org.apache.hadoop.hdfs.server.namenode
Class EditLogFileInputStream

java.lang.Object
  org.apache.hadoop.hdfs.server.namenode.EditLogInputStream
      org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream

All Implemented Interfaces:

Closeable

public class EditLogFileInputStream
extends org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

An implementation of the abstract class EditLogInputStream, which reads edits from a local file.

Constructor Summary

EditLogFileInputStream(File name, long firstTxId, long lastTxId, boolean isInProgress)
Open an EditLogInputStream for the given file.

Method Summary

void	close() Close the stream.
long	getFirstTxId()
long	getLastTxId()
String	getName()
long	getPosition() Get the "position" of in the stream.
int	getVersion() Get the layout version of the data in the stream.
boolean	isInProgress() Return true if this stream is in progress, false if it is finalized.
long	length() Return the size of the current edits log.
protected org.apache.hadoop.hdfs.server.namenode.FSEditLogOp	nextOp() Get the next operation from the stream storage.
protected org.apache.hadoop.hdfs.server.namenode.FSEditLogOp	nextValidOp() Get the next valid operation from the stream storage.
String	toString()

Methods inherited from class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

readOp, resync, skipUntil

Methods inherited from class java.lang.Object

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

Constructor Detail

EditLogFileInputStream

public EditLogFileInputStream(File name,
                              long firstTxId,
                              long lastTxId,
                              boolean isInProgress)
                       throws org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream.LogHeaderCorruptException,
                              IOException

Open an EditLogInputStream for the given file.

Parameters:

name - filename to open

firstTxId - first transaction found in file

lastTxId - last transaction id found in file

Throws:

LogHeaderCorruptException - if the header is either missing or appears to be corrupt/truncated

IOException - if an actual IO error occurs while reading the header

org.apache.hadoop.hdfs.server.namenode.EditLogFileInputStream.LogHeaderCorruptException

Method Detail

getFirstTxId

public long getFirstTxId()
                  throws IOException

Specified by:

getFirstTxId in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Returns:

the first transaction which will be found in this stream

Throws:

IOException

getLastTxId

public long getLastTxId()
                 throws IOException

Specified by:

getLastTxId in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Returns:

the last transaction which will be found in this stream

Throws:

IOException

getName

public String getName()

Specified by:

getName in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Returns:

the name of the EditLogInputStream

nextOp

protected org.apache.hadoop.hdfs.server.namenode.FSEditLogOp nextOp()
                                                             throws IOException

Description copied from class: org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Get the next operation from the stream storage.

Specified by:

nextOp in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Returns:

an operation from the stream or null if at end of stream

Throws:

IOException - if there is an error reading from the stream

nextValidOp

protected org.apache.hadoop.hdfs.server.namenode.FSEditLogOp nextValidOp()

Description copied from class: org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Get the next valid operation from the stream storage. This is exactly like nextOp, except that we attempt to skip over damaged parts of the edit log

Overrides:

nextValidOp in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Returns:

an operation from the stream or null if at end of stream

getVersion

public int getVersion()
               throws IOException

Description copied from class: org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Get the layout version of the data in the stream.

Specified by:

getVersion in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Returns:

the layout version of the ops in the stream.

Throws:

IOException - if there is an error reading the version

getPosition

public long getPosition()

Description copied from class: org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Get the "position" of in the stream. This is useful for debugging and operational purposes. Different stream types can have a different meaning for what the position is. For file streams it means the byte offset from the start of the file.

Specified by:

getPosition in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Returns:

the position in the stream

close

public void close()
           throws IOException

Description copied from class: org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Close the stream.

Specified by:

close in interface Closeable

Specified by:

close in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Throws:

IOException - if an error occurred while closing

length

public long length()
            throws IOException

Description copied from class: org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Return the size of the current edits log.

Specified by:

length in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Throws:

IOException

isInProgress

public boolean isInProgress()

Description copied from class: org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

Return true if this stream is in progress, false if it is finalized.

Specified by:

isInProgress in class org.apache.hadoop.hdfs.server.namenode.EditLogInputStream

toString

public String toString()

Overrides:

toString in class Object