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, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18 
19 package org.apache.hadoop.fs;
20 
21 import java.io.IOException;
22 
23 import org.apache.hadoop.classification.InterfaceAudience;
24 import org.apache.hadoop.classification.InterfaceStability;
25 
26 @InterfaceAudience.Public
27 @InterfaceStability.Evolving
28 public interface CanSetReadahead {
29   /**
30    * Set the readahead on this stream.
31    *
32    * @param readahead     The readahead to use.  null means to use the default.
33    * @throws IOException  If there was an error changing the dropBehind
34    *                      setting.
35    *         UnsupportedOperationException  If this stream doesn't support
36    *                                        setting readahead.
37    */
setReadahead(Long readahead)38   public void setReadahead(Long readahead)
39     throws IOException, UnsupportedOperationException;
40 }
41