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Efficient check on EDataType [message #1740847]

Thu, 18 August 2016 23:28

Johannes Gross

Messages: 28
Registered: July 2009

Junior Member

I am parsing some JSON and putting it in a EMF based model, and for literals i have to distinguish to set them.
Currently i am doing:

if (type.getName().equals("Real")) {
        newobject.eSet(sf, Double.valueOf((String) ((JSONObject) je).get(property)));
} else if (type.getName().equals("Integer")) {
	newobject.eSet(sf, Integer.valueOf((String) ((JSONObject) je).get(property)));
} else {
	newobject.eSet(sf, ((JSONObject) je).get(property));
}

But i dont like it because string comparison is expensive and it should be an instanceof or equals object check. I could not get it to work however. EcorePackage.Literals.EString is just an int but not the type so i can't compare. As well as (type instanceof String) or EString didnt work for me. Any hints what the right approach is?

Thanks,
Joe

[Updated on: Wed, 24 August 2016 17:53]

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Re: Efficiant check on EDataType [message #1740872 is a reply to message #1740847]

Fri, 19 August 2016 09:15

Aurélien Mora

Messages: 38
Registered: July 2014

Member

Hello Joe,

I'm not sure to fully understand, what is your "type" variable ? an EMF object ? Anyway, if you want a quick comparison with no String, you probably should use an EEnum. You'll be able to use it like a java enum :

EType type = myObject.getType();
switch(type)
{
case INTEGER:
	break;
case REAL:
	break;
default:
	break;
}

[Updated on: Fri, 19 August 2016 09:56]

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Re: Efficiant check on EDataType [message #1740882 is a reply to message #1740872]

Fri, 19 August 2016 10:44

Ed Merks

Messages: 33224
Registered: July 2009

Senior Member

It seems NNTP is broken so reposting this on the web forum.
Johannes,

Comments below.

On 19.08.2016 01:28, Johannes Mising name wrote:
> I am parsing some JSON and putting it in a EMF based model, and for literals i have to distinguish to set them.
> Currently i am doing:
>
> if (type.getName().equals("Real")) {
So type here an an EDataType presumably.
> newobject.eSet(sf, Double.valueOf((String) ((JSONObject) je).get(property)));
> } else if (type.getName().equals("Integer")) {
> newobject.eSet(sf, Integer.valueOf((String) ((JSONObject) je).get(property)));
> } else {
> newobject.eSet(sf, ((JSONObject) je).get(property));
> }
>
> But i dont like it because string comparison is expensive and it should be an instanceof or equals object check.
Well for Ecore you can assume identity. So testing type == XyzPackage.Literals.ABC is fine and of course highly efficient.
> I could not get it to work however. EcorePackage.Literals.EString is just an int but not the type so i can't compare.
No, your confusing EcorePackage.ESTRING, which is an int with EcorePackage.Literals.ESTRING, which is an EDataType.
> As well as (type instanceof String) or EString didnt work for me. Any hints what the right approach is?
I think better would be to use EcoreUtil.createFromString(type, (String) ((JSONObject) je).get(property))) in all cases; the factory knows how to convert a literal to a value of the data type. Of course I don't understand if it will always be a String, i.e., without your model, I don't know which cases the final else covers.
> Thanks,
> Joe

Ed Merks
Professional Support: https://www.macromodeling.com/

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Re: Efficiant check on EDataType [message #1741088 is a reply to message #1740882]

Mon, 22 August 2016 22:21

Johannes Gross

Messages: 28
Registered: July 2009

Junior Member

Hi Ed, Aurelien,

thanks for your input! This resolved the issue.
I forgot to mention that type is:

EDataType type = ((EAttribute) sf).getEAttributeType();

where sf is my StructuralFeature that i am currently working with.
So Ed, yes the EcoreUtil works fine and does what it should, however I still would like to understand why i can't:

EDataType myType = EcorePackage.Literals.ESTRING;
if (type instanceof myType) {

}
This gives me a compilation error: myType can't be resolved to a type.
Really weird. If i put the EcorePackage.Literals.ESTRING directly in the check, its the same error. This is only our of interest, so if you have an idea what the reason could be, let me know.

Thanks,
Joe

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Re: Efficiant check on EDataType [message #1741110 is a reply to message #1741088]

Tue, 23 August 2016 07:42

Aurélien Mora

Messages: 38
Registered: July 2014

Member

Hello,

Actually, EcorePackage.Literals.ESTRING is not a type, it is an instance of EDataType, so you can't make an instanceof with that. If you need to make an instanceof, just use the interface EString.

But, in your example, both type and myType are not type of EStrings, they are EDataTypes. So I think the only comparison you can do is :

EDataType type = ((EAttribute) sf).getEAttributeType();
EDataType myType = EcorePackage.Literals.ESTRING;
if (type == myType) {
}

[Updated on: Tue, 23 August 2016 07:53]

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Re: Efficiant check on EDataType [message #1741204 is a reply to message #1741110]

Tue, 23 August 2016 16:19

Johannes Gross

Messages: 28
Registered: July 2009

Junior Member

Got it, thanks Aurelien!

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Re: Efficiant check on EDataType [message #1741988 is a reply to message #1740847]

Fri, 19 August 2016 05:18

Ed Merks

Messages: 33224
Registered: July 2009

Senior Member

Johannes,

Comments below.

On 19.08.2016 01:28, Johannes Mising name wrote:
> I am parsing some JSON and putting it in a EMF based model, and for
> literals i have to distinguish to set them.
> Currently i am doing:
>
> if (type.getName().equals("Real")) {
So type here an an EDataType presumably.
> newobject.eSet(sf, Double.valueOf((String) ((JSONObject)
> je).get(property)));
> } else if
> (type.getName().equals("Integer")) {
> newobject.eSet(sf, Integer.valueOf((String) ((JSONObject)
> je).get(property)));
> } else {
> newobject.eSet(sf, ((JSONObject) je).get(property));
> }
>
> But i dont like it because string comparison is expensive and it
> should be an instanceof or equals object check.
Well for Ecore you can assume identity. So testing type ==
XyzPackage.Literals.ABC is fine and of course highly efficient.
> I could not get it to work however. EcorePackage.Literals.EString is
> just an int but not the type so i can't compare.
No, your confusing EcorePackage.ESTRING, which is an int with
EcorePackage.Literals.ESTRING, which is an EDataType.
> As well as (type instanceof String) or EString didnt work for me. Any
> hints what the right approach is?
I think better would be to use EcoreUtil.createFromString(type, (String)
((JSONObject) je).get(property))) in all cases; the factory knows how to
convert a literal to a value of the data type. Of course I don't
understand if it will always be a String, i.e., without your model, I
don't know which cases the final else covers.
> Thanks,
> Joe

Ed Merks
Professional Support: https://www.macromodeling.com/

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