Examples with ClassWriter org.apache.xbean.asm5.ClassWriter used on opensource projects

Example 11 with ClassWriter

use of org.apache.xbean.asm5.ClassWriter in project tomee by apache.

the class DynamicSubclass method generateBytes.

private static byte[] generateBytes(final Class<?> classToProxy, final boolean proxyNonAbstractMethods) throws ProxyGenerationException {
    final Map<String, MethodVisitor> visitors = new HashMap<String, MethodVisitor>();
    final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);
    final String proxyClassFileName = getSubclassName(classToProxy).replace('.', '/');
    final String classFileName = classToProxy.getName().replace('.', '/');
    cw.visit(V1_5, ACC_PUBLIC + ACC_SUPER, proxyClassFileName, null, classFileName, null);
    cw.visitSource(classFileName + ".java", null);
    // push InvocationHandler field
    cw.visitField(ACC_FINAL + ACC_PRIVATE, "this$handler", "Ljava/lang/reflect/InvocationHandler;", null, null).visitEnd();
    for (final Constructor<?> constructor : classToProxy.getConstructors()) {
        if (!Modifier.isPublic(constructor.getModifiers())) {
            continue;
        }
        final MethodVisitor mv = visitConstructor(cw, proxyClassFileName, classFileName, constructor);
        visitors.put("<init>" + Type.getConstructorDescriptor(constructor), mv);
    }
    final Map<String, List<Method>> methodMap = new HashMap<>();
    getNonPrivateMethods(classToProxy, methodMap);
    // Iterate over the public methods
    for (final Map.Entry<String, List<Method>> entry : methodMap.entrySet()) {
        for (final Method method : entry.getValue()) {
            if (Modifier.isAbstract(method.getModifiers()) || (proxyNonAbstractMethods && Modifier.isPublic(method.getModifiers()))) {
                final MethodVisitor visitor = LocalBeanProxyFactory.visit(cw, method, proxyClassFileName, "this$handler");
                visitors.put(method.getName() + Type.getMethodDescriptor(method), visitor);
            }
        }
    }
    copyClassAnnotations(classToProxy, cw);
    copyMethodAnnotations(classToProxy, visitors);
    // This should never be reached, but just in case
    for (final MethodVisitor visitor : visitors.values()) {
        visitor.visitEnd();
    }
    return cw.toByteArray();
}

Example 12 with ClassWriter

use of org.apache.xbean.asm5.ClassWriter 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;
}