org.egothor.duplicity.file

Class PermutatedMinsFile

java.lang.Object

org.egothor.duplicity.file.DuplicityCheckingFile

org.egothor.duplicity.file.PermutatedMinsFile

public class PermutatedMinsFile
extends DuplicityCheckingFile

Represents the "minimums of permutated unit identificators" file used in duplicity checking algorithm. The file contains instances of UnitPermutatedMin class. That means it contains pairs {min(pi(T(d))), d}, where:

• d is identificator of unit on which we check duplicity (can be document, paragraph or sentence)
• T(d) is set of UIDs of all tokens in the unit d
• pi is a permutation

The file is sorted - the main criteria is min field, in case of tie unitID field.

The file should be used as follows.

1. First it should be created using PermutatedMinsFileProducer or read from the filesystem.
2. It can be merged with another file corresponding to the same permutation by a call to merge(org.egothor.duplicity.file.PermutatedMinsFile) method.

Author:

Kateřina Dufková

Constructor Summary

Constructors

Constructor and Description
PermutatedMinsFile(long permID, String location) Initialializes the file already written to filesystem.

Method Summary

Modifier and Type	Method and Description
SimilarUnitPairsFile	createSimilarUnitPairsFile() From this files, creates the SimilarUnitPairsFile corresponding to it.
String	dump() Dumps the content of the file to string.
String	getFilename() Returns the filename corresponding to this file.
long	getPermID()
SimilarUnitPairsTempFile	getSimilarities(PermutatedMinsFile mpuf) Merges two files externally, on filesystem.
boolean	hasTheSameContent(DuplicityCheckingFile file) Checks if two files has the same content.
void	merge(PermutatedMinsFile mpuf) Merges two files externally, on filesystem.
void	remove(Set<DocumentUnitID> toRemove) Removes all occurences of documents given in the set from the file.
String	toString()

Methods inherited from class org.egothor.duplicity.file.DuplicityCheckingFile

delete, getLocation, getOut, hasTheSameContent

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PermutatedMinsFile

public PermutatedMinsFile(long permID,
                          String location)
                   throws FileNotFoundException

Initialializes the file already written to filesystem. Sets permID and location fields and checks if a file on filesystem exists for this file. The filename is in form returned by getFilename() and will be searched in the location directory.

Parameters:

permID - identification of the permutation to be assigned to this file

location - path and name of the directory in which the file will be created, must end with "/" sign

Throws:

FileNotFoundException - if the file already exists

Method Detail

getFilename

public String getFilename()

Returns the filename corresponding to this file. The location and permID fields MUST be already set. The filename is created in directory given in location field and is in form Constants.PERMUTATED_MINS_FILE_PREFIX<permID>.

Specified by:

getFilename in class DuplicityCheckingFile

getPermID

public long getPermID()

Returns:

createSimilarUnitPairsFile

public SimilarUnitPairsFile createSimilarUnitPairsFile()

From this files, creates the SimilarUnitPairsFile corresponding to it. It will contains all the pairs of units, that have the same minimum.

Returns:

instance of SimilarUnitPairsFile written to the filesystem.

merge

public void merge(PermutatedMinsFile mpuf)
           throws IOException,
                  MergeException

Merges two files externally, on filesystem. The files must correnspond to the same permutation.

Parameters:

mpuf - file to be merged into this

Throws:

MergeException - on attempt to merge files corresponding to different permutations or if temporary file could not be created

IOException

getSimilarities

public SimilarUnitPairsTempFile getSimilarities(PermutatedMinsFile mpuf)
                                         throws IOException,
                                                MergeException

Merges two files externally, on filesystem. The files must correnspond to the same permutation.

Parameters:

mpuf - file to be merged into this

Returns:

SimilarUnitPairsFile with similarities between the duplicity checking units in the merged files, according to permutation with identificator this.permID. Contains all pairs od unitIDs from different merged files, where their mins are equal

Throws:

MergeException - on attempt to merge files corresponding to different permutations or if temporary file could not be created

IOException

toString

public String toString()

Overrides:

toString in class DuplicityCheckingFile

Returns:

dump

public String dump()

Dumps the content of the file to string.

Returns:

string representation of the file including its content

remove

public void remove(Set<DocumentUnitID> toRemove)
            throws IOException

Removes all occurences of documents given in the set from the file.

Parameters:

toRemove - set of document ids to remove

Throws:

IOException

hasTheSameContent

public boolean hasTheSameContent(DuplicityCheckingFile file)

Checks if two files has the same content.

Parameters:

file - the second file to be tested

Returns:

true, if the file contents are the same