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19 package org.apache.hadoop.hbase.replication.regionserver;
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21 import org.apache.commons.logging.Log;
22 import org.apache.commons.logging.LogFactory;
23 import org.apache.hadoop.classification.InterfaceAudience;
24 import org.apache.hadoop.conf.Configuration;
25 import org.apache.hadoop.fs.FileSystem;
26 import org.apache.hadoop.fs.Path;
27 import org.apache.hadoop.hbase.regionserver.wal.HLog;
28 import org.apache.hadoop.hbase.regionserver.wal.WALEditCodec;
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30 import java.io.IOException;
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36 @InterfaceAudience.Private
37 public class ReplicationHLogReaderManager {
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39 private static final Log LOG = LogFactory.getLog(ReplicationHLogReaderManager.class);
40 private final WALEditCodec nonCompressingCodec = new WALEditCodec();
41 private final FileSystem fs;
42 private final Configuration conf;
43 private long position = 0;
44 private HLog.Reader reader;
45 private Path lastPath;
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53 public ReplicationHLogReaderManager(FileSystem fs, Configuration conf) {
54 this.fs = fs;
55 this.conf = conf;
56 }
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64 public HLog.Reader openReader(Path path) throws IOException {
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67 if (this.reader == null || !this.lastPath.equals(path)) {
68 this.closeReader();
69 this.reader = HLog.getReader(this.fs, path, this.conf);
70 this.lastPath = path;
71 } else {
72 try {
73 this.reader.reset();
74 } catch (NullPointerException npe) {
75 throw new IOException("NPE resetting reader, likely HDFS-4380", npe);
76 }
77 }
78 return this.reader;
79 }
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86 public HLog.Entry readNextAndSetPosition() throws IOException {
87 HLog.Entry entry = this.reader.next();
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92 this.position = this.reader.getPosition();
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94 if (entry != null) {
95 entry.getKey().setCompressionContext(null);
96 entry.getEdit().setCodec(nonCompressingCodec);
97 }
98 return entry;
99 }
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105 public void seek() throws IOException {
106 if (this.position != 0) {
107 this.reader.seek(this.position);
108 }
109 }
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115 public long getPosition() {
116 return this.position;
117 }
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119 public void setPosition(long pos) {
120 this.position = pos;
121 }
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127 public void closeReader() throws IOException {
128 if (this.reader != null) {
129 this.reader.close();
130 this.reader = null;
131 }
132 }
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137 public void finishCurrentFile() {
138 this.position = 0;
139 try {
140 this.closeReader();
141 } catch (IOException e) {
142 LOG.warn("Unable to close reader", e);
143 }
144 }
145
146 }