Package dk.netarkivet.archive.arcrepository.bitpreservation

Class DatabaseBasedActiveBitPreservation

java.lang.Object

dk.netarkivet.archive.arcrepository.bitpreservation.DatabaseBasedActiveBitPreservation

All Implemented Interfaces:

ActiveBitPreservation, CleanupIF

public final class DatabaseBasedActiveBitPreservation
extends Object
implements ActiveBitPreservation, CleanupIF

The database based active bit preservation. This is the alternative to the FileBasedActiveBitPreservation.

A database is used to handle the bitpreservation.

Method Summary

Modifier and Type	Method	Description
void	addMissingFilesToAdminData(String... filenames)	Old method, which refers to the checksum replica part of admin data.
void	changeStateForAdminData(String filename)	This should reestablish the state for the file.
void	cleanup()	Method for cleaning up this instance.
void	close()	Method for closing the running instance of this class.
void	findChangedFiles(Replica replica)	The method is used to update the checksum for all the files in a replica.
void	findMissingFiles(Replica replica)	This method retrieves the filelist for the replica, and then it updates the database with this list of filenames.
Iterable<String>	getChangedFiles(Replica replica)	This method retrieves the name of all the files which has a wrong checksum for the replica.
Iterable<String>	getChangedFilesForAdminData()	Old method, which refers to the checksum replica part of admin data.
Date	getDateForChangedFiles(Replica replica)	This method retrieves the date for the latest checksum update was performed for the replica.
Date	getDateForMissingFiles(Replica replica)	This method retrieves the date for the latest filelist update was performed for the replica.
static DatabaseBasedActiveBitPreservation	getInstance()	Method for retrieving the current instance of this class.
Iterable<String>	getMissingFiles(Replica replica)	This method retrieves the name of all the files which are missing for the given replica.
Iterable<String>	getMissingFilesForAdminData()	Old method, which refers to the checksum replica part of admin data.
long	getNumberOfChangedFiles(Replica replica)	The method calculates the number of files which has a wrong checksum for the replica.
long	getNumberOfFiles(Replica replica)	This method finds the number of files which are known to be in the archive of a specific replica.
long	getNumberOfMissingFiles(Replica replica)	This method calculates the number of files which are not found in the given replica.
PreservationState	getPreservationState(String filename)	Method for retrieving the FilePreservationState for a specific file.
Map<String,PreservationState>	getPreservationStateMap(String... filenames)	Method for retrieving the FilePreservationState for a list of files.
void	replaceChangedFile(Replica replica, String filename, String credentials, String checksum)	Check that the checksum of the file is indeed different to the value in admin data and reference replica.
void	uploadMissingFiles(Replica replica, String... filenames)	This method is used to upload missing files to a replica.

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static DatabaseBasedActiveBitPreservation getInstance()

Method for retrieving the current instance of this class.

Returns:

The instance.

getNumberOfChangedFiles

public long getNumberOfChangedFiles(Replica replica)
                             throws ArgumentNotValid

The method calculates the number of files which has a wrong checksum for the replica. This simple counts all the entries in the replicafileinfo table for the replica where the filelist_status is set to CORRUPT.

Specified by:

getNumberOfChangedFiles in interface ActiveBitPreservation

Parameters:

replica - The replica for which to count the number of changed files.

Returns:

The number of files for the replica where the checksum does not correspond to the checksum of the same file in the other replicas.

Throws:

ArgumentNotValid - If the replica is null.

getChangedFiles

public Iterable<String> getChangedFiles(Replica replica)
                                 throws ArgumentNotValid

This method retrieves the name of all the files which has a wrong checksum for the replica. It simple returns the filename of all the entries in the replicafileinfo table for the replica where the filelist_status is set to CORRUPT.

Specified by:

getChangedFiles in interface ActiveBitPreservation

Parameters:

replica - The replica for which the changed files should be found.

Returns:

The names of files in the replica where the checksum does not correspond to the checksum of the same file in the other replicas.

Throws:

ArgumentNotValid - If the replica is null.

getNumberOfMissingFiles

public long getNumberOfMissingFiles(Replica replica)
                             throws ArgumentNotValid

This method calculates the number of files which are not found in the given replica. This simple counts all the entries in the replicafileinfo table for the replica where the filelist_status is set to MISSING.

Specified by:

getNumberOfMissingFiles in interface ActiveBitPreservation

Parameters:

replica - The replica for which to count the number of missing files.

Returns:

The number of files which is missing in the replica.

Throws:

ArgumentNotValid - If the replica is null.

getMissingFiles

public Iterable<String> getMissingFiles(Replica replica)
                                 throws ArgumentNotValid

This method retrieves the name of all the files which are missing for the given replica. It simple returns the filename of all the entries in the replicafileinfo table for the replica where the filelist_status is set to MISSING.

Specified by:

getMissingFiles in interface ActiveBitPreservation

Parameters:

replica - The replica for which the missing files should be found.

Returns:

The names of files in the replica which are missing.

Throws:

ArgumentNotValid - If the replica is null.

getDateForChangedFiles

public Date getDateForChangedFiles(Replica replica)
                            throws ArgumentNotValid

This method retrieves the date for the latest checksum update was performed for the replica. This means the date for the latest the replica has calculated the checksum of all the files within its archive.

This method does not call out to the replicas. It only contacts the local database.

Specified by:

getDateForChangedFiles in interface ActiveBitPreservation

Parameters:

replica - The replica for which the date for last checksum update should be retrieved.

Returns:

The date for the last time the checksums has been update. If the checksum update has never occurred, then a null is returned.

Throws:

ArgumentNotValid - If the replica is null.

getDateForMissingFiles

public Date getDateForMissingFiles(Replica replica)
                            throws ArgumentNotValid

This method retrieves the date for the latest filelist update was performed for the replica. This means the date for the latest the replica has retrieved the list of all the files within the archive.

This method does not call out to the replicas. It only contacts the local database.

Specified by:

getDateForMissingFiles in interface ActiveBitPreservation

Parameters:

replica - The replica for which the date for last filelist update should be retrieved.

Returns:

The date for the last time the filelist has been update. If the filelist update has never occurred, then a null is returned.

Throws:

ArgumentNotValid - If the replica is null.

findChangedFiles

public void findChangedFiles(Replica replica)
                      throws ArgumentNotValid

The method is used to update the checksum for all the files in a replica. The checksum for the replica is retrieved through GetAllChecksumMessages. This will take a very large amount of time for the bitarchive, but a more limited amount of time for the checksumarchive.

The corresponding replicafileinfo entries in the database for the retrieved checksum results will be updated. Then a checksum update will be performed to check for corrupted replicafileinfo.

Each replica can only be updated once at the time.

Specified by:

findChangedFiles in interface ActiveBitPreservation

Parameters:

replica - The replica to find the changed files for.

Throws:

ArgumentNotValid - If the replica is null.

findMissingFiles

public void findMissingFiles(Replica replica)
                      throws ArgumentNotValid

This method retrieves the filelist for the replica, and then it updates the database with this list of filenames. Each replica can only be updated once at the time.

Specified by:

findMissingFiles in interface ActiveBitPreservation

Parameters:

replica - The replica to find the missing files for.

Throws:

ArgumentNotValid - If the replica is null.

getPreservationState

public PreservationState getPreservationState(String filename)
                                       throws ArgumentNotValid

Method for retrieving the FilePreservationState for a specific file.

Specified by:

getPreservationState in interface ActiveBitPreservation

Parameters:

filename - The name of the file for whom the FilePreservationState should be retrieved.

Returns:

The FilePreservationState for the file.

Throws:

ArgumentNotValid - If the filename is null or the empty string.

getPreservationStateMap

public Map<String,PreservationState> getPreservationStateMap(String... filenames)
                                                            throws ArgumentNotValid

Method for retrieving the FilePreservationState for a list of files.

Specified by:

getPreservationStateMap in interface ActiveBitPreservation

Parameters:

filenames - The list of filenames whose FilePreservationState should be retrieved.

Returns:

A mapping between the filenames and their FilePreservationState.

Throws:

ArgumentNotValid - If the list of filenames are null.

getNumberOfFiles

public long getNumberOfFiles(Replica replica)
                      throws ArgumentNotValid

This method finds the number of files which are known to be in the archive of a specific replica. This method will not go out to the replica, but only contact the local database. The number of files in the replica is retrieved from the database by counting the amount of files in the replicafileinfo table which belong to the replica and which has the filelist_status set to OK.

Specified by:

getNumberOfFiles in interface ActiveBitPreservation

Parameters:

replica - The replica for which the number of files should be counted.

Returns:

The number of files for a specific replica.

Throws:

ArgumentNotValid - If the replica is null.

replaceChangedFile

public void replaceChangedFile(Replica replica,
                               String filename,
                               String credentials,
                               String checksum)
                        throws ArgumentNotValid

Check that the checksum of the file is indeed different to the value in admin data and reference replica. If so, remove missing file and upload it from reference replica to this replica.

Specified by:

replaceChangedFile in interface ActiveBitPreservation

Parameters:

replica - The replica to restore file to

filename - The name of the file

credentials - The credentials used to perform this replace operation

checksum - The known bad checksum. Only a file with this bad checksum is attempted repaired.

Throws:

ArgumentNotValid - If any of the arguments are not valid.

uploadMissingFiles

public void uploadMissingFiles(Replica replica,
                               String... filenames)
                        throws ArgumentNotValid,
                               IOFailure

This method is used to upload missing files to a replica. For each file a good version of this file is found, and it is reestablished on the replicas where it is missing.

Specified by:

uploadMissingFiles in interface ActiveBitPreservation

Parameters:

replica - The replica where the files are missing.

filenames - The names of the files which are missing in the given replica.

Throws:

ArgumentNotValid - If the replica or list of filenames is null, or if the list of filenames is empty.

IOFailure - If some files could not be established.

changeStateForAdminData

public void changeStateForAdminData(String filename)
                             throws ArgumentNotValid,
                                    NotImplementedException

This should reestablish the state for the file.

Specified by:

changeStateForAdminData in interface ActiveBitPreservation

Parameters:

filename - The name of the file to change the state for.

Throws:

ArgumentNotValid - If the filename is invalid.

NotImplementedException - This will not be implemented.

getMissingFilesForAdminData

public Iterable<String> getMissingFilesForAdminData()
                                             throws NotImplementedException

Old method, which refers to the checksum replica part of admin data.

Specified by:

getMissingFilesForAdminData in interface ActiveBitPreservation

Returns:

Nothing, since it always throws an exception.

Throws:

NotImplementedException - This method will not be implemented.

getChangedFilesForAdminData

public Iterable<String> getChangedFilesForAdminData()
                                             throws NotImplementedException

Old method, which refers to the checksum replica part of admin data.

Specified by:

getChangedFilesForAdminData in interface ActiveBitPreservation

Returns:

Nothing, since it always throws an exception.

Throws:

NotImplementedException - This method will not be implemented.

addMissingFilesToAdminData

public void addMissingFilesToAdminData(String... filenames)
                                throws ArgumentNotValid,
                                       NotImplementedException

Old method, which refers to the checksum replica part of admin data.

Specified by:

addMissingFilesToAdminData in interface ActiveBitPreservation

Parameters:

filenames - The list of filenames which should be added to admin data.

Throws:

NotImplementedException - This method will not be implemented.

ArgumentNotValid - If filenames invalid.

close

public void close()

Method for closing the running instance of this class.

cleanup

public void cleanup()

Method for cleaning up this instance.

Specified by:

cleanup in interface CleanupIF