Examples with net.sf.cglib.asm.$Label net.sf.cglib.asm.$Label used on opensource projects

Example 16 with net.sf.cglib.asm.$Label

use of net.sf.cglib.asm.$Label in project tomee by apache.

the class LocalBeanProxyFactory method visit.

public static MethodVisitor visit(final ClassWriter cw, final Method method, final String proxyName, final String handlerName) throws ProxyGenerationException {
    final Class<?> returnType = method.getReturnType();
    final Class<?>[] parameterTypes = method.getParameterTypes();
    final Class<?>[] exceptionTypes = method.getExceptionTypes();
    final int modifiers = method.getModifiers();
    // push the method definition
    int modifier = 0;
    if (Modifier.isPublic(modifiers)) {
        modifier = ACC_PUBLIC;
    } else if (Modifier.isProtected(modifiers)) {
        modifier = ACC_PROTECTED;
    }
    final MethodVisitor mv = cw.visitMethod(modifier, method.getName(), getMethodSignatureAsString(returnType, parameterTypes), 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(DUP);
        final Class<?> parameterType = parameterTypes[i];
        // push number onto stack
        pushIntOntoStack(mv, i);
        if (parameterType.isPrimitive()) {
            final String wrapperType = getWrapperType(parameterType);
            mv.visitFieldInsn(GETSTATIC, wrapperType, "TYPE", "Ljava/lang/Class;");
        } else {
            mv.visitLdcInsn(Type.getType(getAsmTypeAsString(parameterType, true)));
        }
        mv.visitInsn(AASTORE);
        if (Long.TYPE.equals(parameterType) || Double.TYPE.equals(parameterType)) {
            length += 2;
        } else {
            length++;
        }
    }
    // invoke getMethod() with the method name and the array of types
    mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Class", "getDeclaredMethod", "(Ljava/lang/String;[Ljava/lang/Class;)Ljava/lang/reflect/Method;", false);
    // store the returned method for later
    mv.visitVarInsn(ASTORE, length);
    // the following code generates bytecode equivalent to:
    // return ((<returntype>) invocationHandler.invoke(this, method, new Object[] { <function arguments }))[.<primitive>Value()];
    final Label l4 = new Label();
    mv.visitLabel(l4);
    mv.visitVarInsn(ALOAD, 0);
    // get the invocationHandler field from this class
    mv.visitFieldInsn(GETFIELD, proxyName, handlerName, "Ljava/lang/reflect/InvocationHandler;");
    // we want to pass "this" in as the first parameter
    mv.visitVarInsn(ALOAD, 0);
    // and the method we fetched earlier
    mv.visitVarInsn(ALOAD, length);
    // need to construct the array of objects passed in
    // create the Object[]
    createArrayDefinition(mv, parameterTypes.length, Object.class);
    int index = 1;
    // push parameters into array
    for (int i = 0; i < parameterTypes.length; i++) {
        // keep copy of array on stack
        mv.visitInsn(DUP);
        final Class<?> parameterType = parameterTypes[i];
        // push number onto stack
        pushIntOntoStack(mv, i);
        if (parameterType.isPrimitive()) {
            final String wrapperType = getWrapperType(parameterType);
            mv.visitVarInsn(getVarInsn(parameterType), index);
            mv.visitMethodInsn(INVOKESTATIC, wrapperType, "valueOf", "(" + getPrimitiveLetter(parameterType) + ")L" + wrapperType + ";", false);
            mv.visitInsn(AASTORE);
            if (Long.TYPE.equals(parameterType) || Double.TYPE.equals(parameterType)) {
                index += 2;
            } else {
                index++;
            }
        } else {
            mv.visitVarInsn(ALOAD, index);
            mv.visitInsn(AASTORE);
            index++;
        }
    }
    // invoke the invocationHandler
    mv.visitMethodInsn(INVOKEINTERFACE, "java/lang/reflect/InvocationHandler", "invoke", "(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;", true);
    // cast the result
    mv.visitTypeInsn(CHECKCAST, getCastType(returnType));
    if (returnType.isPrimitive() && !Void.TYPE.equals(returnType)) {
        // get the primitive value
        mv.visitMethodInsn(INVOKEVIRTUAL, getWrapperType(returnType), getPrimitiveMethod(returnType), "()" + getPrimitiveLetter(returnType), false);
    }
    // push return
    mv.visitLabel(l1);
    if (!Void.TYPE.equals(returnType)) {
        mv.visitInsn(getReturnInsn(returnType));
    } else {
        mv.visitInsn(POP);
        mv.visitInsn(RETURN);
    }
    // catch InvocationTargetException
    if (exceptionTypes.length > 0) {
        mv.visitLabel(l2);
        mv.visitVarInsn(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.getName().replace('.', '/') + ";"));
            mv.visitVarInsn(ALOAD, length);
            mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/reflect/InvocationTargetException", "getCause", "()Ljava/lang/Throwable;", false);
            mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "getClass", "()Ljava/lang/Class;", false);
            mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z", false);
            final Label l6 = new Label();
            mv.visitJumpInsn(IFEQ, l6);
            final Label l7 = new Label();
            mv.visitLabel(l7);
            mv.visitVarInsn(ALOAD, length);
            mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/reflect/InvocationTargetException", "getCause", "()Ljava/lang/Throwable;", false);
            mv.visitTypeInsn(CHECKCAST, exceptionType.getName().replace('.', '/'));
            mv.visitInsn(ATHROW);
            mv.visitLabel(l6);
            if (i == exceptionTypes.length - 1) {
                mv.visitTypeInsn(NEW, "java/lang/reflect/UndeclaredThrowableException");
                mv.visitInsn(DUP);
                mv.visitVarInsn(ALOAD, length);
                mv.visitMethodInsn(INVOKESPECIAL, "java/lang/reflect/UndeclaredThrowableException", "<init>", "(Ljava/lang/Throwable;)V", false);
                mv.visitInsn(ATHROW);
            }
        }
    }
    // finish this method
    mv.visitMaxs(0, 0);
    return mv;
}