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 */ 018package org.apache.hadoop.hbase.io.hfile; 019 020import java.io.IOException; 021import org.apache.hadoop.fs.FSDataInputStream; 022import org.apache.yetus.audience.InterfaceAudience; 023 024@InterfaceAudience.Private 025class HFileUtil { 026 027 /** 028 * guards against NullPointer utility which tries to seek on the DFSIS and will try an alternative 029 * source if the FSDataInputStream throws an NPE HBASE-17501 nnn 030 */ 031 static public void seekOnMultipleSources(FSDataInputStream istream, long offset) 032 throws IOException { 033 try { 034 // attempt to seek inside of current blockReader 035 istream.seek(offset); 036 } catch (NullPointerException e) { 037 // retry the seek on an alternate copy of the data 038 // this can occur if the blockReader on the DFSInputStream is null 039 istream.seekToNewSource(offset); 040 } 041 } 042}