org.apache.hadoop.chukwa.datacollection.adaptor.filetailer
Class FileTailingAdaptor

java.lang.Object
  org.apache.hadoop.chukwa.datacollection.adaptor.AbstractAdaptor
      org.apache.hadoop.chukwa.datacollection.adaptor.filetailer.LWFTAdaptor
          org.apache.hadoop.chukwa.datacollection.adaptor.filetailer.FileTailingAdaptor

All Implemented Interfaces:

Adaptor

Direct Known Subclasses:

CharFileTailingAdaptorUTF8, CharFileTailingAdaptorUTF8NewLineEscaped

public class FileTailingAdaptor
extends LWFTAdaptor

An adaptor that repeatedly tails a specified file, sending the new bytes. This class does not split out records, but just sends everything up to end of file. Subclasses can alter this behavior by overriding extractRecords().

Field Summary

static int	GRACEFUL_PERIOD
static int	MAX_RETRIES
protected RandomAccessFile	reader

Fields inherited from class org.apache.hadoop.chukwa.datacollection.adaptor.filetailer.LWFTAdaptor

conf, DEFAULT_MAX_READ_SIZE, fileReadOffset, MAX_READ_SIZE, MAX_READ_SIZE_OPT, offsetOfFirstByte, tailer

Fields inherited from class org.apache.hadoop.chukwa.datacollection.adaptor.AbstractAdaptor

adaptorID, control, dest, type

Constructor Summary

FileTailingAdaptor()

Method Summary

long	shutdown(AdaptorShutdownPolicy shutdownPolicy) Signals this adaptor to come to an orderly stop.
void	start(long bytes)
boolean	tailFile() Looks at the tail of the associated file, adds some of it to event queue This method is not thread safe.

Methods inherited from class org.apache.hadoop.chukwa.datacollection.adaptor.filetailer.LWFTAdaptor

extractRecords, getCurrentStatus, getStreamName, parseArgs, slurp, toString

Methods inherited from class org.apache.hadoop.chukwa.datacollection.adaptor.AbstractAdaptor

deregisterAndStop, getType, hardStop, parseArgs, shutdown, start

Methods inherited from class java.lang.Object

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

Field Detail

MAX_RETRIES

public static int MAX_RETRIES

GRACEFUL_PERIOD

public static int GRACEFUL_PERIOD

reader

protected RandomAccessFile reader

Constructor Detail

FileTailingAdaptor

public FileTailingAdaptor()

Method Detail

start

public void start(long bytes)

Overrides:

start in class LWFTAdaptor

shutdown

public long shutdown(AdaptorShutdownPolicy shutdownPolicy)

Description copied from interface: Adaptor

Signals this adaptor to come to an orderly stop. The adaptor ought to push out all the data it can before exiting depending of the shutdown policy

Specified by:

shutdown in interface Adaptor

Overrides:

shutdown in class LWFTAdaptor

Returns:

the logical offset at which the adaptor was when the method return

tailFile

public boolean tailFile()
                 throws InterruptedException

Looks at the tail of the associated file, adds some of it to event queue This method is not thread safe. Returns true if there's more data in the file

Overrides:

tailFile in class LWFTAdaptor

Parameters:

eq - the queue to write Chunks into

Throws:

InterruptedException