/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.fs;

import java.io.IOException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

@InterfaceAudience.Public
@InterfaceStability.Evolving
public interface CanSetReadahead {
  /**
   * Set the readahead on this stream.
   *
   * @param readahead     The readahead to use.  null means to use the default.
   * @throws IOException  If there was an error changing the dropBehind
   *                      setting.
   *         UnsupportedOperationException  If this stream doesn't support
   *                                        setting readahead. 
   */
  public void setReadahead(Long readahead)
    throws IOException, UnsupportedOperationException;
}