(Apache Wicket) Set java atrribute from a js function

Question

I am brand new on Apache Wicket and I need to set value on a Java attribute. This value comes from a var on JS filled by a specific function from a specific GIS lib (https://leaflet.github.io/Leaflet.draw/docs/leaflet-draw-latest.html). This setting must be triggered by some component behavior.

Here is a simplified example code:

Wicket web page:

public class MapPage extends WebPage {

private static final long serialVersionUID = 1L;
private Integer coordinates;

// getters and setters

}

Wicket html:

<html xmlns:wicket="http://wicket.apache.org">
<head>

<!-- metas, scripts, and css imports -->
</head>

<body>
<script>
// component declarations

var coordinates = ''

map.on('draw:edited', function (e) {    

  e.layers.eachLayer(function(layer) {
    coordinates = toWKT(layer);
    // send coordinates to coordinates java attribute ??? how?? 
  });
});

</script>
</body>

Thanks a lot!

Bascilly you want to call wicket from javascript: https://cwiki.apache.org/confluence/display/WICKET/Calling+Wicket+from+Javascript — Robert Niestroj, Jan 08 '18 at 13:15
Thank you, @RobertNiestroj. That reference was very usefull. One more question: When Wicket.Ajax.get runs, the whole page is reloaded and I miss my component state. The wicket renderHead method responses the page, but i don't need this. Set attribute value is all I have to do. Any idea about how can i avoid reloading all the page? Thanks again... — cassioramon, Jan 08 '18 at 16:46

score 0 · Accepted Answer · answered Jan 10 '18 at 08:04

This is a piece of code from one of my projects, where I want to handle a click on a (HighCharts) chart. It passes data to Wicket and Wicket then updates another panel to display details related to the click.

The relevant javascript part, where interactionurl is actually the callbackScript that is generated by the behavior later on:

  interactionurl(JSON.stringify(myDataToPass));

The behaviour:

    this.add( this.interactionbehavior = new AbstractDefaultAjaxBehavior()
    {

        @Override
        protected void respond( final AjaxRequestTarget target )
        {
            RequestCycle cycle = RequestCycle.get();
            WebRequest webRequest = (WebRequest) cycle.getRequest();
            String param1 = webRequest.getQueryParameters().getParameterValue( "mydict" ).toString( "" );
            //param1 contains the JSON map passed from javascript.
            //you can also do stuff now, like replacing components using ajax
        }

        @Override
        protected void updateAjaxAttributes( AjaxRequestAttributes attributes )
        {
            super.updateAjaxAttributes( attributes );
            attributes.getExtraParameters().put( "mydict", "__PLACEHOLDER__" );
        }

        @Override
        public CharSequence getCallbackScript()
        {
            String script = super.getCallbackScript().toString().replace( "\"__PLACEHOLDER__\"", "data" );
            return script;
        }
    } );

You only need to pass the interaction url to the page on some moment. For this you can use renderHead in the component that has the behaviour:

    @Override
    public void renderHead( final IHeaderResponse response )
    {
 ...
                //use the `setupCallback` to store the callback script somewhere.., I store it in 'interactionurl'
        String script = String.format(  " setupCallback(this.interactionbehavior.getCallbackScript()); "); 
        response.render( OnDomReadyHeaderItem.forScript( script ) 
    }

(Apache Wicket) Set java atrribute from a js function

1 Answers1