop()):
...
if 0.0 < balance:
balance_null = False
...
2
votes
3answers
1k views
How to implement the repository pattern for an app that will change its database from sql to nosql on in couple of years?
I have been reading a lot about repository implementation. I am confused about which way to implement it for a project I am sure would change its data layer methods because of db migration from MS Sql ...
3
votes
3answers
2k views
Why is it a good practice to keep Javascript code in separate files?
In web development we are commonly used to keep Javascript code in separate files, but sometimes we need this Javascript code to manipulate server side data locally.
For example, making an Ajax Call ...
4
votes
2answers
104 views
Is it a good idea to have a database row that represents an unknown value within a system [closed]
We have two systems, System A imports a list of sports events from system B, it only wants to import the events we will be providing live data for, the filter used to hide events that we are not ...
2
votes
1answer
104 views
Combining Patterns: Fluent Builder and Null Object Pattern
I am currently wrestling around with some GUI code where I have a table whose rows correspond to some object, let's say a Person object. When the table initializes, it fills the table with the Person ...
5
votes
2answers
1k views
TDD with repository pattern
In my new project, I decided to try with TDD. And in very beginning I encountered a problem. First thing that I want to do in my application is to give ability to read data from data source. For this ...
0
votes
1answer
1k views
Design Pattern for Cron/Schedule in MongoDB
I am looking for a good pattern to handle cron-type data in a MongoDB collection (or collections). I have been peeking at the O'Reilly book MongoDB Applied Design Patterns and poking around the ...
2
votes
1answer
268 views
In a Table Data Gateway, where do I put queries that use joins
The book Pattern of Enterprise Application Architecture has the following description over the Table Data Gateway pattern:
“A Table Data Gateway holds all the SQL for accessing a single table or ...
0
votes
1answer
85 views
Does a create() method exist as part of a pattern? [closed]
Is there something special(i.e. a design pattern being related) to a method named create()?
Background
The case is, I often make some instances of objects (of the same class/prototype). These ...
4
votes
3answers
956 views
DDD, modularizing the application and domain layers without breaking the DIP
Quoting DDD theory:
The application layer is thin in terms of domain logic - it merely
coordinates the domain layer objects to perform the actual work.
When it comes to modularization, and ...
