| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache license, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the license for the specific language governing permissions and |
| * limitations under the license. |
| */ |
| package org.apache.logging.log4j.core.config.plugins.validation; |
| |
| import java.lang.annotation.Annotation; |
| import java.lang.reflect.ParameterizedType; |
| import java.lang.reflect.Type; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| |
| import org.apache.logging.log4j.core.util.ReflectionUtil; |
| |
| /** |
| * Utility class to locate an appropriate {@link ConstraintValidator} implementation for an annotation. |
| * |
| * @since 2.1 |
| */ |
| public final class ConstraintValidators { |
| |
| private ConstraintValidators() { |
| } |
| |
| /** |
| * Finds all relevant {@link ConstraintValidator} objects from an array of annotations. All validators will be |
| * {@link ConstraintValidator#initialize(java.lang.annotation.Annotation) initialized} before being returned. |
| * |
| * @param annotations the annotations to find constraint validators for |
| * @return a collection of ConstraintValidators for the given annotations |
| */ |
| public static Collection<ConstraintValidator<?>> findValidators(final Annotation... annotations) { |
| final Collection<ConstraintValidator<?>> validators = |
| new ArrayList<>(); |
| for (final Annotation annotation : annotations) { |
| final Class<? extends Annotation> type = annotation.annotationType(); |
| if (type.isAnnotationPresent(Constraint.class)) { |
| final ConstraintValidator<?> validator = getValidator(annotation, type); |
| if (validator != null) { |
| validators.add(validator); |
| } |
| } |
| } |
| return validators; |
| } |
| |
| private static <A extends Annotation> ConstraintValidator<A> getValidator(final A annotation, |
| final Class<? extends A> type) { |
| final Constraint constraint = type.getAnnotation(Constraint.class); |
| final Class<? extends ConstraintValidator<?>> validatorClass = constraint.value(); |
| if (type.equals(getConstraintValidatorAnnotationType(validatorClass))) { |
| @SuppressWarnings("unchecked") // I don't think we could be any more thorough in validation here |
| final ConstraintValidator<A> validator = (ConstraintValidator<A>) |
| ReflectionUtil.instantiate(validatorClass); |
| validator.initialize(annotation); |
| return validator; |
| } |
| return null; |
| } |
| |
| private static Type getConstraintValidatorAnnotationType(final Class<? extends ConstraintValidator<?>> type) { |
| for (final Type parentType : type.getGenericInterfaces()) { |
| if (parentType instanceof ParameterizedType) { |
| final ParameterizedType parameterizedType = (ParameterizedType) parentType; |
| if (ConstraintValidator.class.equals(parameterizedType.getRawType())) { |
| return parameterizedType.getActualTypeArguments()[0]; |
| } |
| } |
| } |
| return Void.TYPE; |
| } |
| } |