2 * Copyright (c) 2016 Pantheon Technologies s.r.o. 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
8 package org.opendaylight.yangtools.yang.binding.util;
10 import com.google.common.annotations.Beta;
11 import com.google.common.base.Preconditions;
12 import com.google.common.base.Throwables;
13 import java.lang.invoke.MethodHandle;
14 import java.lang.invoke.MethodHandles;
15 import java.lang.invoke.MethodHandles.Lookup;
16 import java.lang.invoke.MethodType;
17 import java.lang.reflect.Constructor;
18 import java.lang.reflect.Field;
19 import java.lang.reflect.InvocationTargetException;
20 import org.slf4j.Logger;
21 import org.slf4j.LoggerFactory;
24 * Utility class for instantiating value-type generated objects with String being the base type. Unlike the normal
25 * constructor, instances of this class bypass string validation.
27 * THE USE OF THIS CLASS IS DANGEROUS AND SHOULD ONLY BE USED TO IMPLEMENT WELL-AUDITED AND CORRECT UTILITY METHODS
28 * SHIPPED WITH MODELS TO PROVIDE INSTANTIATION FROM TYPES DIFFERENT THAN STRING.
30 * APPLICATION CODE <em>MUST NOT</em> USE THIS CLASS DIRECTLY. VIOLATING THIS CONSTRAINT HAS SECURITY AND CORRECTNESS
31 * IMPLICATIONS ON EVERY USER INTERACTING WITH THE RESULTING OBJECTS.
33 * @param <T> Resulting object type
36 public final class StringValueObjectFactory<T> {
37 private static final MethodType CONSTRUCTOR_METHOD_TYPE = MethodType.methodType(Object.class, Object.class);
38 private static final MethodType SETTER_METHOD_TYPE = MethodType.methodType(void.class, Object.class, String.class);
39 private static final Logger LOG = LoggerFactory.getLogger(StringValueObjectFactory.class);
40 private static final Lookup LOOKUP = MethodHandles.lookup();
42 private final MethodHandle constructor;
43 private final MethodHandle setter;
44 private final T template;
46 private StringValueObjectFactory(final T template, final MethodHandle constructor, final MethodHandle setter) {
47 this.template = Preconditions.checkNotNull(template);
48 this.constructor = constructor.bindTo(template);
49 this.setter = Preconditions.checkNotNull(setter);
52 public static <T> StringValueObjectFactory<T> create(final Class<T> clazz, final String templateString) {
53 final Constructor<T> stringConstructor;
55 stringConstructor = clazz.getConstructor(String.class);
56 } catch (NoSuchMethodException e) {
57 throw new IllegalArgumentException(String.format("%s does not have a String constructor", clazz), e);
62 template = stringConstructor.newInstance(templateString);
63 } catch (InstantiationException | InvocationTargetException | IllegalAccessException e) {
64 throw new IllegalArgumentException(String.format("Failed to instantiate template %s for '%s'", clazz,
68 final Constructor<T> copyConstructor;
70 copyConstructor = clazz.getConstructor(clazz);
71 } catch (NoSuchMethodException e) {
72 throw new IllegalArgumentException(String.format("%s does not have a copy constructor", clazz), e);
77 f = clazz.getDeclaredField("_value");
78 } catch (NoSuchFieldException e) {
79 throw new IllegalArgumentException(String.format("%s does not have required internal field", clazz), e);
81 f.setAccessible(true);
83 final StringValueObjectFactory<T> ret;
85 ret = new StringValueObjectFactory<>(template,
86 LOOKUP.unreflectConstructor(copyConstructor).asType(CONSTRUCTOR_METHOD_TYPE),
87 LOOKUP.unreflectSetter(f).asType(SETTER_METHOD_TYPE));
88 } catch (IllegalAccessException e) {
89 throw new IllegalStateException("Failed to instantiate method handles", e);
92 // Let us be very defensive and scream loudly if the invocation does not come from the same package. This
93 // is far from perfect, but better than nothing.
94 final Throwable t = new Throwable("Invocation stack");
96 if (matchesPackage(clazz.getPackage().getName(), t.getStackTrace())) {
97 LOG.info("Instantiated factory for {}", clazz);
99 LOG.warn("Instantiated factory for {} outside its package", clazz, t);
105 private static boolean matchesPackage(final String pkg, final StackTraceElement[] stackTrace) {
106 for (StackTraceElement e : stackTrace) {
107 final String sp = e.getClassName();
108 if (sp.startsWith(pkg) && sp.lastIndexOf('.') == pkg.length()) {
116 public T newInstance(final String string) {
117 Preconditions.checkNotNull(string, "Argument may not be null");
120 final T ret = (T) constructor.invokeExact();
121 setter.invokeExact(ret, string);
122 LOG.trace("Instantiated new object {} value {}", ret.getClass(), string);
124 } catch (Throwable e) {
125 throw Throwables.propagate(e);
129 public T getTemplate() {