org.apache.tephra.persist

Class HDFSTransactionLogReaderV3

java.lang.Object

org.apache.tephra.persist.HDFSTransactionLogReaderV3

All Implemented Interfaces:

Closeable, AutoCloseable, TransactionLogReader

public class HDFSTransactionLogReaderV3
extends Object
implements TransactionLogReader

TransactionLogReader that can read v3 version of Transaction logs. The logs are expected to have commit markers that indicates the size of the batch of TransactionEdits (follows the marker), that were synced together. If the expected number of TransactionEdits are not present then that set of TransactionEdits are discarded.

Constructor Summary

Constructors

Constructor and Description
HDFSTransactionLogReaderV3(org.apache.hadoop.io.SequenceFile.Reader reader)

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
TransactionEdit	next() Returns the next TransactionEdit from the log file, based on the current position, or null if the end of the file has been reached.
TransactionEdit	next(TransactionEdit reuse) Populates reuse with the next TransactionEdit, based on the reader's current position in the log file.

Methods inherited from class java.lang.Object

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

Constructor Detail

HDFSTransactionLogReaderV3

public HDFSTransactionLogReaderV3(org.apache.hadoop.io.SequenceFile.Reader reader)

Method Detail

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

next

public TransactionEdit next()
                     throws IOException

Description copied from interface: TransactionLogReader

Returns the next TransactionEdit from the log file, based on the current position, or null if the end of the file has been reached.

Specified by:

next in interface TransactionLogReader

Throws:

IOException

next

public TransactionEdit next(TransactionEdit reuse)
                     throws IOException

Description copied from interface: TransactionLogReader

Populates reuse with the next TransactionEdit, based on the reader's current position in the log file.

Specified by:

next in interface TransactionLogReader

Parameters:

reuse - The TransactionEdit instance to populate with the log entry data.

Returns:

The TransactionEdit instance, or null if the end of the file has been reached.

Throws:

IOException - If an error is encountered reading the log data.