ml.shifu.guagua.util

Class BytableDiskList<T extends Bytable>

java.lang.Object

ml.shifu.guagua.util.BytableDiskList<T>

All Implemented Interfaces:

Iterable<T>, AppendList<T>

public class BytableDiskList<T extends Bytable>
extends Object
implements AppendList<T>

A list wrapper to implement store Bytable data into disk.

No size limit for this list but user should make sure valid fileName when constructing.

Only two stages support in such kind of list. The first one is WRITE, the next is read. So far random WRITE and READ are not supported in this list.

WARNING: close() should be called at last if use such List.

Author:

Zhang David (pengzhang@paypal.com)

Nested Class Summary

Nested classes/interfaces inherited from interface ml.shifu.guagua.util.AppendList

AppendList.State

Constructor Summary

Constructors

Constructor and Description
BytableDiskList(String fileName, String className) Constructor with file name in current working dir and instance class name.
BytableDiskList(String fileName, String className, BytableSerializer<T> serializer) Constructor with file name in current working dir, class name and serializer instance.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	append(T t) Append object to this list
void	clear() Delete file to store elements.
void	close() This method should be called at the end of BytableDiskList usage to release file descriptors.
BytableSerializer<T>	getSerializer()
Iterator<T>	iterator()
void	reOpen() Re-open stream for iterators.
void	setSerializer(BytableSerializer<T> serializer)
int	size() Return size of this list.
void	switchState() Switch state from WRITE to READ

Methods inherited from class java.lang.Object

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

Constructor Detail

BytableDiskList

public BytableDiskList(String fileName,
               String className)

Constructor with file name in current working dir and instance class name.

BytableDiskList

public BytableDiskList(String fileName,
               String className,
               BytableSerializer<T> serializer)

Constructor with file name in current working dir, class name and serializer instance.

Method Detail

switchState

public void switchState()

Switch state from WRITE to READ

Specified by:

switchState in interface AppendList<T extends Bytable>

reOpen

public void reOpen()

Re-open stream for iterators.

append

public boolean append(T t)

Description copied from interface: AppendList

Append object to this list

Specified by:

append in interface AppendList<T extends Bytable>

Parameters:

t - the object to append

Returns:

whether appending object successful

close

public void close()

This method should be called at the end of BytableDiskList usage to release file descriptors.

iterator

public Iterator<T> iterator()

Specified by:

iterator in interface Iterable<T extends Bytable>

getSerializer

public BytableSerializer<T> getSerializer()

Returns:

the serializer

setSerializer

public void setSerializer(BytableSerializer<T> serializer)

Parameters:

serializer - the serializer to set

size

public int size()

Description copied from interface: AppendList

Return size of this list.

Specified by:

size in interface AppendList<T extends Bytable>

clear

public void clear()

Delete file to store elements. After this method call, user cannot use such list. But clear here is used to clear resources used.

Specified by:

clear in interface AppendList<T extends Bytable>