org.apache.hadoop.hbase.wal

Interface WALStreamReader

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

ProtobufWALStreamReader

@InterfaceAudience.Private
public interface WALStreamReader
extends Closeable

A one way WAL reader, without reset and seek support.

In most cases you should use this interface to read WAL file, as the implementation is simple and robust. For replication, where we want to tail the WAL file which is currently being written, you should use WALTailingReader instead.

See Also:

WALTailingReader

Method Summary

Modifier and Type	Method and Description
void	close() Override to remove the 'throws IOException' as we are just a reader.
long	getPosition() Get the current reading position.
default WAL.Entry	next() Read the next entry in WAL.
WAL.Entry	next(WAL.Entry reuse) Read the next entry in WAL, use the given WAL.Entry if not null to hold the data.

Method Detail

next

default WAL.Entry next()
                throws IOException

Read the next entry in WAL.

In most cases you should just use this method, especially when reading a closed wal file for splitting or printing.

Throws:

IOException

next

WAL.Entry next(WAL.Entry reuse)
        throws IOException

Read the next entry in WAL, use the given WAL.Entry if not null to hold the data.

Mainly used in MR.

Parameters:

reuse - the entry to be used for reading, can be null

Throws:

IOException

getPosition

long getPosition()
          throws IOException

Get the current reading position.

Throws:

IOException

close

void close()

Override to remove the 'throws IOException' as we are just a reader.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable