w3cJigsaw FAQ

Jigsaw Frequently Answered Questions

What is Jigsaw ?

Using Jigsaw

Technical stuff

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What's the purpose of Jigsaw ?

Jigsaw is the new W3C reference server. It's main purpose is to demonstrate new protocol features as they are defined (such as PICS), and to provide the basis for experimentations in the field of server software (such as the provided MUX prototypical implementation).

Where can I get Jigsaw ?

You can download Jigsaw distribution file in various formats, and using either ftp or http:

Windows zip files (1.5Mo)
UNIX gzip tar file (700Ko)

Why is Jigsaw written in Java ?

Java has a number of advantages that fit well with our purposes. It provides portable threads and garbage collection, allows for a very dynamic server architecture. It's ability to move code around may be use in future devlopment to experiment with the mobile code concept.

Jigsaw is written in Java, it must be really slow...

No so true ! Check out the performance evaluation of Jigsaw, which indicates that it performas at least as well as the CERN server.

What are all these informations in the form based resource editor ?

The current version of the generic resource editor is rather terse. At this point, the resource editor will present all the declared resource attribute values and some ways to edit them. All the attributes are declared in each resource reference manual.

Resource editors is an area in which you can expect big improvement in the next release. Right now, it is recommended that you use two browser windows, one displaying the form based editor, and the other one displaying the appropriate reference manual for the resource being edited (which described all the attributes semantics).

How do I setup authentication ?

Setting up authentication through the form based interface requires you to run through the following stages:

  1. Create an authentication realm, if required. This is done through the Realms resource, ususally available as /Admin/Realms. You can of course reuse authentication realms to protect different areas of the server.
  2. Setup an authentication filter on the appropriate resource. The target of the filter can be either a directory resource (in which case the filter will protect all the area defined by the sub-resources of this directory resource), or any other filtered resource (hence allowing you to protect a single resource). Setting up an authentication filter is done by editing the target resource, through the generic resource editor. If you want to protect, say  the /protected directory resource, then you have to bring up its editor, which will usually be available as /Admin/Editor/protected.
  3. Setup the authentication filter parameters. Once the filter is plugged in, you can edit its attribute by clicking on the appropriate link in the bottom of the target resource editor.

That's it ! For more informations, you may want to read through the configuration tutorial.

How can I extend Jigsaw ?

Jigsaw can be extended in a number of ways. Here are just three possible things you can play with, from the simplest to the complex ones:

Why does Jigsaw implement its own persistency mechanism

Jigsaw implements its own persistency mechanism while RMI already provides a way to serialize objects, why is it so, will it change ? What Jigsaw implements in the w3c.jigsaw.resource package is more then then persistency. It provides both a way of serializing objects and a way of describing what and how the object will be dumped. The available meta-description of objects (that you can obtain through the getAttributes method of resources), is a central part of Jigsaw architecture, since it offers the ability to create generic resource editors. This is not likely to disappear.

However, Jigsaw persistency mechanism may be merged in the futur to the RMI interface, just by providing an implementation of the readObject and writeObject method through its existing mechanism.


Anselm Baird-Smith
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