Java Code Examples for org.apache.commons.lang3.reflect.ConstructorUtils#getAccessibleConstructor()

protected Object convertFromStringUnresolved(Class<?> parameterClass, String paramValueStr) {
    try {
        Constructor constructor = ConstructorUtils.getAccessibleConstructor(parameterClass, String.class);
        if (constructor != null) {
            return constructor.newInstance(paramValueStr);
        } else {
            Method valueOf = MethodUtils.getAccessibleMethod(parameterClass, "valueOf", String.class);
            if (valueOf != null) {
                return valueOf.invoke(null, paramValueStr);
            }
        }
    } catch (ReflectiveOperationException e) {
        throw new ReportingException(
                String.format("Could not instantiate object with class [%s] from [%s] string.",
                        parameterClass.getCanonicalName(),
                        paramValueStr));
    }
    return paramValueStr;
}
 

@Test
public void testCustomGetCommonSuperClassImplementation() throws Exception {
    // augment method to take in a single int argument
    methodNode.desc = Type.getMethodDescriptor(Type.VOID_TYPE, Type.INT_TYPE);
    
    
    // augment method instructions
    VariableTable varTable = new VariableTable(classNode, methodNode);
    
    Class<?> iterableClass = Iterable.class;
    Constructor arrayListConstructor = ConstructorUtils.getAccessibleConstructor(ArrayList.class);
    Constructor linkedListConstructor = ConstructorUtils.getAccessibleConstructor(LinkedList.class);
    Constructor hashSetConstructor = ConstructorUtils.getAccessibleConstructor(HashSet.class);
    Method iteratorMethod = MethodUtils.getAccessibleMethod(iterableClass, "iterator");
    
    Type iterableType = Type.getType(iterableClass);
    
    Variable testArg = varTable.getArgument(1);
    Variable listVar = varTable.acquireExtra(iterableType);
    
    /**
     * Collection it;
     * switch(arg1) {
     *     case 0:
     *         it = new ArrayList()
     *         break;
     *     case 1:
     *         it = new LinkedList()
     *         break;
     *     case 2:
     *         it = new HashSet()
     *         break;
     *     default: throw new RuntimeException("must be 0 or 1");
     * }
     * list.iterator();
     */
    LabelNode invokePoint = new LabelNode();
    InsnList methodInsnList
            = merge(tableSwitch(loadVar(testArg),
                            throwRuntimeException("must be 0 or 1"),
                            0,
                            merge(
                                    construct(arrayListConstructor),
                                    saveVar(listVar),
                                    jumpTo(invokePoint)
                            ),
                            merge(
                                    construct(linkedListConstructor),
                                    saveVar(listVar),
                                    jumpTo(invokePoint)
                            ),
                            merge(
                                    construct(hashSetConstructor),
                                    saveVar(listVar),
                                    jumpTo(invokePoint)
                            )
                    ),
                    addLabel(invokePoint),
                    call(iteratorMethod, GenericGenerators.loadVar(listVar)),
                    pop(), // discard results of call
                    returnVoid()
            );
    
    methodNode.instructions = methodInsnList;
    
    
    // attemp to write out class -- since we're branching like this it should call getCommonSuperClass() with the types specified in
    // each of the switch cases. getCommonsuperClass() is the logic we explictly override and are testing. createJarAndLoad uses
    // simpleclasswriter
    try (URLClassLoader cl = createJarAndLoad(classNode)) {
        Object obj = cl.loadClass("SimpleStub").newInstance();
        
        // there should not be any verifer errors here
        MethodUtils.invokeMethod(obj, "fillMeIn", 0);
        MethodUtils.invokeMethod(obj, "fillMeIn", 1);
        MethodUtils.invokeMethod(obj, "fillMeIn", 2);
    }
}
 

@Test
public void testVertificationWithoutUsingClassLoader() throws Exception {

    // augment method to take in a single int argument
    methodNode.desc = Type.getMethodDescriptor(Type.VOID_TYPE, Type.INT_TYPE);

    // augment method instructions
    VariableTable varTable = new VariableTable(classNode, methodNode);

    Class<?> iterableClass = Iterable.class;
    Constructor arrayListConstructor = ConstructorUtils.getAccessibleConstructor(ArrayList.class);
    Constructor linkedListConstructor = ConstructorUtils.getAccessibleConstructor(LinkedList.class);
    Constructor hashSetConstructor = ConstructorUtils.getAccessibleConstructor(HashSet.class);
    Method iteratorMethod = MethodUtils.getAccessibleMethod(iterableClass, "iterator");

    Type iterableType = Type.getType(iterableClass);

    VariableTable.Variable testArg = varTable.getArgument(1);
    VariableTable.Variable listVar = varTable.acquireExtra(iterableType);

    /**
     * Collection it;
     * switch(arg1) {
     *     case 0:
     *         it = new ArrayList()
     *         break;
     *     case 1:
     *         it = new LinkedList()
     *         break;
     *     case 2:
     *         it = new HashSet()
     *         break;
     *     default: throw new RuntimeException("must be 0 or 1");
     * }
     * list.iterator();
     */
    LabelNode invokePoint = new LabelNode();
    InsnList methodInsnList
            = merge(tableSwitch(loadVar(testArg),
                            throwRuntimeException("must be 0 or 1"),
                            0,
                            merge(
                                    construct(arrayListConstructor),
                                    saveVar(listVar),
                                    jumpTo(invokePoint)
                            ),
                            merge(
                                    construct(linkedListConstructor),
                                    saveVar(listVar),
                                    jumpTo(invokePoint)
                            ),
                            merge(
                                    construct(hashSetConstructor),
                                    saveVar(listVar),
                                    jumpTo(invokePoint)
                            )
                    ),
                    addLabel(invokePoint),
                    call(iteratorMethod, loadVar(listVar)),
                    pop(), // discard results of call
                    returnVoid()
            );

    methodNode.instructions = methodInsnList;
    
    
    
    // write out class and read it back in again so maxes and frames can be properly computed for frame analyzer
    SimpleClassWriter writer = new SimpleClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS, classRepo);
    classNode.accept(writer);
    byte[] data = writer.toByteArray();
    
    ClassReader cr = new ClassReader(data);
    classNode = new SimpleClassNode();
    cr.accept(classNode, 0);

    
    methodNode = classNode.methods.get(1);
    

    // analyze
    Frame<BasicValue>[] frames;
    try {
        frames = new Analyzer<>(new SimpleVerifier(classRepo)).analyze(classNode.name, methodNode);
    } catch (AnalyzerException ae) {
        throw new IllegalArgumentException("Analyzer failed to analyze method", ae);
    }
    
    
    // get last frame
    Frame frame = frames[frames.length - 1];
    BasicValue basicValue = (BasicValue) frame.getLocal(listVar.getIndex());
    
    
    // ensure that that the local variable for the collection we created in the switch blocks is an abstract type
    assertEquals("java/util/AbstractCollection", basicValue.getType().getInternalName());
}