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 import org.apache.hadoop.hbase.classification.InterfaceAudience; 24 25 @InterfaceAudience.Private 26 class HFileUtil { 27 28 /** guards against NullPointer 29 * utility which tries to seek on the DFSIS and will try an alternative source 30 * if the FSDataInputStream throws an NPE HBASE-17501 31 * @param istream 32 * @param offset 33 * @throws IOException 34 */ 35 static public void seekOnMultipleSources(FSDataInputStream istream, long offset) throws IOException { 36 try { 37 // attempt to seek inside of current blockReader 38 istream.seek(offset); 39 } catch (NullPointerException e) { 40 // retry the seek on an alternate copy of the data 41 // this can occur if the blockReader on the DFSInputStream is null 42 istream.seekToNewSource(offset); 43 } 44 } 45 }