org.apache.druid.client

Class FilteringSegmentCallback

java.lang.Object

org.apache.druid.client.FilteringSegmentCallback

All Implemented Interfaces:

ServerView.SegmentCallback

public class FilteringSegmentCallback
extends Object
implements ServerView.SegmentCallback

A SegmentCallback that is called only when the given filter satisfies. segmentViewInitialized() is an exception and always called when the view is initialized without using the filter. Callback methods return ServerView.CallbackAction.CONTINUE when the filter does not satisfy.

Constructor Summary

Constructors

Constructor and Description
FilteringSegmentCallback(ServerView.SegmentCallback callback, com.google.common.base.Predicate<Pair<DruidServerMetadata,DataSegment>> filter)

Method Summary

Modifier and Type	Method and Description
ServerView.CallbackAction	segmentAdded(DruidServerMetadata server, DataSegment segment) Called when a segment is added to a server.
ServerView.CallbackAction	segmentRemoved(DruidServerMetadata server, DataSegment segment) Called when a segment is removed from a server.
ServerView.CallbackAction	segmentViewInitialized()

Methods inherited from class java.lang.Object

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

Constructor Detail

FilteringSegmentCallback

public FilteringSegmentCallback(ServerView.SegmentCallback callback,
                                com.google.common.base.Predicate<Pair<DruidServerMetadata,DataSegment>> filter)

Method Detail

segmentAdded

public ServerView.CallbackAction segmentAdded(DruidServerMetadata server,
                                              DataSegment segment)

Description copied from interface: ServerView.SegmentCallback

Called when a segment is added to a server. The return value indicates if this callback has completed its work. Note that even if this callback indicates that it should be unregistered, it is not possible to guarantee that this callback will not get called again. There is a race condition between when this callback runs and other events that can cause the callback to be queued for running. Thus, callbacks shouldn't assume that they will not get called again after they are done. The contract is that the callback will eventually be unregistered, enforcing a happens-before relationship is not part of the contract.

Specified by:

segmentAdded in interface ServerView.SegmentCallback

Parameters:

server - The server that added a segment

segment - The segment that was added

Returns:

UNREGISTER if the callback has completed its work and should be unregistered. CONTINUE if the callback should remain registered.

segmentRemoved

public ServerView.CallbackAction segmentRemoved(DruidServerMetadata server,
                                                DataSegment segment)

Description copied from interface: ServerView.SegmentCallback

Called when a segment is removed from a server. The return value indicates if this callback has completed its work. Note that even if this callback indicates that it should be unregistered, it is not possible to guarantee that this callback will not get called again. There is a race condition between when this callback runs and other events that can cause the callback to be queued for running. Thus, callbacks shouldn't assume that they will not get called again after they are done. The contract is that the callback will eventually be unregistered, enforcing a happens-before relationship is not part of the contract.

Specified by:

segmentRemoved in interface ServerView.SegmentCallback

Parameters:

server - The server that removed a segment

segment - The segment that was removed

Returns:

UNREGISTER if the callback has completed its work and should be unregistered. CONTINUE if the callback should remain registered.

segmentViewInitialized

public ServerView.CallbackAction segmentViewInitialized()

Specified by:

segmentViewInitialized in interface ServerView.SegmentCallback