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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.maven.di.impl;
20  
21  import java.util.Collection;
22  import java.util.List;
23  import java.util.Set;
24  import java.util.function.Consumer;
25  import java.util.function.Function;
26  import java.util.function.Supplier;
27  
28  import org.apache.maven.di.Key;
29  
30  import static java.util.stream.Collectors.toSet;
31  
32  public abstract class BindingInitializer<T> {
33  
34      private final Set<Key<?>> dependencies;
35  
36      protected BindingInitializer(Set<Key<?>> dependencies) {
37          this.dependencies = dependencies;
38      }
39  
40      public Set<Key<?>> getDependencies() {
41          return dependencies;
42      }
43  
44      public abstract Consumer<T> compile(Function<Key<?>, Supplier<?>> compiler);
45  
46      public static <T> BindingInitializer<T> combine(List<BindingInitializer<T>> bindingInitializers) {
47          Set<Key<?>> deps = bindingInitializers.stream()
48                  .map(BindingInitializer::getDependencies)
49                  .flatMap(Collection::stream)
50                  .collect(toSet());
51          return new BindingInitializer<T>(deps) {
52              @Override
53              public Consumer<T> compile(Function<Key<?>, Supplier<?>> compiler) {
54                  return instance -> bindingInitializers.stream()
55                          .map(bindingInitializer -> bindingInitializer.compile(compiler))
56                          .forEach(i -> i.accept(instance));
57              }
58          };
59      }
60  }