Thread: Setting constraints on a field

i am coding a project that has "Shape" as the parent with various shapes (ie rectangle, triangle, etc.) as sub-classes using inheritance. i am supposed "Modify the constructor and set methods of the Shape class to verify the values of X and Y stay between zero and the MAX size. If X or Y are out of range, issue an error message on the console and set the value to zero." for some reason i cannot get it to work. when i run the program it will display the x-value even if it is out of range instead of zero. Here is the code for the parent class "Shape":

public abstract class Shape {

int x;
int y;
protected final static int X_MAX_SIZE=800;
protected final static int Y_MAX_SIZE=600;

//Constructor w/out parameters
public Shape(){
}
//Constructor w/ parameters
public void Shape(int x, int y){
x=getX();
if(x<0 || x>X_MAX_SIZE){
System.out.println("ERROR!");
this.x=0;
} else this.x=x;
y=getY();
}
public int getX(){
return x;
}
public void setX(int x){
if(x<0 || x>X_MAX_SIZE){
System.out.println("ERROR!");
this.x=0;
} else this.x=x;
}
public int getY(){
return y;
}
public void setY(int y){
this.y=y;
}

public abstract double area();
public abstract void display();
public abstract void display(Graphics g);
}

can you please clarify?

so i have a book for java and a professor that say that the following are constructors:

public Shape(){
}

&

public void Shape(int x, int y){
}

which i have both in my code.

Yes the first one is constructor of class Shape but not the second one.
Constructor has no return type, neither void.

so i got rid of the void. not sure why i had it there in the first place cuz i dont have it it any of my other constructors within my project. but i still cant seem to get the program to verify that the variable "x" is in between 0 & 800. when i enter in a negative # (like -20) and run the program it still displays -20 instead of giving me the "ERROR!" message and assigning 0 to x.

x=getX();

What's this line doing? Say, you are passing -20 to x in the parametrized(yours second) constructor and getX() will return you x's value that will be 0 as you didn't yet set.

quite honestly i have no idea why the "x=getX();" line is there, it was just my last effort in trying to get this to work. from my understanding, setX(); is supposed to set the new value for x. when i tried to set the new value for x using my constraints/verification

if(x<0 || x>X_MAX_SIZE){
System.out.println("ERROR!")
this.x=0;
}
else this.x=x;

it just sets the x value as -20

Yeah, so think logically, set before getting. Or simply remove x.getX() from the parametrized constructor.

so i took out the "getX();" line from the shape constructor:

public Shape(int x, int y){
this.x=x;
this.y=y;
}

public int getX(){
return x;
}

public void setX(int x){
if(x<0){
System.out.println("ERROR!");
this.x=0;
} else this.x=x;
}

I ran the program:
"The Circle is located at the x-coordinate of -20 and the y-coordinate of 20 with a raiuds 40."

It should show something like this:
"The Circle is located at the x-coordinate of ERROR! 0 and the y-coordinate of 20 with a raiuds 40."

Can't you just debug it on your own now? Try to find out the behaviour of your program by placing PRINT statements after each statement and find it's behaviour.