001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package org.apache.hadoop.fs;
020    
021    import java.io.IOException;
022    
023    import org.apache.hadoop.classification.InterfaceAudience;
024    import org.apache.hadoop.classification.InterfaceStability;
025    
026    @InterfaceAudience.Public
027    @InterfaceStability.Evolving
028    public interface CanSetDropBehind {
029      /**
030       * Configure whether the stream should drop the cache.
031       *
032       * @param dropCache     Whether to drop the cache.  null means to use the
033       *                      default value.
034       * @throws IOException  If there was an error changing the dropBehind
035       *                      setting.
036       *         UnsupportedOperationException  If this stream doesn't support
037       *                                        setting the drop-behind.
038       */
039      public void setDropBehind(Boolean dropCache) 
040          throws IOException, UnsupportedOperationException;
041    }