Package org.syncany.database

Class FileVersionComparator

java.lang.Object

org.syncany.database.FileVersionComparator

public class FileVersionComparator
extends java.lang.Object

The file version comparator is a helper class to compare FileVersions with each other, or compare FileVersions to local Files.

It captures the FileVersionComparator.FileProperties of two files or file versions and compares them using the various compare*-methods. A comparison returns a set of FileVersionComparator.FileChanges, each of which identifies a certain attribute change (e.g. checksum changed, name changed). A file can be considered equal if the returned set of FileVersionComparator.FileChanges is empty.

The file version comparator distinguishes between cancelling tests and regular tests. Cancelling tests are implemented in performCancellingTests(). They represent significant changes in a file, for which further comparison would not make sense (e.g. new vs. deleted files or files vs. folders). If a cancelling test is not successful, other tests are not performed.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	FileVersionComparator.FileChange
static class	FileVersionComparator.FileProperties
static class	FileVersionComparator.FileVersionComparison

Constructor Summary

Constructors

Constructor	Description
FileVersionComparator(java.io.File rootFolder, java.lang.String checksumAlgorithm)	Creates a new file version comparator helper class.

Method Summary

Modifier and Type	Method	Description
FileVersionComparator.FileProperties	captureFileProperties(java.io.File file, FileContent.FileChecksum knownChecksum, boolean forceChecksum)
FileVersionComparator.FileProperties	captureFileProperties(FileVersion fileVersion)
FileVersionComparator.FileVersionComparison	compare(FileVersionComparator.FileProperties expectedFileProperties, FileVersionComparator.FileProperties actualFileProperties, boolean compareChecksums)
FileVersionComparator.FileVersionComparison	compare(FileVersion expectedFileVersion, java.io.File actualFile, boolean actualFileForceChecksum)	Compares a FileVersion with a local File and returns a FileVersionComparator.FileVersionComparison object.
FileVersionComparator.FileVersionComparison	compare(FileVersion expectedLocalFileVersion, java.io.File actualLocalFile, FileContent.FileChecksum actualFileKnownChecksum, boolean actualFileForceChecksum)	Compares a FileVersion with a local File and returns a FileVersionComparator.FileVersionComparison object.
FileVersionComparator.FileVersionComparison	compare(FileVersion expectedFileVersion, FileVersion actualFileVersion)	Compares two FileVersions to each other and returns a FileVersionComparator.FileVersionComparison object.

Methods inherited from class java.lang.Object

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

Constructor Detail

FileVersionComparator

public FileVersionComparator(java.io.File rootFolder,
                             java.lang.String checksumAlgorithm)

Creates a new file version comparator helper class.

The rootFolder is needed to allow a comparison of the relative file path. The checksumAlgorithm is used for calculate and compare file checksums. Both are used if a local File is compared to a FileVersion.

Parameters:

rootFolder - Base folder to determine a relative path to

checksumAlgorithm - Digest algorithm for checksum calculation, e.g. "SHA1" or "MD5"

Method Detail

compare

public FileVersionComparator.FileVersionComparison compare(FileVersion expectedFileVersion,
                                                           FileVersion actualFileVersion)

Compares two FileVersions to each other and returns a FileVersionComparator.FileVersionComparison object.

Parameters:

expectedFileVersion - The expected file version (that is compared to the actual file version)

actualFileVersion - The actual file version (that is compared to the expected file version)

Returns:

Returns a file version comparison object, indicating if there are differences between the file versions

compare

public FileVersionComparator.FileVersionComparison compare(FileVersion expectedFileVersion,
                                                           java.io.File actualFile,
                                                           boolean actualFileForceChecksum)

Compares a FileVersion with a local File and returns a FileVersionComparator.FileVersionComparison object.

If the actual file does not differ in size, it is necessary to calculate and compare the checksum of the local file to the file version to reliably determine if it has changed. Unless comparing the size and last modified date is enough, the actualFileForceChecksum parameter must be switched to true.

Parameters:

expectedFileVersion - The expected file version (that is compared to the actual file)

actualFile - The actual file (that is compared to the expected file version)

actualFileForceChecksum - Force a checksum comparison if necessary (if size does not differ)

Returns:

Returns a file version comparison object, indicating if there are differences between the file versions

compare

public FileVersionComparator.FileVersionComparison compare(FileVersion expectedLocalFileVersion,
                                                           java.io.File actualLocalFile,
                                                           FileContent.FileChecksum actualFileKnownChecksum,
                                                           boolean actualFileForceChecksum)

Compares a FileVersion with a local File and returns a FileVersionComparator.FileVersionComparison object.

If the actual file does not differ in size, it is necessary to calculate and compare the checksum of the local file to the file version to reliably determine if it has changed. Unless comparing the size and last modified date is enough, the actualFileForceChecksum parameter must be switched to true.

If the actualFileKnownChecksum parameter is set and a checksum comparison is necessary, this parameter is used to compare checksums. If not and force checksum is enabled, the checksum is calculated and compared.

Parameters:

expectedLocalFileVersion - The expected file version (that is compared to the actual file)

actualLocalFile - The actual file (that is compared to the expected file version)

actualFileKnownChecksum - If the checksum of the local file is known, it can be set

actualFileForceChecksum - Force a checksum comparison if necessary (if size does not differ)

Returns:

Returns a file version comparison object, indicating if there are differences between the file versions

compare

public FileVersionComparator.FileVersionComparison compare(FileVersionComparator.FileProperties expectedFileProperties,
                                                           FileVersionComparator.FileProperties actualFileProperties,
                                                           boolean compareChecksums)

captureFileProperties

public FileVersionComparator.FileProperties captureFileProperties(java.io.File file,
                                                                  FileContent.FileChecksum knownChecksum,
                                                                  boolean forceChecksum)

captureFileProperties

public FileVersionComparator.FileProperties captureFileProperties(FileVersion fileVersion)