dk.netarkivet.archive.checksum
Class FileChecksumArchive

java.lang.Object
  dk.netarkivet.archive.checksum.ChecksumArchive
      dk.netarkivet.archive.checksum.FileChecksumArchive

public final class FileChecksumArchive
extends ChecksumArchive

A checksum archive in the form of a file (as alternative to a database).
Each entry in the file is on its own line, thus the number of lines is the number of entries.
The entries on a line is in the format of a ChecksumJob:
'filename' + ## + 'checksum'
The lines are not sorted. If no file exists when the class is instantiated then it will be created, and if an 'admin.data' file exists, then it will be loaded and put into the archive file.

Method Summary

protected java.lang.String	calculateChecksum(java.io.File f) Method for calculating the checksum of a file.
protected java.lang.String	calculateChecksum(java.io.InputStream is) Method for calculating the checksum of a inputstream.
void	cleanup() The method for cleaning up when done.
java.io.File	correct(java.lang.String filename, java.io.File correctFile) Method for correcting a bad entry from the archive.
java.io.File	getAllFilenames() Method for retrieving the names of all the files within the archive as a temporary file.
java.io.File	getArchiveAsFile() Method for retrieving the archive as a temporary file containing the checksum entries.
java.lang.String	getChecksum(java.lang.String filename) Method for retrieving the checksum of a record, based on the filename.
java.lang.String	getFileName() Method for retrieving the name of the checksum file.
static FileChecksumArchive	getInstance() Method for obtaining the current singleton instance of this class.
java.lang.String	getWrongEntryFilename() Method for retrieving the name of the wrongEntryFile.
boolean	hasEnoughSpace() Method for testing where there is enough space left on local drive.
boolean	hasEntry(java.lang.String filename) Method for checking whether an entry exists within the archive.
void	synchronizeWithFile() Ensures that the file and memory archives are identical.
void	upload(RemoteFile file, java.lang.String filename) The method for uploading a file to the archive.

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static FileChecksumArchive getInstance()

Method for obtaining the current singleton instance of this class. If the instance of this class has not yet been constructed, then it will be initialised.

Returns:

The current instance of this class.

getFileName

public java.lang.String getFileName()

Method for retrieving the name of the checksum file.

Returns:

The checksum file name.

getWrongEntryFilename

public java.lang.String getWrongEntryFilename()

Method for retrieving the name of the wrongEntryFile.

Returns:

The wrong entry file name.

hasEnoughSpace

public boolean hasEnoughSpace()

Method for testing where there is enough space left on local drive.

Specified by:

hasEnoughSpace in class ChecksumArchive

Returns:

Whether there is enough space left.

upload

public void upload(RemoteFile file,
                   java.lang.String filename)
            throws ArgumentNotValid,
                   IllegalState

The method for uploading a file to the archive. TODO use file instead of remoteFile. Now the remoteFile is not automatically cleaned up afterwards.

Specified by:

upload in class ChecksumArchive

Parameters:

file - The remote file containing the file to be uploaded.

filename - The name of the arcFile.

Throws:

ArgumentNotValid - If the RemoteFile is null or if the filename is not valid.

IllegalState - If the file already within the archive but with a different checksum.

getChecksum

public java.lang.String getChecksum(java.lang.String filename)
                             throws ArgumentNotValid

Method for retrieving the checksum of a record, based on the filename.

Specified by:

getChecksum in class ChecksumArchive

Parameters:

filename - The name of the file to have recorded in the archive.

Returns:

The checksum of a record, or null if it was not found.

Throws:

ArgumentNotValid - If the filename is not valid (null or empty).

hasEntry

public boolean hasEntry(java.lang.String filename)

Method for checking whether an entry exists within the archive.

Specified by:

hasEntry in class ChecksumArchive

Parameters:

filename - The name of the file whose entry in the archive should be determined.

Returns:

Whether an entry with the filename was found.

calculateChecksum

protected java.lang.String calculateChecksum(java.io.File f)
                                      throws IOFailure

Method for calculating the checksum of a file.

Specified by:

calculateChecksum in class ChecksumArchive

Parameters:

f - The file to calculate the checksum of.

Returns:

The checksum of the file.

Throws:

IOFailure - If a IOException is caught during the calculation of the MD5-checksum.

calculateChecksum

protected java.lang.String calculateChecksum(java.io.InputStream is)
                                      throws IOFailure

Method for calculating the checksum of a inputstream.

Specified by:

calculateChecksum in class ChecksumArchive

Parameters:

is - The inputstream to calculate the checksum of.

Returns:

The checksum of the inputstream.

Throws:

IOFailure - If a error occurs during the generation of the MD5 checksum.

correct

public java.io.File correct(java.lang.String filename,
                            java.io.File correctFile)
                     throws IOFailure,
                            ArgumentNotValid,
                            IllegalState

Method for correcting a bad entry from the archive. The current incorrect entry is put into the wrongEntryFile. Then it calculates the checksum and corrects the entry for the file, and then the checksum file is recreated from the archive in the memory.

Specified by:

correct in class ChecksumArchive

Parameters:

filename - The name of the file whose record should be removed.

correctFile - The file that should replace the current entry

Returns:

A file containing the removed entry.

Throws:

ArgumentNotValid - If one of the arguments are not valid.

IOFailure - If the entry cannot be corrected. Either the bad entry cannot be stored, or the new checksum file cannot be created. Or if a file for the removed entry cannot be created.

IllegalState - If no such entry exists to be corrected, or if the entry has a different checksum than the incorrectChecksum.

getArchiveAsFile

public java.io.File getArchiveAsFile()
                              throws IOFailure

Method for retrieving the archive as a temporary file containing the checksum entries. Each line should contain one checksum entry in the format produced by the ChecksumJob.

Specified by:

getArchiveAsFile in class ChecksumArchive

Returns:

A temporary checksum file, which is a copy of the archive file.

Throws:

IOFailure - If problems occurs during the creation of the file.

getAllFilenames

public java.io.File getAllFilenames()
                             throws IOFailure

Method for retrieving the names of all the files within the archive as a temporary file.

Specified by:

getAllFilenames in class ChecksumArchive

Returns:

A temporary file containing the list of all the filenames. This file has one filename per line.

Throws:

IOFailure - If problems occurs during the creation of the file.

synchronizeWithFile

public void synchronizeWithFile()

Ensures that the file and memory archives are identical. The timestamp of last communication with the file (read/write) will be checked whether it corresponds the 'last modified' date of the file. If they are different, then the memory archive is reloaded from the file.

cleanup

public void cleanup()

The method for cleaning up when done. It sets the checksum file and the instance to null.

Specified by:

cleanup in class ChecksumArchive