I’ve been working on a Wicket project that requires JQuery to be present on every single page rendered by Wicket. I do this by including a reference to JQuery from my base page. However, when I add a wiquery component to a subclass of my base page, it automatically inserts a reference to JQuery as well – resulting in markup that instructs the browser to download jquery.js twice from two different places.

The markup generated by wiquery looks similar to this:

<script
  type="text/javascript"
  src="wicket/resource/org.odlabs.wiquery.core.commons.CoreJavaScriptResourceReference/jquery/jquery-1.5.2-ts1308119960000.js">
</script>

To avoid duplicate JQuery references, we can disable the autoImportJQueryResource property in wiquery’s configuration. There are two ways to do this.

The hacky solution

The simplest way is also the hackiest way, but it gets the job done. Override Application.validateInit() and add the following lines. This must be done in the validateInit() and not the init() method, because Wicket will call init(), then it will initialize your third party components (including wiquery), and finally call validateInit().

@Override
protected void validateInit() {
    super.validateInit();
    final WiQuerySettings wqs = WiQuerySettings.get();
    wqs.setAutoImportJQueryResource(false);
}

The get() method above on line 4 will throw an exception if wiquery has not been initialized.

A better solution

The “correct” way is a bit more involved. It requires creating a wiquery.properties file that points to a custom initializer that you define. This initializer class will set the property as desired. wiquery.properties must reside in your war file under WEB-INF/classes, or packaged in your application’s jar file, depending on how you like to build your war file.

wiquery.properties

initializer: com.pushinginertia.wicket.listeners.WiQueryInitializer

WiQueryInitializer.java

package com.pushinginertia.wicket.listeners;
 
import org.apache.wicket.Application;
import org.odlabs.wiquery.core.commons.IWiQueryInitializer;
import org.odlabs.wiquery.core.commons.WiQuerySettings;
 
/**
 * wiquery custom settings
 */
public class WiQueryInitializer implements IWiQueryInitializer {
    public void init(Application a, WiQuerySettings wqs) {
        wqs.setAutoImportJQueryResource(false);
    }
}

In addition to autoImportJQueryResource, you can also set a few other boolean properties:

• autoImportJQueryUIResource – defines whether to always import JQuery UI or rely on the application to do it
• embedGeneratedStatements – defines whether to generate JavaScript inline or as a virtual filename reference
• enableResourcesMerging
• enableWiqueryResourceManagement – overrides autoImportJQueryResource and autoImportJQueryUIResource
• minifiedResources – defines if JavaScript should be minified (good for production code to keep the size down but makes debugging more difficult in development)