Interface TransferManager
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- All Known Subinterfaces:
FeatureTransferManager
- All Known Implementing Classes:
AbstractTransferManager
,LocalTransferManager
,PathAwareFeatureTransferManager
,ReadAfterWriteConsistentFeatureTransferManager
,RetriableFeatureTransferManager
,TransactionAwareFeatureTransferManager
public interface TransferManager
The transfer manager synchronously connects to the remote storage. It is responsible for file upload, download and deletion.All its operations are strictly synchronous and throw a
StorageException
if they fail. The implementations have to make sure that- the repository is not corrupted, e.g. duplicate files or corrupt files
- files matching the specified file format are complete, i.e. fully uploaded
- methods that need an established connections re-connect if necessary
A transfer manager may organize files according to their type or name as it is optimal for the given storage.
RemoteFile
s can be classified by their sub-type. For network-transfer optimization reasons, it might be useful to placeMultichunkRemoteFile
s andDatabaseRemoteFile
s in a separate sub-folder on the remote storage.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description void
connect()
Establish a connection with the remote storage.boolean
delete(RemoteFile remoteFile)
Deletes an existing file from the remote storage permanently.void
disconnect()
Disconnect from the remote storage.void
download(RemoteFile remoteFile, java.io.File localFile)
Download an existing remote file to the local disk.java.lang.String
getRemoteFilePath(java.lang.Class<? extends RemoteFile> remoteFileClass)
Return the path for a concreteRemoteFile
implementation as it is stored on the remote side *void
init(boolean createIfRequired)
Initialize remote storage.<T extends RemoteFile>
java.util.Map<java.lang.String,T>list(java.lang.Class<T> remoteFileClass)
Retrieves a list of all files in the remote repository, filtered by the type of the desired file, i.e.void
move(RemoteFile sourceFile, RemoteFile targetFile)
Moves an existing file in the online storage.StorageTestResult
test(boolean testCreateTarget)
Tests whether the repository parameters are valid.boolean
testRepoFileExists()
Tests whether the repository file exists (seeSyncanyRemoteFile
).boolean
testTargetCanCreate()
Tests whether the target path/folder can be created (if it does not exist already).boolean
testTargetCanWrite()
Tests whether the target path/folder is writable by the application.boolean
testTargetExists()
Tests whether the target path/folder exists.void
upload(java.io.File localFile, RemoteFile remoteFile)
Update an existing local file to the online storage.
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Method Detail
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connect
void connect() throws StorageException
Establish a connection with the remote storage.This method does not validate the correctness of the repository and it does not create any folders. The former is done by
test(boolean)
, the latter is done byinit(boolean)
.- Throws:
StorageException
- If the connection fails due to no Internet connection, authentication errors, etc.
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disconnect
void disconnect() throws StorageException
Disconnect from the remote storage.- Throws:
StorageException
- If the connection fails due to no Internet connection, authentication errors, etc.
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init
void init(boolean createIfRequired) throws StorageException
Initialize remote storage. This method is called to set up a new repository.- Parameters:
createIfRequired
- true if the method should handle repo creation- Throws:
StorageException
- If the connection drops, or any other exception occurs.
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download
void download(RemoteFile remoteFile, java.io.File localFile) throws StorageException
Download an existing remote file to the local disk.The file is either downloaded completely or nothing at all. In the latter case, a
StorageException
is thrown.Implementations must make sure that if a file matches the specified name schema, it must be complete and consistent.
If remoteFile does not exist, a
StorageFileNotFoundException
is thrown.- Parameters:
remoteFile
- Existing source file on the remote storage. The only required property of the remote file is the name.localFile
- Not existing local file to which the remote file is going to be downloaded.- Throws:
StorageException
- If the connection fails due to no Internet connection, authentication errors, etc.
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upload
void upload(java.io.File localFile, RemoteFile remoteFile) throws StorageException
Update an existing local file to the online storage.The file is either uploaded completely or nothing at all. In the latter case, a
StorageException
is thrown.Implementations must make sure that if a file matches the specified name schema, it must be complete and consistent.
Implementations must NOT upload a file if it already exists and has the same file size as the local file.
- Parameters:
localFile
- Existing local file that is going to be uploaded.remoteFile
- Not existing destination file on the remote storage. The only required property of the remote file is the name.- Throws:
StorageException
- If the connection fails due to no Internet connection, authentication errors, etc.
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move
void move(RemoteFile sourceFile, RemoteFile targetFile) throws StorageException
Moves an existing file in the online storage.If the sourceFile does not exists, a
StorageMoveException
is thrown.- Parameters:
sourceFile
- Existing remote file that is to be moved.targetFile
- Destination for the remote file.- Throws:
StorageException
- If the connection fails due to no Internet connection, authentication errors, etc.
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delete
boolean delete(RemoteFile remoteFile) throws StorageException
Deletes an existing file from the remote storage permanently.In case the remote file does not exist, it returns immediately without any notice. If the file cannot be deleted or the connection breaks, a
StorageException
is thrown.- Parameters:
remoteFile
- Existing remote file to be deleted. The only required property of the remote file is the name.- Throws:
StorageException
- If the connection fails due to no Internet connection, authentication errors, etc
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list
<T extends RemoteFile> java.util.Map<java.lang.String,T> list(java.lang.Class<T> remoteFileClass) throws StorageException
Retrieves a list of all files in the remote repository, filtered by the type of the desired file, i.e. by a sub-class ofRemoteFile
.- Parameters:
remoteFileClass
- Filter class:RemoteFile
or a sub-type thereof- Returns:
- Returns a list of remote files. In the map, the key is the file name,
the value the entire
RemoteFile
object. - Throws:
StorageException
- If the connection fails due to no Internet connection, authentication errors, etc
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test
StorageTestResult test(boolean testCreateTarget)
Tests whether the repository parameters are valid. In particular, the method tests whether a target (folder, bucket, etc.) exists or, if not, whether it can be created. It furthermore tests whether a repository at the target already exists by checking if theSyncanyRemoteFile
exists.The relevant result is determined by the following methods:
testTargetExists()
: Tests whether the target exists.testTargetCanWrite()
: Tests whether the target is writable.testTargetCanCreate()
: Tests whether the target can be created if it does not exist already. This is only called iftestCreateTarget
is set.testRepoFileExists()
: Tests whether the repo file exists.
- Parameters:
testCreateTarget
- Iftrue
, the test will test if the target can be created in case it does not exist. Iffalse
, this test will be skipped.- Returns:
- Returns the result of testing the repository.
- See Also:
StorageTestResult
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testTargetExists
boolean testTargetExists() throws StorageException
Tests whether the target path/folder exists. This might be done by listing the parent path/folder or by retrieving metadata about the target. The method returnstrue
if the target exists,false
otherwise.This method is called by the
test(boolean)
method (only during repository initialization or initial connection).- Returns:
- Returns
true
if the target exists,false
otherwise - Throws:
StorageException
- If the test cannot be performed, e.g. due to a connection failure
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testTargetCanWrite
boolean testTargetCanWrite() throws StorageException
Tests whether the target path/folder is writable by the application. This method may either check the write permissions of the target or actually write a test file to check write access. If the target does not exist,false
is returned. If the target exists and is writable,true
is returned.This method is called by the
test(boolean)
method (only during repository initialization or initial connection).- Returns:
- Returns
true
if the target can be written to,false
otherwise - Throws:
StorageException
- If the test cannot be performed, e.g. due to a connection failure
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testTargetCanCreate
boolean testTargetCanCreate() throws StorageException
Tests whether the target path/folder can be created (if it does not exist already). This method may either check the permissions of the parent path/folder or actually create and delete the target to determine create permissions.If the target already exists, the method returns
true
. If it does not, but it can be created (according to tests of this method), it also returnstrue
. In all other cases,false
is returned.This method is called by the
test(boolean)
method, but only if thetestCreateTarget
flag is set totrue
!- Returns:
- Returns
true
if the target can be created or already exists,false
otherwise - Throws:
StorageException
- If the test cannot be performed, e.g. due to a connection failure
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testRepoFileExists
boolean testRepoFileExists() throws StorageException
Tests whether the repository file exists (seeSyncanyRemoteFile
). This method is called by thetest(boolean)
method (only during repository initialization (or initial connection).This method is called by the
test(boolean)
method (only during repository initialization or initial connection).- Returns:
- Returns
true
if the repository is valid,false
otherwise - Throws:
StorageException
- If the test cannot be performed, e.g. due to a connection failure
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getRemoteFilePath
java.lang.String getRemoteFilePath(java.lang.Class<? extends RemoteFile> remoteFileClass)
Return the path for a concreteRemoteFile
implementation as it is stored on the remote side *- Parameters:
remoteFileClass
- The class to provide the path for- Returns:
- A string pointing to the folder where a file is stored
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