| /* |
| * Copyright 2019 The Android Open Source Project |
| * |
| * 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 android.processor.view.inspector; |
| |
| import java.util.Map; |
| import java.util.Optional; |
| |
| import javax.annotation.processing.ProcessingEnvironment; |
| import javax.lang.model.element.AnnotationMirror; |
| import javax.lang.model.element.AnnotationValue; |
| import javax.lang.model.element.Element; |
| import javax.lang.model.element.ExecutableElement; |
| import javax.lang.model.element.TypeElement; |
| import javax.lang.model.type.TypeMirror; |
| import javax.lang.model.util.Elements; |
| import javax.lang.model.util.Types; |
| |
| /** |
| * Utilities for working with {@link AnnotationMirror}. |
| */ |
| final class AnnotationUtils { |
| private final Elements mElementUtils; |
| private final Types mTypeUtils; |
| |
| AnnotationUtils(ProcessingEnvironment processingEnv) { |
| mElementUtils = processingEnv.getElementUtils(); |
| mTypeUtils = processingEnv.getTypeUtils(); |
| } |
| |
| /** |
| * Get a {@link AnnotationMirror} specified by name from an {@link Element}. |
| * |
| * @param qualifiedName The fully qualified name of the annotation to search for |
| * @param element The element to search for annotations on |
| * @return The mirror of the requested annotation |
| * @throws ProcessingException If there is not exactly one of the requested annotation. |
| */ |
| AnnotationMirror exactlyOneMirror(String qualifiedName, Element element) { |
| final Element targetTypeElment = mElementUtils.getTypeElement(qualifiedName); |
| final TypeMirror targetType = targetTypeElment.asType(); |
| AnnotationMirror result = null; |
| |
| for (AnnotationMirror annotation : element.getAnnotationMirrors()) { |
| final TypeMirror annotationType = annotation.getAnnotationType().asElement().asType(); |
| if (mTypeUtils.isSameType(annotationType, targetType)) { |
| if (result == null) { |
| result = annotation; |
| } else { |
| final String message = String.format( |
| "Element had multiple instances of @%s, expected exactly one", |
| targetTypeElment.getSimpleName()); |
| |
| throw new ProcessingException(message, element, annotation); |
| } |
| } |
| } |
| |
| if (result == null) { |
| final String message = String.format( |
| "Expected an @%s annotation, found none", targetTypeElment.getSimpleName()); |
| throw new ProcessingException(message, element); |
| } else { |
| return result; |
| } |
| } |
| |
| /** |
| * Determine if an annotation with the supplied qualified name is present on the element. |
| * |
| * @param element The element to check for the presence of an annotation |
| * @param annotationQualifiedName The name of the annotation to check for |
| * @return True if the annotation is present, false otherwise |
| */ |
| boolean hasAnnotation(Element element, String annotationQualifiedName) { |
| final TypeElement namedElement = mElementUtils.getTypeElement(annotationQualifiedName); |
| |
| if (namedElement != null) { |
| final TypeMirror annotationType = namedElement.asType(); |
| |
| for (AnnotationMirror annotation : element.getAnnotationMirrors()) { |
| if (mTypeUtils.isSubtype(annotation.getAnnotationType(), annotationType)) { |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Get the typed value of an annotation property by name. |
| * |
| * The returned optional will be empty if the value was left at the default, or if the value |
| * of the property is null. |
| * |
| * @param propertyName The name of the property to search for |
| * @param valueClass The expected class of the property value |
| * @param element The element the annotation is on, used for exceptions |
| * @param annotationMirror An annotation mirror to search for the property |
| * @param <T> The type of the value |
| * @return An optional containing the typed value of the named property |
| */ |
| <T> Optional<T> typedValueByName( |
| String propertyName, |
| Class<T> valueClass, |
| Element element, |
| AnnotationMirror annotationMirror) { |
| return valueByName(propertyName, annotationMirror).map(annotationValue -> { |
| final Object value = annotationValue.getValue(); |
| |
| if (value == null) { |
| throw new ProcessingException( |
| String.format( |
| "Unexpected null value for annotation property \"%s\".", |
| propertyName), |
| element, |
| annotationMirror, |
| annotationValue); |
| } |
| |
| if (valueClass.isAssignableFrom(value.getClass())) { |
| return valueClass.cast(value); |
| } else { |
| throw new ProcessingException( |
| String.format( |
| "Expected annotation property \"%s\" to have type %s, but got %s.", |
| propertyName, |
| valueClass.getCanonicalName(), |
| value.getClass().getCanonicalName()), |
| element, |
| annotationMirror, |
| annotationValue); |
| } |
| }); |
| } |
| |
| /** |
| * Get the untyped value of an annotation property by name. |
| * |
| * The returned optional will be empty if the value was left at the default, or if the value |
| * of the property is null. |
| * |
| * @param propertyName The name of the property to search for |
| * @param element The element the annotation is on, used for exceptions |
| * @param annotationMirror An annotation mirror to search for the property |
| * @return An optional containing the untyped value of the named property |
| * @see AnnotationValue#getValue() |
| */ |
| Optional<Object> untypedValueByName( |
| String propertyName, |
| Element element, |
| AnnotationMirror annotationMirror) { |
| return valueByName(propertyName, annotationMirror).map(annotationValue -> { |
| final Object value = annotationValue.getValue(); |
| |
| if (value == null) { |
| throw new ProcessingException( |
| String.format( |
| "Unexpected null value for annotation property \"%s\".", |
| propertyName), |
| element, |
| annotationMirror, |
| annotationValue); |
| } |
| |
| return value; |
| }); |
| } |
| |
| /** |
| * Extract a {@link AnnotationValue} from a mirror by string property name. |
| * |
| * @param propertyName The name of the property requested property |
| * @param annotationMirror The mirror to search for the property |
| * @return The value of the property |
| */ |
| Optional<AnnotationValue> valueByName(String propertyName, AnnotationMirror annotationMirror) { |
| final Map<? extends ExecutableElement, ? extends AnnotationValue> valueMap = |
| annotationMirror.getElementValues(); |
| |
| for (ExecutableElement method : valueMap.keySet()) { |
| if (method.getSimpleName().contentEquals(propertyName)) { |
| return Optional.ofNullable(valueMap.get(method)); |
| } |
| } |
| |
| // Property not explicitly defined, use default value. |
| return Optional.empty(); |
| } |
| } |