Transcript ppt - Web-Based Mathematics Education

WME MathEdit
(Status Report)
0011 0010 1010 1101 0001 0100 1011 by
K. Cem Karadeniz
Kent State University
Computer Science
March 15th, 2006
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Overview
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• New implementation platform: JAVA
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Why Applet?
Advantages & Disadvantages
Security, Applet Signature, Policy
The Box Model and Animation
Current Package and Class Hierarchy
Serializer, Parser and SAX
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Overview (cont.)
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• Interface Design
– Old Interface vs. New Interface
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• Application Programming Interface (API)
– Interaction with Other WME Components
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• Enabling Web Pages for MathML (brief)
– Use XHML template package (cancelled)
• Demo of the Current Tool
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Refreshing the Requirements
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The WME MathEdit tool,
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requires animation and very intensive input
control (keyboard, mouse) 
has to work online on client side 
has to be able to communicate two ways within
the web page 
should have access to clients’ local hard drives
to read/write files (for also debugging) 
may store formulas as image files 
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Communication Scenario
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• Considering
those
requirements,
we have the following
communication scenario diagram:
WME
Component
API
WME MathEdit
in browser window
question
including
formula
edit
WME page
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insert
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answer
including
formula
API
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Why JAVA?
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• All the requirements can be implemented by
using JAVA and its Applet technology.
• Applets are full JAVA programs and they,
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– allow to create the highly needed symbol
animation,
– are capable to work online,
– can interact with web page,
– may access the client hard drive (!)
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JAVA Applet: Pros[Cons
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• Applets provide ways to fulfill all five
requirements that I just mentioned; they are full
featured programs! <x5
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• Object-oriented code has tremendous advantages
(i.e. plug n play parsers, code reuse and easy
maintenance) <
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• Platform independent coding & execution on
platform dependent JVM
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JAVA Applet: Pros[Cons
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• Applet comes with following constraints as far as
the WME is concerned:
– Extra action needed for security (next)
– Requires a heavy weight plug-in (JRE) ~16MB!
• Like every other tool to implement MathEdit!
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– Relatively slow initialization due to Java nature
(interpreted language) and large bytecode size
• Researching open-source optimizers and tools to convert to
native code (!) – if larger than 300k I will try
• 1.5.0 (or 5.0) is beyond other older versions
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Applet Security
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Applets used to have a bad fame about security
First choice of malicious hackers to hack MS
Windows remotely
JDK’s goal is to enable browsers to run
untrusted applets in a trusted environment
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1. Local policy files (suitable for development)
2. Signed applets (WME will possibly use this)
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Applet Security: Local Policy
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• Plain
files
on client
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Default: .java.policy in the user home directory
Not very practical for WME (why?)
You can use policytool program in SDK
For now WME MathEdit needs the following permissions:
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grantItcodeBase
"file:/e:/javaworld/-"
{
is also possible
to grant all permissions:
permission java.io.FilePermission "<<ALL FILES>>",
"read,
write";
grant
codeBase "file:/e:/javaworld/-" {
permission java.util.PropertyPermission "user.dir",
"read";
permission
java.security.AllPermission;
permission
java.lang.RuntimePermission
"modifyThread";
};
};
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Applet Security: Signed Classes
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• This does not require any file on client <
• Program has to be in a JAR package
• Only the main class must still be present
together with the signed JAR file
• Tools to use in J2SE SDK:
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– jar
– keytool
– jarsigner
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Applet Security: Signed Classes (cont.)
• Signing
an applet
is almost
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like writing a small program! It
needs some effort K. My five-step minimal process below:
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# jar cvf mathedit_unsigned.jar mathedit
# keytool –genkey \
-alias mymathedit \
-keypass keymathedit \
-keystore matheditkey.bin \ (can have multiple keys -alias)
-storepass pubmathedit
3. Answer questions (next slide)
4. # jarsigner -keystore matheditkey.bin
-signedjar mathedit_signed.jar
mathedit_unsigned.jar mymathedit
5. Answer questions (next-next slide)
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Applet Security: Signed Classes (cont.)
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have1101
to answer
when you issue the keytool
command on previous slide. User will grant access depending on them.
• Answers should be explanatory otherwise people will deny access
What is your first and last name?
[Unknown]: The WME Research Team
What is the name of your organizational unit?
[Unknown]: Web-based Mathematics Education
What is the name of your organization?
[Unknown]: Kent State University Computer Science
What is the name of your City or Locality?
[Unknown]: Kent
What is the name of your State or Province?
[Unknown]: OH
What is the two-letter country code for this unit?
[Unknown]: US
Is CN=The WME Research Team, OU=Web-based Mathematics Education,
O=Kent State University Computer Science, L=Kent, ST=OH, C=US
correct?
[no]: yes
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Applet Security: Signed Classes (cont.)
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You
have
to answer
two
more
questions when you issue the
jarsigner command (step 4)
• Answers are from the keytool command (from step 2)
# jarsigner -keystore matheditkey.bin
-signedjar mathedit_signed.jar
mathedit_unsigned.jar mymathedit
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Enter Passphrase for keystore: pubmathedit
Enter key password for mymathedit: keymathedit
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Applet Security: Signed Classes (cont.)
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• If you successfully complete the process you will
get the following message:
Warning: The signer certificate will
expire within six months.
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• You can always buy a permanent certificate that
will allow your applet to run automatically
without any warning message (next)
• From VeriSign or some similar company…
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Running the Applet
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• If you are a developer you will use a policy file like I
showed together with the appletviewer tool
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• You don’t need to sign your applet until you publish it
• To run the applet on your local machine:
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# appletviewer
-J-Djava.security.policy=myappletpolicy
deploy.html
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Applet Security: Signed Classes (cont.)
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JAVA and the Box Model
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• Currently
I implemented
refer as “box model”
• Box is from javax.swing.Box
• private Component ra =
Box.createRigidArea(new Dimension(myD+5,0));
• Creates an invisible Component
Fake cursor (caret)
using thread.sleep
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Edit box with
real cursor
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Animation
 3.141
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Fraction Model Box
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now starts
• private Component ra = Box.createRigidArea(new
Dimension(myDim1+5,0));
• private Component dxra = Box.createRigidArea(new
Dimension(0,myDim2));
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You
must use arrow
keys or mouse
to move cursor here
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Package & Class Hierarchy
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• I have currently 10 (img
and mmlex are different)
packages and 28 classes &
interfaces
• Main package is
mathedit.cem.appmain
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MyEditorApp.html
MyEditorApp.java
MyEditorPanel.java
MyEditorRenderer.j
ava
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Parser and SAX
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• I have a 750 lines MathML parser class, I wrote it
converting from a C++ parser, not easy even to
convert!
• As I mentioned before plug & play, can allow to
change the parser since each parser is a class
obeying some rules (OOP interface concept)
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• public interface Parser { // . . .
• public class MMLParser implements
Parser { // . . . }
}
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Parser and SAX
• Simple API for XML
• Comes as part of JAVA core:
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import org.xml.sax.InputSource;
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public MyBox parse(InputSource source) throws Exception {
DocumentBuilderFactory f =
DocumentBuilderFactory.newInstance();
f.setValidating(true);
f.setNamespaceAware(true);
f.setIgnoringElementContentWhitespace(true);
DocumentBuilder builder = f.newDocumentBuilder();
return parseDom(builder.parse(source)); // XML +
MathML Parse
}
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• Visit http://www.saxproject.org/ for more information
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MathML Serializers (MMLSerializer.java)
• In Java a Serializer converts a Java object to an
XML representation using a specific XML
processing mechanism
• In WME MathEdit: convert what is visually on
the swing panel (on the tool’s typing area) to XML
• XML is MathML in this case
• I have two serializers for now (one for square root
and one for fraction)
• Each added feature will require a new serializer
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private String serializeFraction(FracMyBox box) {
String result = "";
if (attrs.length()>0) {
result += ind()+"<"+tag("mstyle")+attrs+">";
indcnt++;
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result += ind()+"<"+tag("mfrac");
if (box.getLineThickness()!=1)
result += "
linethickness=\""+box.getLineThickness()+"\"";
result += ">";
indcnt++;
result += serializeBox(box.getNumerator()) +
serializeBox(box.getDenominator());
indcnt--;
result += ind()+"</"+tag("mfrac")+">";
if (attrs.length()>0) {
indcnt--;
result += ind()+"</"+tag("mstyle")+">";
}
return result;
}
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private String serializeSqrt(SqrtMyBox box) {
String result = "";
String attrs = checkForStyle(box);
if (attrs.length()>0) {
result += ind()+"<"+tag("mstyle")+attrs+">";
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result += ind()+"<"+tag("msqrt")+">";
indcnt++;
if ( box.getChilds().size()==1 &&
(box.getBase().getType()==MyBox.rowBBox) )
result += serializeBox(box.getBase());
else {
result += ind()+"<"+tag("mrow")+">";
indcnt++;
for (int i=0; i<box.getChilds().size(); i++)
result +=
serializeBox((MyBox)box.getChilds().elementAt(i));
indcnt--;
result += ind()+"</"+tag("mrow")+">";
}
indcnt--;
result += ind()+"</"+tag("msqrt")+">";
if (attrs.length()>0) {
indcnt--;
result += ind()+"</"+tag("mstyle")+">";
}
return result;
}
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API for WME Components
• Other WME components like DMAD, Glossary
Service, Bulletin Board need output of my
program, which brings a need for API
• API is also needed for ordinary WME pages
• I don’t have any JavaScript API yet because the
program is not even half way implemented
• Two APIs are available through <param … />
• Output is simply a string containing full of
MathML tags, attributes, and user input
(see the demo)
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How to Embed the Tool
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files under
mathedit
which is in the root directory of the
web page/site
• File 1: mathedit_signed.jar
• File 2: MyEditorApp.class
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<applet code="mathedit/cem/appmain/MyEditorApp.class“
archive="mathedit/mathedit_signed.jar"
type="application/x-java-applet;version=1.5.0"
width="430"
height="300">
<param name="type" value="application/x-java-applet" />
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(next slide covers HERE, the param API)
</applet>
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Two Applet Parameters
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<param name="openMMLfile" value="ex02.mml" />
<param name="openMMLstr"
value="<math><mrow><mfrac><mrow><mn>1</mn></mro
w>…” />
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• But there is a problem in the second param (why?)
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<param name="openMMLstr"
value="&lt;math&gt;&lt;mrow&gt;&lt;mfrac&gt;&lt
;mrow&gt;&lt;mn&gt;…” />
• JavaScript API should handle the problem
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Interface Design
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Interface Design (cont.)
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Demo
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Thank you
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• Questions?
• Comments?
• Suggestions?
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