PlanetNTF

In the past weeks I was trying something new, at least new for me…

I realised that using jQuery in Xpages is a wonderful idea. Mark Roden has a nice blog with great things you can do with jQuery in XPages. You can find it here: Xomino Also check out his demo site: Xomino JQinX Demo

In one project I wanted to use a gantt chart. I want to write this article to show you how it’s done and warn you about the problems I had.

Let’s start.

To use jQuery you have to download it and integrate it in your database. Build your own version of jQuery here: JQuery Download It is the download page of JQuery UI, a set of many nice plugins and modules for jQuery. A version of the base jQuery is included. You can also configure a custom theme for your jQuery modules. It is on the right menu when you follow the link “design a custom theme“

For the gantt chart I am using this module: Taitems JQuery Gantt Chart Module

So, now you have to integrate these files into your database. You can do this either via the resource category in the database, or via the PackageExplorer (it is an Eclipse View) I recommend using the package explorer, because you can manage your files more easily. Simply drag and drop your files and create some folders to organize them.

Now you have to load them into your application. You can do this easily via a theme with the following statement:

<resource>
<content-type>application/x-javascript</content-type>
<href>js/jquery-1.7.min.js</href>
</resource>

Or you load them directly into your code via the resource properties of the XPage/ Custom Control

<xp:script src="js/jquery-ui-1.8.23.custom.min.js" clientSide="true"/>

You have to do this for the jQuery base module, the UI module and the gantt module, also you have to load the CSS files.

First problem I had to face: The gantt module doesn’t work with every jQuery version. I was using jQuery 1.8.0. But when using this module, I had an error message which complained about some undefined variables (TypeError: m is undefined) Using the 1.7 version was a solution to this.

Now we can get started. On the page of the gantt module is an easy manual how to use this module. It is quite self explaining.

To implement a gantt chart, you only have to put in these few lines of code (client side of course)

<xp:scriptBlock id="scriptBlock1">
<xp:this.value>
// + "/ganttJSONBuilder?OpenAgent";
// + "/js/data.js";
jQuery( function() {
var dataPath = location.href.substring(0,
location.href.lastIndexOf('/') + 1)
+ "/ganttJSONBuilder?OpenAgent;

$(".gantt").gantt( {
source : dataPath
});
});]]>
<<!--xp:this.value>
<<!--xp:scriptBlock>

As data source the module uses JSON data. Use this site to validate your JSON data easily. The structure of your data is explained in the manual site of the module.

Be aware, the module expects a URL as data source. That means you can’t use server side Javascript in that scriptblock to generate the data source. So, we have two options on how to load the data into the module, either via a file which you can put into the WebContent folder in your database, or you call an agent. The agent is probably the better option because you sure want to load data dynamically.

Using an agent to achieve this is basically easy, you only have to write your JSON string into a variable and then you do this:

PrintWriter pw = getAgentOutput();
pw.println(output);

The difficulty of generating the JSON string itself depends on your data. In my case it was a simple project management, so some tasks, projects and editors. I used a view. I looped the entries and parsed the information into a JSON String.

There are some nice little things you should know when doing so.

The first line of your JSON string has to be the content type of the output, for JSON it is: Content-type: application/json; charset=utf-8\n
Also, it is very important that you use line breaks in the string, simply by using \n. If you aren’t doing that, your JSON string will not be properly interpreted and the module shows nothing but a nice grey bar.
Easily to overlook, but also important, in JSON you have to use a comma to separate your entries. Be sure you have no comma behind your last entry or parameter. It will result in a misinterpretion of the data.
The next important thing is, in the JSON data, you have to provide all entries defined in the manual. That means, if you forgot to write one of the parameters into the string, it is valid, but not recognized by the gantt module and isn’t doing anything. All of them need a value. providing nothing will have the same result: Nothing =)
I wanted to have my projects and tasks separated. In one line the project and then in the other lines the related tasks. This is possible by writing an extra entry to your JSON string, in which you only write the information about the project. When writing the tasks of the project, you probably don’t want to write the project in front of each task. If you think you can define an empty string for the name parameter of the JSON entry, you are wrong. The module needs a value of at least one character. Using an empty string results in not displaying the chart and some nice error messages. Using a space (” “) is the solution.
Also, you have to provide a start and end date for each entry. I wanted to have no duration for the project, so I didn’t provide the “from” and “to” parameter, it rewarded me with some other javascript errors. So I used the whole duration of the project for the project entry, it’s a good feature anyway.

A nice feature: You can use HTML in your JSON parameters, so, if you use
tags for example in your desc parameter and some formatting tags, you can make the mouseOver of the entries look more beautiful and put some more information into it.

If you think the styleClasses available for your entries in the chart (ganttRed, ganttGreen, ganttOrange) are not that beautiful, or you want to use some more, you can easily define some. There is a css file in the module. Looks like this:

.fn-gantt .ganttOrange {
background-color: #FCD29A;
}
.fn-gantt .ganttOrange .fn-label {
color: #714715 !important;
}

Copy those entries and do your own styles, the class at the end of the definition is recognized by the module, so you can use it directly in the “customClass” parameter of your JSON.

But there is one big problem when using this module. Above the chart, I have some buttons. I wanted to load different charts with those buttons. Easily done I thought, just firing a partial execute on the chart container to set another data source or something. But, nothing happens, in fact really nothing, not even an event which I could see in my FireBug. Some other buttons with only clientside code are working fine. All other buttons on the whole page are working fine, only those I have directly above my chart didn’t wanted to work. I haven’t figured out what’s the problem, if I find it, I will let you know.

Another problem is that the gantt chart is not working in the Notes Client. If I open the Xpage in my Notes client, the chart isn’t loaded, only a nice grey bar. Other jQuery modules are working fine, for example the accordion or flip is working, but not the module. If you want to use it in the NotesClient you should think about another solution… or wait until I find a solution for this problem =)

Another thing you should consider are loading times. The loading time is increasing dramatically proportional on how many entries you display (rowsPerPage parameter in the gantt function) and how many years they cover. If you want to display some tasks from a period of 10 years or more, you have to wait a bit. I tried a period of 30 years… not a good idea, my browser crashed… after about 5 minutes of loading.

So, I think that’s all I know about the module and how to use it. Despite all the small and big problems I have a nice application with some really nice gantt charts. If you are interested in such an application, you should visit this page (Cobalt Software GmbH), the new version should be available soon. Ok, sorry for the advertisement…

If you have any questions or solutions for my unsolved problems, the comment section is all yours =)

Hope it was useful for some of you.

Filed under: Notes & XPages Tagged: Chart, Cobalt Software GmbH, CSS, Datasource, Gantt, Javascript, JQuery, JSON, Mark Roden, Notes, Parameter, Plugin, Serverside Javascript, Taitem, Tools, Xomino, XPages, Xpages in NotesClient, XpInc