Demo of several major modifications to Jade

"Jade" is a circuit diagram application originally written by Chris Terman, James Knight and Milan Minsky at MIT for use in the 6.004 lecture course.

For the intelligent book project, I have been making large modifications to Jade. These include enabling circuit currents and voltages to be marked up on the circuit, adding an XPath API to a allow a external applications to set property values in the circuit, allowing Attributes to be recorded on properties (needed for the API), fixing up the applet code, and a few other things. These changes will be checked back into the CVS repository of Jade shortly.

Amir Hirsch assisted with the applet code by making a rough pass over the original Jade to identify which bits prevented it from running as an applet.

Beneath the applet are some HTML controls for making calls into Jade to test the APIs.

At the foot of the page is a description of some of the changes I have made to Jade.

Note:The combined JARs are about 700kB, so it could take a while to download at first

Couldn't start the Jade tools!

SetValue( Module: " " , XPath: , Value: ) Go!

Sets values of items in the schematic. Although the Jade internals do not have an XML document structure, the navigation is set to behave as if it does. Interesting items are instance, property, terminal, and wire.

Example xpath: instance[@name="Q1"]/terminal[@name="C"]/property[@name="i"]/@value

(The current into the Collector terminal of instance Q1)

SetAttribute( Module: " " , XPath: , Name: Value: ) Go!

Used for setting an attribute on an item, including if that attribute does not yet exist on that item

Recent changes:

(Several of these were normally being worked on at once)

10 Oct 2003 Fixed bug with selecting terminals on rotated components. Fixed bug with xpath generated by a change to a terminal property.
9 Oct 2003 After neglecting this demo (while working on others) for a while, I have updated the circuit to a simpler one, and fixed up the terminal orientations
23 Sept 2003 I have linked in the notes page for the demo.
19 Sept 2003 I have implemented the SetAttribute API. It should be noted that SetValue cannot set an attribute that does not yet exist in the document (since the xpath cannot resolve to it). SetAttribute can.
15 Sept 2003 I have added name attributes to InstanceObject and InstanceTerminal (these previously did not have an attribute axis). This allows for much shorter xpaths.
13 Sept 2003 I have refactored the applet code. The current CVS version of Jade did not work as an applet (it failed due to security exceptions). Amir Hirsch made some initial investigations involving commenting out chunks of code until it would run as an applet. However Amir's commentings-out naturally broke some of the functionality in the application version of Jade, and he didn't get as far as making Jade work as both an application and an applet.
So, I've gone through and refactored bits of Jade so that it can be run as an application and as an applet. Changes included ensuring the Jython interpreter is loaded on-demand rather than as part of class initialisation, writing new constructors for Jade, JadePane and JadePanel, and a new function in the library manager for loading from a premade URL.
11 Sept 2003 I have implemented XPath navigation of the Schematic Aspect structure, using Jaxen. Jade does not use an XML document structure for its internal data, so this required writing a custom implementation of the DocumentNavigator interface to work around this. Several internal structures in Jade needed modifications to provide the required axis iterators. At the moment, only the ChildAxis and AttributeAxis are supported, but this seems to allow the kinds of XPath expressions we need.
11 Sept 2003 I have added some Attribute classes. Properties now naturally have two attributes: name and value. Other attributes can be added as required.
30 July 2003 I altered Jade's internal structures to allow properties to be added to Wires and Terminals. This invoved refactoring a lot of the terminal code so that terminals could be uniquely distinguished between instances of the same module. Some of the terminal drawing code had to be changed too, and the code for identifying what part receives a mouse-click.