Rtyjn

Accessing a private field from one class to another not related to the former class in C++ (OOP) I have 2 classes - A and B . Class A has a member list<int> and a method addData() that adds a number to this list. The second class B has a function displayContent() - it iterates through the list of the class A and prints its content (the added numbers). The problem I face is that I cannot access the private (cannot be changed to public) field list of class A from the newly instantiated object (from class B ). I would like to ask how can this be achieved with getters/setters , or a copy constructor ? A and B A list<int> addData() B displayContent() A private list A B getters/setters copy constructor //identifier 'a' is undefined? - you didn't pass an instance of A as a variable and B is not a child of A, so how can a be defined? – user4035 Jun 30 at 7:39 ...

Best design pattern to avoid instanceof when working with classes that cannot be modified? I am overriding a method provided by third-party library class and trying to record exceptions that occur: @Override someJavaMethod(arg1, arg2, Exception ex){ //Declare some variables with default values if (ex instanceof SpecificException1) //Set values for the variables else if (ex instanceof SpecificException2) //Set some other values for the variables else //Do nothing } The issue here is that SpecificException1 and SpecificException2 are both third-party exceptions and I cannot modify them. SpecificException1 SpecificException2 I understand that using instanceof is not a great way to handle this. What design pattern / OO principles I should use to handle this? instanceof 2 Answers 2 There are no fundamentally different ways of solving this (at least not in Ja...

Object Mapping without losing existing data Usually Object Mappers are for scenarios to map a larger set of data to small set (example: Entity object has a lot of data but we want to return only a few of them). Entity Object mappers usually create a new Instance of destination object of small set and set the required fields from source object with larger set, but I have opposite scenario: I have a destination object which already contains some data and now I need to map a new source object with smaller data set into destination object. Source Class public class SrcObj { private String name; private int i; Destination Class public class DestObj { private String name; private int i; private float f; private boolean b; DesObj already contains the value of int i and float f, SrcObj has String name and int, i need to save SrcObj data into DestObj without losing existing data. Model Mapper always creating a new Object of DestObj which will map SrcObj into it but rest of the...