/**
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hbase.regionserver.wal;
import java.io.IOException;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.regionserver.wal.HLog.Reader;
import org.apache.hadoop.hbase.regionserver.wal.HLog.Writer;
public class HLogFactory {
private static final Log LOG = LogFactory.getLog(HLogFactory.class);
public static HLog createHLog(final FileSystem fs, final Path root, final String logName,
final Configuration conf) throws IOException {
return new FSHLog(fs, root, logName, conf);
}
public static HLog createHLog(final FileSystem fs, final Path root, final String logName,
final String oldLogName, final Configuration conf) throws IOException {
return new FSHLog(fs, root, logName, oldLogName, conf);
}
public static HLog createHLog(final FileSystem fs, final Path root, final String logName,
final Configuration conf, final List<WALActionsListener> listeners,
final String prefix) throws IOException {
return new FSHLog(fs, root, logName, conf, listeners, prefix);
}
public static HLog createMetaHLog(final FileSystem fs, final Path root, final String logName,
final Configuration conf, final List<WALActionsListener> listeners,
final String prefix) throws IOException {
return new FSHLog(fs, root, logName, HConstants.HREGION_OLDLOGDIR_NAME,
conf, listeners, false, prefix, true);
}
/*
* WAL Reader
*/
private static Class<? extends Reader> logReaderClass;
static void resetLogReaderClass() {
logReaderClass = null;
}
/**
* Create a reader for the WAL. If you are reading from a file that's being written to
* and need to reopen it multiple times, use {@link HLog.Reader#reset()} instead of this method
* then just seek back to the last known good position.
* @return A WAL reader. Close when done with it.
* @throws IOException
*/
public static HLog.Reader createReader(final FileSystem fs,
final Path path, Configuration conf)
throws IOException {
try {
if (logReaderClass == null) {
logReaderClass = conf.getClass("hbase.regionserver.hlog.reader.impl",
SequenceFileLogReader.class, Reader.class);
}
HLog.Reader reader = logReaderClass.newInstance();
reader.init(fs, path, conf);
return reader;
} catch (IOException e) {
throw e;
}
catch (Exception e) {
throw new IOException("Cannot get log reader", e);
}
}
/*
* WAL writer
*/
private static Class<? extends Writer> logWriterClass;
/**
* Create a writer for the WAL.
* @return A WAL writer. Close when done with it.
* @throws IOException
*/
public static HLog.Writer createWriter(final FileSystem fs,
final Path path, Configuration conf)
throws IOException {
try {
if (logWriterClass == null) {
logWriterClass = conf.getClass("hbase.regionserver.hlog.writer.impl",
SequenceFileLogWriter.class, Writer.class);
}
HLog.Writer writer = (HLog.Writer) logWriterClass.newInstance();
writer.init(fs, path, conf);
return writer;
} catch (Exception e) {
throw new IOException("cannot get log writer", e);
}
}
}