CODEWITHSUNDEEP
jsfprimefacesdestroyview-scoperemotecommand
Jürgen Simon
Jürgen Simon

Reputation: 896

p:remoteCommand destroys @ViewScoped managed bean

I am having trouble adding a p:remoteCommand to a form. It looks something like:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core"
    xmlns:util="http://java.sun.com/jsf/composite/components/util"
    xmlns:c="http://java.sun.com/jsp/jstl/core" xmlns:fn="http://java.sun.com/jsp/jstl/functions"
    xmlns:p="http://primefaces.org/ui">
    <h:head>
        <title>Reset Test</title>
        <link type="text/css" rel="stylesheet" href="/treetable-sscce/css/example.css" />
        <h:outputScript library="primefaces" name="jquery/jquery.js"/>
    </h:head>

    <div class="box">
        <h2>Box</h2>
        <h:panelGroup id="mypanel">
            Headline: <h:outputText value="#{resetBean.headline}" />
            <br/>
            Message : <h:outputText value="#{resetBean.message}" />
            <br/>
        </h:panelGroup>
    </div>

    <div class="box">
        <h2>Form</h2>
        <h:form id="myform" acceptcharset="utf-8">

            <p:growl id="growl" showDetail="true" sticky="false" severity="info, warn" />       

            <!--  register custom validate event -->
            <f:event listener="#{resetBean.validateForm}" type="postValidate" />

            <p:remoteCommand name="resetByEscape" action="#{resetBean.resetAction}" 
                immediate="true" update=":myform :mypanel" />

            <h:outputLabel for="headline">Meldungsüberschrift</h:outputLabel>
            <h:inputText id="headline" value="#{resetBean.headline}" />
            <br/>

            <h:outputLabel for="message">Meldungsüberschrift</h:outputLabel>
            <h:inputTextarea id="message" value="#{resetBean.message}" />
            <br/>

            <h:commandButton action="#{resetBean.resetAction}"  
                        value="Reset" immediate="true" onclick="resetForm()"/>

            <h:commandButton action="#{resetBean.submitAction}" value="Submit"  immediate="false"/>

        </h:form>
    </div>

    <script type="text/javascript">
        <!--//--><![CDATA[//><!--

        var resetForm = function()
        {
            $("[id$='headline']").val(null)
            $("[id$='message']").val(null)
        }

        var escapePressed = function()
        {
            resetForm();
            resetByEscape();
        } 

        $(document).keyup(function(e) {if (e.keyCode == 27) escapePressed();});

        //--><!]]>
    </script>
</html>

Here is the bean code:

package de.example.beans;

import java.io.Serializable;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
import javax.faces.event.ComponentSystemEvent;
import javax.faces.validator.ValidatorException;

import org.apache.log4j.Logger;

@ViewScoped
@ManagedBean
public class ResetBean implements Serializable 
{
    private static final long serialVersionUID = 7282752623428425109L;
    private static final Logger log = Logger.getLogger(ResetBean.class);

    protected String headline = null;
    protected String message = null;

    public ResetBean() {
        log.error("ResetBean");
    }

    @PostConstruct
    public void postConstruct() {
        log.error("postConstruct");
    }

    @PreDestroy
    public void preDestroy() {
        log.error("preDestroy");
    }

    public void resetAction() {
        log.error("resetAction");
        headline = null;
        message = null;
    }

    public void submitAction() {
        log.error("submitAction headline="+headline+" message="+message);
    }

    public void validateForm(ComponentSystemEvent event) throws ValidatorException {
        log.error("validateForm");
    }

    public String getHeadline() {
        return headline;
    }

    public void setHeadline(String headline) {
        this.headline = headline;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

}

Both the h:command button and the p:remoteCommand execute the same action in the same fashion. The difference is, that the h:command button responds to a mouse click, while the ESC key triggers the p:remoteCommand via javascript on using ESC key.

The problem is, that the route via p:remoteCommand seems to destroy the backing bean somehow (the bean is @ViewScoped). The @PreDestroy annotated method is never called, however: the next action on the page after using the p:remoteCommand forces the component to be created from scratch! Default constructor and @PostConstruct are called. Naturally some important parameters are missing now and the whole view gets shot to hell.

Any idea what is happening? Why the difference between p:remoteCommmand and h:commandButton in this instance? Any chance of working around the problem?

Upvotes: 3

Views: 1379

Answers (1)

Gabriel Pegoraro
Gabriel Pegoraro

Reputation: 41

I could reproduce the problem. In my case and maybe the same case here (question provides only 'sample' code, not real one) it was caused by nested forms template->page.

If you have a ui:composition template or something similar to that, at the end of the generated HTML on client side it may creates nested forms like this:

<h:form>
...
  <h:form>
   ...
  </h:form>
...
</h:form>

which is invalid HTML code.

Remove unnecessary forms or reorganize code and test again. It should not call @postConstruct method when p:remoteCommand is called through JavaScript

Upvotes: 1

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