Line data    Source code

       1             : // Copyright (C) 2012 The Android Open Source Project
       2             : //
       3             : // Licensed under the Apache License, Version 2.0 (the "License");
       4             : // you may not use this file except in compliance with the License.
       5             : // You may obtain a copy of the License at
       6             : //
       7             : // http://www.apache.org/licenses/LICENSE-2.0
       8             : //
       9             : // Unless required by applicable law or agreed to in writing, software
      10             : // distributed under the License is distributed on an "AS IS" BASIS,
      11             : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12             : // See the License for the specific language governing permissions and
      13             : // limitations under the License.
      14             : 
      15             : package com.google.gerrit.extensions.registration;
      16             : 
      17             : import com.google.gerrit.common.Nullable;
      18             : import com.google.inject.Binding;
      19             : import com.google.inject.Inject;
      20             : import com.google.inject.Injector;
      21             : import com.google.inject.Key;
      22             : import com.google.inject.Provider;
      23             : import com.google.inject.ProvisionException;
      24             : import com.google.inject.TypeLiteral;
      25             : import java.util.List;
      26             : 
      27             : class DynamicItemProvider<T> implements Provider<DynamicItem<T>> {
      28             :   private final TypeLiteral<T> type;
      29             :   private final Key<DynamicItem<T>> key;
      30             : 
      31             :   @Inject private Injector injector;
      32             : 
      33         152 :   DynamicItemProvider(TypeLiteral<T> type, Key<DynamicItem<T>> key) {
      34         152 :     this.type = type;
      35         152 :     this.key = key;
      36         152 :   }
      37             : 
      38             :   @Override
      39             :   public DynamicItem<T> get() {
      40         151 :     return new DynamicItem<>(key, find(injector, type), PluginName.GERRIT);
      41             :   }
      42             : 
      43             :   @Nullable
      44             :   private static <T> Provider<T> find(Injector src, TypeLiteral<T> type) {
      45         151 :     List<Binding<T>> bindings = src.findBindingsByType(type);
      46         151 :     if (bindings != null && bindings.size() == 1) {
      47         151 :       return bindings.get(0).getProvider();
      48         150 :     } else if (bindings != null && bindings.size() > 1) {
      49           0 :       throw new ProvisionException(
      50           0 :           String.format(
      51             :               "Multiple providers bound for DynamicItem<%s>\n"
      52             :                   + "This is not allowed; check the server configuration.",
      53             :               type));
      54             :     } else {
      55         150 :       return null;
      56             :     }
      57             :   }
      58             : }