its.backbone.sdd
Class SddTransmitter

java.lang.Object
  its.backbone.sdd.SddTransmitter

Direct Known Subclasses:

DemoTransmitter

public class SddTransmitter

extends java.lang.Object

Field Summary

protected Contents	contents Contains the parsed Contents object after a successful call to transmitContents.
boolean	parseDataFrame By default, SddTransmitter runs the SDD Contents parser on Contents and Data frames.
protected Schema	schema Contains the parsed Schema object after a successful call to transmitSchema.
protected short	timeout
boolean	useCompression By default, SddTransmitter uses GZIPOutputStream to compress each frame.

Constructor Summary

SddTransmitter(int requestPort)
constructor: starts listening for connections on the given port

SddTransmitter(int requestPort, AccessManager accessManager)

Method Summary

int	getClientCount() Returns the number of clients currently connected to this data stream.
void	setContentsSerialNumber(java.lang.String sn)
void	setSchemaSerialNumber(java.lang.String sn)
void	setSerialNumbers(java.lang.String sn)
void	setSerialNumbers(java.lang.String schemaSN, java.lang.String contentsSN)
void	setTimeout(int s) Sets the value placed in the "timeout" field of the ItsFrame objects created by SddTransmitter.
void	startPulse(int frequencySeconds) Starts a thread that sends an empty data frame after the given interval has elapsed with no network activity.
void	stop()
void	stopPulse() Stops the thread that was started by startPulse.
void	transmitContents(java.lang.String contents) Creates and sends an ITSFrame containing two BER encoded packets: a serial number encoding of the current time and the given contents.
void	transmitContentsFile(java.lang.String contentsFileName) for convenience, reads the contents from a file and transmits it.
void	transmitData(byte[] data) creates and sends an ITSFrame containing two BER encoded packets: a serial number matching the current contents and the given data.
void	transmitData(java.lang.String data) creates and sends an ITSFrame containing two BER encoded packets: a serial number matching the current contents and the given data.
void	transmitExtractor(java.lang.String jarFileName) creates and sends an ITSFrame containing two BER encoded packets: a serial number matching the current schema, and the contents of the given jar file (which had better contain an implementation of DataFactory.)
void	transmitSchema(java.lang.String schema) Creates and sends an ITSFrame containing two BER encoded packets: a serial number encoding of the current time and the given schema.
void	transmitSchemaFile(java.lang.String schemaFileName) for convenience, reads the schema from a file and transmits it.

Methods inherited from class java.lang.Object

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

Field Detail

useCompression

public boolean useCompression

By default, SddTransmitter uses GZIPOutputStream to compress each frame. To disable this behavior, set useCompression to false.

parseDataFrame

public boolean parseDataFrame

By default, SddTransmitter runs the SDD Contents parser on Contents and Data frames. If an application-specific format for the data frame is required, the parser can be disabled by setting parseDataFrame to false.

schema

protected Schema schema

Contains the parsed Schema object after a successful call to transmitSchema.

contents

protected Contents contents

Contains the parsed Contents object after a successful call to transmitContents.

timeout

protected short timeout

Constructor Detail

SddTransmitter

public SddTransmitter(int requestPort)
               throws java.io.IOException

constructor: starts listening for connections on the given port

Parameters:

requestPort - the port others will use to connect to this transmitter

SddTransmitter

public SddTransmitter(int requestPort,
                      AccessManager accessManager)
               throws java.io.IOException

Method Detail

setSerialNumbers

public void setSerialNumbers(java.lang.String sn)

setSerialNumbers

public void setSerialNumbers(java.lang.String schemaSN,
                             java.lang.String contentsSN)

setSchemaSerialNumber

public void setSchemaSerialNumber(java.lang.String sn)

setContentsSerialNumber

public void setContentsSerialNumber(java.lang.String sn)

transmitSchemaFile

public void transmitSchemaFile(java.lang.String schemaFileName)
                        throws java.io.IOException,
                               SchemaParserException

for convenience, reads the schema from a file and transmits it.

Parameters:

schemaFileName - name of text file containing the schema

Throws:

java.io.IOException - if the file cannot be read

ItsException - if the schema contains parse errors

SchemaParserException

transmitSchema

public void transmitSchema(java.lang.String schema)
                    throws SchemaParserException

Creates and sends an ITSFrame containing two BER encoded packets: a serial number encoding of the current time and the given schema. If the schema has changed since the last time transmitSchema was called, a new serial number will be generated; otherwise, the original serial number is retained.

Parameters:

schema - the schema encoded as a String

Throws:

SchemaParserException - if the schema contains parse errors

transmitContents

public void transmitContents(java.lang.String contents)
                      throws ContentsParserException,
                             MissingSchemaException

Creates and sends an ITSFrame containing two BER encoded packets: a serial number encoding of the current time and the given contents. If the contents information has changed since the last time transmitContents was called, a new serial number will be generated; otherwise, the original serial number is retained.

Parameters:

contents - the contents encoded as a String

Throws:

ContentsParserException - if the contents data contains parse errors or does not match the current schema

MissingSchemaException - if transmitSchema has not already been called successfully

transmitContentsFile

public void transmitContentsFile(java.lang.String contentsFileName)
                          throws java.io.IOException,
                                 ContentsParserException,
                                 MissingSchemaException

for convenience, reads the contents from a file and transmits it.

Parameters:

contentsFileName - name of text file containing the schema

Throws:

java.io.IOException - if the file cannot be read

ContentsParserException - if the contents contains parse errors

MissingSchemaException - if transmitSchema has not already been called successfully

transmitData

public void transmitData(byte[] data)
                  throws ContentsParserException,
                         MissingContentsException

creates and sends an ITSFrame containing two BER encoded packets: a serial number matching the current contents and the given data.

Parameters:

data - the data encoded as an array of bytes

Throws:

MissingContentsException - if transmitContents has not already been called successfully

ContentsParserException

transmitData

public void transmitData(java.lang.String data)
                  throws ContentsParserException,
                         MissingContentsException

creates and sends an ITSFrame containing two BER encoded packets: a serial number matching the current contents and the given data.

Parameters:

data - the data encoded as a String

Throws:

MissingContentsException - if transmitContents has not already been called successfully

ContentsParserException

transmitExtractor

public void transmitExtractor(java.lang.String jarFileName)
                       throws java.io.IOException,
                              MissingSchemaException

creates and sends an ITSFrame containing two BER encoded packets: a serial number matching the current schema, and the contents of the given jar file (which had better contain an implementation of DataFactory.)

Parameters:

jarFileName - name of jar file containing extractor

Throws:

java.io.IOException - if the file cannot be read

MissingSchemaException

See Also:

DataFactory

setTimeout

public void setTimeout(int s)

Sets the value placed in the "timeout" field of the ItsFrame objects created by SddTransmitter. Receivers can use this field to determine the maximum number of seconds to wait for the next data frame. If the field contains 0, receivers use a default timeout of 30 seconds. If the data stream being implemented generates data frames less frequently, it is important to specify a timeout value longer than this default.

stop

public void stop()

startPulse

public void startPulse(int frequencySeconds)

Starts a thread that sends an empty data frame after the given interval has elapsed with no network activity. This is one way for the transmitter to provide a "heartbeat" packet that informs its clients that their connection is still valid, the stream is still alive, but there is no new data. This can be useful for implementing asynchronous streams, where a long interval may pass between updates to large data sets. In this case, the large data set should be transmitted in the Contents frame, so that the pulse frame doesn't take its place as the most recent data frame, and newly connected clients will receive the most recent data set.

stopPulse

public void stopPulse()

Stops the thread that was started by startPulse. Calling startPulse again with a different frequency achieves the same result.

getClientCount

public int getClientCount()

Returns the number of clients currently connected to this data stream.