com.openxc

Class DataPipeline

java.lang.Object

com.openxc.DataPipeline

All Implemented Interfaces:

SourceCallback

public class DataPipeline
extends java.lang.Object
implements SourceCallback

A pipeline that ferries data from VehicleDataSources to VehicleDataSinks. A DataPipeline accepts two types of components - sources and sinks. The sources (implementing VehicleDataSource call the receive(VehicleMessage) method on the this class when new values arrive. The DataPipeline then passes this value on to all currently registered data sinks. The Pipeline can have an optional Operator, which implements a few callbacks to check the status of the pipeline - e.g. if some source in the pipeline is active.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	DataPipeline.Operator

Constructor Summary

Constructors

Constructor and Description
DataPipeline()
DataPipeline(DataPipeline.Operator operator)

Method Summary

Modifier and Type	Method and Description
VehicleDataSink	addSink(VehicleDataSink sink) Add a new sink to the pipeline.
VehicleDataSource	addSource(VehicleDataSource source) Add a new source to the pipeline.
void	clearSinks() Remove and stop all sinks in the pipeline.
void	clearSources() Remove and stop all sources in the pipeline.
KeyedMessage	get(MessageKey key) Return the last received value for the keyed message if known.
int	getMessageCount()
java.util.List<VehicleDataSink>	getSinks()
java.util.List<VehicleDataSource>	getSources()
boolean	isActive()
boolean	isActive(VehicleDataSource skipSource) Return true if at least one source is active.
void	receive(VehicleMessage message) Accept new values from data sources and send it out to all registered sinks.
void	removeSink(VehicleDataSink sink) Remove a previously added sink from the pipeline.
void	removeSource(VehicleDataSource source) Remove a previously added source from the pipeline.
void	sourceConnected(VehicleDataSource source) At least one source is active - notify the operator.
void	sourceDisconnected(VehicleDataSource source) At least one source is not active - if all sources are inactive, notify the operator.
void	stop() Clear all sources and sinks from the pipeline and stop all of them.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

DataPipeline

public DataPipeline()

DataPipeline

public DataPipeline(DataPipeline.Operator operator)

Method Detail

receive

public void receive(VehicleMessage message)

Accept new values from data sources and send it out to all registered sinks. This method is required to implement the SourceCallback interface. If any data sink throws a DataSinkException when receiving data, it will be removed from the list of sinks.

Specified by:

receive in interface SourceCallback

Parameters:

message - the new measurement.

addSink

public VehicleDataSink addSink(VehicleDataSink sink)

Add a new sink to the pipeline.

removeSink

public void removeSink(VehicleDataSink sink)

Remove a previously added sink from the pipeline. Once removed, the sink will no longer receive any new messages from the pipeline's sources. The sink's VehicleDataSink.stop() method is also called.

Parameters:

sink - if the value is null, it is ignored.

addSource

public VehicleDataSource addSource(VehicleDataSource source)

Add a new source to the pipeline. The source is given a reference to this DataPipeline as its callback.

removeSource

public void removeSource(VehicleDataSource source)

Remove a previously added source from the pipeline. Once removed, the source should no longer use this pipeline for its callback.

Parameters:

source - if the value is null, it is ignored.

getSources

public java.util.List<VehicleDataSource> getSources()

getSinks

public java.util.List<VehicleDataSink> getSinks()

stop

public void stop()

Clear all sources and sinks from the pipeline and stop all of them.

clearSources

public void clearSources()

Remove and stop all sources in the pipeline.

clearSinks

public void clearSinks()

Remove and stop all sinks in the pipeline.

get

public KeyedMessage get(MessageKey key)

Return the last received value for the keyed message if known.

Parameters:

key - the key of the message to retrieve, if any available.

Returns:

a VehicleMessage with the last known value, or null if no value has been received.

getMessageCount

public int getMessageCount()

Returns:

number of messages received since instantiation.

isActive

public boolean isActive()

isActive

public boolean isActive(VehicleDataSource skipSource)

Return true if at least one source is active.

Parameters:

skipSource - don't consider this data source when determining if the pipeline is active.

sourceDisconnected

public void sourceDisconnected(VehicleDataSource source)

At least one source is not active - if all sources are inactive, notify the operator.

Specified by:

sourceDisconnected in interface SourceCallback

sourceConnected

public void sourceConnected(VehicleDataSource source)

At least one source is active - notify the operator.

Specified by:

sourceConnected in interface SourceCallback

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object