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      1 /**
      2  * Copyright (C) 2015 Google Inc.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 package com.google.inject.daggeradapter;
     17 
     18 import com.google.common.collect.ImmutableSet;
     19 import com.google.inject.Binder;
     20 import com.google.inject.Key;
     21 import com.google.inject.internal.UniqueAnnotations;
     22 import com.google.inject.multibindings.Multibinder;
     23 import com.google.inject.spi.InjectionPoint;
     24 import com.google.inject.spi.ModuleAnnotatedMethodScanner;
     25 
     26 import dagger.Provides;
     27 import dagger.Provides.Type;
     28 
     29 import java.lang.annotation.Annotation;
     30 import java.lang.reflect.Method;
     31 import java.util.Set;
     32 
     33 /**
     34  * A scanner to process provider methods on Dagger modules.
     35  *
     36  * @author cgruber (at) google.com (Christian Gruber)
     37  */
     38 final class DaggerMethodScanner extends ModuleAnnotatedMethodScanner {
     39   static DaggerMethodScanner INSTANCE = new DaggerMethodScanner();
     40 
     41   @Override public Set<? extends Class<? extends Annotation>> annotationClasses() {
     42     return ImmutableSet.of(dagger.Provides.class);
     43   }
     44 
     45   @Override public <T> Key<T> prepareMethod(
     46       Binder binder, Annotation rawAnnotation, Key<T> key, InjectionPoint injectionPoint) {
     47     Method providesMethod = (Method) injectionPoint.getMember();
     48     Provides annotation = (Provides) rawAnnotation;
     49     switch (annotation.type()) {
     50       case UNIQUE:
     51         return key;
     52       case MAP:
     53         /* TODO(cgruber) implement map bindings */
     54         binder.addError("Map bindings are not yet supported.");
     55       case SET:
     56         return processSetBinding(binder, key);
     57       case SET_VALUES:
     58         binder.addError(Type.SET_VALUES.name() + " contributions are not supported by Guice.",
     59             providesMethod);
     60         return key;
     61       default:
     62         binder.addError("Unknown @Provides type " + annotation.type() + ".", providesMethod);
     63         return key;
     64     }
     65   }
     66 
     67   private static <T> Key<T> processSetBinding(Binder binder, Key<T> key) {
     68     Multibinder<T> setBinder = Multibinder.newSetBinder(binder, key.getTypeLiteral());
     69     Key<T> newKey = Key.get(key.getTypeLiteral(), UniqueAnnotations.create());
     70     setBinder.addBinding().to(newKey);
     71     return newKey;
     72   }
     73 
     74   private DaggerMethodScanner() {}
     75 }