Show different values two objects of one class

Question

I use in my java tests asserting actual and expected values. Ofcouse, throw assert exception if two objects is different. But I want to know, what different.

If anybody know java library, answer me.

Simple: I want print to console all different fields: public, protected, private (primitive types). Object's class can have many inherited class. I want log only simple fields: String, Number, Boolean, Char, items of array[] / collections.

If field is another class, don't log it value (toString function). I want show different only simple fields for this subclass.

For Collections show only different values.

For example:

class A {
private String a;
protected int b;
}


class A1 { 
private int c;
private String d;
}

class B extends A {
private byte[] array;
private List<A> collection
private A1 a1;
}

So, we compare to object class B. If different fields a/b, I show:

field: a. values: Tom / Jerry.

If don't equals a1, then I want know, what field:

field: a1.c. value: 10 / 12.

Similarly for array and collections.

I can parse all fields for all inherited classes. I get each field, get field type. If it simple (String, Number, Boolean...) log different values.

If it's another subclass with own field I can recursively repeat for extract all fields. But I have issue: how I can extract from field value, if it's array or collection? I get from Field::get() object.

How I understood and get from object -> Type[] or Collection{Type} and that class is Type? If I can it, then simple. I compare arrays/collections by size. If size equals, then start equals each item.

Answer 1

To know if you field's type is an array, use isArray() method from Class .

From Collection{Type}, the type of the field is 'Collection', 'Type' is a generic. You can do extra check if you want on the generic by retrieving it with ((ParameterizedTypeImpl) myField.getGenericType()).getActualTypeArguments() but that's probably not necessary.