org.lsst.ccs.gconsole.plugins.trending

Class RestSource

java.lang.Object

org.lsst.ccs.gconsole.plugins.trending.RestSource

public class RestSource
extends Object

Source of trending data based on a REST server. Provides getters for retrieving the list of known trending channels and the data for specified channels.

This sources watches for external events that can change the list of known channels, and notifies listeners when this happens.

Current implementation note. This class maintains a map of paths to DataChannel, but only the list of paths is externally available. Metadata provided by DataChannel is unused. Accordingly, whenever the map is updated (due to time window or REST server change), listeners are not notified unless the set of available paths changes.

Author:

onoprien

Method Summary

Modifier and Type	Method and Description
void	addListener(ChangeListener listener) Registers a listener to be notified if the list of channels available from this trending source changes.
protected void	fireEvent() Notifies listeners of changes in this source.
TrendData	get(String path, long begin, long end, EnumSet<Trend.Meta> metadata, TrendData history) Retrieves from the REST server and processes historical data for the specified trending channel.
List<String>	getChannels() Returns the list of known data channel paths.
void	refresh() Refreshes the list of channels by retrieving them from the REST server.
void	removeAllListeners() Removes all listeners.
void	removeListener(ChangeListener listener) Removes a listener.

Methods inherited from class java.lang.Object

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

Method Detail

refresh

public void refresh()

Refreshes the list of channels by retrieving them from the REST server.

addListener

public void addListener(ChangeListener listener)

Registers a listener to be notified if the list of channels available from this trending source changes. This method can be called on any thread. The listeners are notified on the EDT.

Parameters:

listener - Listener to be added.

removeListener

public void removeListener(ChangeListener listener)

Removes a listener. This method can be called on any thread.

Parameters:

listener - Listener to be removed.

removeAllListeners

public void removeAllListeners()

Removes all listeners. This method can be called on any thread.

fireEvent

protected void fireEvent()

Notifies listeners of changes in this source. Can be called on any thread. Listeners are notified on EDT.

getChannels

public List<String> getChannels()

Returns the list of known data channel paths. Calling this method does not retrieve data from the REST server.

Returns:

List of channel paths.

get

public TrendData get(String path,
                     long begin,
                     long end,
                     EnumSet<Trend.Meta> metadata,
                     TrendData history)

Retrieves from the REST server and processes historical data for the specified trending channel.

Parameters:

path - Channel path.

begin - Beginning of time window.

end - End of time window.

metadata - Set of metadata types to be included.

history - Previously known data.

Returns:

Newly created data container, or null if retrieval fails for any reason.