edu.iu.dsc.tws.comms.shuffle

Class ControlledFileReader

java.lang.Object

edu.iu.dsc.tws.comms.shuffle.ControlledFileReader

All Implemented Interfaces:

ControlledReader<Tuple>, Restorable, RestorableIterator<Tuple>, java.lang.Comparable<ControlledReader<Tuple>>, java.util.Iterator<Tuple>

public class ControlledFileReader
extends java.lang.Object
implements ControlledReader<Tuple>

Constructor Summary

Constructors

Constructor and Description
ControlledFileReader(ControlledFileReaderFlags meta, java.lang.String filePath, MessageType keyType, MessageType dataType, java.util.Comparator keyComparator)

Method Summary

Modifier and Type	Method and Description
void	clearRestorePoint()
int	compareTo(ControlledReader o)
void	createRestorePoint()
boolean	hasNext()
boolean	hasRestorePoint()
Tuple	next()
java.lang.Object	nextKey() Get the next key
void	open() Open the reader
void	releaseResources() This method tries to do following things in order, Try to unmamp, release memoery mapped buffer Close file channels Make this.buffer garbage collectible
void	restore()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Constructor Detail

ControlledFileReader

public ControlledFileReader(ControlledFileReaderFlags meta,
                            java.lang.String filePath,
                            MessageType keyType,
                            MessageType dataType,
                            java.util.Comparator keyComparator)

Method Detail

open

public void open()

Description copied from interface: ControlledReader

Open the reader

Specified by:

open in interface ControlledReader<Tuple>

releaseResources

public void releaseResources()

This method tries to do following things in order,

1. Try to unmamp, release memoery mapped buffer
2. Close file channels
3. Make this.buffer garbage collectible

If unmapping fails, we expect GC to take care of releasing resources. But this could fail when we have a large heap space(mmap limit could hit before GC runs). For those cases, only option is to increase max_map_count of OS.

Specified by:

releaseResources in interface ControlledReader<Tuple>

hasNext

public boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator<Tuple>

nextKey

public java.lang.Object nextKey()

Description copied from interface: ControlledReader

Get the next key

Specified by:

nextKey in interface ControlledReader<Tuple>

Returns:

return the next key

next

public Tuple next()

Specified by:

next in interface java.util.Iterator<Tuple>

compareTo

public int compareTo(ControlledReader o)

Specified by:

compareTo in interface java.lang.Comparable<ControlledReader<Tuple>>

createRestorePoint

public void createRestorePoint()

Specified by:

createRestorePoint in interface Restorable

restore

public void restore()

Specified by:

restore in interface Restorable

clearRestorePoint

public void clearRestorePoint()

Specified by:

clearRestorePoint in interface Restorable

hasRestorePoint

public boolean hasRestorePoint()

Specified by:

hasRestorePoint in interface Restorable