从另一个构造函数和非法参数异常中调用构造函数

Question

for my two parameter constructor to call the four parameter constructor is it proper with what I have done(I am still learning). Also it is supposed to instantiate open interval so is that still correct? for the copy constructor how would I make a copy of the explicit value constructor? Also how do I throw an exception if memory has not been allocated for object being copied?

Answer 1

for the copy constructor how would I make a copy of the explicit value constructor?

There is no built-in in Java for this. You'd have to manually copy the fields you want to copy

public LetsCallThisClassInterval(LetsCallThisClassInterval other){
    this(other.left, other.right, other.stuff)
}

But this class looks like it should be immutable, so there is no real need for a copy constructor.

Also how do I throw an exception if memory has not been allocated for object being copied?

That just does not happen in Java. Memory is managed for you, and if you get an object reference, it will have been properly allocated already.

Or are you talking about other being null in the above example? In that case, you will get a NullPointerException automatically. If you prefer an IllegalArgumentException (debatable), you can add a null check:

if (other == null) 
  throw new IllegalArgumentException("other interval cannot be null");

Answer 2

Let me see if I get this right, you want to do a constructor inception? In this case what you would want to do is use the Constructor(//insert the variables that correspond); that should fix the problem.

Using "this" will make the constructor refer to itself, I mean the same method. For example it would be.

public Constructor(char leftsym, double left, double right, char rightsymb){
     new Constructor(left, right);
}

Now as a side note, the Constructor class already exists between the core classes in Java, I suggest that if you want to simplify your life change your java class name such as Constructor_1 or something like that.

Good Luck