Developing a plug-in for Jameleon requires writing two classes, a session tag, and an abstract function tag. Most interfaces require some sort of handle on the application/system being tested. This handle is across multiple function tags. For lack of a better word at the time, this handle is represented as a session tag.

A session may contain several generic tags (csv tag, map-variable tag, etc ...) as well as plug-in specific function tags. This function tag is what is used to test components of the application. Please be sure to read Architectural Overview for a better understanding of the basic design of Jameleon.

Design Phase

The first step to developing anything is usually designing it. Even if it's a simple design, at least some thought needs to be put into it. The first thing to do is decide whether or not the state of the application will need to be known between functional points.

If a handle is not required, then only a very simple implementation of SessioTag needs to be implemented. In fact, all that is required is a class that extends SessioTag and that does nothing else. However, if it is required that the functional points have a handle on the application's state or just the application itself, then a bit more complex implementation of SessionTag is required.

The next phase is to decide how to implement a base function tag that others can implement to test their applications. The first decision to make is how much control is desired and how easy a function tag will be to use. For the current plug-ins, the facade pattern was used to create a single place where all methods could be called from. If the library you are wishing to add support for doesn't use listeners for application access or state change, then developing this base function tag will likely be more involved.

Developing a Session Tag

For the most part, the steps to develop a session tag are documented in the javadocs for SessionTag. Please refer there for now.

To register your new session tag in Jameleon, all you need to do is add @jameleon.function name="tag-name" to the class-level javadocs, as described here.

Some things to keep in mind when developing a session tag.

  • The plug-in's session tag should not require an extension to use.
  • Everything it needs should be configurable via the script itself.
  • If the application type being tested requires some sort of handle, then create an instance variable which represents this handle and create corresponding public set and get methods for it.

Developing an abstract Function Tag

Creating an abstract Function Tag is as simple as creating a class that extends FunctionTag and nothing more. The steps to creating a Function Tag for a plug-in are listed in the FunctionTag javadocs.

The important thing to remember is that the session will likely contain some sort of handle on the application. The handle on the application should be referenced locally in the Function Tag. This action should occur in the setupEnvironment method. Don't forget to call super.setupEnvironment() before doing anything else in this method. Please see the source code for HttpUnitFunctionTag and HttpFunctionTag for more examples of this. This method can also be used to enforce that the new Function Tag only exist under the plug-in provided Session Tag. An example of this might look like:

* Only used to guarantee that the parent of this tag is
public void setupEnvironment() {
Object obj =  findAncestorWithClass(JUnitSessionTag.class);
JUnitSessionTag s = null;
if (obj instanceof JUnitSessionTag) {
s = (JUnitSessionTag)obj;
} else {
throw new ClassCastException("Can only execute a JUnit"+
                         "function tag under the JUnit"+
                         "session tag");

Do not provide a @jameleon.function javadoc for this class since it is abstract and should not be used directly for behavior. To create attributes that all extending function tags can use, please read the section on javadocs.

Register Plug-in Tags

The last step to writing a plug-in is to registering the plug-in specific tags into a properties file with an appropriate name. This is documented at the Tag Registration Ant Task.


This just a begining to a much more thorough document. Before it can become more thorough however, we will need feedback as to what could be explained better. We ask that everyone attempting to develop a plug-in to notify us and we will try our best to provide special attention to those that require it.

Please send all extensions to open-source libaries to a Jameleon administrator for inclusion into the Jameleon release. This way, before any major changes are made to API, we will know what side affects may occur. This also assumes unit and acceptances are written for each plug-in. Full credit will be given to the plug-in contributor(s) and depending on the complexity of the plug-in, commit access to CVS may be given to the plug-in contributor(s).