Re: Not happy with approaches.. looking for better/other suggestions

2004-09-12 Thread struts Dude 
Just a silly question.

Where did ListUtils come from?? I can't find this
in my JDK1.4.2.

Thanks


- Original Message - 
From: Hubert Rabago [EMAIL PROTECTED]
To: Struts Users Mailing List [EMAIL PROTECTED]
Sent: Friday, September 03, 2004 7:40 AM
Subject: Re: Not happy with approaches.. looking for better/other
suggestions


 Have you tried using ListUtils.lazyList() for this?  I just tried it
 on a sample app and it works in cases like this.

 - Hubert

 On Thu, 02 Sep 2004 14:27:32 -0400, Rick Reumann [EMAIL PROTECTED]
wrote:
  One of the most frustrating things I run into when developing Struts
  applications is the problem of when you want to use a request scoped
  ActionForm but you need to populate a collection that is one of your
  ActionForm properties. The problem is the classic index out of bounds
  exception if you do not have your collection populated with enough
objects.
 
  For example imagine the case where you might want to edit a bunch of
  Access definitions on one form.
 
  So in an ActionForm property you have:
 
  Collection accessDefinitions;
 
  In your Action before you get to the form you populate your form:
 
  ((AccessForm)form).setAccessDefinitions( aCollectionOfDefs );
 
  Your JSP then displays the access definition properties for the user to
  edit:
 
  (condensed and table formatting removed:)
 
  c:forEach items=${accessForm.accessDefinitions} var=access
  varStatus=status
html:text property=accessDefinitions[${status.index}].name/
html:text property=accessDefinitions[${status.index}].description/
  /c:forEach
 
  Now the problem will be when you submit this form. If this form was
  given request scope in the action mapping, you'll end up with errors
  since BeanUtils can not populate the Collection. You need to have the
  correct size in place for 'accessDefinitions' to allow for population.
 
  There are several solutions that have been proposed by searching the
  list archives.
 
  The easiest alternative is of course to just put your form in Session
  scope, but that is such a waste in my opinion.
 
  Another approach would be something like:
 
  In reset() of ActionForm:
 
  public void reset(ActionMapping actionMapping, HttpServletRequest
request) {
  if ( request.getParameter(accessDefinitionsSize) != null ) {
  int accessDefinitionsSize = new
  Integer(request.getParameter(accessDefinitionsSize)).intValue();
  accessDefinitions = new ArrayList(accessDefinitionsSize);
  for (int i=0;iaccessDefinitionsSize;i++) {
  accessDefinitions.add(new AccessDefinitionVO());
  }
  }
  }
 
  Then in your JSP (code snipped just showing releveant portion):
 
  c:forEach items=${accessForm.accessDefinitions} var=access
  varStatus=status

c:set var=accessDefinitionsSize value=${status.count}/
  /c:forEach
  input type=hidden name=accessDefinitionsSize
  value=${accessDefinitionsSize}/
 
  The above works 'ok' but it's so much extra code. I've thought of just
  adding the accessDefinitionsSize attribute to the Session in the Action
  that is called right be the form is set up. Then the reset method can
  pull it right from there. An int in the session won't be too much
  overhead. But I'm not sure if I like that approach that much either
  (although I'm leaning towards just doing it that way).
 
  Of course I don't like the approaches that call a business class from
  the reset to get the size.
 
  Any suggestions welcome.
 
  --
  Rick
 
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Re: Not happy with approaches.. looking for better/other suggestions

2004-09-12 Thread Yves Sy 
Dude all you have to do is do something as simple as entering
ListUtils in Google and you'll find out.

-Yves-

On Mon, 13 Sep 2004 17:04:18 +1200, struts Dude [EMAIL PROTECTED] wrote:
 Just a silly question.
 
 Where did ListUtils come from?? I can't find this
 in my JDK1.4.2.
 
 Thanks
 
 
 
 
 - Original Message -
 From: Hubert Rabago [EMAIL PROTECTED]
 To: Struts Users Mailing List [EMAIL PROTECTED]
 Sent: Friday, September 03, 2004 7:40 AM
 Subject: Re: Not happy with approaches.. looking for better/other
 suggestions
 
  Have you tried using ListUtils.lazyList() for this?  I just tried it
  on a sample app and it works in cases like this.
 
  - Hubert
 
  On Thu, 02 Sep 2004 14:27:32 -0400, Rick Reumann [EMAIL PROTECTED]
 wrote:
   One of the most frustrating things I run into when developing Struts
   applications is the problem of when you want to use a request scoped
   ActionForm but you need to populate a collection that is one of your
   ActionForm properties. The problem is the classic index out of bounds
   exception if you do not have your collection populated with enough
 objects.
  
   For example imagine the case where you might want to edit a bunch of
   Access definitions on one form.
  
   So in an ActionForm property you have:
  
   Collection accessDefinitions;
  
   In your Action before you get to the form you populate your form:
  
   ((AccessForm)form).setAccessDefinitions( aCollectionOfDefs );
  
   Your JSP then displays the access definition properties for the user to
   edit:
  
   (condensed and table formatting removed:)
  
   c:forEach items=${accessForm.accessDefinitions} var=access
   varStatus=status
 html:text property=accessDefinitions[${status.index}].name/
 html:text property=accessDefinitions[${status.index}].description/
   /c:forEach
  
   Now the problem will be when you submit this form. If this form was
   given request scope in the action mapping, you'll end up with errors
   since BeanUtils can not populate the Collection. You need to have the
   correct size in place for 'accessDefinitions' to allow for population.
  
   There are several solutions that have been proposed by searching the
   list archives.
  
   The easiest alternative is of course to just put your form in Session
   scope, but that is such a waste in my opinion.
  
   Another approach would be something like:
  
   In reset() of ActionForm:
  
   public void reset(ActionMapping actionMapping, HttpServletRequest
 request) {
   if ( request.getParameter(accessDefinitionsSize) != null ) {
   int accessDefinitionsSize = new
   Integer(request.getParameter(accessDefinitionsSize)).intValue();
   accessDefinitions = new ArrayList(accessDefinitionsSize);
   for (int i=0;iaccessDefinitionsSize;i++) {
   accessDefinitions.add(new AccessDefinitionVO());
   }
   }
   }
  
   Then in your JSP (code snipped just showing releveant portion):
  
   c:forEach items=${accessForm.accessDefinitions} var=access
   varStatus=status
 
 c:set var=accessDefinitionsSize value=${status.count}/
   /c:forEach
   input type=hidden name=accessDefinitionsSize
   value=${accessDefinitionsSize}/
  
   The above works 'ok' but it's so much extra code. I've thought of just
   adding the accessDefinitionsSize attribute to the Session in the Action
   that is called right be the form is set up. Then the reset method can
   pull it right from there. An int in the session won't be too much
   overhead. But I'm not sure if I like that approach that much either
   (although I'm leaning towards just doing it that way).
  
   Of course I don't like the approaches that call a business class from
   the reset to get the size.
  
   Any suggestions welcome.
  
   --
   Rick
  
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   For additional commands, e-mail: [EMAIL PROTECTED]
  
  
 
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Re: Not happy with approaches.. looking for better/other suggestions

2004-09-02 Thread Woodchuck 
hi Rick,

have you tried defining the following in your ActionForm? (assuming
your collection has MyFooBar objects):

public MyFooBar getAccessDefinitions(int i)
{
  if(null == accessDefinitions)
accessDefinitions = new ArrayList();
  while(i = accessDefinitions.size())
((ArrayList)accessDefinitions).add(new MyFooBar())

  return (MyFooBar) ((ArrayList)accessDefinitions).get(i);
}

can this help you to populate form data onto your ActionForm
collection?

woodchuck


--- Rick Reumann [EMAIL PROTECTED] wrote:

 One of the most frustrating things I run into when developing Struts 
 applications is the problem of when you want to use a request scoped 
 ActionForm but you need to populate a collection that is one of your 
 ActionForm properties. The problem is the classic index out of bounds
 
 exception if you do not have your collection populated with enough
 objects.
 
 For example imagine the case where you might want to edit a bunch of 
 Access definitions on one form.
 
 So in an ActionForm property you have:
 
 Collection accessDefinitions;
 
 In your Action before you get to the form you populate your form:
 
 ((AccessForm)form).setAccessDefinitions( aCollectionOfDefs );
 
 Your JSP then displays the access definition properties for the user
 to 
 edit:
 
 (condensed and table formatting removed:)
 
 c:forEach items=${accessForm.accessDefinitions} var=access 
 varStatus=status
html:text property=accessDefinitions[${status.index}].name/
html:text
 property=accessDefinitions[${status.index}].description/
 /c:forEach
 
 Now the problem will be when you submit this form. If this form was 
 given request scope in the action mapping, you'll end up with errors 
 since BeanUtils can not populate the Collection. You need to have the
 
 correct size in place for 'accessDefinitions' to allow for
 population.
 
 There are several solutions that have been proposed by searching the 
 list archives.
 
 The easiest alternative is of course to just put your form in Session
 
 scope, but that is such a waste in my opinion.
 
 Another approach would be something like:
 
 In reset() of ActionForm:
 
 public void reset(ActionMapping actionMapping, HttpServletRequest
 request) {
  if ( request.getParameter(accessDefinitionsSize) != null ) {
  int accessDefinitionsSize = new 
 Integer(request.getParameter(accessDefinitionsSize)).intValue();
  accessDefinitions = new ArrayList(accessDefinitionsSize);
  for (int i=0;iaccessDefinitionsSize;i++) {
  accessDefinitions.add(new AccessDefinitionVO());
  }
  }
 }
 
 Then in your JSP (code snipped just showing releveant portion):
 
 c:forEach items=${accessForm.accessDefinitions} var=access 
 varStatus=status

c:set var=accessDefinitionsSize value=${status.count}/
 /c:forEach
 input type=hidden name=accessDefinitionsSize 
 value=${accessDefinitionsSize}/
 
 The above works 'ok' but it's so much extra code. I've thought of
 just 
 adding the accessDefinitionsSize attribute to the Session in the
 Action 
 that is called right be the form is set up. Then the reset method can
 
 pull it right from there. An int in the session won't be too much 
 overhead. But I'm not sure if I like that approach that much either 
 (although I'm leaning towards just doing it that way).
 
 Of course I don't like the approaches that call a business class from
 
 the reset to get the size.
 
 Any suggestions welcome.
 
 -- 
 Rick
 
 
 
 -
 To unsubscribe, e-mail: [EMAIL PROTECTED]
 For additional commands, e-mail: [EMAIL PROTECTED]
 
 




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Re: Not happy with approaches.. looking for better/other suggestions

2004-09-02 Thread Hubert Rabago 
Have you tried using ListUtils.lazyList() for this?  I just tried it
on a sample app and it works in cases like this.

- Hubert

On Thu, 02 Sep 2004 14:27:32 -0400, Rick Reumann [EMAIL PROTECTED] wrote:
 One of the most frustrating things I run into when developing Struts
 applications is the problem of when you want to use a request scoped
 ActionForm but you need to populate a collection that is one of your
 ActionForm properties. The problem is the classic index out of bounds
 exception if you do not have your collection populated with enough objects.
 
 For example imagine the case where you might want to edit a bunch of
 Access definitions on one form.
 
 So in an ActionForm property you have:
 
 Collection accessDefinitions;
 
 In your Action before you get to the form you populate your form:
 
 ((AccessForm)form).setAccessDefinitions( aCollectionOfDefs );
 
 Your JSP then displays the access definition properties for the user to
 edit:
 
 (condensed and table formatting removed:)
 
 c:forEach items=${accessForm.accessDefinitions} var=access
 varStatus=status
   html:text property=accessDefinitions[${status.index}].name/
   html:text property=accessDefinitions[${status.index}].description/
 /c:forEach
 
 Now the problem will be when you submit this form. If this form was
 given request scope in the action mapping, you'll end up with errors
 since BeanUtils can not populate the Collection. You need to have the
 correct size in place for 'accessDefinitions' to allow for population.
 
 There are several solutions that have been proposed by searching the
 list archives.
 
 The easiest alternative is of course to just put your form in Session
 scope, but that is such a waste in my opinion.
 
 Another approach would be something like:
 
 In reset() of ActionForm:
 
 public void reset(ActionMapping actionMapping, HttpServletRequest request) {
 if ( request.getParameter(accessDefinitionsSize) != null ) {
 int accessDefinitionsSize = new
 Integer(request.getParameter(accessDefinitionsSize)).intValue();
 accessDefinitions = new ArrayList(accessDefinitionsSize);
 for (int i=0;iaccessDefinitionsSize;i++) {
 accessDefinitions.add(new AccessDefinitionVO());
 }
 }
 }
 
 Then in your JSP (code snipped just showing releveant portion):
 
 c:forEach items=${accessForm.accessDefinitions} var=access
 varStatus=status
   
   c:set var=accessDefinitionsSize value=${status.count}/
 /c:forEach
 input type=hidden name=accessDefinitionsSize
 value=${accessDefinitionsSize}/
 
 The above works 'ok' but it's so much extra code. I've thought of just
 adding the accessDefinitionsSize attribute to the Session in the Action
 that is called right be the form is set up. Then the reset method can
 pull it right from there. An int in the session won't be too much
 overhead. But I'm not sure if I like that approach that much either
 (although I'm leaning towards just doing it that way).
 
 Of course I don't like the approaches that call a business class from
 the reset to get the size.
 
 Any suggestions welcome.
 
 --
 Rick
 
 -
 To unsubscribe, e-mail: [EMAIL PROTECTED]
 For additional commands, e-mail: [EMAIL PROTECTED]
 


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Re: Not happy with approaches.. looking for better/other suggestions

2004-09-02 Thread Rick Reumann 
Hubert Rabago wrote:
Have you tried using ListUtils.lazyList() for this?  I just tried it
on a sample app and it works in cases like this.
No I haven't tried that. Even with that, how is the lazy load going to 
know the size to load without calling a business class behind the 
scenes? (which seems really goofy just to get a size).

--
Rick
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Re: Not happy with approaches.. looking for better/other suggestions

2004-09-02 Thread Hubert Rabago 
It doesn't.  What happens is, when Struts tries to access the nth bean
to populate it, the lazyList creates a bean and puts it at the nth
index.
Here's what I put in my ActionForm:

public class CollForm 
extends ActionForm {

Collection accessDefinitions;

public Collection getAccessDefinitions() {
return accessDefinitions;
}

public void setAccessDefinitions(Collection accessDefinitions) {
this.accessDefinitions = accessDefinitions;
}

public void reset(ActionMapping mapping, HttpServletRequest request) {
super.reset(mapping, request);
accessDefinitions = ListUtils.lazyList(new java.util.ArrayList(),
new Factory() {
public Object create() {
return new AccessDefinition();
}
});
}

public static class AccessDefinition {
String name;
String description;

public AccessDefinition() { }
public AccessDefinition(String name, String description) {
this.name = name;
this.description = description;
}

public String getName() { return name; }
public void setName(String name) { this.name = name; }
public String getDescription() { return description; }
public void setDescription(String description) {
this.description = description; }
}

}

=
Here's what I have in my action to prepopulate it:
public ActionForward execute(ActionMapping mapping,
 ActionForm actionForm,
 HttpServletRequest request,
 HttpServletResponse response)
throws Exception {
CollForm form = new CollForm();
form.reset(mapping, request);
Collection accessDefinitions = form.getAccessDefinitions();
accessDefinitions.add(new CollForm.AccessDefinition(http,internet));
accessDefinitions.add(new CollForm.AccessDefinition(jms,messaging));
form.setAccessDefinitions(accessDefinitions);
request.setAttribute(collForm, form);
return mapping.findForward(jsp);
}
=
If you use an actual factory class instead of the anonymous one I used
in CollForm.reset(), you won't have to call reset() in your Action,
just call ListUtils.lazyList() directly.

hth,
Hubert

On Thu, 02 Sep 2004 15:52:20 -0400, Rick Reumann [EMAIL PROTECTED] wrote:
 Hubert Rabago wrote:
 
  Have you tried using ListUtils.lazyList() for this?  I just tried it
  on a sample app and it works in cases like this.
 
 No I haven't tried that. Even with that, how is the lazy load going to
 know the size to load without calling a business class behind the
 scenes? (which seems really goofy just to get a size).
 
 
 
 --
 Rick
 
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Re: Not happy with approaches.. looking for better/other suggestions

2004-09-02 Thread Rick Reumann 
Hubert Rabago wrote:
public void reset(ActionMapping mapping, HttpServletRequest request) {
super.reset(mapping, request);
accessDefinitions = ListUtils.lazyList(new java.util.ArrayList(),
new Factory() {
public Object create() {
return new AccessDefinition();
}
});
Ok that is just way too cool:) This is perfect. Now I have to look at 
the API to figure out what's going on. Way awesome.

--
Rick
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