How to do objectexist in 2017

[marco_baccalaro]

[ FlexSim 17.0.0 ]

I read that the objectexists is deprecated and to use treenode.rank instead.

How do I have to do it correctly? I'm not sure I'm doing it in the correct way.

If I do like this I get an exception when object does not exist:

Object box = item.first;
if (box.rank)
	box.color = Color(1,0,0);

[Matthew_Gillespie · Accepted solution]

The treenode.rank line is a copy-paste mistake. If the object doesn't exist the variable should be null and so you just put the variable into an if statement.

Object box = model().find("Queue1").first;
if(box)
	box.color = Color.red;

[sebastian_hemmannE3JAU]

And how does this work, if I want to know if a Label exists?

[Matthew_Gillespie]

You would need to get a reference to the label node:

if(box.labels["myLabel"])
	box.color = Color.red;

[ralf_gruber]

Would this be ok to use, if looking for a label "MyLabel" on Queue1 in the model? Or is there a better way?

treenode thelabel = model().find("Queue1>labels/MyLabel");
if(thelabel)
	return thelabel.value;

[Matthew_Gillespie]

If you just want to get the value of the label if the label exists there is an easier way to do this using the ? operator:

return model().find("Queue1").MyLabel?;

Your code works, but the preferred way to get a label node is using the labels property:

treenode thelabel = model().find("Queue1").labels["MyLabel"];

[cameron_pluim]

Similar to @Matthew Gillespie's comment, you could also use:

if(box.myLabel?)
        box.color = Color.red;

[Matthew_Gillespie]

Using the ? in this case would give you slightly different behavior depending on what the value of the label is:

//myLabel = 0

if(box.labels["myLabel"])	//true
if(box.myLabel?)		//false

//myLabel = 1

if(box.labels["myLabel"])	//true
if(box.myLabel?)		//true

//myLabel doesn't exist

if(box.labels["myLabel"])	//false
if(box.myLabel?)		//false

[cameron_pluim]

I didn't realize that. I thought it would always give true if the label exists. Thanks for the clarification

[Matthew_Gillespie]

box.myLabel returns the value of myLabel, not the node.

box.myLabel? does the same thing, but returns nullvar if the label doesn't exist

So either statement just gets you the value of the label. The if statement then gets given whatever that value is and it interprets certain things like 0's and null values as false.

[christoph_gruber]

Sorry, but I do not understand exectly:

//myLabel doesn't exist
 if(item.labels["myLabel"] == 0){
     msg ("Info", "Label myLabel doesen´t exist!");
}

This code does not work in 17.03 - it only works in 17.1!

But why doesn´t work the code below in 17.1?

@Ralf Gruber ; @Matthew Gillespie

//myLabel exist
if (item.labels["CControl"] == 1){
    msg ("Info", "Label myLabel exist!");
}

[ralf_gruber]

@Matthew Gillespie,

seems I am too stupid to figure this out by myself: Attached is a model as a sample. OnEntry of the Queue, I create a label MyLabel with the value of "1" on 50% of all items. On sendtport of that Queue, I want to send the item through the label value's port number ("1"), if the label exists and through port 2, if it does not exist.

Everything I tried does not work or throws an exception, because the label does not exist.

Can you please help me (and @christoph gruber) here?

Thanks

iflabeldoesnotexist.fsm

[cameron_pluim]

@Ralf Gruber, I'm seeing the errors as well, however if I replace the send to port to the following code:

if(item.MyLabel?)
	return item.MyLabel;
else
	return 2;

Then it correctly checks for the label, and doesn't throw the error.

But if you change the OnEntry to create a label with a value of "0" (so it can go to any output) then the above if statements returns false, and will return 2 instead of 0.

I'm not sure why your code throws an error, especially since the error is saying that the label MyLabel does not exist when that is what we are checking.

[ralf_gruber]

Cam,

that makes totally sense to me: Your expression checks the value of the label, while I want to check for the bare existence of that label. If you change the label value to "0" the condition never becomes true and all items go to port 2.

It throws the error for the 50% of items, where I do not create the label...I want my "objectexists()" back!

Thanks

Ralf

[Matthew_Gillespie]

You just need to be on 17.0.4 (or 17.1). The second line in the What's New for 17.0.4 says:

• Fixed an issue with the [] operator throwing an exception when the node doesn't exist.

This isn't an issue that objectexists would solve, the issue was that the [] operator on the labels property was being too strict.

[Matthew_Gillespie]

You shouldn't be comparing the label node to 0 or 1. If the label does exist it will return a valid treenode (which doesn't equal 1 or 0) and if it doesn't exist it will return nullvar (which also doesn't equal 1 or 0). So your code examples should look like this:

//myLabel doesn't exist
 if(!item.labels["myLabel"]){
     msg ("Info", "Label myLabel does not exist!");
}

//myLabel exist
if (item.labels["myLabel"]){
    msg ("Info", "Label myLabel exists!");
}

[ralf_gruber]

Matt,

thanks for clarification, it does work in the newer release. @christoph gruber

[arunTTT2P]

I am getting invalid exception error for the following code.

Object Box = current.subnodes[2];
if(Box)
{
		 current.color = Color.black;
}

Also see the attached model. The code is written in the process finish trigger of the processor.

objectexists-error.fsm

[mischa_spelt]

Have you checked that the current node actually has two subnodes?

if(current.subnodes.length >= 2)
{
	Object box = current.subnodes[2];
	current.color = Color.black; // Did you mean: box.color = .. ?
}

[arunTTT2P]

Hi Misha,

Thanks for the reply, your code will help.

The current doesn't have two sub nodes, only one. Conceptually, objectexists condition using

 if(current.subnodes[2])
{
		 current.color = Color.black;//I meant current.color only
}

shouldn't throw an exception right?

Regards,

Arun KR