| /** |
| * Copyright (C) 2015 Google Inc. |
| * |
| * 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 com.google.inject.multibindings; |
| |
| import com.google.common.collect.ImmutableSet; |
| import com.google.inject.AbstractModule; |
| import com.google.inject.Binder; |
| import com.google.inject.Key; |
| import com.google.inject.Module; |
| import com.google.inject.TypeLiteral; |
| import com.google.inject.spi.InjectionPoint; |
| import com.google.inject.spi.ModuleAnnotatedMethodScanner; |
| |
| import java.lang.annotation.Annotation; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.util.Set; |
| |
| /** |
| * Scans a module for annotations that signal multibindings, mapbindings, and optional bindings. |
| */ |
| public class MultibindingsScanner { |
| |
| private MultibindingsScanner() {} |
| |
| /** |
| * Returns a module that, when installed, will scan all modules for methods with the annotations |
| * {@literal @}{@link ProvidesIntoMap}, {@literal @}{@link ProvidesIntoSet}, and |
| * {@literal @}{@link ProvidesIntoOptional}. |
| * |
| * <p>This is a convenience method, equivalent to doing |
| * {@code binder().scanModulesForAnnotatedMethods(MultibindingsScanner.scanner())}. |
| */ |
| public static Module asModule() { |
| return new AbstractModule() { |
| @Override protected void configure() { |
| binder().scanModulesForAnnotatedMethods(Scanner.INSTANCE); |
| } |
| }; |
| } |
| |
| /** |
| * Returns a {@link ModuleAnnotatedMethodScanner} that, when bound, will scan all modules for |
| * methods with the annotations {@literal @}{@link ProvidesIntoMap}, |
| * {@literal @}{@link ProvidesIntoSet}, and {@literal @}{@link ProvidesIntoOptional}. |
| */ |
| public static ModuleAnnotatedMethodScanner scanner() { |
| return Scanner.INSTANCE; |
| } |
| |
| private static class Scanner extends ModuleAnnotatedMethodScanner { |
| private static final Scanner INSTANCE = new Scanner(); |
| |
| @Override |
| public Set<? extends Class<? extends Annotation>> annotationClasses() { |
| return ImmutableSet.of( |
| ProvidesIntoSet.class, ProvidesIntoMap.class, ProvidesIntoOptional.class); |
| } |
| |
| @SuppressWarnings({"unchecked", "rawtypes"}) // mapKey doesn't know its key type |
| @Override |
| public <T> Key<T> prepareMethod(Binder binder, Annotation annotation, Key<T> key, |
| InjectionPoint injectionPoint) { |
| Method method = (Method) injectionPoint.getMember(); |
| AnnotationOrError mapKey = findMapKeyAnnotation(binder, method); |
| if (annotation instanceof ProvidesIntoSet) { |
| if (mapKey.annotation != null) { |
| binder.addError("Found a MapKey annotation on non map binding at %s.", method); |
| } |
| return Multibinder.newRealSetBinder(binder, key).getKeyForNewItem(); |
| } else if (annotation instanceof ProvidesIntoMap) { |
| if (mapKey.error) { |
| // Already failed on the MapKey, don't bother doing more work. |
| return key; |
| } |
| if (mapKey.annotation == null) { |
| // If no MapKey, make an error and abort. |
| binder.addError("No MapKey found for map binding at %s.", method); |
| return key; |
| } |
| TypeAndValue typeAndValue = typeAndValueOfMapKey(mapKey.annotation); |
| return MapBinder.newRealMapBinder(binder, typeAndValue.type, key) |
| .getKeyForNewValue(typeAndValue.value); |
| } else if (annotation instanceof ProvidesIntoOptional) { |
| if (mapKey.annotation != null) { |
| binder.addError("Found a MapKey annotation on non map binding at %s.", method); |
| } |
| switch (((ProvidesIntoOptional)annotation).value()) { |
| case DEFAULT: |
| return OptionalBinder.newRealOptionalBinder(binder, key).getKeyForDefaultBinding(); |
| case ACTUAL: |
| return OptionalBinder.newRealOptionalBinder(binder, key).getKeyForActualBinding(); |
| } |
| } |
| throw new IllegalStateException("Invalid annotation: " + annotation); |
| } |
| } |
| |
| private static class AnnotationOrError { |
| final Annotation annotation; |
| final boolean error; |
| AnnotationOrError(Annotation annotation, boolean error) { |
| this.annotation = annotation; |
| this.error = error; |
| } |
| |
| static AnnotationOrError forPossiblyNullAnnotation(Annotation annotation) { |
| return new AnnotationOrError(annotation, false); |
| } |
| |
| static AnnotationOrError forError() { |
| return new AnnotationOrError(null, true); |
| } |
| } |
| |
| private static AnnotationOrError findMapKeyAnnotation(Binder binder, Method method) { |
| Annotation foundAnnotation = null; |
| for (Annotation annotation : method.getAnnotations()) { |
| MapKey mapKey = annotation.annotationType().getAnnotation(MapKey.class); |
| if (mapKey != null) { |
| if (foundAnnotation != null) { |
| binder.addError("Found more than one MapKey annotations on %s.", method); |
| return AnnotationOrError.forError(); |
| } |
| if (mapKey.unwrapValue()) { |
| try { |
| // validate there's a declared method called "value" |
| Method valueMethod = annotation.annotationType().getDeclaredMethod("value"); |
| if (valueMethod.getReturnType().isArray()) { |
| binder.addError("Array types are not allowed in a MapKey with unwrapValue=true: %s", |
| annotation.annotationType()); |
| return AnnotationOrError.forError(); |
| } |
| } catch (NoSuchMethodException invalid) { |
| binder.addError("No 'value' method in MapKey with unwrapValue=true: %s", |
| annotation.annotationType()); |
| return AnnotationOrError.forError(); |
| } |
| } |
| foundAnnotation = annotation; |
| } |
| } |
| return AnnotationOrError.forPossiblyNullAnnotation(foundAnnotation); |
| } |
| |
| @SuppressWarnings({"unchecked", "rawtypes"}) |
| static TypeAndValue<?> typeAndValueOfMapKey(Annotation mapKeyAnnotation) { |
| if (!mapKeyAnnotation.annotationType().getAnnotation(MapKey.class).unwrapValue()) { |
| return new TypeAndValue(TypeLiteral.get(mapKeyAnnotation.annotationType()), mapKeyAnnotation); |
| } else { |
| try { |
| Method valueMethod = mapKeyAnnotation.annotationType().getDeclaredMethod("value"); |
| valueMethod.setAccessible(true); |
| TypeLiteral<?> returnType = |
| TypeLiteral.get(mapKeyAnnotation.annotationType()).getReturnType(valueMethod); |
| return new TypeAndValue(returnType, valueMethod.invoke(mapKeyAnnotation)); |
| } catch (NoSuchMethodException e) { |
| throw new IllegalStateException(e); |
| } catch (SecurityException e) { |
| throw new IllegalStateException(e); |
| } catch (IllegalAccessException e) { |
| throw new IllegalStateException(e); |
| } catch (InvocationTargetException e) { |
| throw new IllegalStateException(e); |
| } |
| } |
| } |
| |
| private static class TypeAndValue<T> { |
| final TypeLiteral<T> type; |
| final T value; |
| |
| TypeAndValue(TypeLiteral<T> type, T value) { |
| this.type = type; |
| this.value = value; |
| } |
| } |
| } |