/*
 * 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.beam.sdk.testing;

import com.google.common.base.Predicate;
import com.google.common.collect.FluentIterable;
import java.lang.annotation.Annotation;
import java.util.Arrays;
import javax.annotation.Nonnull;
import org.junit.experimental.categories.Category;

/**
 * A utility class for querying annotations.
 */
class Annotations {

  /**
   * Annotation predicates.
   */
  static class Predicates {

    static Predicate<Annotation> isAnnotationOfType(final Class<? extends Annotation> clazz) {
      return new Predicate<Annotation>() {

        @Override
        public boolean apply(@Nonnull final Annotation annotation) {
          return annotation.annotationType() != null
              && annotation.annotationType().equals(clazz);
        }
      };
    }

    static Predicate<Annotation> isCategoryOf(final Class<?> value, final boolean allowDerived) {
      return new Predicate<Annotation>() {

        @Override
        public boolean apply(@Nonnull final Annotation category) {
          return
              FluentIterable
                  .from(Arrays.asList(((Category) category).value()))
                  .anyMatch(new Predicate<Class<?>>() {

                    @Override
                    public boolean apply(final Class<?> aClass) {
                      return
                          allowDerived
                              ? value.isAssignableFrom(aClass)
                              : value.equals(aClass);
                    }
                  });
        }
      };
    }
  }
}