Prevent Infinite Looping between Objects

[Steve Dyke]

This is my vendor object. As shown one of the properties is LastShippingAddress.

public class Vendor {
	
	private String vendorcode = "All";
	private String vendorname = "All";
	private String vendorAdd1 = "";
	private LastShippingAddress lastShippingAddress = new LastShippingAddress();
		
	public Vendor() {}

	public String getVendorcode() {
		return vendorcode;
	}

	public void setVendorcode(String vendorcode) {
		this.vendorcode = vendorcode;
	}

	public String getVendorname() {
		return vendorname;
	}

	public void setVendorname(String vendorname) {
		this.vendorname = vendorname;
	}

	public String getVendorAdd1() {
		return vendorAdd1;
	}

	public void setVendorAdd1(String vendorAdd1) {
		this.vendorAdd1 = vendorAdd1;
	}

	public LastShippingAddress getLastShippingAddress() {
		return lastShippingAddress;
	}

	public void setLastShippingAddress(LastShippingAddress lastShippingAddress) {
		this.lastShippingAddress = lastShippingAddress;
	}
}

public class LastShippingAddress {
	
	public Vendor lastShippingAddress = new Vendor();
	
	public LastShippingAddress() {}

	public Vendor getLastShippingAddress() {
		return lastShippingAddress;
	}

	public void setLastShippingAddress(Vendor lastShippingAddress) {
		this.lastShippingAddress = lastShippingAddress;
	}

}

This creates an infinite loop unless I change  public Vendor lastShippingAddress = new VendorV8(); to public VendorV8 lastShippingAddress = null;
Is there another way to do this without setting to null?

[Carey Brown]

You have confusing variable names for lastShippingAddress, one place it's of type LastShippingAddress and the other it's Vendor. Fix that first.

[Carey Brown]

Don't edit your first post anymore now that it has been responded to.

[Liutauras Vilda]

Steve Dyke wrote:This creates an infinite loop

Do you have an idea why would that happen?

[Steve Dyke]

Liutauras Vilda wrote:

Steve Dyke wrote:This creates an infinite loop

Do you have an idea why would that happen?

Yes I understand why it is looping.
I am just curious is there a way to do this without having to set private Vendor lastShippingAddress = new Vendor(); to null
I am trying to move away from setting any object properties to null.

[Steve Dyke]

Carey Brown wrote:You have confusing variable names for lastShippingAddress, one place it's of type LastShippingAddress and the other it's Vendor. Fix that first.

Not sure what to do to fix this.
The LastShippingAddress Object has a property of Vendor()
Vendor has a property of LastShippingAddress

[Carey Brown]

public class Vendor
{
	private LastShippingAddress		lastShippingAddress;
	
	public Vendor()
	{
		lastShippingAddress = new LastShippingAddress();
	}
}

class LastShippingAddress
{
	public Vendor					lastShippingAddress;
	
	public LastShippingAddress()
	{
		lastShippingAddress = new Vendor();
	}
}

This is what you have stripped down to the bare bones. On line 13 you don't have a 'lastShippingAddress' you have a 'vendor'.

It is not clear at all what you are trying to do, you obviously have a circular dependency. So, when you create a new Vendor, what should its lastShiippingAddress be if not null?

[Ron McLeod]

What is the relationship between Vendor and LastShippingAddress?

[Carey Brown]

You could use 'Optional' instead of null, e.g. Optional<Vendor> lastShippingAddress = Optional.empty();. Now instead of checking for null you have to check for isEmpty() or isPresent().

[Steve Dyke]

Carey Brown wrote:

etqMRVDetail.setVendorname(vendorV8.getLastShippingAddress().getLastShippingAddress().getVendorname());

I am sorry I can't describe this more precisely.

[Carey Brown]

Any reason why 'lastShippingAddress' is not the same type as 'vendorAdd1', i.e. 'String'?
Like...

public class Vendor {
    
    private String vendorcode = "All";
    private String vendorname = "All";
    private String vendorAdd1 = "";
    private String lastShippingAddress = "";
         
    public Vendor() {}
 
    public String getVendorcode() {
        return vendorcode;
    }
 
    public void setVendorcode(String vendorcode) {
        this.vendorcode = vendorcode;
    }
 
    public String getVendorname() {
        return vendorname;
    }
 
    public void setVendorname(String vendorname) {
        this.vendorname = vendorname;
    }
 
    public String getVendorAdd1() {
        return vendorAdd1;
    }
 
    public void setVendorAdd1(String vendorAdd1) {
        this.vendorAdd1 = vendorAdd1;
    }
 
    public String getLastShippingAddress() {
        return lastShippingAddress;
    }
 
    public void setLastShippingAddress(String lastShippingAddress) {
        this.lastShippingAddress = lastShippingAddress;
    }
}

[Lou Hamers]

Ron McLeod wrote:What is the relationship between Vendor and LastShippingAddress?

This is where I would start. This is more of a design and data model topic than a "How can I code monkey this thing to make it work?" thing. I suspect there's a broader data modeling issue, and we need a better high level view of the overall data model.

A Vendor is pretty obvious, but what is a "LastShipppingAddress" referring to? (And why isn't it just an "Address" type with a field named lastShippingAddress? After all an address is an address, right?) Is it the last shipping address for a customer/buyer/user? It doesn't seem like it belongs inside Vendor at all.

[Steve Dyke]

Carey Brown wrote:Any reason why 'lastShippingAddress' is not the same type as 'vendorAdd1', i.e. 'String'?

Sorry, but on my initial code I did not list all of the Vendor properties.

The Vendor records are pulled into my application from a remote data source as a list of Vendor objects.
There is a property for Vendor Code, Vendor Name, Street Address 1, Street Address 2, City, State, Zip, etc. This all represents the Vendor default data.
Therefor the Vendor address is made up of several properties.
Some times we will ship to an alternate address, maybe several times. Instead of our Purchasing agent retyping this alternate address every time I save the LastShipedAddress into a remote data file with a field that links back to the original Vendor record.
So both a remote Vendor record has the same structure as a LastShippedAddress record.
When a Vendor record is selected the Purchasing agent can leave as default address of chose the alternate LastShippedAddress.

[Carey Brown]

So, in your original Vendor record you could link to the alternate Vendor record or vice versa. Technically I don't see this as a 'lastAddress'.

What's your objection to using 'null' to indicate that there's no such link if one doesn't exist?

[Carey Brown]

Steve Dyke wrote:The Vendor records are pulled into my application from a remote data source as a list of Vendor objects....

Thank you. That's a good description.