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Development of Java tools using

SWT and WALA

Infinit Højniveausprog, 10 February 2010

Hans Søndergaard

• Builder example

• SWT, - The Standard Widget Toolkit

• WALA, - for static analysis of Java bytecode

• Example: Profile generator

• Conclusion

Model: JemBuilder

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aJile Systems:• Builder for the aJile Java processor

GUI programming using SWT

• SWT : The Standard Widget Toolkit – designed to provide efficient, portable access

to the user-interface facilities of the operating systems on which it is implemented

– part of Eclipse– many code snippets– see http://www.eclipse.org/swt/

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SWT versus Swing

• No clear difference as to performance

• Swing – has more memory consumption than SWT – has all its components implemented by itself

• has much more classes to be loaded in runtime.

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Analysis of Java bytecode

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• WALA provides static analysis capabilities for Java bytecode

• WALA features include:

Java type system and class hierarchy analysis Interprocedural dataflow analysis Pointer analysis and call graph construction General framework for iterative dataflow General analysis utilities and data structures A dynamic load-time instrumentation library for Java

• open source license• http://wala.sourceforge.net/wiki/index.php/Main_Page

Example: PositiveListChecker

• Scans a list of classes to be checked• A Profile must be available

– a positive list of classes with methods• The result is written in a report file.

Generated report file:

Not on positive list ====================

(type, class, method)

(7, java/lang/Object, null)

(10, hello/NotPositiveClass, staticMethod1)

(7, hello/NotPositiveClass, null)

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Profile generator

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Profile generator: Add to Available classes

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Code snippet: Available classes: Add

Button addButton = new Button (composite, SWT.PUSH);

addButton.setText (" Add ");

addButton.addSelectionListener (new SelectionAdapter () {

public void widgetSelected (SelectionEvent e) {

FileDialog fileDialog = new FileDialog(fileList.getShell(), SWT.OPEN);

String[] filterNames = new String[] {"Class Files“,"Jar Files“,"All Files(*)"};

String [] filterExtensions = new String [] {"*.class", "*.jar", "*"};

...

String fileName = fileDialog.open();

... // see next slide

}

});

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Code snippet: Available classes: Add

String[] args = {fileName}; // class or jar file

try {

pjchecker.ClassList list = new ClassList (args); // uses WALA lib

HashSet<ClassInfo> classSet = list.getClassList();

Iterator<ClassInfo> itr = classSet.iterator();

for (; itr.hasNext(); )

{

ClassInfo info = itr.next();

if (info.methodName == null) // a class

availableClassList.addClass(info.className);

else // a method

availableClassList.addMethod(info.className, info.methodName);

}

createTree (availableListTree, availableClassList);

}

catch(...) {...}

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Code snippet: Using WALA classes

• com.ibm.wala.shrikeBT.shrikeCT.OfflineInstrumenter;

OfflineInstrumenter oi = new OfflineInstrumenter(); oi.parseStandardArgs(args);

• com.ibm.wala.shrikeBT.shrikeCT.ClassInstrumenter;

ClassInstrumenter ci;

oi.beginTraversal();

while ((ci = oi.nextClass()) != null)

doClass( ci.getReader() );

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Code snippet: Using WALA classes

• com.ibm.wala.shrikeCT.ClassReader;

String className = cr.getName();

ClassInfo c = new ClassInfo (ClassConstants.CONSTANT_Class, className, null);

classSet.add(c);

for (int i = 1; i < cr.getMethodCount(); i++) {

int accessFlag = cr.getMethodAccessFlags(i);

if ((accessFlag & 0x0002) != 0x0002) // private methods not included in list

{

if (! cr.getMethodName(i).equals("<init>") &&

!cr.getMethodName(i).equals("<clinit>")) {

c = new ClassInfo ( ClassConstants.CONSTANT_MethodRef,

className, cr.getMethodName(i));

classSet.add(c);

}

}

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Conclusion

• SWT is an alternative to Swing– part of Eclipse– less classes and less memory consumption– many code snippets

• WALA– harder to install and get down to use– but many features for static analysis of Java

bytecode

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