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Value bean or backing bean?

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posted 20 years ago

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Hi all,

Just a general query... Is it better/easier to use a backing bean (a bean that contains input objects that are "bound" to the front end screens) or a value bean (a bean that contains the "values" entered/to be displayed on the front end) to managed the front end of an application. I've tried both of them and they both seem to have pros and cons. All opinions welcome!

Cheers,

Kev

Gregg Bolinger

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posted 20 years ago

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I do a slight combination of both. For very simple pages I use the managed beans that are stricktly related to the page itself. For more complex pages I'll have a managed beans but I might also have a value object that I have in the session.

For example, in one of my applications I have a page where I gather information about a Help Desk Issue. I have a VO called Issue that stores all the important information. I always have an instance of a current issue in another VO called Visit which is stored in the session. On my newissue.jsp I just update the current issue directly instead of gathering up values in the managed bean and then copying them over. So I'll have something like:

<h:inputText value="#{visit.currentIssue.machineName}" .../>

I haven't ran into any snags with this approach yet.

Kev D'Arcy

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posted 20 years ago

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Greg,

I have a reasonably complex page and I'm using a value bean to present data to the front end, but I'm seeing some inconsistencies... Sometimes the data is displayed correctly and sometimes it isn't. I'm wondering if I should just use a backing bean to present/receive the data and just transfer the values to/from the value bean...

Gregg Bolinger

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posted 20 years ago

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I'd so go with what works.

That being said, how are you storing your value bean? Session, Request, etc? When and how are you updating it?

Varun Khanna

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posted 20 years ago

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I use a combination of both and seems to wrok fine till now.

Originally posted by Kev D'Arcy:
Greg,

I have a reasonably complex page and I'm using a value bean to present data to the front end, but I'm seeing some inconsistencies... ...

What kind of inconsistencies ?

- Varun

Kev D'Arcy

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posted 20 years ago

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Greg,

I'm storing the value bean in a session object. It get's updated either via front end forms (through value links to inputs), or via code in the app to clear down values.

Kev

Kev D'Arcy

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posted 20 years ago

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Varun,

What I'm seeing is that when the value bean gets cleared down (either explicitly through the application or by going to a new page) and a user returns to the page displaying the value bean properties, some of the value beans properties don't get displayed on the JSP.

Kev

Gregg Bolinger

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posted 20 years ago

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Originally posted by Kev D'Arcy:
Varun,

What I'm seeing is that when the value bean gets cleared down (either explicitly through the application or by going to a new page) and a user returns to the page displaying the value bean properties, some of the value beans properties don't get displayed on the JSP.

Kev

What do you mean by "cleared down" and how are they returning to the previous page? I think your problem may just be a logic issue rather than a technical issue. I have no problems updating the properties in session objects from pages or code.

Kev D'Arcy

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posted 20 years ago

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It's probably easier if I show you the code. Can i upload it somewhere or will I just embed it into a post?

Gregg Bolinger

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posted 20 years ago

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Just post the code in here. Be sure and use UBB code tags

[/code]

And disable smilies.

Kev D'Arcy

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posted 20 years ago

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Greg,

This is the JSP 1.:

This is an example of one of the jspfs:

<f:subview id="inputID">
<table width="100%">
<tr>
<td class="tablebg">
<h:outputText styleClass="smalltitle" value="#{labels.input_issueID}"/>
<table align="left" class="tablebg" width="100%">
<tr>
<td><h:outputText value="#{labels.input_issueID}"/></td>
<td><h:outputText value="#{labels.input_division}"/></td>
<td><h:outputText value="#{labels.input_externalRef}"/></td>
<td><h:outputText value="#{labels.input_source}"/></td>
</tr>
<tr>
<td><h:inputText id="issueId" readonly="true" size="9" value="#{inputHandler.issue.issueIdString}" styleClass="disabled"/></td>
<td>
<h:selectOneMenu id="division" value="#{inputHandler.issue.divisionIdString}" disabled="#{rules.inputFieldDivisionDisabled}" required="#{user.superUser}">
<f:selectItem itemLabel="" itemValue=""/>
<f:selectItems value="#{divisions.divisions}"/>
</h:selectOneMenu>
</td>
<td><h:inputText id="externalRef" size="9" value="#{inputHandler.issue.externalReference}" disabled="#{rules.inputFieldDisabled}"/></td>
<td>
<h:selectOneMenu id="source" value="#{inputHandler.issue.sourceIdString}" disabled="#{rules.inputFieldDisabled}" required="#{!user.superUser}">
<f:selectItem itemLabel="" itemValue=""/>
<f:selectItems value="#{sources.issueSources}"/>
</h:selectOneMenu>
</td>
</tr>
<tr>
<td/>
<td><h:message styleClass="message" for="division"/></td>
<td><h:message styleClass="message" for="externalRef"/></td>
<td><h:message styleClass="message" for="source"/></td>
</tr>
<tr>
<td/>
<td><h:outputText value="#{labels.input_dateOccurred}"/></td>
<td><h:outputText value="#{labels.input_dateRaised}"/></td>
<td><h:outputText value="#{labels.input_dateClosed}"/></td>
</tr>
<tr>
<td/>
<td>
<h:inputText id="dateOccurred" size="13" value="#{inputHandler.issue.dateOccurred}" disabled="#{rules.inputFieldDisabled}" required="#{!user.superUser}">
<f:convertDateTime pattern="dd/MM/yyyy"/>
<hx:inputHelperDatePicker/>
<hx:validateDateTimeRange maximum="#{now}"/>
</h:inputText>
</td>
<td>
<h:inputText id="dateRaised" size="13" value="#{inputHandler.issue.dateRaised}" disabled="#{rules.inputFieldDisabled}" required="#{!user.superUser}">
<f:convertDateTime pattern="dd/MM/yyyy"/>
<hx:inputHelperDatePicker/>
</h:inputText>
</td>
<td>
<h:inputText id="dateClosed" size="13" value="#{inputHandler.issue.dateClose}" disabled="#{rules.inputFieldDisabled}">
<f:convertDateTime pattern="dd/MM/yyyy"/>
<hx:inputHelperDatePicker/>
<hx:validateDateTimeRange maximum="#{now}"/>
</h:inputText>
</td>
</tr>
<tr>
<td/>
<td><h:message styleClass="message" for="dateOccurred"/></td>
<td><h:message styleClass="message" for="dateRaised"/></td>
<td><h:message styleClass="message" for="dateClosed"/></td>
</tr>
</table>
</td>
</tr>
</table>
</f:subview>

And the code in the action bean:

public final class InputHandler extends Handler {
 
private Issue issue = null;
private IssueStatus currentStatus = null;
private ListDataModel statusList = null;
 
public InputHandler() {
super();
}

public final String createReport() {
return Constants.NAV_SUCCESS;
}

/**
 * @return Returns the currentStatus.
 */
public final IssueStatus getCurrentStatus() {
return (currentStatus == null) ? new IssueStatus() : currentStatus;
}
 
/**
 * @return Returns the issue.
 */
public final Issue getIssue() {
if (issue == null) {
setIssue(setIssueDefaults(new Issue(true)));
}
return issue;
}

public final String getIssueData() {
Issue currentIssue = null;
GetIssueOperation getIssueOp = null;
GetIssueStatusOperation getIssueStatusOp = null;
try {
currentIssue = getIssue();
getIssueOp = new GetIssueOperation(getUser(), issue.getIssueId());
getIssueOp.execute();
currentIssue = getIssueOp.getResults();
getIssueStatusOp = new GetIssueStatusOperation(getUser(), issue.getIssueId());
getIssueStatusOp.execute();
currentIssue.setUpdates(getIssueStatusOp.getResults());
setIssue(currentIssue);
setStatusList(new ListDataModel(getIssueStatusOp.getResults()));
}
catch (DBException e) {
FacesUtils.addResponseMessage("issueFrm", e.getMessage());
setIssue(new Issue(true));
return Constants.NAV_FAILURE;
}
finally {
currentIssue = null;
getIssueOp = null;
getIssueStatusOp = null;
}
return Constants.NAV_SUCCESS;
}

public final String getIssueStatusData() {
setCurrentStatus((IssueStatus) getStatusList().getRowData());
return Constants.NAV_UPDATE_ISSUE_STATUS;
}
 
public final ListDataModel getStatusList() {
return (statusList == null) ? new ListDataModel() : statusList;
}
 
public final String newIssueStatus() {
IssueStatus status = new IssueStatus();
status.setInputBy(getUser().getUsername());
status.setInputDate(new Date());
status.setIssueId(getIssue().getIssueId());
status.setUpdateDate(null);
setCurrentStatus(status);
return Constants.NAV_NEW_ISSUE_STATUS;
}

/** Clear down the state of this object */
public final void reset() {
setIssue(setIssueDefaults(new Issue()));
setCurrentStatus(setIssueStatusDefaults(new IssueStatus()));
setStatusList(new ListDataModel());
}

/**
 * @param currentStatus The currentStatus to set.
 */
public final void setCurrentStatus(IssueStatus currentStatus) {
this.currentStatus = currentStatus;
}
 
/**
 * @param issue The issue to set.
 */
public final void setIssue(Issue issue) {
forceRegion(issue);
this.issue = issue;
}

public final void setStatusList(ListDataModel statusList) {
this.statusList = statusList;
}
 
/**
 * Save an <code>Issue</code> to the database
 * @return
 */
public final String saveIssue() {
Issue issue = null;
try {
if (getUser().isReadOnly()) {
FacesUtils.addResponseMessage("issueFrm", Constants.MSG_ILLEGAL_UPDATE);
return Constants.NAV_FAILURE;
}
if (getIssue().isClosed()) {
FacesUtils.addResponseMessage("issueFrm", Constants.MSG_ISSUE_CLOSED);
return Constants.NAV_FAILURE;
}
issue = getIssue();
forceRegion(issue);
issue.setLastUpdatedBy(getUser().getUsername());
issue.setLastUpdatedDate(new Date());
if (issue.getIssueId() == Constants.DEF_ISSUE_ID) {
// new issue
issue.setInputBy(getUser().getUsername());
issue.setInputDate(new Date());
issue.setInputPc(FacesUtils.getRemoteHost());
CreateIssueOperation cio = new CreateIssueOperation(getUser(), issue);
cio.execute();
setIssue(cio.getIssue());
cio = null;
}
else {
// update to existing issue
issue.setLastUpdatedDate(new Date());
issue.setLastUpdatedPc(FacesUtils.getRemoteHost());
UpdateIssueOperation uio = new UpdateIssueOperation(getUser(), issue);
uio.execute();
setIssue(uio.getIssue());
uio = null;
}
return getIssueData();
}
catch (DBException e) {
FacesUtils.addResponseMessage("issueFrm", e.getMessage());
return Constants.NAV_FAILURE;
}
}

/**
 * Save an <code>Issue</code> to the database
 * @return
 */
public final String saveIssueStatus() {
IssueStatus is = null;
try {
if (getUser().isReadOnly()) {
FacesUtils.addResponseMessage("statusFrm", Constants.MSG_ILLEGAL_UPDATE);
return Constants.NAV_FAILURE;
}
if (getIssue().isClosed()) {
FacesUtils.addResponseMessage("statusFrm", Constants.MSG_ISSUE_CLOSED);
return Constants.NAV_FAILURE;
}
is = getCurrentStatus();
is.setUpdateBy(getUser().getUsername());
is.setUpdateDate(new Date());
if (is.getStatusId() == Constants.DEF_STATUS_ID) {
// new issue status
is.setInputBy(getUser().getUsername());
is.setInputDate(new Date());
is.setInputPc(FacesUtils.getRemoteHost());
CreateIssueStatusOperation ciso = new CreateIssueStatusOperation(getUser(), is);
ciso.execute();
setCurrentStatus(ciso.getIssueStatus());
ciso = null;
}
else {
// update to existing issue stauts
is.setUpdateDate(new Date());
is.setUpdatePc(FacesUtils.getRemoteHost());
UpdateIssueStatusOperation uiso = new UpdateIssueStatusOperation(getUser(), is);
uiso.execute();
setCurrentStatus(uiso.getIssueStatus());
uiso = null;
}
FacesUtils.addResponseMessage("statusFrm", Constants.MSG_UPDATE_SUCCESSFUL);
return getIssueData();
}
catch (DBException e) {
FacesUtils.addResponseMessage("statusFrm", e.getMessage());
return Constants.NAV_FAILURE;
}
}

/**
 * If this user is not a super user, restrict the issue division
 * to their division id
 * @param si SearchInput The search params
 */
private final void forceRegion(Issue issue) {
if (issue.isNew() && Rules.forceRegion(getUser())) {
issue.setDivisionId(getUser().getDivisionId());
}
}

private final Issue setIssueDefaults(Issue issue) {
issue.setDateRaised(new Date());
issue.setInputBy(getUser().getUsername());
issue.setInputDate(new Date());
issue.setLastUpdatedBy(getUser().getUsername());
issue.setLastUpdatedDate(new Date());
return issue;
}

private final IssueStatus setIssueStatusDefaults(IssueStatus issueStatus) {
issueStatus.setInputBy(getUser().getUsername());
issueStatus.setInputDate(new Date());
issueStatus.setUpdateBy(getUser().getUsername());
issueStatus.setUpdateDate(new Date());
return issueStatus;
}
}

Kev D'Arcy

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Posts: 75

posted 20 years ago

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Greg,

What happens is that when I'm clearing down the form, I use a javascript function to clear the form values and the blank fields get sent up and handled by and "immediate" action funtion. If someone leaves this page (via a hyperlink), and then returns to it with the value bean having already been populated with new values (via the getIssueData() method), the new values are not displayed on the screen (the default values form the form clear are though).

Zafar Hakim

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posted 16 years ago

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Does any one know solution to this problem. I too am facing similar problem.

Problem:
I have a page with data table --- I open a new modal dialog window (window.showModalDialog) on click of menu item on a page --> It opens the page to view details of the item. When I close it and select different row of the table and open to see the details it shows the previous data.

The data on the form fields are populated from a backing bean which is session scoped. I am sure the backing bean is updated with new data. Only that it is not displayed/refreshed in the page rendered.

Thanks for your time.

Regards,
Hakim

Bauke Scholtz

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posted 16 years ago

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Please do not resurrect old topics nor hijack other´s topics. Start your own for each independent problem. Users here usually respond to the topicstarter only.

Zafar Hakim

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posted 16 years ago

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Bauke,
thanks for your suggestion..