java/dagger/android/processor/MoreDaggerElements.java

/*
 * Copyright (C) 2021 The Dagger Authors.
 *
 * Licensed 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 dagger.android.processor;

import static dagger.internal.codegen.extension.DaggerStreams.toImmutableSet;

import com.google.auto.common.MoreElements;
import com.google.common.collect.ImmutableSet;
import com.squareup.javapoet.ClassName;
import java.util.Optional;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;

// TODO(bcorso): Dedupe with dagger/internal/codegen/langmodel/DaggerElements.java?
// TODO(bcorso): Contribute upstream to auto common?
/** Similar to auto common, but uses {@link ClassName} rather than {@link Class}. */
final class MoreDaggerElements {
  /**
   * Returns {@code true} iff the given element has an {@link AnnotationMirror} whose {@linkplain
   * AnnotationMirror#getAnnotationType() annotation type} has the same canonical name as that of
   * {@code annotationClass}. This method is a safer alternative to calling {@link
   * Element#getAnnotation} and checking for {@code null} as it avoids any interaction with
   * annotation proxies.
   */
  public static boolean isAnnotationPresent(Element element, ClassName annotationName) {
    return getAnnotationMirror(element, annotationName).isPresent();
  }

  /**
   * Returns an {@link AnnotationMirror} for the annotation of type {@code annotationClass} on
   * {@code element}, or {@link Optional#empty()} if no such annotation exists. This method is a
   * safer alternative to calling {@link Element#getAnnotation} as it avoids any interaction with
   * annotation proxies.
   */
  public static Optional<AnnotationMirror> getAnnotationMirror(
      Element element, ClassName annotationName) {
    String annotationClassName = annotationName.canonicalName();
    for (AnnotationMirror annotationMirror : element.getAnnotationMirrors()) {
      TypeElement annotationTypeElement =
          MoreElements.asType(annotationMirror.getAnnotationType().asElement());
      if (annotationTypeElement.getQualifiedName().contentEquals(annotationClassName)) {
        return Optional.of(annotationMirror);
      }
    }
    return Optional.empty();
  }

  public static ImmutableSet<AnnotationMirror> getAnnotatedAnnotations(
      Element element, ClassName annotationName) {
    return element.getAnnotationMirrors().stream()
        .filter(input -> isAnnotationPresent(input.getAnnotationType().asElement(), annotationName))
        .collect(toImmutableSet());
  }

  private MoreDaggerElements() {}
}