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The <o:scriptParam> is a component that extends the standard <f:viewParam> with support for setting results of client-side evaluated JavaScript code in bean.

Usage

It's similar to the <f:viewParam>.

 <f:metadata>
     <o:scriptParam script="new Date().getTimezoneOffset()" value="#{bean.clientTimeZoneOffset}" />
     <o:scriptParam script="window.screen.width" value="#{bean.clientScreenWidth}" />
     <o:scriptParam script="someFunctionName()" value="#{bean.resultOfSomeFunctionName}" />
 </f:metadata>
 

You can use the render attribute to declare which components should be updated when a script parameter has been set.

 <f:metadata>
     <o:scriptParam script="foo()" value="#{bean.resultOfFoo}" render="fooResult" />
 </f:metadata>
 ...
 <h:body>
     ...
     <h:panelGroup id="fooResult">
         <ui:fragment rendered="#{not empty bean.resultOfFoo}">
             The result of foo() script is: #{bean.resultOfFoo}
         </ui:fragment>
     </h:panelGroup>
     ...
 </h:body>
 

Note that as it extends from the standard <f:viewParam>, its built-in conversion and validation functionality is also supported on this component. So, the following is also possible:

 <f:metadata>
     <o:scriptParam script="window.navigator" value="#{bean.clientNavigator}" />
 </f:metadata>
 

With a clientNavigator being an instance of jakarta.json.JsonObject:

 private JsonObject clientNavigator;
 

And this converter:

 package com.example;

 import java.io.StringReader;
 import jakarta.faces.component.UIComponent;
 import jakarta.faces.context.FacesContext;
 import jakarta.faces.convert.Converter;
 import jakarta.faces.convert.ConverterException;
 import jakarta.faces.convert.FacesConverter;
 import jakarta.json.Json;
 import jakarta.json.JsonObject;

 @FacesConverter(forClass = JsonObject.class)
 public class JsobObjectConverter implements Converter<JsonObject> {

     @Override
     public String getAsString(FacesContext context, UIComponent component, JsonObject modelValue) {
         if (modelValue == null) {
             return "";
         }

         return modelValue.toString();
     }

     @Override
     public JsonObject getAsObject(FacesContext context, UIComponent component, String submittedValue) {
         if (submittedValue == null || submittedValue.isEmpty()) {
             return null;
         }

         try {
             return Json.createReader(new StringReader(submittedValue)).readObject();
         }
         catch (Exception e) {
             throw new ConverterException("Not a valid JSON object", e);
         }
     }
 }
 

Events

When the script params have been set, then any method with the PostScriptParam annotation will be fired:

 @PostScriptParam
 public void initScriptParams() {
     // ...
 }
 

This is useful in case you want to preload the model for whatever is rendered by <o:scriptParam render>.