[groovy-user] What is this in static context ?

[Ista Pouss]

Hi,

i read at http://groovy.codehaus.org/Differences+from+Java "this" in a
static context refer to the class.

So if I do :

class Dev
{
public static void main(String[] args)
{
println this
}
}

... this print "class pack.Dev". I Understand. I suppose "this" is an
object of class Class here.

But if I write "println this.getClass()" -> syntax error ?
this.name -> syntax error ?
this.hashCode() -> syntax error ?

So what is this ?

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[Roshan Dawrani]

Looks like these issues are not there anymore - I am currently able to try only on 1.7-rc-1 and see none of the issues you mention - this.name, this.hasCode(), etc work fine.

My guess is that it is something that would be fixed on latest 1.6.6 as well.

What version of groovy are you on?

rgds,
Roshan

[Saager Mhatre]

On 1.6.5 running on 32 bit JVM 1.6.0u15 I get ClassCastExceptions (cannot cast j.l.Class to g.l.GroovyObject) when accessing properties the groovy way, but can still invoke the getters directly.
hashCode works, though; sorry Ista! :P

groovy:000> class Dev { public static void main(String[] arg) { println this.hashCode() } }; Dev.main([] as String[]);
25563270
===> null
groovy:000> class Dev { public static void main(String[] arg) { println this.name } }; Dev.main([] as String[]);     
ERROR java.lang.ClassCastException: java.lang.Class cannot be cast to groovy.lang.GroovyObject
        at Dev.main (groovysh_evaluate:2)
        at groovysh_evaluate.run (groovysh_evaluate:2)
        ...

--
Saager Mhatre

[Ista Pouss]

2009/12/1 Roshan Dawrani <roshan...@codehaus.org>:

>
> What version of groovy are you on?
>

I use groovy 1.6.4 with JVM 1.6.0_14 and Netbeans 6.7.1

So it's a groovy 1.6.4 bug ?

I'm going to download the 1.6.6...

Thanks.

[Roshan Dawrani]

At this point I only know about 1.7-rc-1 - that the issues you mentioned are not there. That the problem is not there on 1.6.6 is just a guess at this point, as I don't have access to it. Maybe someone else can confirm...else, I will do it later..

[Jochen Theodorou]

Roshan Dawrani schrieb:

> At this point I only know about 1.7-rc-1 - that the issues you mentioned
> are not there. That the problem is not there on 1.6.6 is just a guess at
> this point, as I don't have access to it. Maybe someone else can
> confirm...else, I will do it later..

I fixed several bugs in that area a while back, not sure if I did for
1.6.6 as well

bye blackdrag

--
Jochen "blackdrag" Theodorou
The Groovy Project Tech Lead (http://groovy.codehaus.org)
http://blackdragsview.blogspot.com/

[Ista Pouss]

I've downloaded 1.6.6 and it's always same.

During Netbeans code parsing there this an error

java.lang.NullPointerException
at org.codehaus.groovy.ast.CodeVisitorSupport.visitListOfExpressions(CodeVisitorSupport.java:264)
at org.codehaus.groovy.ast.CodeVisitorSupport.visitTupleExpression(CodeVisitorSupport.java:165)
at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitTupleExpression(PathFinderVisitor.java:358)
at org.codehaus.groovy.ast.CodeVisitorSupport.visitArgumentlistExpression(CodeVisitorSupport.java:274)
at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitArgumentlistExpression(PathFinderVisitor.java:542)
at org.codehaus.groovy.ast.expr.ArgumentListExpression.visit(ArgumentListExpression.java:73)
at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitMethodCallExpression(PathFinderVisitor.java:285)
at org.codehaus.groovy.ast.expr.MethodCallExpression.visit(MethodCallExpression.java:63)
at org.codehaus.groovy.ast.CodeVisitorSupport.visitExpressionStatement(CodeVisitorSupport.java:63)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitExpressionStatement(ClassCodeVisitorSupport.java:159)
at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitExpressionStatement(PathFinderVisitor.java:205)
at org.codehaus.groovy.ast.stmt.ExpressionStatement.visit(ExpressionStatement.java:40)
at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitBlockStatement(PathFinderVisitor.java:170)
at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:52)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:73)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:80)
at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitConstructorOrMethod(PathFinderVisitor.java:145)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:88)
at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitMethod(PathFinderVisitor.java:571)
at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:907)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:48)
at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitClass(PathFinderVisitor.java:556)
at org.netbeans.modules.groovy.editor.api.AstPath.find(AstPath.java:182)
at org.netbeans.modules.groovy.editor.api.AstPath.findPathTo(AstPath.java:139)
at org.netbeans.modules.groovy.editor.api.AstPath.<init>(AstPath.java:91)
at org.netbeans.modules.groovy.editor.api.parser.GroovyOccurrencesFinder.run(GroovyOccurrencesFinder.java:142)
at org.netbeans.modules.groovy.editor.api.parser.GroovyOccurrencesFinder.run(GroovyOccurrencesFinder.java:72)
at org.netbeans.modules.csl.editor.semantic.MarkOccurrencesHighlighter.processImpl(MarkOccurrencesHighlighter.java:170)
at org.netbeans.modules.csl.editor.semantic.MarkOccurrencesHighlighter.run(MarkOccurrencesHighlighter.java:122)
at org.netbeans.modules.csl.editor.semantic.MarkOccurrencesHighlighter.run(MarkOccurrencesHighlighter.java:81)
at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:668)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
[catch] at java.lang.Thread.run(Thread.java:619)

I suppose it's on :

public static void main(String[] args)
{

println this.getClass() // here.
}

Same with .hashCode(), .equals(), .name, .getName()...

2009/12/1 Jochen Theodorou <blac...@gmx.org>:

[Jochen Theodorou]

Ista Pouss schrieb:

> I've downloaded 1.6.6 and it's always same.
>
> During Netbeans code parsing there this an error
>
> java.lang.NullPointerException
> at org.codehaus.groovy.ast.CodeVisitorSupport.visitListOfExpressions(CodeVisitorSupport.java:264)
> at org.codehaus.groovy.ast.CodeVisitorSupport.visitTupleExpression(CodeVisitorSupport.java:165)
> at org.netbeans.modules.groovy.editor.api.PathFinderVisitor.visitTupleExpression(PathFinderVisitor.java:358)

[...]

> [catch] at java.lang.Thread.run(Thread.java:619)
>
> I suppose it's on :
>
> public static void main(String[] args)
> {
> println this.getClass() // here.
> }
>
> Same with .hashCode(), .equals(), .name, .getName()...

netbeans is messing around with the compiler, as it shows up in the
trace at positions were only the groovy internals are t be expected. SO
you need to try it outside of the IDE, since it is possible the netbeans
guys missed a possible NPE here