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2 votes
4 answers
2k views

Is a class with a high number of member variables bad and is there a design structure for data processing?

Context: Java, fairly new developer I have inherited code from a friend for a project that processes variables. The first thing i notice is the class has a ton of member variables. I have always been ...
Ian's user avatar
  • 137
1 vote
1 answer
476 views

Design Chess - Object Oriented Design

I am trying to design online chess game(figuring out required classes). Need some suggestion on choosing better option to validate the move. So, lets say, I have below class Option 1 : My ...
Jeevi's user avatar
  • 159
1 vote
1 answer
171 views

How to add supporting information to the existing java object?

Is there a way or design pattern to add supporting information to the existing java object? Example I have a model class Parent and it has child models. Its nothing but hibernate entities with parent-...
Javee's user avatar
  • 19
1 vote
1 answer
242 views

Let a subclass determine the implementation of its superclass field(s)?

Say I have two classes abstract class A, class B extends A, and I let A has a private field of type List<String> to indicate that every subclass has a field of type List<String>(so I don't ...
NingW's user avatar
  • 269
0 votes
4 answers
375 views

methods that has only behavior and not manage class state, is that violation of encapsulation

This is a simple scenario in an office with employees and their manager. In this scenario, both managers and employees have a name attribute. Only the manager can change his own name Only the ...
Susantha7's user avatar
  • 406
4 votes
6 answers
2k views

The ID of an object is null at start. Does that make the object state invalid and violate encapsulation?

This question is related to How should an `Employee` class be designed? In the above question, to uniquely identify an employee, each Employee object has an id field as shown below class Employee { ...
Susantha7's user avatar
  • 406
6 votes
4 answers
35k views

A DTO class having an ArrayList of its own type - is this considered a good design?

I came across a DTO class like the below one. class PersonDTO { private String firstName; private String middleName; private String lastName; private String dob; // some 50 fields ...
madan's user avatar
  • 127
1 vote
1 answer
170 views

Can the has-a relation in OOP become ambiguous or difficult to know?

Assume I have the following code. class D { static Integer i1 = 42; } Is it true that D has an Integer? Or is it only for instance variable that we can have a has-a relation? I also wonder about ...
Niklas Rosencrantz's user avatar
3 votes
2 answers
4k views

Class design for writing multiple versions of multiple files

I am writing a web service in Java which reads some information from a DB and generates multiple JSON files which are written to S3. For each type of file, I have a POJO which is serialized to JSON ...
vjain27's user avatar
  • 81
5 votes
3 answers
1k views

When is an object of real world a (computational) object in OOP world?

In an OOP design phase strategy, Any physical/conceptual object of a system can be modeled(considered) as computational object in your OOP designed program based on below two conditions: First ...
overexchange's user avatar
  • 2,305
0 votes
3 answers
9k views

Have Superclass Contain List of Subclass?

For the GUI of a program, I want it to list several items, all of which are, from a programming side, just subclasses. They can add one of these items to a list. I don't want to hard-code which ...
sinθ's user avatar
  • 1,311
3 votes
2 answers
5k views

When to use inheritance or composition/aggregation?

In general, how do I decide whether to use make a class a super class, or to make it a private data member of another class? For example, given two classes, how does one decide whether to do this: ...
rurouniwallace's user avatar