Package com.storedobject.ui.util

Class DownloadStream

java.lang.Object

com.storedobject.ui.util.DownloadStream

All Implemented Interfaces:

Serializable

public class DownloadStream
extends Object
implements Serializable

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final String	CONTENT_DISPOSITION
static final int	DEFAULT_BUFFER_SIZE
static final long	DEFAULT_CACHE_TIME

Constructor Summary

Constructors

Constructor	Description
DownloadStream(ContentProducer producer, String contentType, String fileName)	Creates a new instance of DownloadStream.

Method Summary

Modifier and Type	Method	Description
int	getBufferSize()	Gets the size of the download buffer.
long	getCacheTime()	Gets length of cache expiration time.
static String	getContentDispositionFilename(String filename)	Returns the filename formatted for inclusion in a Content-Disposition header.
String	getContentType()	Gets stream content type.
String	getFileName()	Returns the file name.
String	getParameter(String name)	Gets a parameter for download stream.
Iterator<String>	getParameterNames()	Gets the names of the parameters.
static String	rfc5987Encode(String value)	Encodes the given string to UTF-8 value-chars as defined in RFC5987 for use in e.g. the Content-Disposition HTTP header.
void	setBufferSize(int bufferSize)	Sets the size of the download buffer.
void	setCacheTime(long cacheTime)	Sets length of cache expiration time.
void	setContentType(String contentType)	Sets stream content type.
void	setFileName(String fileName)	Sets the file name.
void	setParameter(String name, String value)	Sets a parameter for download stream.
void	writeResponse(com.vaadin.flow.server.VaadinRequest request, com.vaadin.flow.server.VaadinResponse response)	Writes this download stream to a Vaadin response.

Methods inherited from class java.lang.Object

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

Field Details

CONTENT_DISPOSITION

public static final String CONTENT_DISPOSITION

See Also:

• Constant Field Values

DEFAULT_CACHE_TIME

public static final long DEFAULT_CACHE_TIME

See Also:

• Constant Field Values

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE

See Also:

• Constant Field Values

Constructor Details

DownloadStream

public DownloadStream(ContentProducer producer,
 String contentType,
 String fileName)

Creates a new instance of DownloadStream.

Parameters:

producer - Content producer

contentType - Mime type of the content

fileName - Name of the file (for the browser to save the content)

Method Details

getContentType

public String getContentType()

Gets stream content type.

Returns:

type of the stream content.

setContentType

public void setContentType(String contentType)

Sets stream content type.

Parameters:

contentType - the contentType to set

getFileName

public String getFileName()

Returns the file name.

Returns:

the name of the file.

setFileName

public void setFileName(String fileName)

Sets the file name.

Parameters:

fileName - the file name to set.

setParameter

public void setParameter(String name,
 String value)

Sets a parameter for download stream. Parameters are optional information about the downloadable stream and their meaning depends on the used adapter. For example in WebAdapter they are interpreted as HTTP response headers.

If the parameters by this name exists, the old value is replaced.

Parameters:

name - the Name of the parameter to set.

value - the Value of the parameter to set.

getParameter

public String getParameter(String name)

Gets a parameter for download stream. Parameters are optional information about the downloadable stream and their meaning depends on the used adapter. For example in WebAdapter they are interpreted as HTTP response headers.

Parameters:

name - the Name of the parameter to set.

Returns:

Value of the parameter or null if the parameter does not exist.

getParameterNames

public Iterator<String> getParameterNames()

Gets the names of the parameters.

Returns:

Iterator of names or null if no parameters are set.

getCacheTime

public long getCacheTime()

Gets length of cache expiration time. This gives the adapter the possibility cache streams sent to the client. The caching may be made in adapter or at the client if the client supports caching. Default is DEFAULT_CACHE_TIME.

Returns:

Cache time in milliseconds

setCacheTime

public void setCacheTime(long cacheTime)

Sets length of cache expiration time. This gives the adapter the possibility cache streams sent to the client. The caching may be made in adapter or at the client if the client supports caching. Zero or negative value disables the caching of this stream.

Parameters:

cacheTime - the cache time in milliseconds.

getBufferSize

public int getBufferSize()

Gets the size of the download buffer.

Returns:

int The size of the buffer in bytes.

setBufferSize

public void setBufferSize(int bufferSize)

Sets the size of the download buffer.

Parameters:

bufferSize - the size of the buffer in bytes.

writeResponse

public void writeResponse(com.vaadin.flow.server.VaadinRequest request,
 com.vaadin.flow.server.VaadinResponse response)
                   throws IOException

Writes this download stream to a Vaadin response. This takes care of setting response headers according to what is defined in this download stream (getContentType(), getCacheTime(), getFileName()) and transferring the data from the stream to the response. Defined parameters ( getParameterNames()) are also included as headers in the response. If there is a parameter named Location, a redirect (302 Moved temporarily) is sent instead of the contents of this stream.

Parameters:

request - the request for which the response should be written

response - the Vaadin response to write this download stream to

Throws:

IOException - Passed through from the Vaadin response

getContentDispositionFilename

public static String getContentDispositionFilename(String filename)

Returns the filename formatted for inclusion in a Content-Disposition header. Includes both a plain version of the name and a UTF-8 version

Parameters:

filename - The filename to include

Returns:

A value for inclusion in a Content-Disposition header

rfc5987Encode

public static String rfc5987Encode(String value)

Encodes the given string to UTF-8 value-chars as defined in RFC5987 for use in e.g. the Content-Disposition HTTP header.

Parameters:

value - the string to encode, not null

Returns:

the encoded string