MethodVisitor mv = cw.visitMethod(modifier, method.getName(), Type.getMethodDescriptor(method), null, null);
mv.visitCode();
// push try/catch block, to catch declared exceptions, and to catch java.lang.Throwable
final Label l0 = new Label();
final Label l1 = new Label();
final Label l2 = new Label();
if (exceptionTypes.length > 0)
{
mv.visitTryCatchBlock(l0, l1, l2, "java/lang/reflect/InvocationTargetException");
}
// push try code
mv.visitLabel(l0);
final String classNameToOverride = method.getDeclaringClass().getName().replace('.', '/');
mv.visitLdcInsn(Type.getType("L" + classNameToOverride + ";"));
// the following code generates the bytecode for this line of Java:
// Method method = <proxy>.class.getMethod("add", new Class[] { <array of function argument classes> });
// get the method name to invoke, and push to stack
mv.visitLdcInsn(method.getName());
// create the Class[]
createArrayDefinition(mv, parameterTypes.length, Class.class);
int length = 1;
// push parameters into array
for (int i = 0; i < parameterTypes.length; i++)
{
// keep copy of array on stack
mv.visitInsn(Opcodes.DUP);
final Class<?> parameterType = parameterTypes[i];
// push number onto stack
pushIntOntoStack(mv, i);
if (parameterType.isPrimitive())
{
String wrapperType = getWrapperType(parameterType);
mv.visitFieldInsn(Opcodes.GETSTATIC, wrapperType, "TYPE", "Ljava/lang/Class;");
}
else
{
mv.visitLdcInsn(Type.getType(parameterType));
}
mv.visitInsn(Opcodes.AASTORE);
if (Long.TYPE.equals(parameterType) || Double.TYPE.equals(parameterType))
{
length += 2;
}
else
{
length++;
}
}
// the following code generates bytecode equivalent to:
// return ((<returntype>) invocationHandler.invoke(this, {methodIndex}, new Object[] { <function arguments }))[.<primitive>Value()];
final Label l4 = new Label();
mv.visitLabel(l4);
mv.visitVarInsn(Opcodes.ALOAD, 0);
// get the invocationHandler field from this class
mv.visitFieldInsn(Opcodes.GETFIELD, proxyClassFileName, FIELD_INTERCEPTOR_HANDLER, Type.getDescriptor(InterceptorHandler.class));
// add the Method from the static array as first parameter
mv.visitFieldInsn(Opcodes.GETSTATIC, proxyClassFileName, FIELD_INTERCEPTED_METHODS, Type.getDescriptor(Method[].class));
// push the methodIndex of the current method
if (methodIndex <128)
{
mv.visitIntInsn(Opcodes.BIPUSH, methodIndex);
}
else if (methodIndex < 32267)
{
// for methods > 127 we need to push a short number as index
mv.visitIntInsn(Opcodes.SIPUSH, methodIndex);
}
else
{
throw new ProxyGenerationException("Sorry, we only support Classes with 2^15 methods...");
}
// and now load the Method from the array
mv.visitInsn(Opcodes.AALOAD);
// prepare the parameter array as Object[] and store it on the stack
pushMethodParameterArray(mv, parameterTypes);
// invoke the invocationHandler
mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, Type.getInternalName(InterceptorHandler.class), "invoke",
"(Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;", true);
// cast the result
mv.visitTypeInsn(Opcodes.CHECKCAST, getCastType(returnType));
if (returnType.isPrimitive() && (!Void.TYPE.equals(returnType)))
{
// get the primitive value
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, getWrapperType(returnType), getPrimitiveMethod(returnType),
"()" + Type.getDescriptor(returnType), false);
}
// push return
mv.visitLabel(l1);
if (!Void.TYPE.equals(returnType))
{
mv.visitInsn(getReturnInsn(returnType));
}
else
{
mv.visitInsn(Opcodes.POP);
mv.visitInsn(Opcodes.RETURN);
}
// catch InvocationTargetException
if (exceptionTypes.length > 0)
{
mv.visitLabel(l2);
mv.visitVarInsn(Opcodes.ASTORE, length);
final Label l5 = new Label();
mv.visitLabel(l5);
for (int i = 0; i < exceptionTypes.length; i++)
{
final Class<?> exceptionType = exceptionTypes[i];
mv.visitLdcInsn(Type.getType("L" + exceptionType.getCanonicalName().replace('.', '/') + ";"));
mv.visitVarInsn(Opcodes.ALOAD, length);
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/reflect/InvocationTargetException", "getCause",
"()Ljava/lang/Throwable;", false);
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false);
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z", false);
final Label l6 = new Label();
mv.visitJumpInsn(Opcodes.IFEQ, l6);
final Label l7 = new Label();
mv.visitLabel(l7);
mv.visitVarInsn(Opcodes.ALOAD, length);
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/reflect/InvocationTargetException", "getCause",
"()Ljava/lang/Throwable;", false);