de.hpi.fgis.dude.util.sorting.sorter
Class TwoPhaseMultiWayMergeSorter

java.lang.Object
  de.hpi.fgis.dude.util.sorting.sorter.AbstractDuDeObjectSorter
      de.hpi.fgis.dude.util.sorting.sorter.TwoPhaseMultiWayMergeSorter

All Implemented Interfaces:

DuDeObjectSorter

public class TwoPhaseMultiWayMergeSorter
extends AbstractDuDeObjectSorter

TwoPhaseMultiWayMergeSorter implements a file-based sorting using the Two-Phase Multi-Way Merge-Sort algorithm (TPMMS).

Author:

Matthias Pohl

Constructor Summary

TwoPhaseMultiWayMergeSorter()
Initializes a TwoPhaseMultiWayMergeSorter with no SortingKey.

TwoPhaseMultiWayMergeSorter(SortingKey key)
Initializes a TwoPhaseMultiWayMergeSorter with the passed SortingKey.

Method Summary

void	add(DuDeObject record) Adds a DuDeObject to the collection that will be sorted.
void	clear() Clears the already added data.
protected void	generateSortedFile() Sorts the in-memory data and writes it into a file.
protected String	getNextTemporaryFilename() Returns the name of the next temporary DuDeObjectFile.
DuDeStorage<DuDeObject>	getSortedCollection() Returns the sorted data.
protected String	getSortedDataFilename() Returns the name of the DuDeObjectFile containing the sorted data.

Methods inherited from class de.hpi.fgis.dude.util.sorting.sorter.AbstractDuDeObjectSorter

addAll, getInMemoryData, getSortingKey, memoryLimitReached, setSortingKey

Methods inherited from class java.lang.Object

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

Constructor Detail

TwoPhaseMultiWayMergeSorter

public TwoPhaseMultiWayMergeSorter()

Initializes a TwoPhaseMultiWayMergeSorter with no SortingKey.

TwoPhaseMultiWayMergeSorter

public TwoPhaseMultiWayMergeSorter(SortingKey key)

Initializes a TwoPhaseMultiWayMergeSorter with the passed SortingKey.

Parameters:

key - The sorting key that defines the sorting order.

Method Detail

clear

public void clear()

Description copied from interface: DuDeObjectSorter

Clears the already added data.

Specified by:

clear in interface DuDeObjectSorter

Overrides:

clear in class AbstractDuDeObjectSorter

add

public void add(DuDeObject record)

Description copied from interface: DuDeObjectSorter

Adds a DuDeObject to the collection that will be sorted.

Specified by:

add in interface DuDeObjectSorter

Overrides:

add in class AbstractDuDeObjectSorter

Parameters:

record - The DuDeObject.

getSortedCollection

public DuDeStorage<DuDeObject> getSortedCollection()
                                            throws IOException

Description copied from class: AbstractDuDeObjectSorter

Returns the sorted data. This method needs to be implemented by each sub-class. It should sort the data in some way and return it.

Specified by:

getSortedCollection in interface DuDeObjectSorter

Specified by:

getSortedCollection in class AbstractDuDeObjectSorter

Returns:

A sorted collection of the data.

Throws:

IOException - If an error occurs while sorting the data file-based.

generateSortedFile

protected void generateSortedFile()

Sorts the in-memory data and writes it into a file. This file is encapsulated in an SortedDataFile that will be added to sortedDataFiles.

getNextTemporaryFilename

protected String getNextTemporaryFilename()

Returns the name of the next temporary DuDeObjectFile.

Returns:

The next file name that shall be used.

getSortedDataFilename

protected String getSortedDataFilename()

Returns the name of the DuDeObjectFile containing the sorted data. This file name is a concatenation of SORTED_DATA_FILENAME_PREFIX and the current time in milliseconds.

Returns:

The name of the file that contains the sorted data.