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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.io.function;
19  
20  import java.util.Objects;
21  import java.util.stream.BaseStream;
22  
23  /**
24   * Abstracts an {@link IOBaseStream} implementation.
25   *
26   * Keep package-private for now.
27   *
28   * @param <T> the type of the stream elements.
29   * @param <S> the type of the stream extending {@code IOBaseStream}.
30   */
31  abstract class IOBaseStreamAdapter<T, S extends IOBaseStream<T, S, B>, B extends BaseStream<T, B>> implements IOBaseStream<T, S, B> {
32  
33      /**
34       * The underlying base stream.
35       */
36      private final B delegate;
37  
38      /**
39       * Constructs an instance.
40       *
41       * @param delegate the delegate.
42       */
43      IOBaseStreamAdapter(final B delegate) {
44          this.delegate = Objects.requireNonNull(delegate, "delegate");
45      }
46  
47      @Override
48      public B unwrap() {
49          return delegate;
50      }
51  
52  }