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    /** This interface for flush/sync operation. */
027    @InterfaceAudience.Public
028    @InterfaceStability.Evolving
029    public interface Syncable {
030      /**
031       * @deprecated As of HADOOP 0.21.0, replaced by hflush
032       * @see #hflush()
033       */
034      @Deprecated  public void sync() throws IOException;
035      
036      /** Flush out the data in client's user buffer. After the return of
037       * this call, new readers will see the data.
038       * @throws IOException if any error occurs
039       */
040      public void hflush() throws IOException;
041      
042      /** Similar to posix fsync, flush out the data in client's user buffer 
043       * all the way to the disk device (but the disk may have it in its cache).
044       * @throws IOException if error occurs
045       */
046      public void hsync() throws IOException;
047    }