You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@wicket.apache.org by Emond Papegaaij <em...@topicus.nl> on 2011/03/28 15:59:22 UTC
Moving from isVisible/isEnabled overrides to onConfigure
Hi all,
We are trying to migrate our projects from overriding isVisible and isEnabled
to the new onConfigure method, but are having some problems with the new API.
I'll start with explaining the old situation. We find it good practice to
always call super.isVisible() in an overriding isVisible method. A typical
implementation would look like this:
public class MyComponent extends WebMarkupContainer {
public boolean isVisible() {
return super.isVisible() && isConditionSatisfied();
}
}
Doing things this way, ensures the component will never be visible when the
condition is not satisfied, nor when the component is explicitly hidden with
setVisible(false).
Trying to convert this to the new API, we started with:
public class MyComponent extends WebMarkupContainer {
protected void onConfigure() {
super.onConfigure();
setVisible(isVisible() && isConditionSatisfied());
}
}
However, we soon realized this will not work because a hidden component can
never become visible again. Even when the condition is satisfied, isVisible()
will still be false, causing the component to remain hidden. Therefore, our
second attempt was to remove the call to isVisible():
public class MyComponent extends WebMarkupContainer {
protected void onConfigure() {
super.onConfigure();
setVisible(isConditionSatisfied());
}
}
This, however, suffers from another problem: manual setVisible(...) calls are
now ignored. The visibility flag is always overridden by onConfigure. On our
third attempt, we decided to use the visibilityAllowed flag for onConfigure,
like this:
public class MyComponent extends WebMarkupContainer {
protected void onConfigure() {
super.onConfigure();
setVisibilityAllowed(isConditionSatisfied());
}
}
This works great. It mixes with calls to setVisible. It even mixes well with
isVisible overrides in subclasses. However, this approach only works for
component visibility. There is no setEnabledAllowed. There is a
isEnableAllowed(), but it is security related (the counterpart of
isRenderAllowed()).
Would it be possible to add a new property to Component (both in 1.4 and 1.5):
enabledAllowed? This property would have a final getter (isEnabledAllowed) and
setter (setEnabledAllowed), just as with visibilityAllowed. The naming of
isEnableAllowed() would be a bit unfortunate, but I don't think that method
can be changed. It is part of the public API. This new property would make it
significantly easier to move to onConfigure.
Best regards,
Emond Papegaaij
Re: Moving from isVisible/isEnabled overrides to onConfigure
Posted by Emond Papegaaij <em...@topicus.nl>.
I've created the issue: https://issues.apache.org/jira/browse/WICKET-3568
I'm not asking to change the behavior of isEnableAllowed(), merely to add a
new isEnable*d*Allowed(), with corresponding setEnabledAllowed(). Visibility
of a component is determined by 3 factors:
isVisible() && isRenderAllowed() && isVisibilityAllowed();
Whereas whether a component is enabled or not, only relies on 2 factors:
isEnabled() && isEnableAllowed();
I agree the naming of this new property is a bit unfortunate. Perhaps someone
can come up with another name? I don't think you should change the current
isEnableAllowed(). It is the counterpart of isRenderAllowed() and serves to
implement security. People may depend on that behavior.
I've added this clarification to the JIRA issue. Do you want to continue this
discussion on the list, or at JIRA?
Best regards,
Emond Papegaaij
On Monday 28 March 2011 18:30:07 Igor Vaynberg wrote:
> please add a request to jira to do this, referencing or pasting this
> email. i dont think we can do this for 1.4 as it would change the
> semantics of isEnabledAllowed() transparently. but, in 1.5 we can make
> the change.
>
> -Igor
>
>
> On Mon, Mar 28, 2011 at 6:59 AM, Emond Papegaaij
>
> <em...@topicus.nl> wrote:
> > Hi all,
> >
> > We are trying to migrate our projects from overriding isVisible and
> > isEnabled to the new onConfigure method, but are having some problems
> > with the new API.
> >
> > I'll start with explaining the old situation. We find it good practice to
> > always call super.isVisible() in an overriding isVisible method. A
> > typical implementation would look like this:
> >
> > public class MyComponent extends WebMarkupContainer {
> > public boolean isVisible() {
> > return super.isVisible() && isConditionSatisfied();
> > }
> > }
> >
> > Doing things this way, ensures the component will never be visible when
> > the condition is not satisfied, nor when the component is explicitly
> > hidden with setVisible(false).
> >
> > Trying to convert this to the new API, we started with:
> >
> > public class MyComponent extends WebMarkupContainer {
> > protected void onConfigure() {
> > super.onConfigure();
> > setVisible(isVisible() && isConditionSatisfied());
> > }
> > }
> >
> > However, we soon realized this will not work because a hidden component
> > can never become visible again. Even when the condition is satisfied,
> > isVisible() will still be false, causing the component to remain hidden.
> > Therefore, our second attempt was to remove the call to isVisible():
> >
> > public class MyComponent extends WebMarkupContainer {
> > protected void onConfigure() {
> > super.onConfigure();
> > setVisible(isConditionSatisfied());
> > }
> > }
> >
> > This, however, suffers from another problem: manual setVisible(...) calls
> > are now ignored. The visibility flag is always overridden by
> > onConfigure. On our third attempt, we decided to use the
> > visibilityAllowed flag for onConfigure, like this:
> >
> > public class MyComponent extends WebMarkupContainer {
> > protected void onConfigure() {
> > super.onConfigure();
> > setVisibilityAllowed(isConditionSatisfied());
> > }
> > }
> >
> > This works great. It mixes with calls to setVisible. It even mixes well
> > with isVisible overrides in subclasses. However, this approach only
> > works for component visibility. There is no setEnabledAllowed. There is
> > a
> > isEnableAllowed(), but it is security related (the counterpart of
> > isRenderAllowed()).
> >
> > Would it be possible to add a new property to Component (both in 1.4 and
> > 1.5): enabledAllowed? This property would have a final getter
> > (isEnabledAllowed) and setter (setEnabledAllowed), just as with
> > visibilityAllowed. The naming of isEnableAllowed() would be a bit
> > unfortunate, but I don't think that method can be changed. It is part of
> > the public API. This new property would make it significantly easier to
> > move to onConfigure.
> >
> >
> > Best regards,
> > Emond Papegaaij
Re: Moving from isVisible/isEnabled overrides to onConfigure
Posted by Igor Vaynberg <ig...@gmail.com>.
please add a request to jira to do this, referencing or pasting this
email. i dont think we can do this for 1.4 as it would change the
semantics of isEnabledAllowed() transparently. but, in 1.5 we can make
the change.
-Igor
On Mon, Mar 28, 2011 at 6:59 AM, Emond Papegaaij
<em...@topicus.nl> wrote:
> Hi all,
>
> We are trying to migrate our projects from overriding isVisible and isEnabled
> to the new onConfigure method, but are having some problems with the new API.
>
> I'll start with explaining the old situation. We find it good practice to
> always call super.isVisible() in an overriding isVisible method. A typical
> implementation would look like this:
>
> public class MyComponent extends WebMarkupContainer {
> public boolean isVisible() {
> return super.isVisible() && isConditionSatisfied();
> }
> }
>
> Doing things this way, ensures the component will never be visible when the
> condition is not satisfied, nor when the component is explicitly hidden with
> setVisible(false).
>
> Trying to convert this to the new API, we started with:
>
> public class MyComponent extends WebMarkupContainer {
> protected void onConfigure() {
> super.onConfigure();
> setVisible(isVisible() && isConditionSatisfied());
> }
> }
>
> However, we soon realized this will not work because a hidden component can
> never become visible again. Even when the condition is satisfied, isVisible()
> will still be false, causing the component to remain hidden. Therefore, our
> second attempt was to remove the call to isVisible():
>
> public class MyComponent extends WebMarkupContainer {
> protected void onConfigure() {
> super.onConfigure();
> setVisible(isConditionSatisfied());
> }
> }
>
> This, however, suffers from another problem: manual setVisible(...) calls are
> now ignored. The visibility flag is always overridden by onConfigure. On our
> third attempt, we decided to use the visibilityAllowed flag for onConfigure,
> like this:
>
> public class MyComponent extends WebMarkupContainer {
> protected void onConfigure() {
> super.onConfigure();
> setVisibilityAllowed(isConditionSatisfied());
> }
> }
>
> This works great. It mixes with calls to setVisible. It even mixes well with
> isVisible overrides in subclasses. However, this approach only works for
> component visibility. There is no setEnabledAllowed. There is a
> isEnableAllowed(), but it is security related (the counterpart of
> isRenderAllowed()).
>
> Would it be possible to add a new property to Component (both in 1.4 and 1.5):
> enabledAllowed? This property would have a final getter (isEnabledAllowed) and
> setter (setEnabledAllowed), just as with visibilityAllowed. The naming of
> isEnableAllowed() would be a bit unfortunate, but I don't think that method
> can be changed. It is part of the public API. This new property would make it
> significantly easier to move to onConfigure.
>
>
> Best regards,
> Emond Papegaaij
>