2 * Copyright (c) 2017 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
9 package org.opendaylight.mdsal.binding.javav2.util;
11 import static java.util.Objects.requireNonNull;
13 import com.google.common.annotations.Beta;
14 import com.google.common.base.Throwables;
15 import java.lang.invoke.MethodHandle;
16 import java.lang.invoke.MethodHandles;
17 import java.lang.invoke.MethodHandles.Lookup;
18 import java.lang.invoke.MethodType;
19 import java.lang.reflect.Constructor;
20 import java.lang.reflect.Field;
21 import java.lang.reflect.InvocationTargetException;
22 import org.slf4j.Logger;
23 import org.slf4j.LoggerFactory;
26 * Utility class for instantiating value-type generated objects with String being the base type. Unlike the normal
27 * constructor, instances of this class bypass string validation.
29 * THE USE OF THIS CLASS IS DANGEROUS AND SHOULD ONLY BE USED TO IMPLEMENT WELL-AUDITED AND CORRECT UTILITY METHODS
30 * SHIPPED WITH MODELS TO PROVIDE INSTANTIATION FROM TYPES DIFFERENT THAN STRING.
32 * APPLICATION CODE <em>MUST NOT</em> USE THIS CLASS DIRECTLY. VIOLATING THIS CONSTRAINT HAS SECURITY AND CORRECTNESS
33 * IMPLICATIONS ON EVERY USER INTERACTING WITH THE RESULTING OBJECTS.
35 * @param <T> Resulting object type
38 public final class StringValueObjectFactory<T> {
40 private static final MethodType CONSTRUCTOR_METHOD_TYPE = MethodType.methodType(Object.class, Object.class);
41 private static final MethodType SETTER_METHOD_TYPE = MethodType.methodType(void.class, Object.class, String.class);
42 private static final Logger LOG = LoggerFactory.getLogger(StringValueObjectFactory.class);
43 private static final Lookup LOOKUP = MethodHandles.lookup();
45 private final MethodHandle constructor;
46 private final MethodHandle setter;
47 private final T template;
49 private StringValueObjectFactory(final T template, final MethodHandle constructor, final MethodHandle setter) {
50 this.template = requireNonNull(template);
51 this.constructor = constructor.bindTo(template);
52 this.setter = requireNonNull(setter);
55 public static <T> StringValueObjectFactory<T> create(final Class<T> clazz, final String templateString) {
56 final Constructor<T> stringConstructor;
58 stringConstructor = clazz.getConstructor(String.class);
59 } catch (NoSuchMethodException e) {
60 throw new IllegalArgumentException(String.format("%s does not have a String constructor", clazz), e);
65 template = stringConstructor.newInstance(templateString);
66 } catch (InstantiationException | InvocationTargetException | IllegalAccessException e) {
67 throw new IllegalArgumentException(String.format("Failed to instantiate template %s for '%s'", clazz,
71 final Constructor<T> copyConstructor;
73 copyConstructor = clazz.getConstructor(clazz);
74 } catch (NoSuchMethodException e) {
75 throw new IllegalArgumentException(String.format("%s does not have a copy constructor", clazz), e);
80 f = clazz.getDeclaredField("_value");
81 } catch (NoSuchFieldException e) {
82 throw new IllegalArgumentException(String.format("%s does not have required internal field", clazz), e);
84 f.setAccessible(true);
86 final StringValueObjectFactory<T> ret;
88 ret = new StringValueObjectFactory<>(template,
89 LOOKUP.unreflectConstructor(copyConstructor).asType(CONSTRUCTOR_METHOD_TYPE),
90 LOOKUP.unreflectSetter(f).asType(SETTER_METHOD_TYPE));
91 } catch (IllegalAccessException e) {
92 throw new IllegalStateException("Failed to instantiate method handles", e);
95 // Let us be very defensive and scream loudly if the invocation does not come from the same package. This
96 // is far from perfect, but better than nothing.
97 final Throwable t = new Throwable("Invocation stack");
99 if (matchesPackage(clazz.getPackage().getName(), t.getStackTrace())) {
100 LOG.info("Instantiated factory for {}", clazz);
102 LOG.warn("Instantiated factory for {} outside its package", clazz, t);
108 private static boolean matchesPackage(final String pkg, final StackTraceElement[] stackTrace) {
109 for (StackTraceElement e : stackTrace) {
110 final String sp = e.getClassName();
111 if (sp.startsWith(pkg) && sp.lastIndexOf('.') == pkg.length()) {
119 public T newInstance(final String string) {
120 requireNonNull(string, "Argument may not be null");
123 final T ret = (T) constructor.invokeExact();
124 setter.invokeExact(ret, string);
125 LOG.trace("Instantiated new object {} value {}", ret.getClass(), string);
127 } catch (Throwable e) {
128 throw Throwables.propagate(e);
132 public T getTemplate() {