io.milton.zsync

Class UploadMakerEx

java.lang.Object

io.milton.zsync.UploadMakerEx

public class UploadMakerEx
extends Object

A slight variation of UploadMaker that accommodates updating of potentially redundant files, ie files containing blocks that repeat at multiple offsets.

It is not necessary to use this class rather than UploadMaker. This class simply decreases the amount of data that needs to be transmitted for certain cases of redundant files. The sole difference from UploadMaker is that this class uses methods that expect a reverse block-matching in the form of an array where f[serverIndex] = localOffset (actually implemented as a List of OffsetPairs), whereas UploadMaker expects f[localOffset] = serverIndex.

The main advantage of the reverse mapping is that it allows multiple identical block ranges in the local file to be mapped to a single range in the server file. If a given block occurs more times on the local file than on the server file, the f[serverIndex] array will not identify all of those local occurences, and the unmatched ones will be transmitted needlessly.

Author:

Nick

Field Summary

Fields

Modifier and Type	Field and Description
File	localCopy The local file that will replace the server file
File	serversMetafile The .zsync of the server file to be replaced

Constructor Summary

Constructors

Constructor and Description
UploadMakerEx(File sourceFile, File zsFile) Constructor that initializes an Upload object and invokes methods to parse the zsync file.

Method Summary

Modifier and Type	Method and Description
static InputStream	getDataRanges(List<Range> ranges, File local) Constructs the List of DataRange objects containing the portions of the client file to be uploaded to the server.
File	getUploadFile() Generates the upload content to a temp file.
InputStream	makeUpload() Returns the stream of bytes to be used as the body of a ZSync PUT.
static InputStream	serversMissingRangesEx(List<OffsetPair> reverseMap, File local, int blockSize) Determines the byte ranges from the client file that need to be uploaded to the server.
static InputStream	serversRelocationRangesEx(List<OffsetPair> reverseMap, int blockSize, long fileLength, boolean combineRanges) Determines the instructions needed by the server to relocate blocks of data already contained in its version of the file.

Methods inherited from class java.lang.Object

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

Field Detail

localCopy

public final File localCopy

The local file that will replace the server file

serversMetafile

public final File serversMetafile

The .zsync of the server file to be replaced

Constructor Detail

UploadMakerEx

public UploadMakerEx(File sourceFile,
                     File zsFile)
              throws IOException

Constructor that initializes an Upload object and invokes methods to parse the zsync file.

Parameters:

sourceFile - The client file to be uploaded

zsFile - The zsync of the server's file

Throws:

IOException

Method Detail

serversMissingRangesEx

public static InputStream serversMissingRangesEx(List<OffsetPair> reverseMap,
                                                 File local,
                                                 int blockSize)
                                          throws UnsupportedEncodingException,
                                                 IOException

Determines the byte ranges from the client file that need to be uploaded to the server.

Parameters:

reverseMap - The List of block-matches obtained from MakeContextEx

local - The local file being uploaded

blockSize - The block size used in reverseMap

Returns:

An InputStream containing the dataStream portion of an Upload

Throws:

IOException

UnsupportedEncodingException

See Also:

UploadMaker.serversMissingRanges(long[], java.io.File, int)

serversRelocationRangesEx

public static InputStream serversRelocationRangesEx(List<OffsetPair> reverseMap,
                                                    int blockSize,
                                                    long fileLength,
                                                    boolean combineRanges)
                                             throws UnsupportedEncodingException,
                                                    IOException

Determines the instructions needed by the server to relocate blocks of data already contained in its version of the file.

Parameters:

reverseMap - The List of block-matches obtained from MakeContextEx

blockSize - The block size used to generate reverseMap

fileLength - The length of the client file being uploaded

combineRanges - Whether to combine consecutive block matches into a single RelocateRange

Returns:

The InputStream of RelocateRanges that need to be sent to the server

Throws:

IOException

UnsupportedEncodingException

See Also:

UploadMaker#serversRelocationRanges}

getDataRanges

public static InputStream getDataRanges(List<Range> ranges,
                                        File local)
                                 throws IOException

Constructs the List of DataRange objects containing the portions of the client file to be uploaded to the server. Currently unused.

Parameters:

ranges - The List of Ranges from the client file needed by the server, which can be obtained from #serversMissingRangesEx(List, long, int)

local - The client file to be uploaded

Returns:

An InputStream containing the dataStream portion of an Upload

Throws:

IOException

makeUpload

public InputStream makeUpload()
                       throws IOException

Returns the stream of bytes to be used as the body of a ZSync PUT.

Note: Any temporary files used to store the data for the stream will be deleted after the stream is closed, so a second invocation of this method may not work.

Returns:

The InputStream containing the data for a ZSync PUT

Throws:

UnsupportedEncodingException

IOException

getUploadFile

public File getUploadFile()
                   throws IOException

Generates the upload content to a temp file.

Returns:

Throws:

IOException