net.snowflake.client.jdbc

Class SFBaseFileTransferAgent

java.lang.Object

net.snowflake.client.jdbc.SFBaseFileTransferAgent

All Implemented Interfaces:

SnowflakeFixedView

Direct Known Subclasses:

SnowflakeFileTransferAgent

public abstract class SFBaseFileTransferAgent
extends Object
implements SnowflakeFixedView

Base class for file transfers: given a SnowflakeConnection, files may be uploaded or downloaded from/to an InputStream.

Note that while SnowflakeFileTransferAgent is used liberally throughout the codebase for performing uploads, the "alternative" implementations may have quite different ways of uploading to cloud storage, so this is a rather "thin" abstract class that leaves much of the implementation up to the implementing class.

It is also expected that a command (GET/PUT) is parsed by the FileTransferAgent before either execute() or downloadStream() is called. This is not enforced by the abstract class's interface, but will be passed to the SFConnectionHandler's getFileTransferAgent().

In general, besides the abstract methods execute() and downloadStream(), an implementing class needs to also populate the statusRows List with the file-metadata rows forming the fixed view, as well as set the showEncryptionParameter boolean (usually returned by the session parameter; default is false).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SFBaseFileTransferAgent.CommandType The types of file transfer: upload and download.
class	SFBaseFileTransferAgent.DownloadCommandEncryptionFacade
class	SFBaseFileTransferAgent.DownloadCommandFacade A class for encapsulating the columns to return for the download command
static class	SFBaseFileTransferAgent.UploadColumns A class for encapsulating the columns to return for the upload command
class	SFBaseFileTransferAgent.UploadCommandEncryptionFacade
class	SFBaseFileTransferAgent.UploadCommandFacade

Field Summary

Fields

Modifier and Type	Field and Description
protected SFBaseFileTransferAgent.CommandType	commandType
protected boolean	compressSourceFromStream
protected String	destFileNameForStreamSource
protected String	destStagePath
protected boolean	showEncryptionParameter
protected boolean	sourceFromStream
protected InputStream	sourceStream
protected List<Object>	statusRows

Constructor Summary

Constructors

Constructor and Description
SFBaseFileTransferAgent()

Method Summary

Modifier and Type	Method and Description
List<SnowflakeColumnMetadata>	describeColumns(SFBaseSession session) Describe the metadata of a fixed view.
abstract InputStream	downloadStream(String fileName) Download data from a stage.
abstract boolean	execute() Run the PUT/GET command, if a command has been set.
List<Object>	getNextRow() Move on to the next row of file metadata.
int	getTotalRows() Gets the total number of rows that this GET/PUT command's output returns in the fixed-view result.
void	setCompressSourceFromStream(boolean compressSourceFromStream) Whether to compress the source stream before upload.
void	setDestFileNameForStreamSource(String destFileNameForStreamSource) Sets the target filename for uploading
void	setDestStagePath(String destStagePath) Sets the destination stage path
void	setSourceStream(InputStream sourceStream) Sets the source data stream to be uploaded.

Methods inherited from class java.lang.Object

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

Field Detail

compressSourceFromStream

protected boolean compressSourceFromStream

destStagePath

protected String destStagePath

destFileNameForStreamSource

protected String destFileNameForStreamSource

sourceStream

protected InputStream sourceStream

sourceFromStream

protected boolean sourceFromStream

showEncryptionParameter

protected boolean showEncryptionParameter

statusRows

protected List<Object> statusRows

commandType

protected SFBaseFileTransferAgent.CommandType commandType

Constructor Detail

SFBaseFileTransferAgent

public SFBaseFileTransferAgent()

Method Detail

getTotalRows

public int getTotalRows()

Gets the total number of rows that this GET/PUT command's output returns in the fixed-view result. The statusRows list must be populated with the FileMetadata.

Specified by:

getTotalRows in interface SnowflakeFixedView

Returns:

The number of rows that this fixed-view represents.

getNextRow

public List<Object> getNextRow()
                        throws Exception

Move on to the next row of file metadata. The statusRows list must be populated with the file-metadata output of the GET/PUT command.

Specified by:

getNextRow in interface SnowflakeFixedView

Returns:

The row, represented as a list of Object.

Throws:

Exception

describeColumns

public List<SnowflakeColumnMetadata> describeColumns(SFBaseSession session)
                                              throws Exception

Describe the metadata of a fixed view.

Specified by:

describeColumns in interface SnowflakeFixedView

Returns:

list of column meta data

Throws:

Exception - failed to construct list

setSourceStream

public void setSourceStream(InputStream sourceStream)

Sets the source data stream to be uploaded.

Parameters:

sourceStream - The source data to upload.

setDestStagePath

public void setDestStagePath(String destStagePath)

Sets the destination stage path

Parameters:

destStagePath - The target destination stage path.

setDestFileNameForStreamSource

public void setDestFileNameForStreamSource(String destFileNameForStreamSource)

Sets the target filename for uploading

Parameters:

destFileNameForStreamSource - The target destination filename once the file is uploaded.

setCompressSourceFromStream

public void setCompressSourceFromStream(boolean compressSourceFromStream)

Whether to compress the source stream before upload.

Parameters:

compressSourceFromStream - boolean for whether to compress the data stream before upload.

execute

public abstract boolean execute()
                         throws SQLException

Run the PUT/GET command, if a command has been set.

Returns:

Whether the operation was completed successfully, and completely.

Throws:

SQLException - for SQL or upload errors

downloadStream

public abstract InputStream downloadStream(String fileName)
                                    throws SnowflakeSQLException

Download data from a stage.

Parameters:

fileName - A file on a stage to download.

Returns:

An InputStream for the requested file.

Throws:

SnowflakeSQLException - If the file does not exist, or if an error occurred during transport.