Development of Java tools using SWT and WALA

1. Development of Java tools using SWT and WALA • Builder example • SWT, - The Standard Widget Toolkit • WALA, - for static analysis of Java bytecode • Example: Profile generator • Conclusion Infinit Højniveausprog, 10 February 2010 Hans Søndergaard

2. Model: JemBuilder • aJile Systems: • Builder for the aJile Java processor

3. 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/

4. 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.

5. Analysis of Java bytecode • 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

6. 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)

7. Profile generator

8. Profile generator: Add to Available classes

9. 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 } });

10. 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(...) {...}

11. 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() );

12. 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); } } }

13. 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