@Override
protected void updateAjaxAttributes(AjaxRequestAttributes attributes) {
    super.updateAjaxAttributes(attributes);

    IAjaxCallListener listener = new AjaxCallListener() {
        @Override
        public CharSequence getPrecondition(Component component) {
            //this javascript code evaluates wether an ajaxcall is necessary.
            //Here only by keyocdes for F9 and F10
            return "var keycode = Wicket.Event.keyCode(attrs.event);" +
                    "if ((keycode == 112) || (keycode == 113) || (keycode == 114) || (keycode == 115))" +
                    "    return true;" +
                    "else" +
                    "    return false;";
        }
    };
    attributes.getAjaxCallListeners().add(listener);

    //Append the pressed keycode to the ajaxrequest
    attributes.getDynamicExtraParameters()
            .add("var eventKeycode = Wicket.Event.keyCode(attrs.event);" +
                    "return {keycode: eventKeycode};");

    //whithout setting, no keyboard events will reach any inputfield
    attributes.setPreventDefault(true);
}
 

@Override
protected void updateAjaxAttributes(AjaxRequestAttributes attributes) {
    super.updateAjaxAttributes(attributes);

    IAjaxCallListener listener = new AjaxCallListener() {
        @Override
        public CharSequence getPrecondition(Component component) {
            //this javascript code evaluates wether an ajaxcall is necessary.
            //Here only by keyocdes for F9 and F10
            return "var keycode = Wicket.Event.keyCode(attrs.event);" +
                    "if ((keycode == 112) || (keycode == 113) || (keycode == 114) || (keycode == 115))" +
                    "    return true;" +
                    "else" +
                    "    return false;";
        }
    };
    attributes.getAjaxCallListeners().add(listener);

    //Append the pressed keycode to the ajaxrequest
    attributes.getDynamicExtraParameters()
            .add("var eventKeycode = Wicket.Event.keyCode(attrs.event);" +
                    "return {keycode: eventKeycode};");

    //whithout setting, no keyboard events will reach any inputfield
    attributes.setPreventDefault(true);
}
 

@Override
public CharSequence getBeforeHandler(Component component) {
	StringBuffer mergedBeforeHandler = new StringBuffer();
	for (IAjaxCallListener listener: listeners) {
		CharSequence beforeHandler = listener.getBeforeHandler(component);
		if (beforeHandler != null)
			mergedBeforeHandler.append(beforeHandler);
	}
	if (mergedBeforeHandler.length() != 0)
		return mergedBeforeHandler;
	else
		return null;
}
 

@Override
public CharSequence getPrecondition(Component component) {
	StringBuffer mergedPrecondition = new StringBuffer();
	for (IAjaxCallListener listener: listeners) {
		CharSequence precondition = listener.getPrecondition(component);
		if (precondition != null)
			mergedPrecondition.append(precondition);
	}
	if (mergedPrecondition.length() != 0)
		return mergedPrecondition;
	else
		return null;
}
 

@Override
public CharSequence getBeforeSendHandler(Component component) {
	StringBuffer mergedBeforeSendHandler = new StringBuffer();
	for (IAjaxCallListener listener: listeners) {
		CharSequence beforeSendHandler = listener.getBeforeSendHandler(component);
		if (beforeSendHandler != null)
			mergedBeforeSendHandler.append(beforeSendHandler);
	}
	if (mergedBeforeSendHandler.length() != 0)
		return mergedBeforeSendHandler;
	else
		return null;
}
 

@Override
public CharSequence getAfterHandler(Component component) {
	StringBuffer mergedAfterHandler = new StringBuffer();
	for (IAjaxCallListener listener: listeners) {
		CharSequence afterHandler = listener.getAfterHandler(component);
		if (afterHandler != null)
			mergedAfterHandler.append(afterHandler);
	}
	if (mergedAfterHandler.length() != 0)
		return mergedAfterHandler;
	else
		return null;
}
 

@Override
public CharSequence getSuccessHandler(Component component) {
	StringBuffer mergedSuccessHandler = new StringBuffer();
	for (IAjaxCallListener listener: listeners) {
		CharSequence successHandler = listener.getSuccessHandler(component);
		if (successHandler != null)
			mergedSuccessHandler.append(successHandler);
	}
	if (mergedSuccessHandler.length() != 0)
		return mergedSuccessHandler;
	else
		return null;
}
 

@Override
public CharSequence getFailureHandler(Component component) {
	StringBuffer mergedFailureHandler = new StringBuffer();
	for (IAjaxCallListener listener: listeners) {
		CharSequence failureHandler = listener.getFailureHandler(component);
		if (failureHandler != null)
			mergedFailureHandler.append(failureHandler);
	}
	if (mergedFailureHandler.length() != 0)
		return mergedFailureHandler;
	else
		return null;
}
 

@Override
public CharSequence getCompleteHandler(Component component) {
	StringBuffer mergedCompleteHandler = new StringBuffer();
	for (IAjaxCallListener listener: listeners) {
		CharSequence completeHandler = listener.getCompleteHandler(component);
		if (completeHandler != null)
			mergedCompleteHandler.append(completeHandler);
	}
	if (mergedCompleteHandler.length() != 0)
		return mergedCompleteHandler;
	else
		return null;
}
 

@Override
public void renderHead(Component component, IHeaderResponse response) {
	for (IAjaxCallListener listener: listeners) {
		if (listener instanceof IComponentAwareHeaderContributor) {
			IComponentAwareHeaderContributor headerContributor = (IComponentAwareHeaderContributor) listener;
			headerContributor.renderHead(component, response);
		}
	}
}
 

public CompositeAjaxCallListener(IAjaxCallListener... listeners) {
	this.listeners = listeners;
}
 

protected IAjaxCallListener getAjaxCallListener()
{
	return null;
}
 

protected IAjaxCallListener getAjaxCallListener()
{
	return null;
}