One way of checking correct use of the EDT of a whole Application is to use a java agent. The Code below is an improved version of the Agent posted under Debugging Swing, the final Summary. It works with ASM 4.1. Create a Jar containing asm-all-4.1.jar (unpacked), the compiled code and a manifest specifying the agent as Premain-Class and get going.
/**
* A java agent which transforms the Swing Component classes in such a way that a stack
* trace will be dumped or an exception will be thrown when they are accessed from a wrong thread.
*
* To use it, add
* <pre>
* -javaagent:${workspace_loc:MyProject/tool/util/swingEDTCheck}/swingEDTCheck.jar
* </pre>
*
* to the VM arguments of a run configuration. This will cause the stack traces to be dumped.
*
* Use
* <pre>
* -javaagent:${workspace_loc:MyProject/tool/util/swingEDTCheck}/swingEDTCheck.jar=throw
* </pre>
* to throw exceptions.
*
*/
public class SwingEDTCheckAgent {
public static void premain(String args, Instrumentation inst) {
boolean throwing = false;
if ("throw".equals(args)) {
throwing = true;
}
inst.addTransformer(new Transformer(throwing));
}
private static class Transformer implements ClassFileTransformer {
private final boolean throwing;
public Transformer(boolean throwing) {
this.throwing = throwing;
}
@Override
public byte[] transform(ClassLoader loader,
String className,
Class classBeingRedefined,
ProtectionDomain protectionDomain,
byte[] classfileBuffer)
throws IllegalClassFormatException {
// Process all classes in javax.swing package which names start with J
if (className.startsWith("javax/swing/J")) {
ClassReader cr = new ClassReader(classfileBuffer);
ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_FRAMES);
ClassVisitor cv = new EdtCheckerClassAdapter(cw, throwing);
cr.accept(cv, 0);
return cw.toByteArray();
}
return classfileBuffer;
}
}
private static class EdtCheckerClassAdapter extends ClassVisitor {
private final boolean throwing;
public EdtCheckerClassAdapter(ClassVisitor classVisitor, boolean throwing) {
super(Opcodes.ASM4, classVisitor);
this.throwing = throwing;
}
@Override
public MethodVisitor visitMethod(final int access,
final String name,
final String desc,
final String signature,
final String[] exceptions) {
MethodVisitor mv =
cv.visitMethod(access, name, desc, signature, exceptions);
if (name.startsWith("set") || name.startsWith("get") || name.startsWith("is")) {
return new EdtCheckerMethodAdapter(mv, throwing);
} else {
return mv;
}
}
}
private static class EdtCheckerMethodAdapter extends MethodVisitor {
private final boolean throwing;
public EdtCheckerMethodAdapter(MethodVisitor methodVisitor, boolean throwing) {
super(Opcodes.ASM4, methodVisitor);
this.throwing = throwing;
}
@Override
public void visitCode() {
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/awt/EventQueue", "isDispatchThread", "()Z");
Label l1 = new Label();
mv.visitJumpInsn(Opcodes.IFNE, l1);
Label l2 = new Label();
mv.visitLabel(l2);
if (throwing) {
// more Aggressive: throw exception
mv.visitTypeInsn(Opcodes.NEW, "java/lang/RuntimeException");
mv.visitInsn(Opcodes.DUP);
mv.visitLdcInsn("Swing Component called from outside the EDT");
mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/RuntimeException", "<init>", "(Ljava/lang/String;)V");
mv.visitInsn(Opcodes.ATHROW);
} else {
// this just dumps the Stack Trace
mv.visitMethodInsn(Opcodes.INVOKESTATIC, "java/lang/Thread", "dumpStack", "()V");
}
mv.visitLabel(l1);
}
}
}
