Parsing mathml document using JScience

Question

I was trying to parse mathml document using JScience but was not succeed. Following is my piece of code.

import JSci.io.*;
import JSci.mathml.*;
  .
  .
public class ParsingMathML(){
 try {
        ....
        //inputFile is an xml file containing mathml code
 InputSource file = new InputSource(new FileReader(inputFile));  
 MathMLParser parser = new MathMLParser();
 parser.parse(file);

 Object[] parseList = parser.translateToJSciObjects();
}catch (Exception e) {
 e.printStackTrace();
}
}

I got error from here, so I could not do anything further. Following is the StackTrace:

Exception in thread "AWT-EventQueue-0" java.lang.NoClassDefFoundError: JSci/maths/fields/Ring$Member
 at JSci.io.MathMLParser.translateToJSciObjects(Unknown Source)
 at JSci.io.MathMLParser.translateToJSciObjects(Unknown Source)
 at mathML.ProcessMathML.processFile(ParsingMathML.java:109)
 at mathML.ProcessMathML.actionPerformed(ParsingMathML.java:72)
 at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
 at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
 at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
 at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
 at javax.swing.AbstractButton.doClick(Unknown Source)
 at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
 at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unknown Source)
 at java.awt.Component.processMouseEvent(Unknown Source)
 at javax.swing.JComponent.processMouseEvent(Unknown Source)
 at java.awt.Component.processEvent(Unknown Source)
 at java.awt.Container.processEvent(Unknown Source)
 at java.awt.Component.dispatchEventImpl(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
 at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
 at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Window.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.EventQueue.dispatchEvent(Unknown Source)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: JSci.maths.fields.Ring$Member
 at java.net.URLClassLoader$1.run(Unknown Source)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(Unknown Source)
 at java.lang.ClassLoader.loadClass(Unknown Source)
 at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
 at java.lang.ClassLoader.loadClass(Unknown Source)
 at java.lang.ClassLoader.loadClassInternal(Unknown Source)
 ... 31 more

Also, does any one have any idea how to use MathMLApplyElementImpl, MathMLDocumentImpl or any other classes from JSci.mathml package?

It will be great if you can provide some example of code on how to parse mathml document.

Any idea will be highly appreciated. Thanks

Rizzo

Answer 1

Cocnerning your precise bug, it seems the class JSci.maths.fields.Ring$Member does not exists, which throws a ClassNotFoundException in the method JSci.io.MathMLParser.translateToJSciObjects.

Lets go see this source code. In MathMLParser, the most notable usage of Ring.Member is as a return value. But it can be found at numerous locations. And, since Ring.Member is in JSci.maths.fields, which seems to be in the same JAR than MathMLParser, I guess your problem is far more complicated than a simple ClassNotFoundException.

First, can you open the JScience jar to ensure that JSci.maths.fields.Ring$Member does exists ?

If not the case, do you use multiple class loaders in the same application ? (things like OSGi)

Lune

Great! Thank you Riduiel. I could fix that error by importing package <JSci.math>, which contains <JSci.maths.fields.Ring class> as you guessed. However, the parseList[] is an empty array no matter which file I use in the parser.parse(file). Do you have any idea? Thanks – Rizzo