org.apache.solr.cloud.autoscaling

Interface AutoScaling.Trigger

All Superinterfaces:

AutoCloseable, Closeable, Runnable

All Known Implementing Classes:

IndexSizeTrigger, MetricTrigger, NodeAddedTrigger, NodeLostTrigger, ScheduledTrigger, SearchRateTrigger, TriggerBase

Enclosing class:

AutoScaling

public static interface AutoScaling.Trigger
extends Closeable, Runnable

Interface for a Solr trigger. Each trigger implements Runnable and Closeable interface. A trigger is scheduled using a ScheduledExecutorService so it is executed as per a configured schedule to check whether the trigger is ready to fire. The setProcessor(AutoScaling.TriggerEventProcessor) method should be used to set a processor which is used by implementation of this class whenever ready.

As per the guarantees made by the ScheduledExecutorService a trigger implementation is only ever called sequentially and therefore need not be thread safe. However, it is encouraged that implementations be immutable with the exception of the associated listener which can be get/set by a different thread than the one executing the trigger. Therefore, implementations should use appropriate synchronization around the listener.

When a trigger is ready to fire, it calls the AutoScaling.TriggerEventProcessor.process(TriggerEvent) event with the proper trigger event object. If that method returns false then it should be interpreted to mean that Solr is not ready to process this trigger event and therefore we should retain the state and fire at the next invocation of the run() method.

Method Summary

Modifier and Type	Method and Description
void	configure(SolrResourceLoader loader, SolrCloudManager cloudManager, Map<String,Object> properties) Called when trigger is created but before it's initialized or scheduled for use.
List<TriggerAction>	getActions() Actions to execute when event is fired.
TriggerEventType	getEventType() Event type generated by this trigger.
String	getName() Trigger name.
AutoScaling.TriggerEventProcessor	getProcessor() Get event processor.
Map<String,Object>	getProperties() Trigger properties.
int	getWaitForSecond() Number of seconds to wait between fired events ("waitFor" property).
void	init() Called before a trigger is scheduled.
boolean	isClosed() Return true when this trigger is closed and cannot be used.
boolean	isEnabled() Returns true if this trigger is enabled.
void	restoreState() Restore internal state of this trigger from ZooKeeper.
void	restoreState(AutoScaling.Trigger old) Set internal state of this trigger from another instance.
void	saveState() Save internal state of this trigger in ZooKeeper.
void	setProcessor(AutoScaling.TriggerEventProcessor processor) Set event processor to call when event is fired.

Methods inherited from interface java.io.Closeable

close

Methods inherited from interface java.lang.Runnable

run

Method Detail

getName

String getName()

Trigger name.

getEventType

TriggerEventType getEventType()

Event type generated by this trigger.

isEnabled

boolean isEnabled()

Returns true if this trigger is enabled.

getProperties

Map<String,Object> getProperties()

Trigger properties.

getWaitForSecond

int getWaitForSecond()

Number of seconds to wait between fired events ("waitFor" property).

getActions

List<TriggerAction> getActions()

Actions to execute when event is fired.

setProcessor

void setProcessor(AutoScaling.TriggerEventProcessor processor)

Set event processor to call when event is fired.

getProcessor

AutoScaling.TriggerEventProcessor getProcessor()

Get event processor.

isClosed

boolean isClosed()

Return true when this trigger is closed and cannot be used.

restoreState

void restoreState(AutoScaling.Trigger old)

Set internal state of this trigger from another instance.

saveState

void saveState()

Save internal state of this trigger in ZooKeeper.

restoreState

void restoreState()

Restore internal state of this trigger from ZooKeeper.

configure

void configure(SolrResourceLoader loader,
               SolrCloudManager cloudManager,
               Map<String,Object> properties)
        throws TriggerValidationException

Called when trigger is created but before it's initialized or scheduled for use. This method should also verify that the trigger configuration parameters are correct. It may be called multiple times.

Parameters:

properties - configuration properties

Throws:

TriggerValidationException - contains details of invalid configuration parameters.

init

void init()
   throws Exception

Called before a trigger is scheduled. Any heavy object creation or initialisation should be done in this method instead of the Trigger's constructor.

Throws:

Exception