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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.pipeline;
19  
20  
21  /**
22   * This interface represents a data channel into which objects can be fed.
23   * Feeders act as intermediaries between stages in a pipeline and the drivers
24   * for subsequent stages. Each {@link StageDriver} implementation will
25   * ordinarily provide a custom Feeder implementation that integrates receiving
26   * objects with its internal stage processing workflow.
27   */
28  public interface Feeder {
29      /**
30       * This Feeder implementation provides a standard, no-op sink for objects.
31       * It is useful for situations like the terminus of a pipeline, where
32       * there is nothing to be done with a generated object.
33       */
34      public static final Feeder VOID = new Feeder() {
35          public void feed(Object obj) { }
36      };
37      
38      /**
39       * Feeds the specified object to an underlying receiver.
40       * @param obj The object being fed to the receiver.
41       */
42      public void feed(Object obj);
43  }