Code Snippets

What JSF is missing

Well I've been playing with JSF for awhile and while I like it, it has some major holes in it's capabilities. What I have hit so far:

• The error messages are useless more often than not. So you slowly add controls to your jsp page, test, and when you hit an error, back out the last change. So it's slow...
• You can set a new object as a backing bean - but it does not update it in the session map also - so you have to do both. And I am hoping it is not store the information in a 3rd place...
• If you do change the backing bean object, it does not update any other beans with references to it. So you must call each bean's setter for that object to update it.
• There is no way to have a backing bean called on a per page basis before rendering and then re-direct if necessary. Youe you can do a filter or phase listener - but that is not terribly object oriented.
• There is no way to add parameters to a url that you go to via <h:commandButton action="#{orderHandler.submitPayment}" value="Generate Invoice"/> where the backing bean method submitPayment() needs to set the url parameters. You can do it with a link, but not a button.
• f:selectItem does not have a rendered attribute and cannout have other tags inside a <f:selectItem...>...</f:selectItem>
• You have to get the htm library for htm:table/tr/td as the two standard grids are no where near as powerful.
• And for an array of objects where they need to go in a grid - you are limited to the h:dataTable - which itself is pretty limited.
• more to come...

But it is robust and the concept is good.

Do you find this useful? If so please check out Windward Reports.

JSF - booleans for a check box

If you want to have an initital value set for a checkbox or radio button, and want it's property to be a get/set boolean, here is how you do it.

In faces-config.xml (note it is application scope):

<managed-bean>
  <description>Globally static data like list of countries.</description>
  <managed-bean-name>global</managed-bean-name>
  <managed-bean-class>net.windward.store.util.GlobalData</managed-bean-class>
  <managed-bean-scope>application</managed-bean-scope>
</managed-bean>

The code:

public class GlobalData {
public boolean isAlwaysTrue() {
  return true;
}
public boolean isAlwaysFalse() {
  return false;
}
}

And then in the jsp file:

      <h:selectOneRadio layout="pageDirection"  value="#{cart.acceptTerms}">
            <f:selectItem itemLabel="I accept all of the above terms, conditions, and license" itemValue="#{global.alwaysTrue}"/>
            <f:selectItem itemLabel="I decline the above terms, conditions, and/or License (cancel demo request)" itemValue="#{global.alwaysFalse}"/>
           </h:selectOneRadio>

One warning - don't name the methods isTrue/isFalse - that won't work.

The method cart.getAcceptTerms() and cart.setAcceptTerms pass a boolean. Works great.

Do you find this useful? If so please check out Windward Reports.

JSF - what page is being rendered

Hi;

I got this from one of the gurus on the JSF mail-list and am passing it on. If you need to know what page is about to be rendered, add the following to your faces-config.xml:

And then here is your code that will be called as each page is first about to be rendered:

<lifecycle>
  <phase-listener>net.windward.store.util.StorePhaseListener</phase-listener>
</lifecycle>

Do you find this useful? If so please check out Windward Reports.

public class StorePhaseListener  implements PhaseListener {

public void afterPhase(PhaseEvent phaseEvent) {

  String page = FacesContext.getCurrentInstance().getViewRoot().getViewId();
  if (page.endsWith(".faces"))
   page = page.substring(0, page.length() - 6);
  if (page.endsWith(".jsp"))
   page = page.substring(0, page.length() - 4);
  if (page.startsWith("/"))
   page = page.substring(1);
  // bugbug - security check
  /*
       if (!loginPage && !loggedIn()) {
            NavigationHandler nh = fc.getApplication().getNavigationHandler();
            nh.handleNavigation(fc, null, "logout");
        }
  */
}

public void beforePhase(PhaseEvent phaseEvent) {
}

public PhaseId getPhaseId() {
  return PhaseId.RESTORE_VIEW;
}
}