Class ViewStateManagerImpl
- java.lang.Object
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- org.apache.sling.discovery.commons.providers.base.ViewStateManagerImpl
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- All Implemented Interfaces:
ViewStateManager
public class ViewStateManagerImpl extends java.lang.Object implements ViewStateManager
The ViewStateManager is at the core of managing TopologyEventListeners, the 'view state' (changing vs changed) and sending out the appropriate and according TopologyEvents to the registered listeners.Note re synchronization: this class rquires a lock object to be passed in the constructor - this will be applied to all public methods appropriately. Additionally, the ClusterSyncService callback will also be locked using the provided lock object.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
bind(TopologyEventListener eventListener)
Binds the given eventListener, sending it an INIT event if applicable.void
handleActivated()
Handles activation - ie marks this manager as activated thus the TOPOLOGY_INIT event can be sent to already bound listeners and subsequent calls to handleChanging/handleNewView will result in according/appropriate TOPOLOGY_CHANGING/ TOPOLOGY_CHANGED events.void
handleChanging()
Handles the fact that some (possibly early) indicator of a change in a topology has been detected and that a new view is being agreed upon (whatever that means, be it voting or similar).void
handleDeactivated()
Must be called when the corresponding service (typically a DiscoveryService implementation) is deactivated.void
handleNewView(BaseTopologyView newView)
Handles the fact that a new view became true/established and sends out TOPOLOGY_INIT to uninitialized listeners and TOPOLOGY_CHANGED to already initialized listeners (in the latter case, also sends a TOPOLOGY_CHANGING if that has not yet been done)void
installMinEventDelayHandler(DiscoveryService discoveryService, Scheduler scheduler, long minEventDelaySecs)
Installs an optional 'min event delay handler' which, using the given scheduler, delays sending TOPOLOGY_CHANGED event after receiving a handleNewView - with the idea as to limit the number of toggling between view states.boolean
unbind(TopologyEventListener eventListener)
Unbinds the given eventListener, returning whether or not it was bound at all.int
waitForAsyncEvents(long timeout)
for testing only: wait for any potentially queued async events to be delivered before returning.
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Method Detail
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installMinEventDelayHandler
public void installMinEventDelayHandler(DiscoveryService discoveryService, Scheduler scheduler, long minEventDelaySecs)
Description copied from interface:ViewStateManager
Installs an optional 'min event delay handler' which, using the given scheduler, delays sending TOPOLOGY_CHANGED event after receiving a handleNewView - with the idea as to limit the number of toggling between view states.- Specified by:
installMinEventDelayHandler
in interfaceViewStateManager
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bind
public void bind(TopologyEventListener eventListener)
Description copied from interface:ViewStateManager
Binds the given eventListener, sending it an INIT event if applicable.- Specified by:
bind
in interfaceViewStateManager
- Parameters:
eventListener
- the eventListener that is to bind
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unbind
public boolean unbind(TopologyEventListener eventListener)
Description copied from interface:ViewStateManager
Unbinds the given eventListener, returning whether or not it was bound at all.- Specified by:
unbind
in interfaceViewStateManager
- Parameters:
eventListener
- the eventListner that is to unbind- Returns:
- whether or not the listener was added in the first place
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handleActivated
public void handleActivated()
Description copied from interface:ViewStateManager
Handles activation - ie marks this manager as activated thus the TOPOLOGY_INIT event can be sent to already bound listeners and subsequent calls to handleChanging/handleNewView will result in according/appropriate TOPOLOGY_CHANGING/ TOPOLOGY_CHANGED events.- Specified by:
handleActivated
in interfaceViewStateManager
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handleDeactivated
public void handleDeactivated()
Description copied from interface:ViewStateManager
Must be called when the corresponding service (typically a DiscoveryService implementation) is deactivated.Will mark this manager as deactivated and flags the last available view as not current.
- Specified by:
handleDeactivated
in interfaceViewStateManager
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handleChanging
public void handleChanging()
Description copied from interface:ViewStateManager
Handles the fact that some (possibly early) indicator of a change in a topology has been detected and that a new view is being agreed upon (whatever that means, be it voting or similar).Will send out TOPOLOGY_CHANGING to all initialized listeners.
- Specified by:
handleChanging
in interfaceViewStateManager
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handleNewView
public void handleNewView(BaseTopologyView newView)
Description copied from interface:ViewStateManager
Handles the fact that a new view became true/established and sends out TOPOLOGY_INIT to uninitialized listeners and TOPOLOGY_CHANGED to already initialized listeners (in the latter case, also sends a TOPOLOGY_CHANGING if that has not yet been done)- Specified by:
handleNewView
in interfaceViewStateManager
- Parameters:
newView
- the new, established view true if we were either in changing mode or the newView was different from the previous one.
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waitForAsyncEvents
public int waitForAsyncEvents(long timeout)
Description copied from interface:ViewStateManager
for testing only: wait for any potentially queued async events to be delivered before returning.- Specified by:
waitForAsyncEvents
in interfaceViewStateManager
- Parameters:
timeout
- time in millis to wait for at max - 0 to not wait at all - -1 to wait indefinitely- Returns:
- 0 if no more async events exist, or the number of queued or in-flight (being sent) events if the timeout hit early
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