Setting an array variable being passed to a function

Question

Ok this is a guess a really simple problem which I am having a black out about.... however it is killing my head. Here is the source:

import java.util.Arrays;
public class InputValues {  
    public int[] myarrayvar;
    public InputValues(int[] myarraypass) {     
    ---- help here
    }
    public void init() {        
    ---help here
    }
    public int[] getmyarrayvar() {
        return myarrayvar;
    }
    public void setmyarrayvar(int[] myarraypass) {
        this.myarrayvar= mayarraypass;
    }
}

I call the this with

InputValues inputValues = new InputValues(myarraypass);
inputValues.init();

myarraypass is of type int[].

Like I said this should be really easy.... but I can't get it to work for some reason....

In what sense you cannot get it work? What is the problem you have encountered? — Adrian Shum
– Adrian Shum, Commented Oct 19, 2012 at 9:48

Arham · Accepted Answer · 2012-10-19 09:44:02Z

1

In case your myarrayvar is public then why would you need a setter and getter. You need them only when your member is inaccessible to the outside world, i.e. it's marked private.
Nest, you can use the following in your constructor for setting the array,

public InputValues(int[] myarraypass) { 

    this.myarrayvar = new int[myarraypass.length];    

    System.arraycopy(myarraypass, 0, this.myarrayvar, 0, myarraypass.length );

}

answered Oct 19, 2012 at 9:44

Arham

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Azodious · Accepted Answer · 2012-10-19 09:38:58Z

1

You can try following things:

Change the instance variable access from public to private.
in constructor you can use following line:

this.myarrayvar = myarraypass;

But remember, if myarraypass is modified outside class InputValues, myarrayvar will also be affected.

If you don't want that behavior to occur, you should copy index-by-index.

this.myarrayvar = new int[myarraypass.length];
for(int i=0; i<myarraypass.length;i++)
    this.myarrayvar[i] = myarraypass[i];

OR

this.myarrayvar = (int[]) myarraypass.clone();

OR

this.myarrayvar = new int[myarraypass.length];
System.arraycopy(myarraypass, 0, this.myarrayvar, 0, myarraypass.length);

answered Oct 19, 2012 at 9:38

Azodious

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2 Comments

Thevagabond Over a year ago

I did 1. and inserted a print cmd in the setter... but that is never printing .. so I guess it is never called and I use the array to do a calc later and that returns a NullPointerException. for some reason the var is not set.

Thevagabond Over a year ago

Got it to work.. I placed the source way out of brakets... works fine now that I did that right.. :-) Thanks

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