Eclipse Community Forums: EMF » Problem with Generic

Help

Home

Home » Modeling » EMF » Problem with Generic

Show: Today's Messages :: Show Polls :: Message Navigator

Problem with Generic [message #686690]

Mon, 09 May 2011 21:36

Alain Picard

Messages: 266
Registered: July 2009

Senior Member

I have a Eclass defined as follow:
public interface BaseNode<T extends BaseNode<T>> extends
AbstractIstElement {

and I'm getting an error in the generated switch class here:
if (result == null) result = caseBaseNode(baseCodeNode);
error:Type mismatch: cannot convert from Object to T1

and the method is defined as:
public <T extends BaseNode<T>> T1 caseBaseNode(BaseNode<T> object) {

I am doing anything wrong? The rest of the code is generated correctly.

Thanks,
Alain

Report message to a moderator

Re: Problem with Generic [message #686703 is a reply to message #686690]

Tue, 10 May 2011 15:26

Ed Merks

Messages: 33142
Registered: July 2009

Senior Member

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Alain, 
 
I tried it and produced 
 
  public <T extends Derived<T>> T1
caseDerived(Derived<T> object) 
  { 
    return null; 
  } 
 
along with 
 
  protected T1 doSwitch(int classifierID, EObject theEObject) 
  { 
    switch (classifierID) 
    { 
      case AlainPackage.BASE: 
      { 
        Base base = (Base)theEObject; 
        T1 result = caseBase(base); 
        if (result == null) result = defaultCase(theEObject); 
        return result; 
      } 
      case AlainPackage.DERIVED: 
      { 
        Derived<?> derived = (Derived<?>)theEObject; 
        T1 result = caseDerived(derived); 
        if (result == null) result = caseBase(derived); 
        if (result == null) result = defaultCase(theEObject); 
        return result; 
      } 
      default: return defaultCase(theEObject); 
    } 
  
I don't see any errors.  I even tried created a concrete derived class
to produce this, but still it works fine... 
 
      case AlainPackage.CONCRETE: 
      { 
        Concrete concrete = (Concrete)theEObject; 
        T1 result = caseConcrete(concrete); 
        if (result == null) result = caseDerived(concrete); 
        if (result == null) result = caseBase(concrete); 
        if (result == null) result = defaultCase(theEObject); 
        return result; 
      } 
 
Which version of EMF are you using? 
 
 
 
Alain Picard wrote:
<blockquote cite="mid:iq9m96$g2p$1@news.eclipse.org" type="cite">I have
a Eclass defined as follow:
 
public interface BaseNode<T extends BaseNode<T>> extends
AbstractIstElement {
 
 
and I'm getting an error in the generated switch class here:
 
if (result == null) result = caseBaseNode(baseCodeNode);
 
error:Type mismatch: cannot convert from Object to T1
 
 
and the method is defined as:
 
public <T extends BaseNode<T>> T1
caseBaseNode(BaseNode<T> object) {
 
 
I am doing anything wrong? The rest of the code is generated correctly.
 
 
Thanks,
 
Alain
 
</blockquote>
</body>
</html>

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

Report message to a moderator

Re: Problem with Generic [message #686704 is a reply to message #686703]

Tue, 10 May 2011 16:54

Alain Picard

Messages: 266
Registered: July 2009

Senior Member

Ed,
I am using 2.6.0. Tried with 20100914 and 20110128 and 20110502.

I am getting the error only in the concrete case, but everything looks
exactly like what you're showing:
case IstPackage.BASE_NODE: {
BaseNode<?> baseNode = (BaseNode<?>)theEObject;
T1 result = caseBaseNode(baseNode);
if (result == null) result = caseAbstractIstElement(baseNode);
if (result == null) result = caseEntity(baseNode);
if (result == null) result = caseModelElement(baseNode);
if (result == null) result = caseElement(baseNode);
if (result == null) result = caseEObject(baseNode);
if (result == null) result = defaultCase(theEObject);
return result;
}

case IstPackage.BASE_CODE_NODE: {
BaseCodeNode baseCodeNode = (BaseCodeNode)theEObject;
T1 result = caseBaseCodeNode(baseCodeNode);
if (result == null) result = caseBaseNode(baseCodeNode); <===error here
if (result == null) result = caseComparable(baseCodeNode);
if (result == null) result = caseAbstractIstElement(baseCodeNode);
if (result == null) result = caseEntity(baseCodeNode);
if (result == null) result = caseModelElement(baseCodeNode);
if (result == null) result = caseElement(baseCodeNode);
if (result == null) result = caseEObject(baseCodeNode);
if (result == null) result = defaultCase(theEObject);
return result;
}

public <T extends BaseNode<T>> T1 caseBaseNode(BaseNode<T> object) {
return null;
}

Even stranger I guess. What could it be?

Alain

On 5/10/2011 11:26 AM, Ed Merks wrote:
> Alain,
>
> I tried it and produced
>
> public <T extends Derived<T>> T1 caseDerived(Derived<T> object)
> {
> return null;
> }
>
> along with
>
> protected T1 doSwitch(int classifierID, EObject theEObject)
> {
> switch (classifierID)
> {
> case AlainPackage.BASE:
> {
> Base base = (Base)theEObject;
> T1 result = caseBase(base);
> if (result == null) result = defaultCase(theEObject);
> return result;
> }
> case AlainPackage.DERIVED:
> {
> Derived<?> derived = (Derived<?>)theEObject;
> T1 result = caseDerived(derived);
> if (result == null) result = caseBase(derived);
> if (result == null) result = defaultCase(theEObject);
> return result;
> }
> default: return defaultCase(theEObject);
> }
>
> I don't see any errors. I even tried created a concrete derived class to
> produce this, but still it works fine...
>
> case AlainPackage.CONCRETE:
> {
> Concrete concrete = (Concrete)theEObject;
> T1 result = caseConcrete(concrete);
> if (result == null) result = caseDerived(concrete);
> if (result == null) result = caseBase(concrete);
> if (result == null) result = defaultCase(theEObject);
> return result;
> }
>
> Which version of EMF are you using?
>
>
>
> Alain Picard wrote:
>> I have a Eclass defined as follow:
>> public interface BaseNode<T extends BaseNode<T>> extends
>> AbstractIstElement {
>>
>> and I'm getting an error in the generated switch class here:
>> if (result == null) result = caseBaseNode(baseCodeNode);
>> error:Type mismatch: cannot convert from Object to T1
>>
>> and the method is defined as:
>> public <T extends BaseNode<T>> T1 caseBaseNode(BaseNode<T> object) {
>>
>> I am doing anything wrong? The rest of the code is generated correctly.
>>
>> Thanks,
>> Alain

Report message to a moderator

Re: Problem with Generic [message #686705 is a reply to message #686704]

Tue, 10 May 2011 17:12

Ed Merks

Messages: 33142
Registered: July 2009

Senior Member

Alain,

I can't explain it. To me it looks like a compiler error. It's clear
that caseBaseNode must return a T1 regardless of the type of the
argument (and it's not complaining about the type of the argument).
It's also possible something else subtle is going on that's missing from
my test case and that you've not elaborated. Could you reduce your test
case and provide the Ecore file for it?

Alain Picard wrote:
> Ed,
> I am using 2.6.0. Tried with 20100914 and 20110128 and 20110502.
>
> I am getting the error only in the concrete case, but everything looks
> exactly like what you're showing:
> case IstPackage.BASE_NODE: {
> BaseNode<?> baseNode = (BaseNode<?>)theEObject;
> T1 result = caseBaseNode(baseNode);
> if (result == null) result = caseAbstractIstElement(baseNode);
> if (result == null) result = caseEntity(baseNode);
> if (result == null) result = caseModelElement(baseNode);
> if (result == null) result = caseElement(baseNode);
> if (result == null) result = caseEObject(baseNode);
> if (result == null) result = defaultCase(theEObject);
> return result;
> }
>
> case IstPackage.BASE_CODE_NODE: {
> BaseCodeNode baseCodeNode = (BaseCodeNode)theEObject;
> T1 result = caseBaseCodeNode(baseCodeNode);
> if (result == null) result = caseBaseNode(baseCodeNode); <===error here
> if (result == null) result = caseComparable(baseCodeNode);
> if (result == null) result = caseAbstractIstElement(baseCodeNode);
> if (result == null) result = caseEntity(baseCodeNode);
> if (result == null) result = caseModelElement(baseCodeNode);
> if (result == null) result = caseElement(baseCodeNode);
> if (result == null) result = caseEObject(baseCodeNode);
> if (result == null) result = defaultCase(theEObject);
> return result;
> }
>
> public <T extends BaseNode<T>> T1 caseBaseNode(BaseNode<T> object) {
> return null;
> }
>
>
> Even stranger I guess. What could it be?
>
> Alain
>
>
>
> On 5/10/2011 11:26 AM, Ed Merks wrote:
>> Alain,
>>
>> I tried it and produced
>>
>> public <T extends Derived<T>> T1 caseDerived(Derived<T> object)
>> {
>> return null;
>> }
>>
>> along with
>>
>> protected T1 doSwitch(int classifierID, EObject theEObject)
>> {
>> switch (classifierID)
>> {
>> case AlainPackage.BASE:
>> {
>> Base base = (Base)theEObject;
>> T1 result = caseBase(base);
>> if (result == null) result = defaultCase(theEObject);
>> return result;
>> }
>> case AlainPackage.DERIVED:
>> {
>> Derived<?> derived = (Derived<?>)theEObject;
>> T1 result = caseDerived(derived);
>> if (result == null) result = caseBase(derived);
>> if (result == null) result = defaultCase(theEObject);
>> return result;
>> }
>> default: return defaultCase(theEObject);
>> }
>>
>> I don't see any errors. I even tried created a concrete derived class to
>> produce this, but still it works fine...
>>
>> case AlainPackage.CONCRETE:
>> {
>> Concrete concrete = (Concrete)theEObject;
>> T1 result = caseConcrete(concrete);
>> if (result == null) result = caseDerived(concrete);
>> if (result == null) result = caseBase(concrete);
>> if (result == null) result = defaultCase(theEObject);
>> return result;
>> }
>>
>> Which version of EMF are you using?
>>
>>
>>
>> Alain Picard wrote:
>>> I have a Eclass defined as follow:
>>> public interface BaseNode<T extends BaseNode<T>> extends
>>> AbstractIstElement {
>>>
>>> and I'm getting an error in the generated switch class here:
>>> if (result == null) result = caseBaseNode(baseCodeNode);
>>> error:Type mismatch: cannot convert from Object to T1
>>>
>>> and the method is defined as:
>>> public <T extends BaseNode<T>> T1 caseBaseNode(BaseNode<T> object) {
>>>
>>> I am doing anything wrong? The rest of the code is generated correctly.
>>>
>>> Thanks,
>>> Alain
>

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

Report message to a moderator

Re: Problem with Generic [message #686706 is a reply to message #686704]

Tue, 10 May 2011 17:14

Alain Picard

Messages: 266
Registered: July 2009

Senior Member

Ed,

Well I got it.

The problem seems to be related to the editor and not the generator.

I first created my model without the generics, which I forgot. I then
added the generic type, but that didn't change concrete subclasses.

Even then, I couldn't add the type parameter. I had to delete the
supertype reference, save the ecore and then re-add the super-type. Then
I was able to specify the type parameter information.

So there is probably a bug in the editor, but not in the most important
code generator.

Thanks for your help and sorry to have raised the wrong issue.

Cheers,
Alain

Report message to a moderator