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.Closeable;
022 import java.io.IOException;
023
024 import org.apache.avro.file.SeekableInput;
025 import org.apache.hadoop.classification.InterfaceAudience;
026 import org.apache.hadoop.classification.InterfaceStability;
027
028 /** Adapts an {@link FSDataInputStream} to Avro's SeekableInput interface. */
029 @InterfaceAudience.Public
030 @InterfaceStability.Stable
031 public class AvroFSInput implements Closeable, SeekableInput {
032 private final FSDataInputStream stream;
033 private final long len;
034
035 /** Construct given an {@link FSDataInputStream} and its length. */
036 public AvroFSInput(final FSDataInputStream in, final long len) {
037 this.stream = in;
038 this.len = len;
039 }
040
041 /** Construct given a {@link FileContext} and a {@link Path}. */
042 public AvroFSInput(final FileContext fc, final Path p) throws IOException {
043 FileStatus status = fc.getFileStatus(p);
044 this.len = status.getLen();
045 this.stream = fc.open(p);
046 }
047
048 @Override
049 public long length() {
050 return len;
051 }
052
053 @Override
054 public int read(byte[] b, int off, int len) throws IOException {
055 return stream.read(b, off, len);
056 }
057
058 @Override
059 public void seek(long p) throws IOException {
060 stream.seek(p);
061 }
062
063 @Override
064 public long tell() throws IOException {
065 return stream.getPos();
066 }
067
068 @Override
069 public void close() throws IOException {
070 stream.close();
071 }
072 }