de.caluga.morphium.query

Class PrefetchingQueryIterator<T>

java.lang.Object

de.caluga.morphium.query.PrefetchingQueryIterator<T>

All Implemented Interfaces:

MorphiumIterator<T>, MorphiumQueryIterator<T>, Iterable<T>, Iterator<T>

public class PrefetchingQueryIterator<T>
extends Object
implements MorphiumQueryIterator<T>

iterating over huge collections using the db interal cursor. This iterator does create a thread reading the data

Constructor Summary

Constructors

Constructor and Description
PrefetchingQueryIterator()

Method Summary

Modifier and Type	Method and Description
void	ahead(int jump) move the cursor position ahead
void	back(int jump) get back some positions
long	getCount() how many elements are to be processed.
List<T>	getCurrentBuffer() get the current buffer.
int	getCurrentBufferSize() retruns the number of elements now in buffer.
int	getCursor() returns current cursor position
int	getNumberOfAvailableThreads()
int	getNumberOfThreads()
List<List<T>>	getPrefetchBuffer()
Query<T>	getQuery()
int	getWindowSize()
boolean	hasNext()
boolean	isMultithreaddedAccess()
Iterator<T>	iterator()
T	next()
void	setMultithreaddedAccess(boolean mu)
void	setNumberOfPrefetchWindows(int n)
void	setPrefetchBuffer(List<List<T>> prefetchBuffer)
void	setQuery(Query<T> q)
void	setWindowSize(int sz)

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Constructor Detail

PrefetchingQueryIterator

public PrefetchingQueryIterator()

Method Detail

getPrefetchBuffer

public List<List<T>> getPrefetchBuffer()

setPrefetchBuffer

public void setPrefetchBuffer(List<List<T>> prefetchBuffer)

getWindowSize

public int getWindowSize()

Specified by:

getWindowSize in interface MorphiumIterator<T>

setWindowSize

public void setWindowSize(int sz)

Specified by:

setWindowSize in interface MorphiumIterator<T>

getQuery

public Query<T> getQuery()

Specified by:

getQuery in interface MorphiumQueryIterator<T>

setQuery

public void setQuery(Query<T> q)

Specified by:

setQuery in interface MorphiumQueryIterator<T>

getCurrentBufferSize

public int getCurrentBufferSize()

Description copied from interface: MorphiumIterator

retruns the number of elements now in buffer. Max windowsize

Specified by:

getCurrentBufferSize in interface MorphiumIterator<T>

Returns:

list

getCurrentBuffer

public List<T> getCurrentBuffer()

Description copied from interface: MorphiumIterator

get the current buffer. Maximum length is specified windowsize

Specified by:

getCurrentBuffer in interface MorphiumIterator<T>

Returns:

list

getCount

public long getCount()

Description copied from interface: MorphiumIterator

how many elements are to be processed. Attention: this count is not updated. It shows how many elements are there at the beginning of the interation!

Specified by:

getCount in interface MorphiumIterator<T>

Returns:

count

getCursor

public int getCursor()

Description copied from interface: MorphiumIterator

returns current cursor position

Specified by:

getCursor in interface MorphiumIterator<T>

Returns:

int

ahead

public void ahead(int jump)

Description copied from interface: MorphiumIterator

move the cursor position ahead

Specified by:

ahead in interface MorphiumIterator<T>

Parameters:

jump - number of elements to jump

back

public void back(int jump)

Description copied from interface: MorphiumIterator

get back some positions

Specified by:

back in interface MorphiumIterator<T>

Parameters:

jump - number of elements to jump back

setNumberOfPrefetchWindows

public void setNumberOfPrefetchWindows(int n)

Specified by:

setNumberOfPrefetchWindows in interface MorphiumIterator<T>

getNumberOfAvailableThreads

public int getNumberOfAvailableThreads()

Specified by:

getNumberOfAvailableThreads in interface MorphiumIterator<T>

getNumberOfThreads

public int getNumberOfThreads()

Specified by:

getNumberOfThreads in interface MorphiumIterator<T>

isMultithreaddedAccess

public boolean isMultithreaddedAccess()

Specified by:

isMultithreaddedAccess in interface MorphiumIterator<T>

setMultithreaddedAccess

public void setMultithreaddedAccess(boolean mu)

Specified by:

setMultithreaddedAccess in interface MorphiumIterator<T>

iterator

public Iterator<T> iterator()

Specified by:

iterator in interface Iterable<T>

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<T>

next

public T next()

Specified by:

next in interface Iterator<T>