o

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);
        }
    }
}