co.cask.tephra.persist

Class HDFSTransactionLog

java.lang.Object

co.cask.tephra.persist.AbstractTransactionLog

co.cask.tephra.persist.HDFSTransactionLog

All Implemented Interfaces:

TransactionLog

public class HDFSTransactionLog
extends AbstractTransactionLog

Allows reading from and writing to a transaction write-ahead log stored in HDFS.

Nested Class Summary

Nested classes/interfaces inherited from class co.cask.tephra.persist.AbstractTransactionLog

AbstractTransactionLog.Entry

Field Summary

Fields inherited from class co.cask.tephra.persist.AbstractTransactionLog

timestamp

Constructor Summary

Constructors

Constructor and Description
HDFSTransactionLog(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.conf.Configuration hConf, org.apache.hadoop.fs.Path logPath, long timestamp, MetricsCollector metricsCollector) Creates a new HDFS-backed write-ahead log for storing transaction state.

Method Summary

Methods

Modifier and Type	Method and Description
protected TransactionLogWriter	createWriter() Returns a log writer to be used for appending any new TransactionEdit objects.
String	getName()
TransactionLogReader	getReader()

Methods inherited from class co.cask.tephra.persist.AbstractTransactionLog

append, append, close, getTimestamp, init, isClosed

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HDFSTransactionLog

public HDFSTransactionLog(org.apache.hadoop.fs.FileSystem fs,
                  org.apache.hadoop.conf.Configuration hConf,
                  org.apache.hadoop.fs.Path logPath,
                  long timestamp,
                  MetricsCollector metricsCollector)

Creates a new HDFS-backed write-ahead log for storing transaction state.

Parameters:

fs - Open FileSystem instance for opening log files in HDFS.

hConf - HDFS cluster configuration.

logPath - Path to the log file.

Method Detail

createWriter

protected TransactionLogWriter createWriter()
                                     throws IOException

Description copied from class: AbstractTransactionLog

Returns a log writer to be used for appending any new TransactionEdit objects.

Specified by:

createWriter in class AbstractTransactionLog

Throws:

IOException

getName

public String getName()

Specified by:

getName in interface TransactionLog

Specified by:

getName in class AbstractTransactionLog

getReader

public TransactionLogReader getReader()
                               throws IOException

Specified by:

getReader in interface TransactionLog

Specified by:

getReader in class AbstractTransactionLog

Throws:

IOException