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      1 /*
      2  * Copyright (C) 2014 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 dagger.internal.codegen;
     17 
     18 import com.google.common.base.Function;
     19 import com.google.common.collect.FluentIterable;
     20 import com.google.common.collect.ImmutableSet;
     21 import dagger.MembersInjector;
     22 import dagger.producers.Producer;
     23 import javax.inject.Provider;
     24 
     25 import static com.google.common.collect.Iterables.getOnlyElement;
     26 
     27 /**
     28  * A mapper for associating a {@link DependencyRequest} to a framework class, dependent on
     29  * the type of code to be generated (e.g., for {@link Provider} or {@link Producer}).
     30  *
     31  *  @author Jesse Beder
     32  *  @since 2.0
     33  */
     34 abstract class DependencyRequestMapper {
     35   abstract Class<?> getFrameworkClass(DependencyRequest request);
     36 
     37   /**
     38    * Returns the framework class to use for a collection of requests of the same {@link BindingKey}.
     39    * This allows factories to only take a single argument for multiple requests of the same key.
     40    */
     41   Class<?> getFrameworkClass(Iterable<DependencyRequest> requests) {
     42     ImmutableSet<Class<?>> classes = FluentIterable.from(requests)
     43         .transform(new Function<DependencyRequest, Class<?>>() {
     44           @Override public Class<?> apply(DependencyRequest request) {
     45             return getFrameworkClass(request);
     46           }
     47         })
     48         .toSet();
     49     if (classes.size() == 1) {
     50       return getOnlyElement(classes);
     51     } else if (classes.equals(ImmutableSet.of(Producer.class, Provider.class))) {
     52       return Provider.class;
     53     } else {
     54       throw new IllegalStateException("Bad set of framework classes: " + classes);
     55     }
     56   }
     57 
     58   private static final class MapperForProvider extends DependencyRequestMapper {
     59     @Override public Class<?> getFrameworkClass(DependencyRequest request) {
     60       switch (request.kind()) {
     61         case INSTANCE:
     62         case PROVIDER:
     63         case LAZY:
     64           return Provider.class;
     65         case MEMBERS_INJECTOR:
     66           return MembersInjector.class;
     67         case PRODUCED:
     68         case PRODUCER:
     69           throw new IllegalArgumentException();
     70         default:
     71           throw new AssertionError();
     72       }
     73     }
     74   }
     75 
     76   static final DependencyRequestMapper FOR_PROVIDER = new MapperForProvider();
     77 
     78   private static final class MapperForProducer extends DependencyRequestMapper {
     79     @Override public Class<?> getFrameworkClass(DependencyRequest request) {
     80       switch (request.kind()) {
     81         case INSTANCE:
     82         case PRODUCED:
     83         case PRODUCER:
     84           return Producer.class;
     85         case PROVIDER:
     86         case LAZY:
     87           return Provider.class;
     88         case MEMBERS_INJECTOR:
     89           return MembersInjector.class;
     90         default:
     91           throw new AssertionError();
     92       }
     93     }
     94   }
     95 
     96   static final DependencyRequestMapper FOR_PRODUCER = new MapperForProducer();
     97 }
     98