alluxio.master.journal

Interface JournalReader

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

NoopJournalReader, UfsJournalReader

@NotThreadSafe
public interface JournalReader
extends Closeable

This class manages reading from the journal.

Method Summary

Modifier and Type	Method and Description
long	getNextSequenceNumber() Gets the the sequence number of the next journal log entry to read.
Journal.JournalEntry	read() Reads an entry from the journal.

Methods inherited from interface java.io.Closeable

close

Method Detail

read

Journal.JournalEntry read()
                   throws IOException,
                          InvalidJournalEntryException

Reads an entry from the journal. Return null if there is no more entry left.

Returns:

the journal entry, null if no more entry left

Throws:

InvalidJournalEntryException - if the journal entry is invalid (e.g. corrupted entry)

IOException

getNextSequenceNumber

long getNextSequenceNumber()

Gets the the sequence number of the next journal log entry to read. This method is valid no matter whether this JournalReader is closed or not.

Returns:

the next sequence number