Re: please help : GroovyCastException: why ? - introduce @ClassName annotation ?
Glad the community could help you & things look Groovy now G-) Cheers, mg On 28/02/2020 09:02, Mickaël SALMON wrote: Thank you very much for your support. Except this tricky use case for which I'm sure will find a solution for refactoring the existing scripts, Groovy integration in my Java application is OK Now. Chers, Mickael. *From:* Jochen Theodorou *Sent:* Thursday, February 27, 2020 16:39 *To:* Mickaël SALMON *Subject:* Re: please help : GroovyCastException: why ? Am 27.02.20 um 16:16 schrieb Mickaël SALMON: > Okay. > > In fact, I don't understand which this code works in Java but not in > Groovy (even if naming a variable with a class name, not in camel case, > is weird ...). That is because Groovy has an overlap of variable names and class names Java does not have. In Java a=b is clearely assigning the value of variable b to a. If a is a class instead it will fail compilation. If there is a variable b and b class a, then the variable will be taken. To ensure you do mean the class, you have to write a=b.class In Groovy a=b is different.here b could be also a class b. if there is no local variable b, then b might be still a class or (dynamic) property. Thus the compiler will first check if it is a class and then proceed to make it a (dynamic) property access. In dynamic Groovy this expression def a=b may never fail compilation, because even if there is no class b and no local variable b and no static property b, there is still a possibly dynamic property b. If it then does not exist at runtime, you will get a MissingPropertyException. But this mechanism proofed to be problematic for the users. It turned out to be a problem for the performance. Which is why we said, that if the name b follows the class naming conventions of upper-case and camel-case, it must be a class name and otherwise not. bye Jochen
Re: please help : GroovyCastException: why ?
Thank you very much for your support. Except this tricky use case for which I'm sure will find a solution for refactoring the existing scripts, Groovy integration in my Java application is OK Now. Chers, Mickael. From: Jochen Theodorou Sent: Thursday, February 27, 2020 16:39 To: Mickaël SALMON Subject: Re: please help : GroovyCastException: why ? Am 27.02.20 um 16:16 schrieb Mickaël SALMON: > Okay. > > In fact, I don't understand which this code works in Java but not in > Groovy (even if naming a variable with a class name, not in camel case, > is weird ...). That is because Groovy has an overlap of variable names and class names Java does not have. In Java a=b is clearely assigning the value of variable b to a. If a is a class instead it will fail compilation. If there is a variable b and b class a, then the variable will be taken. To ensure you do mean the class, you have to write a=b.class In Groovy a=b is different.here b could be also a class b. if there is no local variable b, then b might be still a class or (dynamic) property. Thus the compiler will first check if it is a class and then proceed to make it a (dynamic) property access. In dynamic Groovy this expression def a=b may never fail compilation, because even if there is no class b and no local variable b and no static property b, there is still a possibly dynamic property b. If it then does not exist at runtime, you will get a MissingPropertyException. But this mechanism proofed to be problematic for the users. It turned out to be a problem for the performance. Which is why we said, that if the name b follows the class naming conventions of upper-case and camel-case, it must be a class name and otherwise not. bye Jochen
Re: please help : GroovyCastException: why ?
Okay.
In fact, I don't understand which this code works in Java but not in Groovy
(even if naming a variable with a class name, not in camel case, is weird ...).
I made this test class to illustrate this :
package com.sylob.cochise.test;
import groovy.lang.Binding;
import groovy.lang.GroovyShell;
public class TestMyWeirdScript {
public static class MyClass {
private final String code;
public MyClass(String code) {
super();
this.code = code;
}
@Override
public String toString() {
return this.code;
}
}
public static String SCRIPT_SRC =
"import com.sylob.cochise.test.TestMyWeirdScript.MyClass;\r\n"
+ "MyClass instance = MyClass;\r\n" + "\r\n" +
"System.out.println(instance);";
public static void main(String[] args) {
MyClass instance = new MyClass("code");
// throws :
org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object
// 'class com.sylob.cochise.test.TestMyWeirdScript$MyClass' with class
'java.lang.Class' to
// class 'com.sylob.cochise.test.TestMyWeirdScript$MyClass'
TestMyWeirdScript.execGroovy(instance);
// Compilation & exec OK
TestMyWeirdScript.execJava(instance);
}
public static void execGroovy(MyClass instance) {
Binding binding = new Binding();
binding.setVariable("MyClass", instance);
new GroovyShell(binding).evaluate(TestMyWeirdScript.SCRIPT_SRC);
}
public static void execJava(MyClass MyClass) {
MyClass instance = MyClass;
System.out.println(instance);
}
}
Definitly no solution to handle this case, without refactoring existing scripts
?
Cheers, Mickael.
From: Paul King
Sent: Tuesday, February 25, 2020 11:57
To: users@groovy.apache.org
Subject: Re: please help : GroovyCastException: why ?
It is still a bit hard to let you know the best way to proceed from just the
sample you have shown without more context.
If I had a class Article and an instance Article (I am assuming from the
binding), then I would either:
* use an alias for the class, i.e.:
import Article as MyArticle // then use MyArticle everywhere (in that script)
where you want the class but you'd still need to be careful, some things won't
work; or
* just reserve the Article binding variable name for the binding only, e.g.:
def article = binding.variables.get('Article') // at start of script
// ... use article instance through script ...
binding.variables.put('Article', article) // at end of script
Cheers, Paul.
On Tue, Feb 25, 2020 at 8:37 PM Mickaël SALMON
mailto:m...@sylob.com>> wrote:
User scripts were coded Beanshell, I try to migrate to Groovy ...
From: Alessio Stalla mailto:alessiosta...@gmail.com>>
Sent: Tuesday, February 25, 2020 11:16
To: users@groovy.apache.org<mailto:users@groovy.apache.org>
mailto:users@groovy.apache.org>>
Subject: Re: please help : GroovyCastException: why ?
If the user scripts are already existing, which version of Groovy were they
targeting? I've seen this behavior (of treating identifiers starting with an
uppercase letter as potential class names) for my entire life as a Groovy
developer, which started several years ago.
On Tue, 25 Feb 2020 at 10:19, Mickaël SALMON
mailto:m...@sylob.com>> wrote:
Unfortunatly yes, that's what I need to do, passing an Article instance into a
variable named "Article", not "article" like it should be ...
Because of existing user scripts which must continue to work without
refactoring.
How can I deal with it ?
From: MG mailto:mg...@arscreat.com>>
Sent: Monday, February 24, 2020 23:30
To: users@groovy.apache.org<mailto:users@groovy.apache.org>
mailto:users@groovy.apache.org>>; Mickaël SALMON
mailto:m...@sylob.com>>
Subject: Re: please help : GroovyCastException: why ?
Article articleTmp = (Article) Article;
in Groovy is the same as
Article articleTmp = (Article) Article.getClass();
in Java.
Article.getClass()
is of type Class, so casting it to Article will fail - what you want
to do ist pass an Article instance, not the class, I presume...
hth,
mg
On 24/02/2020 18:24, Mickaël SALMON wrote:
Hello,
I'm using last Groovy version (3.0.1) in my Java application to run user
defined scripts (Java based).
Here is how a script is executed (sorry for the formatting) :
public Object eval(String scriptName, String script, Map
mapVariable)
throws CochiseException {
groovy.lang.Script groovyScript = this.scriptCache.get(scriptName);
if (groovyScript == null) {
groovyScript = new GroovyShell().parse(script);
this.scriptCache.put(scriptName, groovyScript);
}
groovy
Re: please help : GroovyCastException: why ?
It is still a bit hard to let you know the best way to proceed from just
the sample you have shown without more context.
If I had a class Article and an instance Article (I am assuming from the
binding), then I would either:
* use an alias for the class, i.e.:
import Article as MyArticle // then use MyArticle everywhere (in that
script) where you want the class but you'd still need to be careful, some
things won't work; or
* just reserve the Article binding variable name for the binding only, e.g.:
def article = binding.variables.get('Article') // at start of script
// ... use article instance through script ...
binding.variables.put('Article', article) // at end of script
Cheers, Paul.
On Tue, Feb 25, 2020 at 8:37 PM Mickaël SALMON wrote:
> User scripts were coded Beanshell, I try to migrate to Groovy ...
> --
> *From:* Alessio Stalla
> *Sent:* Tuesday, February 25, 2020 11:16
> *To:* users@groovy.apache.org
> *Subject:* Re: please help : GroovyCastException: why ?
>
> If the user scripts are already existing, which version of Groovy were
> they targeting? I've seen this behavior (of treating identifiers starting
> with an uppercase letter as potential class names) for my entire life as a
> Groovy developer, which started several years ago.
>
> On Tue, 25 Feb 2020 at 10:19, Mickaël SALMON wrote:
>
> Unfortunatly yes, that's what I need to do, passing an Article instance
> into a variable named "Article", not "article" like it should be ...
> Because of existing user scripts which must continue to work without
> refactoring.
>
> How can I deal with it ?
> --
> *From:* MG
> *Sent:* Monday, February 24, 2020 23:30
> *To:* users@groovy.apache.org ; Mickaël SALMON <
> m...@sylob.com>
> *Subject:* Re: please help : GroovyCastException: why ?
>
> Article articleTmp = (Article) Article;
>
> in Groovy is the same as
>
> Article articleTmp = (Article) Article.getClass();
>
> in Java.
>
> Article.getClass()
>
> is of type Class, so casting it to Article will fail - what you
> want to do ist pass an Article instance, not the class, I presume...
>
> hth,
> mg
>
>
> On 24/02/2020 18:24, Mickaël SALMON wrote:
>
> Hello,
>
> I'm using last Groovy version (3.0.1) in my Java application to run user
> defined scripts (Java based).
> Here is how a script is executed (sorry for the formatting) :
>
>public Object eval(String scriptName, String script, Map Object> mapVariable)
>throws CochiseException {
>groovy.lang.Script groovyScript = this.scriptCache.get(scriptName);
>if (groovyScript == null) {
>groovyScript = new GroovyShell().parse(script);
>this.scriptCache.put(scriptName, groovyScript);
>}
>groovyScript.setBinding(new Binding(mapVariable));
>return groovyScript.run();
>}
>
> I have the following exception when I pass the object "Article" of class
> "com.sylob.cochise.dm1.ejb.entite.article.Article" in the Map of variables :
>
> org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast
> object 'interface com.sylob.cochise.dm1.ejb.entite.article.Article' with
> class 'java.lang.Class' to class
> 'com.sylob.cochise.dm1.ejb.entite.article.Article'
>
>
> Here is the script :
>
> import com.sylob.cochise.dm1.ejb.entite.article.Article;
>
> println "CL import Article : " + Article.class.getClassLoader()
> println "CL var Article: " + Article.getClass().getClassLoader()
>
> Article articleTmp = (Article) Article;
> // ... some stuff
>
>
> This not seem to be a classLoader problem, because same class loader is
> used to load both com.sylob.cochise.dm1.ejb.entite.article.Article class
> in the script and "Article" object in the calling application.
> Also tested with 2.5.9, same error.
>
> What's wrong here ?
>
> Thanks.
>
>
>
Re: please help : GroovyCastException: why ?
User scripts were coded Beanshell, I try to migrate to Groovy ...
From: Alessio Stalla
Sent: Tuesday, February 25, 2020 11:16
To: users@groovy.apache.org
Subject: Re: please help : GroovyCastException: why ?
If the user scripts are already existing, which version of Groovy were they
targeting? I've seen this behavior (of treating identifiers starting with an
uppercase letter as potential class names) for my entire life as a Groovy
developer, which started several years ago.
On Tue, 25 Feb 2020 at 10:19, Mickaël SALMON
mailto:m...@sylob.com>> wrote:
Unfortunatly yes, that's what I need to do, passing an Article instance into a
variable named "Article", not "article" like it should be ...
Because of existing user scripts which must continue to work without
refactoring.
How can I deal with it ?
From: MG mailto:mg...@arscreat.com>>
Sent: Monday, February 24, 2020 23:30
To: users@groovy.apache.org<mailto:users@groovy.apache.org>
mailto:users@groovy.apache.org>>; Mickaël SALMON
mailto:m...@sylob.com>>
Subject: Re: please help : GroovyCastException: why ?
Article articleTmp = (Article) Article;
in Groovy is the same as
Article articleTmp = (Article) Article.getClass();
in Java.
Article.getClass()
is of type Class, so casting it to Article will fail - what you want
to do ist pass an Article instance, not the class, I presume...
hth,
mg
On 24/02/2020 18:24, Mickaël SALMON wrote:
Hello,
I'm using last Groovy version (3.0.1) in my Java application to run user
defined scripts (Java based).
Here is how a script is executed (sorry for the formatting) :
public Object eval(String scriptName, String script, Map
mapVariable)
throws CochiseException {
groovy.lang.Script groovyScript = this.scriptCache.get(scriptName);
if (groovyScript == null) {
groovyScript = new GroovyShell().parse(script);
this.scriptCache.put(scriptName, groovyScript);
}
groovyScript.setBinding(new Binding(mapVariable));
return groovyScript.run();
}
I have the following exception when I pass the object "Article" of class
"com.sylob.cochise.dm1.ejb.entite.article.Article" in the Map of variables :
org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast
object 'interface com.sylob.cochise.dm1.ejb.entite.article.Article' with class
'java.lang.Class' to class 'com.sylob.cochise.dm1.ejb.entite.article.Article'
Here is the script :
import com.sylob.cochise.dm1.ejb.entite.article.Article;
println "CL import Article : " + Article.class.getClassLoader()
println "CL var Article: " + Article.getClass().getClassLoader()
Article articleTmp = (Article) Article;
// ... some stuff
This not seem to be a classLoader problem, because same class loader is used to
load both com.sylob.cochise.dm1.ejb.entite.article.Article class in the script
and "Article" object in the calling application.
Also tested with 2.5.9, same error.
What's wrong here ?
Thanks.
Re: please help : GroovyCastException: why ?
If the user scripts are already existing, which version of Groovy were they
targeting? I've seen this behavior (of treating identifiers starting with
an uppercase letter as potential class names) for my entire life as a
Groovy developer, which started several years ago.
On Tue, 25 Feb 2020 at 10:19, Mickaël SALMON wrote:
> Unfortunatly yes, that's what I need to do, passing an Article instance
> into a variable named "Article", not "article" like it should be ...
> Because of existing user scripts which must continue to work without
> refactoring.
>
> How can I deal with it ?
> --
> *From:* MG
> *Sent:* Monday, February 24, 2020 23:30
> *To:* users@groovy.apache.org ; Mickaël SALMON <
> m...@sylob.com>
> *Subject:* Re: please help : GroovyCastException: why ?
>
> Article articleTmp = (Article) Article;
>
> in Groovy is the same as
>
> Article articleTmp = (Article) Article.getClass();
>
> in Java.
>
> Article.getClass()
>
> is of type Class, so casting it to Article will fail - what you
> want to do ist pass an Article instance, not the class, I presume...
>
> hth,
> mg
>
>
> On 24/02/2020 18:24, Mickaël SALMON wrote:
>
> Hello,
>
> I'm using last Groovy version (3.0.1) in my Java application to run user
> defined scripts (Java based).
> Here is how a script is executed (sorry for the formatting) :
>
>public Object eval(String scriptName, String script, Map Object> mapVariable)
>throws CochiseException {
>groovy.lang.Script groovyScript = this.scriptCache.get(scriptName);
>if (groovyScript == null) {
>groovyScript = new GroovyShell().parse(script);
>this.scriptCache.put(scriptName, groovyScript);
>}
>groovyScript.setBinding(new Binding(mapVariable));
>return groovyScript.run();
>}
>
> I have the following exception when I pass the object "Article" of class
> "com.sylob.cochise.dm1.ejb.entite.article.Article" in the Map of variables :
>
> org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast
> object 'interface com.sylob.cochise.dm1.ejb.entite.article.Article' with
> class 'java.lang.Class' to class
> 'com.sylob.cochise.dm1.ejb.entite.article.Article'
>
>
> Here is the script :
>
> import com.sylob.cochise.dm1.ejb.entite.article.Article;
>
> println "CL import Article : " + Article.class.getClassLoader()
> println "CL var Article: " + Article.getClass().getClassLoader()
>
> Article articleTmp = (Article) Article;
> // ... some stuff
>
>
> This not seem to be a classLoader problem, because same class loader is
> used to load both com.sylob.cochise.dm1.ejb.entite.article.Article class
> in the script and "Article" object in the calling application.
> Also tested with 2.5.9, same error.
>
> What's wrong here ?
>
> Thanks.
>
>
>
Re: please help : GroovyCastException: why ?
Unfortunatly yes, that's what I need to do, passing an Article instance into a
variable named "Article", not "article" like it should be ...
Because of existing user scripts which must continue to work without
refactoring.
How can I deal with it ?
From: MG
Sent: Monday, February 24, 2020 23:30
To: users@groovy.apache.org ; Mickaël SALMON
Subject: Re: please help : GroovyCastException: why ?
Article articleTmp = (Article) Article;
in Groovy is the same as
Article articleTmp = (Article) Article.getClass();
in Java.
Article.getClass()
is of type Class, so casting it to Article will fail - what you want
to do ist pass an Article instance, not the class, I presume...
hth,
mg
On 24/02/2020 18:24, Mickaël SALMON wrote:
Hello,
I'm using last Groovy version (3.0.1) in my Java application to run user
defined scripts (Java based).
Here is how a script is executed (sorry for the formatting) :
public Object eval(String scriptName, String script, Map
mapVariable)
throws CochiseException {
groovy.lang.Script groovyScript = this.scriptCache.get(scriptName);
if (groovyScript == null) {
groovyScript = new GroovyShell().parse(script);
this.scriptCache.put(scriptName, groovyScript);
}
groovyScript.setBinding(new Binding(mapVariable));
return groovyScript.run();
}
I have the following exception when I pass the object "Article" of class
"com.sylob.cochise.dm1.ejb.entite.article.Article" in the Map of variables :
org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast
object 'interface com.sylob.cochise.dm1.ejb.entite.article.Article' with class
'java.lang.Class' to class 'com.sylob.cochise.dm1.ejb.entite.article.Article'
Here is the script :
import com.sylob.cochise.dm1.ejb.entite.article.Article;
println "CL import Article : " + Article.class.getClassLoader()
println "CL var Article: " + Article.getClass().getClassLoader()
Article articleTmp = (Article) Article;
// ... some stuff
This not seem to be a classLoader problem, because same class loader is used to
load both com.sylob.cochise.dm1.ejb.entite.article.Article class in the script
and "Article" object in the calling application.
Also tested with 2.5.9, same error.
What's wrong here ?
Thanks.
Re: please help : GroovyCastException: why ?
Article articleTmp = (Article) Article;
in Groovy is the same as
Article articleTmp = (Article) Article.getClass();
in Java.
Article.getClass()
is of type Class, so casting it to Article will fail - what you
want to do ist pass an Article instance, not the class, I presume...
hth,
mg
On 24/02/2020 18:24, Mickaël SALMON wrote:
Hello,
I'm using last Groovy version (3.0.1) in my Java application to run
user defined scripts (Java based).
Here is how a script is executed (sorry for the formatting) :
public Object eval(String scriptName, String script, MapObject> mapVariable)
throws CochiseException {
groovy.lang.Script groovyScript = this.scriptCache.get(scriptName);
if (groovyScript == null) {
groovyScript = new GroovyShell().parse(script);
this.scriptCache.put(scriptName, groovyScript);
}
groovyScript.setBinding(new Binding(mapVariable));
return groovyScript.run();
}
I have the following exception when I pass the object "Article" of
class "com.sylob.cochise.dm1.ejb.entite.article.Article" in the Map of
variables :
org.codehaus.groovy.runtime.typehandling.GroovyCastException:
Cannot cast object 'interface
com.sylob.cochise.dm1.ejb.entite.article.Article' with class
'java.lang.Class' to class
'com.sylob.cochise.dm1.ejb.entite.article.Article'
Here is the script :
import com.sylob.cochise.dm1.ejb.entite.article.Article;
println "CL import Article : " + Article.class.getClassLoader()
println "CL var Article: " + Article.getClass().getClassLoader()
Article articleTmp = (Article) Article;
// ... some stuff
This not seem to be a classLoader problem, because same class loader
is used to load both com.sylob.cochise.dm1.ejb.entite.article.Article
class in the script and "Article" object in the calling application.
Also tested with 2.5.9, same error.
What's wrong here ?
Thanks.
