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 package org.apache.hadoop.hbase.io.hfile; 19 20 import java.io.IOException; 21 22 import org.apache.hadoop.fs.FSDataInputStream; 23 24 public class HFileUtil { 25 26 /** guards against NullPointer 27 * utility which tries to seek on the DFSIS and will try an alternative source 28 * if the FSDataInputStream throws an NPE HBASE-17501 29 * @param istream 30 * @param offset 31 * @throws IOException 32 */ 33 static public void seekOnMultipleSources(FSDataInputStream istream, long offset) throws IOException { 34 try { 35 // attempt to seek inside of current blockReader 36 istream.seek(offset); 37 } catch (NullPointerException e) { 38 // retry the seek on an alternate copy of the data 39 // this can occur if the blockReader on the DFSInputStream is null 40 istream.seekToNewSource(offset); 41 } 42 } 43 }