LWFTAdaptor (chukwa 0.3.0 API)

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

All Implemented Interfaces:

Adaptor

Direct Known Subclasses:

FileTailingAdaptor
```
public class LWFTAdaptor
extends AbstractAdaptor
```
A base class for file tailing adaptors. Intended to mandate as little policy as possible, and to use as few system resources as possible. If the file does not exist, this class will continue to retry quietly forever and will start tailing if it's eventually created.

Field Summary

Fields
Modifier and Type	Field and Description
`protected org.apache.hadoop.conf.Configuration`	`conf`
`static int`	`DEFAULT_MAX_READ_SIZE` This is the maximum amount we'll read from any one file before moving on to the next.
`protected long`	`fileReadOffset` next PHYSICAL offset to read
`static int`	`MAX_READ_SIZE`
`static String`	`MAX_READ_SIZE_OPT`
`protected long`	`offsetOfFirstByte` The logical offset of the first byte of the file
`protected static org.apache.hadoop.chukwa.datacollection.adaptor.filetailer.FileTailer`	`tailer`

Fields inherited from class org.apache.hadoop.chukwa.datacollection.adaptor.AbstractAdaptor
adaptorID, control, dest, type

Constructor Summary

Constructors
Constructor and Description

LWFTAdaptor()

Constructors
Constructor and Description
`LWFTAdaptor()`

Method Summary

Methods
Modifier and Type	Method and Description
`protected int`	`extractRecords(ChunkReceiver eq, long buffOffsetInFile, byte[] buf)` Extract records from a byte sequence
`String`	`getCurrentStatus()` Return the adaptor's state Should not include class name or byte offset, which are written by caller.
`String`	`getStreamName()`
`void`	`hardStop()` Signals this adaptor to come to an abrupt stop, as quickly as it can.
`String`	`parseArgs(String params)` Parse args, return stream name.
`long`	`shutdown()` Signals this adaptor to come to an orderly stop.
`long`	`shutdown(AdaptorShutdownPolicy shutdownPolicy)` Signals this adaptor to come to an orderly stop.
`protected boolean`	`slurp(long len, RandomAccessFile reader)`
`void`	`start(long offset)`
`boolean`	`tailFile(ChunkReceiver eq)`
`String`	`toString()`

Methods inherited from class org.apache.hadoop.chukwa.datacollection.adaptor.AbstractAdaptor
deregisterAndStop, getType, start

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - DEFAULT_MAX_READ_SIZE
```
public static final int DEFAULT_MAX_READ_SIZE
```
    This is the maximum amount we'll read from any one file before moving on to the next. This way, we get quick response time for other files if one file is growing rapidly.
    
    See Also:
    Constant Field Values
  - MAX_READ_SIZE_OPT
```
public static final String MAX_READ_SIZE_OPT
```
    See Also:
    Constant Field Values
  - MAX_READ_SIZE
```
public static int MAX_READ_SIZE
```
  - tailer
```
protected static org.apache.hadoop.chukwa.datacollection.adaptor.filetailer.FileTailer tailer
```
  - fileReadOffset
```
protected long fileReadOffset
```
    next PHYSICAL offset to read
  - offsetOfFirstByte
```
protected long offsetOfFirstByte
```
    The logical offset of the first byte of the file
  - conf
```
protected org.apache.hadoop.conf.Configuration conf
```
- Constructor Detail
  - LWFTAdaptor
```
public LWFTAdaptor()
```
- Method Detail
  - start
```
public void start(long offset)
```
    Specified by:
    
    start in class AbstractAdaptor
  - getCurrentStatus
```
public String getCurrentStatus()
```
    Description copied from interface: Adaptor
    
    Return the adaptor's state Should not include class name or byte offset, which are written by caller. The datatype should, however, be written by this method.
    
    Returns:
    the adaptor state as a string
    See Also:
    Adaptor.getCurrentStatus()
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getStreamName
```
public String getStreamName()
```
  - parseArgs
```
public String parseArgs(String params)
```
    Description copied from interface: Adaptor
    
    Parse args, return stream name. Do not start running. Return the stream name, given params. The stream name is the part of the Adaptor status that's used to determine uniqueness.
    
    Returns:
    Stream name as a string, null if params are malformed
  - hardStop
```
public void hardStop()
              throws AdaptorException
```
    Description copied from interface: Adaptor
    
    Signals this adaptor to come to an abrupt stop, as quickly as it can. The use case here is "Whups, I didn't mean to start that adaptor tailing a gigabyte file, stop it now". Adaptors might need to do something nontrivial here, e.g., in the case in which they have registered periodic timer interrupts, or use a shared worker thread from which they need to disengage. This method is synchronous: In other words, after shutdown() returns, no new data should be written.
    
    Throws:
    
    AdaptorException
  - shutdown
```
public long shutdown()
              throws AdaptorException
```
    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. This method is synchronous up to 60 seconds
    
    Returns:
    the logical offset at which the adaptor stops
    
    Throws:
    
    AdaptorException
  - shutdown
```
public long shutdown(AdaptorShutdownPolicy shutdownPolicy)
              throws AdaptorException
```
    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
    
    Returns:
    the logical offset at which the adaptor was when the method return
    
    Throws:
    
    AdaptorException
  - extractRecords
```
protected int extractRecords(ChunkReceiver eq,
                 long buffOffsetInFile,
                 byte[] buf)
                      throws InterruptedException
```
    Extract records from a byte sequence
    
    Parameters:
    eq - the queue to stick the new chunk[s] in
    buffOffsetInFile - the byte offset in the stream at which buf[] begins
    buf - the byte buffer to extract records from
    
    Returns:
    the number of bytes processed
    
    Throws:
    
    InterruptedException
  - slurp
```
protected boolean slurp(long len,
            RandomAccessFile reader)
                 throws IOException,
                        InterruptedException
```
    Throws:
    
    IOException
    
    InterruptedException
  - tailFile
```
public boolean tailFile(ChunkReceiver eq)
                 throws InterruptedException
```
    Throws:
    
    InterruptedException

Class LWFTAdaptor

Field Summary

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

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_MAX_READ_SIZE

MAX_READ_SIZE_OPT

MAX_READ_SIZE

tailer

fileReadOffset

offsetOfFirstByte

conf

Constructor Detail

LWFTAdaptor

Method Detail

start

getCurrentStatus

toString

getStreamName

parseArgs

hardStop

shutdown

shutdown

extractRecords

slurp

tailFile