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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: AddString[] args = {fileName}; // class or jar filetry { 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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