I'm interested What is the proper way to use JSF pages with AJAX when I use CDI.
I tested to configure the CDI beans with #SessionScoped but I found that there is a problem with AJAX.
Is it proper to use AJAX with CDI beans configured with #ConversationScoped?
And I found that I have to put conversation.begin(); into the Bean constructor and conversation.end(); into Java method which must be when the session is completed. Can I somehow do this automatically?
P.S Can I use this code to automatically free the resource when the user closes the page?
#Remove
public void finishIt(){
conversation.end();
}
And I found that I have to put conversation.begin(); into the Bean constructor and conversation.end(); into Java method which must be when the session is completed.
That's correct. See also among others How to replace #ManagedBean / #ViewScope by CDI in JSF 2.0/2.1 for a concrete code example.
Can I somehow do this automatically?
If you want a bean which must live as long as you're postbacking on a single view, then upgrade to at least JSF 2.2. It provides a CDI compatible #ViewScoped out the box.
If you however want a bean which must live as long as you reference it in a view, regardless of the view you're sitting in, then consider using #ViewAccessScoped of DeltaSpike instead. Once you navigate to a view which doesn't reference the bean anywhere, it will be trashed.
See also:
How to choose the right bean scope?
By default the Conversation object is in transient state. Invocation of the begin method marks it as long-running (when a real conversation starts). Ending conversation (by invoking end method) marks Conversation object as transient.
A transient conversation scoped bean will live for a life cycle of single request .
long-ending conversation(initiated by conversation.begin) will run unless conversation.end is called.
Related
This doesn't seem right. I was doing some cleanup of my code and I just noticed this. Every ajax request is firing the constructor and #PostConstruct of my #ViewScoped bean. Even a simple database pagination is firing it.
I understood that #ViewScoped is longer than #RequestScoped and that it shouldn't be reconstructed on every request. Only after a complete page reload by GET.
In other words, your #ViewScoped bean behaves like a #RequestScoped bean. It's been recreated from scratch on every postback request. There are many possible causes for this, most of which boils down that the associated JSF view is not available anymore in the JSF state which in turn is by default associated with the HTTP session.
Provided that you can assure that the HTTP session itself is not the root cause of the problem, i.e. when #SessionScoped works absolutely fine, then walk through the below list of possible causes. Otherwise, if the HTTP session itself is also trashed and recreated on every single request, then you need to take a step back and look at session cookie and server configuration. Any cause related to a broken HTTP session is at least beyond the context of JSF.
You're using Mojarra 2.1.17 or older, and the view contains EL expressions which bind a view scoped bean property to a tag attribute which is evaluated during view build time. Examples are JSTL <c:if>, <c:forEach>, etc or JSF <ui:include>, <x:someComponent id="#{...}", <x:someComponent binding="#{...}">, etc. This is caused by a bug in Mojarra (issue 1496). See also Why does #PostConstruct callback fire every time even though bean is #ViewScoped? JSF
This is already fixed in Mojarra version 2.1.18. If you can't upgrade to a newer version, the workaround is to disable partial state saving as below in web.xml, see also JSTL in JSF2 Facelets... makes sense?
<context-param>
<param-name>javax.faces.PARTIAL_STATE_SAVING</param-name>
<param-value>false</param-value>
</context-param>
Or when you want to target a specific set of JSF views only:
<context-param>
<param-name>javax.faces.FULL_STATE_SAVING_VIEW_IDS</param-name>
<param-value>/foo.xhtml;/bar.xhtml;/folder/baz.xhtml</param-value>
</context-param>
Important to mention is that binding the value of JSF component's id or binding attribute to a view scoped bean property is a bad practice. Those should really be bound to a request scoped bean property, or an alternative should be sought. See also How does the 'binding' attribute work in JSF? When and how should it be used?
You're using Mojarra 2.2.0, only that version has a (yet unknown) bug in maintaining the view scope which is already fixed in 2.2.1, see also issue 2916. Solution is to upgrade to a newer version.
The #ViewScoped annotation is imported from the wrong package. JSF offers two #ViewScoped annotations, one from javax.faces.bean package for JSF managed beans annotated with #ManagedBean, and another one from javax.faces.view package for CDI managed beans annotated with #Named. When the bean scope annotation does not match the bean management annotation, then the actual bean scope will become the bean management framework's default scope, which is #RequestScoped in JSF managed beans and #Dependent in CDI managed beans.
You need to ensure that you have either of the following constructs and don't mix them, see also #ViewScoped bean recreated on every postback request when using JSF 2.2.
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
#ManagedBean
#ViewScoped
public class CorrectJSFViewScopedBean implements Serializable {
import javax.inject.Named;
import javax.faces.view.ViewScoped;
#Named
#ViewScoped
public class CorrectCDIViewScopedBean implements Serializable {
The view is (accidentally?) marked transient via <f:view transient="true">. This basically turns on "stateless JSF", which is new since Mojarra 2.1.19. Hereby the JSF view simply won't be saved in the JSF state at all and logical consequence is that all referenced view scoped beans can't be associated with the JSF view anymore. See also What is the usefulness of statelessness in JSF?
The web application is configured with com.sun.faces.enableRestoreView11Compatibility context param set to true in an incorrect attempt to "avoid" ViewExpiredException. With this context param, the ViewExpiredException will never be thrown, but the view (and all associated view scoped beans) will just be recreated from scratch. However, if that happens on every request, then this approach actually hides another problem: the views expire way too soon. This indicates a possible problem in maintaining the JSF view states and/or the HTTP session. How to solve/configure that properly, head to javax.faces.application.ViewExpiredException: View could not be restored.
The web application's runtime classpath is polluted with multiple different versioned JSF API or impl related classes. This causes a corruption/mismatch in the identifiers/markers for the JSF view state. You need to make sure you don't have multiple JSF API JAR files in webapp's /WEB-INF/lib. In case you're using Maven, make carefully sure that you mark server-provided libraries as <scope>provided</scope>. See also "Installing JSF" section in our JSF wiki page and the answer to this related question: How to properly install and configure JSF libraries via Maven?.
When you're using PrimeFaces <p:dialog>, then make sure that the <p:dialog> has its own <h:form> and that it is not nested in another <h:form>. See also p:fileUpload inside p:dialog losing #ViewScoped values.
When you're combining PrimeFaces FileUploadFilter with PrettyFaces, then make sure that the FileUploadFilter also runs on PrettyFaces-rewritten/forwarded requests. See also ViewScoped bean rebuilt when FileUploadListener called using PrettyFaces and How to use PrimeFaces p:fileUpload? Listener method is never invoked or UploadedFile is null / throws an error / not usable.
When you're using PrettyFaces, a badly configured rewrite rule which redirects CSS/JS/image resources to a JSF page tied to a #ViewScoped bean will also give misleading behavior. See also CDI ViewScope & PrettyFaces: Multiple calls to #PostConstruct (JSF 2.2).
This doesn't seem right. I was doing some cleanup of my code and I just noticed this. Every ajax request is firing the constructor and #PostConstruct of my #ViewScoped bean. Even a simple database pagination is firing it.
I understood that #ViewScoped is longer than #RequestScoped and that it shouldn't be reconstructed on every request. Only after a complete page reload by GET.
In other words, your #ViewScoped bean behaves like a #RequestScoped bean. It's been recreated from scratch on every postback request. There are many possible causes for this, most of which boils down that the associated JSF view is not available anymore in the JSF state which in turn is by default associated with the HTTP session.
Provided that you can assure that the HTTP session itself is not the root cause of the problem, i.e. when #SessionScoped works absolutely fine, then walk through the below list of possible causes. Otherwise, if the HTTP session itself is also trashed and recreated on every single request, then you need to take a step back and look at session cookie and server configuration. Any cause related to a broken HTTP session is at least beyond the context of JSF.
You're using Mojarra 2.1.17 or older, and the view contains EL expressions which bind a view scoped bean property to a tag attribute which is evaluated during view build time. Examples are JSTL <c:if>, <c:forEach>, etc or JSF <ui:include>, <x:someComponent id="#{...}", <x:someComponent binding="#{...}">, etc. This is caused by a bug in Mojarra (issue 1496). See also Why does #PostConstruct callback fire every time even though bean is #ViewScoped? JSF
This is already fixed in Mojarra version 2.1.18. If you can't upgrade to a newer version, the workaround is to disable partial state saving as below in web.xml, see also JSTL in JSF2 Facelets... makes sense?
<context-param>
<param-name>javax.faces.PARTIAL_STATE_SAVING</param-name>
<param-value>false</param-value>
</context-param>
Or when you want to target a specific set of JSF views only:
<context-param>
<param-name>javax.faces.FULL_STATE_SAVING_VIEW_IDS</param-name>
<param-value>/foo.xhtml;/bar.xhtml;/folder/baz.xhtml</param-value>
</context-param>
Important to mention is that binding the value of JSF component's id or binding attribute to a view scoped bean property is a bad practice. Those should really be bound to a request scoped bean property, or an alternative should be sought. See also How does the 'binding' attribute work in JSF? When and how should it be used?
You're using Mojarra 2.2.0, only that version has a (yet unknown) bug in maintaining the view scope which is already fixed in 2.2.1, see also issue 2916. Solution is to upgrade to a newer version.
The #ViewScoped annotation is imported from the wrong package. JSF offers two #ViewScoped annotations, one from javax.faces.bean package for JSF managed beans annotated with #ManagedBean, and another one from javax.faces.view package for CDI managed beans annotated with #Named. When the bean scope annotation does not match the bean management annotation, then the actual bean scope will become the bean management framework's default scope, which is #RequestScoped in JSF managed beans and #Dependent in CDI managed beans.
You need to ensure that you have either of the following constructs and don't mix them, see also #ViewScoped bean recreated on every postback request when using JSF 2.2.
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
#ManagedBean
#ViewScoped
public class CorrectJSFViewScopedBean implements Serializable {
import javax.inject.Named;
import javax.faces.view.ViewScoped;
#Named
#ViewScoped
public class CorrectCDIViewScopedBean implements Serializable {
The view is (accidentally?) marked transient via <f:view transient="true">. This basically turns on "stateless JSF", which is new since Mojarra 2.1.19. Hereby the JSF view simply won't be saved in the JSF state at all and logical consequence is that all referenced view scoped beans can't be associated with the JSF view anymore. See also What is the usefulness of statelessness in JSF?
The web application is configured with com.sun.faces.enableRestoreView11Compatibility context param set to true in an incorrect attempt to "avoid" ViewExpiredException. With this context param, the ViewExpiredException will never be thrown, but the view (and all associated view scoped beans) will just be recreated from scratch. However, if that happens on every request, then this approach actually hides another problem: the views expire way too soon. This indicates a possible problem in maintaining the JSF view states and/or the HTTP session. How to solve/configure that properly, head to javax.faces.application.ViewExpiredException: View could not be restored.
The web application's runtime classpath is polluted with multiple different versioned JSF API or impl related classes. This causes a corruption/mismatch in the identifiers/markers for the JSF view state. You need to make sure you don't have multiple JSF API JAR files in webapp's /WEB-INF/lib. In case you're using Maven, make carefully sure that you mark server-provided libraries as <scope>provided</scope>. See also "Installing JSF" section in our JSF wiki page and the answer to this related question: How to properly install and configure JSF libraries via Maven?.
When you're using PrimeFaces <p:dialog>, then make sure that the <p:dialog> has its own <h:form> and that it is not nested in another <h:form>. See also p:fileUpload inside p:dialog losing #ViewScoped values.
When you're combining PrimeFaces FileUploadFilter with PrettyFaces, then make sure that the FileUploadFilter also runs on PrettyFaces-rewritten/forwarded requests. See also ViewScoped bean rebuilt when FileUploadListener called using PrettyFaces and How to use PrimeFaces p:fileUpload? Listener method is never invoked or UploadedFile is null / throws an error / not usable.
When you're using PrettyFaces, a badly configured rewrite rule which redirects CSS/JS/image resources to a JSF page tied to a #ViewScoped bean will also give misleading behavior. See also CDI ViewScope & PrettyFaces: Multiple calls to #PostConstruct (JSF 2.2).
My question is related to this one (and probably others):
#PreDestroy never called on #ViewScoped
As stated there, there's no trivial solution to either have view-scoped beans destroyed upon navigation and the same seems to hold true for when the session expires.
What would a non-trivial approach to release (calling the #PreDestroy method) JSF view-scoped beans look like, or more specifically as soon as the session expires?
I'm using Java EE 6 and Mojarra 2.1.x on GlassFish 3.1.2.
Create a #SessionScoped bean to hold the resources (in some collection/array?) and inject it in the #ViewScoped bean and then rely on the #PreDestroy of the session scoped bean.
True, this way the resources live a little longer than you want, but that's the most easy and reliable solution you can get. If you want to keep the #PreDestroy in the view scoped bean, then you'd need to somehow make sure that the enduser always performs navigation by a HTTP POST request on exactly this view scoped bean. You can't reliably guarantee that (the enduser's PC might crash and so on).
This doesn't seem right. I was doing some cleanup of my code and I just noticed this. Every ajax request is firing the constructor and #PostConstruct of my #ViewScoped bean. Even a simple database pagination is firing it.
I understood that #ViewScoped is longer than #RequestScoped and that it shouldn't be reconstructed on every request. Only after a complete page reload by GET.
In other words, your #ViewScoped bean behaves like a #RequestScoped bean. It's been recreated from scratch on every postback request. There are many possible causes for this, most of which boils down that the associated JSF view is not available anymore in the JSF state which in turn is by default associated with the HTTP session.
Provided that you can assure that the HTTP session itself is not the root cause of the problem, i.e. when #SessionScoped works absolutely fine, then walk through the below list of possible causes. Otherwise, if the HTTP session itself is also trashed and recreated on every single request, then you need to take a step back and look at session cookie and server configuration. Any cause related to a broken HTTP session is at least beyond the context of JSF.
You're using Mojarra 2.1.17 or older, and the view contains EL expressions which bind a view scoped bean property to a tag attribute which is evaluated during view build time. Examples are JSTL <c:if>, <c:forEach>, etc or JSF <ui:include>, <x:someComponent id="#{...}", <x:someComponent binding="#{...}">, etc. This is caused by a bug in Mojarra (issue 1496). See also Why does #PostConstruct callback fire every time even though bean is #ViewScoped? JSF
This is already fixed in Mojarra version 2.1.18. If you can't upgrade to a newer version, the workaround is to disable partial state saving as below in web.xml, see also JSTL in JSF2 Facelets... makes sense?
<context-param>
<param-name>javax.faces.PARTIAL_STATE_SAVING</param-name>
<param-value>false</param-value>
</context-param>
Or when you want to target a specific set of JSF views only:
<context-param>
<param-name>javax.faces.FULL_STATE_SAVING_VIEW_IDS</param-name>
<param-value>/foo.xhtml;/bar.xhtml;/folder/baz.xhtml</param-value>
</context-param>
Important to mention is that binding the value of JSF component's id or binding attribute to a view scoped bean property is a bad practice. Those should really be bound to a request scoped bean property, or an alternative should be sought. See also How does the 'binding' attribute work in JSF? When and how should it be used?
You're using Mojarra 2.2.0, only that version has a (yet unknown) bug in maintaining the view scope which is already fixed in 2.2.1, see also issue 2916. Solution is to upgrade to a newer version.
The #ViewScoped annotation is imported from the wrong package. JSF offers two #ViewScoped annotations, one from javax.faces.bean package for JSF managed beans annotated with #ManagedBean, and another one from javax.faces.view package for CDI managed beans annotated with #Named. When the bean scope annotation does not match the bean management annotation, then the actual bean scope will become the bean management framework's default scope, which is #RequestScoped in JSF managed beans and #Dependent in CDI managed beans.
You need to ensure that you have either of the following constructs and don't mix them, see also #ViewScoped bean recreated on every postback request when using JSF 2.2.
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
#ManagedBean
#ViewScoped
public class CorrectJSFViewScopedBean implements Serializable {
import javax.inject.Named;
import javax.faces.view.ViewScoped;
#Named
#ViewScoped
public class CorrectCDIViewScopedBean implements Serializable {
The view is (accidentally?) marked transient via <f:view transient="true">. This basically turns on "stateless JSF", which is new since Mojarra 2.1.19. Hereby the JSF view simply won't be saved in the JSF state at all and logical consequence is that all referenced view scoped beans can't be associated with the JSF view anymore. See also What is the usefulness of statelessness in JSF?
The web application is configured with com.sun.faces.enableRestoreView11Compatibility context param set to true in an incorrect attempt to "avoid" ViewExpiredException. With this context param, the ViewExpiredException will never be thrown, but the view (and all associated view scoped beans) will just be recreated from scratch. However, if that happens on every request, then this approach actually hides another problem: the views expire way too soon. This indicates a possible problem in maintaining the JSF view states and/or the HTTP session. How to solve/configure that properly, head to javax.faces.application.ViewExpiredException: View could not be restored.
The web application's runtime classpath is polluted with multiple different versioned JSF API or impl related classes. This causes a corruption/mismatch in the identifiers/markers for the JSF view state. You need to make sure you don't have multiple JSF API JAR files in webapp's /WEB-INF/lib. In case you're using Maven, make carefully sure that you mark server-provided libraries as <scope>provided</scope>. See also "Installing JSF" section in our JSF wiki page and the answer to this related question: How to properly install and configure JSF libraries via Maven?.
When you're using PrimeFaces <p:dialog>, then make sure that the <p:dialog> has its own <h:form> and that it is not nested in another <h:form>. See also p:fileUpload inside p:dialog losing #ViewScoped values.
When you're combining PrimeFaces FileUploadFilter with PrettyFaces, then make sure that the FileUploadFilter also runs on PrettyFaces-rewritten/forwarded requests. See also ViewScoped bean rebuilt when FileUploadListener called using PrettyFaces and How to use PrimeFaces p:fileUpload? Listener method is never invoked or UploadedFile is null / throws an error / not usable.
When you're using PrettyFaces, a badly configured rewrite rule which redirects CSS/JS/image resources to a JSF page tied to a #ViewScoped bean will also give misleading behavior. See also CDI ViewScope & PrettyFaces: Multiple calls to #PostConstruct (JSF 2.2).
I've noticed that when using Ajax heavy JSF 1.2 implementations like Richfaces you're somehow forced to declare more managed beans than you'll want as Session scoped so that state can be maintained across multiple Ajax requests; there are components that will just stop working.
For instance, I developed this application lately in which I had to declare almost all my JSF Backing Beans as Session Scoped in order to have component "x" working. Is there a way out of this, do you consider it a bad practice, or is just the price to pay for having Ajax enabled component in JSF 1.2.
Thanks in advance.
Session scope beans increase memory usage.
Another available scope is View Scope - This allows to keep a state of a bean between requests, while the user is still on the same view.
If you are using JSF2, please consider using #ViewScope above the bean name:
#ViewScope
public class myBean{
..
}
If you use RichFaces and JSF1.2, consider using <a4j:keepAlive /> under <f:view> in the view. for example:
<a4j:keepAlive beanName = "#{myBean}"/>
Read more info here
Another option is to use Seam conversation. Also, I wouldn't say components stop working, they still work.. it's your logic that needs to maintain some sort of state on the server.