General guidelines on how to design classes with best known industry practices.

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Should I ever reset object state?

I have a series of TextBlocks which are drawn on frames to make a video of a book. I do it when user click on Make Video. User may change the content of some blocks and click again on Make Video. I ...
2
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2answers
143 views

Abstract classes and constants

I have two classes that share a lot of code and are conceptually variations on a common class. So I want an abstract class that contains all their common code and then they can each inherit from it ...
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0answers
78 views

How do I translate my source file to Java bytecode? [closed]

I'm creating a new programming with JavaCC which is the parser. I want the parsed data to be translated to Java bytecode and compiled to Class file which later will be executed by JVM Edit: I'm a ...
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1answer
72 views

Is there a name for classes that only contain variables (and getters and setters)? [closed]

For example public class Student { private int id; private String firstName; private String lastName; /*getters, setters, constructors*/ } As opposed to public class Course { ...
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2answers
107 views

Distinguishing Classes: How to catch system behavior in classes (Library System Case)

Suppose a Library System. if I think about Data, I can just distinguish Book, Member classes or at most Author or Publisher... (Are they only classes?), but I have some use cases, scenarios (Borrow, ...
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2answers
108 views

Object oriented Classes and single responsibility [duplicate]

I'm reading a book that explain that it is a good thing that classes have a single responsibility, that is, that they do a single thing. I can understand how to implement this in some cases I ...
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2answers
77 views

How to organize code which converts from one type to another

If I have a DateRange class, and I want to translate a DateRange into SQL (e.g. some_col >= '2015-3-5' AND some_col <= '2015-3-5'), where should I put the method that does the translating? ...
5
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3answers
221 views

OOP Practice: how to best handle dependent dependencies

I have a problem with the design shown in the picture. My Section class has some TextBlocks (or simply Blocks). The section should be drawn on a page (a Bitmap as device context). It sets the blocks ...
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2answers
76 views

Literal strings vs. object properties in JavaScript

JavaScript libraries in the same space (UI widgets) use two different approaches for instantiating components: Literal strings to specify types, and inlining as much as possible, for example: var ...
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3answers
82 views

Heuristics on when should one subclass and when not [closed]

Are there any good tips, when one should subclass and when should not? It's clear that we should not subclass when we want to reuse a single method of some class we override all methods, changing ...
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1answer
151 views

Adding a graphical view to a system

I currently have an program in Java that simulates railway movements. Essentially, trains arrive on platforms, pick up and drop off passengers, and then proceed, respecting signalling where possible. ...
12
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2answers
556 views

Taming the 'utility functions' classes

In our Java codebase I keep seeing the following pattern: /** This is a stateless utility class that groups useful foo-related operations, often with side effects. */ public class FooUtil { ...
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2answers
128 views

Flexible and easy to use settings class

I am thinking about a way to create a flexible "settings class" in C#. The question is: How to provide a confortable way to provide default values to the settings. I want the programmer to access the ...
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3answers
117 views

where should put showSchedule method in school system

In my school management system I have this partial class diagram: 1- In one use case student want to see his schedule of classes in week. this is what i suppose to do: get student object from ...
1
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1answer
145 views

Does dynamically generating classes in python affect readability/performance?

I have a set of classes that represent different objects (tables in a database): class ObjA: # some class specific attributes and methods def refresh(self): # implementation ...
1
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2answers
287 views

many to many relation in database schema and oop class diagram

I have Student and Group entities. Student can have many groups and Group can have many students too. so in database I should have middle class and change many-to-many relation to one-to-many and ...
5
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2answers
274 views

Should I use events or abstract methods?

Lets say I create an abstract class that manages some network functionality for me. I want to be able to be notified when something changes. For example: OnConnect or OnDisconnect. Should I create ...
2
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3answers
399 views

Class design - should methods call other methods?

I'm writing a very basic custom class for coupons and I've come up with a basic layout for the class, which consists of a number of small methods as I generally understand is a best practice. What ...
0
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1answer
116 views

Should I use a class as a wrapper?

Lets say I have a class representing a chemical compound class Compound(networkx.Graph): def __init__(self): super(Compound, self).__init__() And lets say that I want to add some ...
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2answers
69 views

My class diagram needs to model a relationship with varying quantities

I am trying to design a restaurant ordering system in UML, which should also include the stock system. One of the classes is a Dish (i.e. a dish on the menu), and another is an Ingredient. My ...
2
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2answers
196 views

Passing by value multiple times vs. Creating a public class variable

Suppose I have a series of methods across different classes that all use the same five core variables defined in my main method. I could chain these five variables as method arguments from one method ...
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3answers
560 views

Force Derived Class to Implement Static Method C#

So the situation is like, I have few classes, all of which have a standard CRUD methods but static. I want to create a base class which will be inherited so that it can force to implement this CRUD ...
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1answer
43 views

How name class which display data? [closed]

Houston, we have a problem. I can't think of a simple class name. I have abstract class, something like that: public abstract class DataDisplay { public abstract void dataDisplay(Data data); } ...
51
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7answers
6k views

Should a getter throw an exception if its object has invalid state?

I often run into this problem, especially in Java, even if I think it's a general OOP issue. That is: raising an exception reveals a design problem. Suppose that I have a class that has a String name ...
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1answer
241 views

How to store a potentially large amount of optional properties of objects?

I'm using Entity Framework Code First with ASP.NET MVC. This handles my database design based on the domain models within my application. As it stands, the engine I'm writing will have a website ...
0
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1answer
69 views

Storing Form Data in a class

I have a form that writes to a database. Other than creating a class handle an external API, this project is done. However, the processing script is your standard procedural calling of queries using ...
2
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2answers
191 views

Design - Parser.hasInfo(MyClass) vs MyClass.hasInfo()

I'm working on a document processing system. I feel confident with a Document class which represents each document being processed. The issue: Each Document can have a CoverSheet, and if it does, ...
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2answers
81 views

How to improve code that has to handle list-objects in general and special cases?

I do have an implementation issue that I condensed to the following code snippet, because the real code is much more complicated. The core problem is that I do have a container object that has a mixed ...
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3answers
93 views

Should foreign keys be represented directly when mapping database tables to classes? [closed]

Ok, in my database I have a table Event and a table Room. Each Room can have many Event. Room table roomID-roomName 1 - cafe102 ... Event table eventID- Time -type -roomID 1 - 11:20 - 1 ...
36
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9answers
5k views

Is creating subclasses for specific instances a bad practice?

Consider the following design public class Person { public virtual string Name { get; } public Person (string name) { this.Name = name; } } public class Karl : Person { ...
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1answer
217 views

Is class with callbacks a code smell in JavaScript? [closed]

When writing JavaScript (especially in node.js), I tend to use plain functions and callbacks. However, sometimes there's some context to share between some functions and I don't like to pass this ...
0
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1answer
231 views

When should a class be final? [duplicate]

I've only really seen this on Java's wrapper classes (String, Integer, etc.), but never in open-source projects, and I was never taught about it in any books or classes. I know it means the class ...
2
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4answers
513 views

When should something be a class? And are my chosen classes good OO design?

My background: I am new to programming. Python is my only programming knowledge. I program as a hobby, and I'm teaching myself by reading copious amounts of books. I understand enough about OOP to ...
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1answer
94 views

How to split a Service class in two but still use them like one?

I've got a class: AuthenticationService findLoggedInUser() Checks session if User is logged in. If not, check client persistent user login cookie and log in. loginUser($email, $pw, $remember = ...
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4answers
702 views

c++ coding practice class vs. “free” functions

I am currently writing my first bigger project in c++. Its basic linear algebra. I am aware that boost libraries and others exist, but for various reasons I need to write my own. Purpose of the ...
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2answers
140 views

Class hierarchy question - do you implement separate classes for the same behavior? [closed]

NOTE: The language I am using is C#. I am currently working on a 'The Quest' mingame where there is a player and some enemies. My design so far involves a base abstract class called 'Mover' and an ...
4
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2answers
297 views

dealing with a very large state machine in a class

I am currently implementing a class for a network protocol. The protocol uses a quite complex and extensive finite state machine. A pair of an event plus a state is mapped to a function, which does ...
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2answers
194 views

Why friend in C++ should be in the header file? [closed]

Friend function/class, FriendOfX for some arbitrary class X is an implementation detail of class X. Why in C++ we have to declare them in the header file? Are there any compelling reasons to make this ...
2
votes
1answer
108 views

class hierarchy with structurally different subclasses

I want to implement a protocol layer which sits on top of the TCP/IP stack. There is a limited set of PDUs that can be sent and for each PDU there is a class which represents it in a structured form. ...
1
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1answer
269 views

Entity Component System Coupling

Lately I've been working on a small personal project which is basically an Entity Component System framework with autoupdated Systems. While I have a pretty good idea on the way the framework should ...
0
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2answers
163 views

Designing Nested List<Class> Property in a Class

I'm currently in the class modeling phase of my project. Real life Scenario: Let's say I have a Project that is composed of Main Components and each Main Component is composed of Sub Components and ...
2
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2answers
629 views

One boilerplate class or many similar classes?

Lets say I'm trying to model a variety of objects that are virtually identical, the only difference being their class variables. Am I better off creating one boilerplate class and just calling the ...
4
votes
1answer
167 views

Implementing a Username Class

I am attempting to encapsulate several features about a user in a single class. Although the main use for this class would be to initialize it once and never have to call set any variables again, I ...
5
votes
1answer
373 views

Decoupling when constructors have non-contractual parameters

By non-contractual parameters, I mean parameters that are not interfaces or service dependencies, something like class Person(string name). I am writing a webpage scraping application, and so far ...
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1answer
123 views

Clarification about MVC Design pattern

I've been reading up on MVC and I had a doubt. The example where the Model, View and Controller are all individual classes whose objects are created and used to deploy the application in another ...
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0answers
124 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. ...
1
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1answer
44 views

What is Object Services class purpose?

I'm reading a book on TDD: (btw this question has nothing to to with TDD) link to the book on amazon Author often mentions/uses Service Classes For example we would have a Person Object Person would ...
2
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0answers
230 views

Have I created a Big Ball of Mud?

I'm working on a WPF application, trying to stay strict in separating View, ViewModel and Model. My application has a few different views in a relatively flat hierarchy. There is one view for editing ...
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2answers
136 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 ...
0
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0answers
67 views

Reporting Logic vs Domain Logic

Should the reporting logic to extract domain data in a certain format reside in domain objects or separate reporting objects? The reporting logic needs to: select entities/data which match selection ...