+++ /dev/null
-/*
- * Copyright (c) 2017 Cisco Systems, Inc. and others. All rights reserved.
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Public License v1.0 which accompanies this distribution,
- * and is available at http://www.eclipse.org/legal/epl-v10.html
- */
-
-package org.opendaylight.mdsal.binding.javav2.util;
-
-import static java.util.Objects.requireNonNull;
-
-import com.google.common.annotations.Beta;
-import com.google.common.base.Throwables;
-import java.lang.invoke.MethodHandle;
-import java.lang.invoke.MethodHandles;
-import java.lang.invoke.MethodHandles.Lookup;
-import java.lang.invoke.MethodType;
-import java.lang.reflect.Constructor;
-import java.lang.reflect.Field;
-import java.lang.reflect.InvocationTargetException;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Utility class for instantiating value-type generated objects with String being the base type. Unlike the normal
- * constructor, instances of this class bypass string validation.
- *
- * THE USE OF THIS CLASS IS DANGEROUS AND SHOULD ONLY BE USED TO IMPLEMENT WELL-AUDITED AND CORRECT UTILITY METHODS
- * SHIPPED WITH MODELS TO PROVIDE INSTANTIATION FROM TYPES DIFFERENT THAN STRING.
- *
- * APPLICATION CODE <em>MUST NOT</em> USE THIS CLASS DIRECTLY. VIOLATING THIS CONSTRAINT HAS SECURITY AND CORRECTNESS
- * IMPLICATIONS ON EVERY USER INTERACTING WITH THE RESULTING OBJECTS.
- *
- * @param <T> Resulting object type
- */
-@Beta
-public final class StringValueObjectFactory<T> {
-
- private static final MethodType CONSTRUCTOR_METHOD_TYPE = MethodType.methodType(Object.class, Object.class);
- private static final MethodType SETTER_METHOD_TYPE = MethodType.methodType(void.class, Object.class, String.class);
- private static final Logger LOG = LoggerFactory.getLogger(StringValueObjectFactory.class);
- private static final Lookup LOOKUP = MethodHandles.lookup();
-
- private final MethodHandle constructor;
- private final MethodHandle setter;
- private final T template;
-
- private StringValueObjectFactory(final T template, final MethodHandle constructor, final MethodHandle setter) {
- this.template = requireNonNull(template);
- this.constructor = constructor.bindTo(template);
- this.setter = requireNonNull(setter);
- }
-
- public static <T> StringValueObjectFactory<T> create(final Class<T> clazz, final String templateString) {
- final Constructor<T> stringConstructor;
- try {
- stringConstructor = clazz.getConstructor(String.class);
- } catch (NoSuchMethodException e) {
- throw new IllegalArgumentException(String.format("%s does not have a String constructor", clazz), e);
- }
-
- final T template;
- try {
- template = stringConstructor.newInstance(templateString);
- } catch (InstantiationException | InvocationTargetException | IllegalAccessException e) {
- throw new IllegalArgumentException(String.format("Failed to instantiate template %s for '%s'", clazz,
- templateString), e);
- }
-
- final Constructor<T> copyConstructor;
- try {
- copyConstructor = clazz.getConstructor(clazz);
- } catch (NoSuchMethodException e) {
- throw new IllegalArgumentException(String.format("%s does not have a copy constructor", clazz), e);
- }
-
- final Field f;
- try {
- f = clazz.getDeclaredField("_value");
- } catch (NoSuchFieldException e) {
- throw new IllegalArgumentException(String.format("%s does not have required internal field", clazz), e);
- }
- f.setAccessible(true);
-
- final StringValueObjectFactory<T> ret;
- try {
- ret = new StringValueObjectFactory<>(template,
- LOOKUP.unreflectConstructor(copyConstructor).asType(CONSTRUCTOR_METHOD_TYPE),
- LOOKUP.unreflectSetter(f).asType(SETTER_METHOD_TYPE));
- } catch (IllegalAccessException e) {
- throw new IllegalStateException("Failed to instantiate method handles", e);
- }
-
- // Let us be very defensive and scream loudly if the invocation does not come from the same package. This
- // is far from perfect, but better than nothing.
- final Throwable t = new Throwable("Invocation stack");
- t.fillInStackTrace();
- if (matchesPackage(clazz.getPackage().getName(), t.getStackTrace())) {
- LOG.info("Instantiated factory for {}", clazz);
- } else {
- LOG.warn("Instantiated factory for {} outside its package", clazz, t);
- }
-
- return ret;
- }
-
- private static boolean matchesPackage(final String pkg, final StackTraceElement[] stackTrace) {
- for (StackTraceElement e : stackTrace) {
- final String sp = e.getClassName();
- if (sp.startsWith(pkg) && sp.lastIndexOf('.') == pkg.length()) {
- return true;
- }
- }
-
- return false;
- }
-
- public T newInstance(final String string) {
- requireNonNull(string, "Argument may not be null");
-
- try {
- final T ret = (T) constructor.invokeExact();
- setter.invokeExact(ret, string);
- LOG.trace("Instantiated new object {} value {}", ret.getClass(), string);
- return ret;
- } catch (Throwable e) {
- throw Throwables.propagate(e);
- }
- }
-
- public T getTemplate() {
- return template;
- }
-}
Code Review / mdsal.git / blobdiff