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Posted to users@wicket.apache.org by "Seldon, Richard" <Ri...@landg.com> on 2007/12/04 12:23:17 UTC
Component toString() implementation and java.lang.StackOverflowError
Working with Wicket 1.2.6. Having trouble with the implementation of
Component toString() - it has been implemented by wicket framework to
use an overloaded 'detailed' version that contains the following:
.append((isRenderAllowed() && isVisible())
The repercussions of this is that where component.toString() is called
from within an overridden instance of component isVisible() method we
get ourselves into a recursive loop. Eventually, this leads to a
java.lang.StackOverflowError with varying results depending on app
server. In IBM Websphere version 6.0.2.2 it actually crashes the server
altogether.
Unfortunately, the wicket framework itself unwittingly corroborates in
this situation arising. A contrived example code and scenario where this
can occur is in wicket.model.AbstractDetachableModel :-
public final Object getObject(final Component component)
{
attach();
try
{
return onGetObject(component);
}
catch (RuntimeException e)
{
throw new WicketRuntimeException("unable to get
object, model: " + this
+ ", called with component " +
component, e);
}
}
Above the WicketRuntimeException message string calls the
component.toString() method. Below is an overridden isVisible()
implementation (from within MyPage component) where a PropertyModel
fails to find the appropriate getXXX for the expression XXX leading to a
WicketRuntimeException in wicket.util.lang.PropertyResolver. For
instance:-
final PropertyModel model = new PropertyModel(this,
"incorrectNameOfListGetMethod");
Panel myPanel = new MyPanel("myPanel") {
public boolean isVisible() {
return
((List)model.getObject(this)).size() > 0;
}
};
Stacktrace of error:-
at
wicket.util.lang.PropertyResolver.findGetter(PropertyResolver.java:374)
at
wicket.util.lang.PropertyResolver.getGetAndSetter(PropertyResolver.java:
233)
at
wicket.util.lang.PropertyResolver.getObjectAndGetSetter(PropertyResolver
.java:200)
at
wicket.util.lang.PropertyResolver.getValue(PropertyResolver.java:88)
at
wicket.model.AbstractPropertyModel.onGetObject(AbstractPropertyModel.jav
a:132)
at
wicket.model.AbstractDetachableModel.getObject(AbstractDetachableModel.j
ava:104)
at com.arcs.spike.page.MyPage$1.isVisible(MyPage.java:29)
Is there some way we can work easily around this sort of issue? Eg. A
hook in the framework etc to create our own versions of components (with
overridden implementaiton of toString() via a factory? Would rather
avoid patching the wicket jar if possible. Thanks in advance for any
help.
>> apologies if footer of email is verbose - company policy restricts us
to include this and have no other email account available <<
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Re: Component toString() implementation and java.lang.StackOverflowError
Posted by Johan Compagner <jc...@gmail.com>.
This sounds famliar. I think we already fixed something like this but
dont know if it is done in the 1.2.x stream
Send in a patch if you like and attach it to a jira issue
2007/12/4, Seldon, Richard <Ri...@landg.com>:
>
> Working with Wicket 1.2.6. Having trouble with the implementation of
> Component toString() - it has been implemented by wicket framework to
> use an overloaded 'detailed' version that contains the following:
>
> .append((isRenderAllowed() && isVisible())
>
> The repercussions of this is that where component.toString() is called
> from within an overridden instance of component isVisible() method we
> get ourselves into a recursive loop. Eventually, this leads to a
> java.lang.StackOverflowError with varying results depending on app
> server. In IBM Websphere version 6.0.2.2 it actually crashes the server
> altogether.
>
> Unfortunately, the wicket framework itself unwittingly corroborates in
> this situation arising. A contrived example code and scenario where this
> can occur is in wicket.model.AbstractDetachableModel :-
>
> public final Object getObject(final Component component)
> {
> attach();
> try
> {
> return onGetObject(component);
> }
> catch (RuntimeException e)
> {
> throw new WicketRuntimeException("unable to get
> object, model: " + this
> + ", called with component " +
> component, e);
> }
> }
>
> Above the WicketRuntimeException message string calls the
> component.toString() method. Below is an overridden isVisible()
> implementation (from within MyPage component) where a PropertyModel
> fails to find the appropriate getXXX for the expression XXX leading to a
> WicketRuntimeException in wicket.util.lang.PropertyResolver. For
> instance:-
>
> final PropertyModel model = new PropertyModel(this,
> "incorrectNameOfListGetMethod");
>
> Panel myPanel = new MyPanel("myPanel") {
> public boolean isVisible() {
> return
> ((List)model.getObject(this)).size() > 0;
> }
> };
>
> Stacktrace of error:-
>
> at
> wicket.util.lang.PropertyResolver.findGetter(PropertyResolver.java:374)
> at
> wicket.util.lang.PropertyResolver.getGetAndSetter(PropertyResolver.java:
> 233)
> at
> wicket.util.lang.PropertyResolver.getObjectAndGetSetter(PropertyResolver
> .java:200)
> at
> wicket.util.lang.PropertyResolver.getValue(PropertyResolver.java:88)
> at
> wicket.model.AbstractPropertyModel.onGetObject(AbstractPropertyModel.jav
> a:132)
> at
> wicket.model.AbstractDetachableModel.getObject(AbstractDetachableModel.j
> ava:104)
> at com.arcs.spike.page.MyPage$1.isVisible(MyPage.java:29)
>
>
> Is there some way we can work easily around this sort of issue? Eg. A
> hook in the framework etc to create our own versions of components (with
> overridden implementaiton of toString() via a factory? Would rather
> avoid patching the wicket jar if possible. Thanks in advance for any
> help.
>
> >> apologies if footer of email is verbose - company policy restricts us
> to include this and have no other email account available <<
>
> **********************************************************************
> This email (and any attachments) may contain privileged and/or confidential
> information. If you are not the intended recipient please do not disclose,
> copy, distribute, disseminate or take any action in reliance on it. If you
> have received this message in error please reply and tell us and then delete
> it. Should you wish to communicate with us by email we cannot guarantee the
> security of any data outside our own computer systems. For the protection of
> Legal & General's systems and staff, incoming emails will be automatically
> scanned. Any information contained in this message may be subject to
> applicable terms and conditions and must not be construed as giving
> investment advice within or outside the United Kingdom.
>
> Legal & General Group plc is registered in England under company number
> 1417162 and is a holding company.
>
> The registered office for all companies in the Legal & General group is One
> Coleman Street London EC2R 5AA.
>
> The following subsidiary companies of Legal & General Group Plc are
> authorised and regulated by the Financial Services Authority: Legal &
> General Partnership Services Limited, Legal & General Insurance Limited,
> Legal & General Assurance Society Limited, Legal & General (Unit Trust
> Managers) Limited and Legal & General (Portfolio Management Services)
> Limited.
>
> Legal & General International (Ireland) is incorporated in Ireland under
> company number 440141 with its registered office at Alexandra House, The
> Sweepstakes, Ballsbridge, Dublin 4 and is authorised by the Financial
> Regulator in Ireland and by the Financial Services Authority for the conduct
> of insurance business in the UK.
>
> Full details can be found at http://www.legalandgeneralgroup.com/
>
> **********************************************************************
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
> For additional commands, e-mail: users-help@wicket.apache.org
>
>
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