org.apache.cassandra.triggers

Class TriggerExecutor

java.lang.Object

org.apache.cassandra.triggers.TriggerExecutor

public class TriggerExecutor
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field and Description
static TriggerExecutor	instance

Method Summary

Modifier and Type	Method and Description
java.util.Collection<Mutation>	execute(java.util.Collection<? extends IMutation> mutations) Takes a collection of mutations and possibly augments it by adding extra mutations generated by configured triggers.
PartitionUpdate	execute(PartitionUpdate updates) Augment a partition update by executing triggers to generate an intermediate set of mutations, then merging the update from each mutation with those supplied.
ITrigger	loadTriggerInstance(java.lang.String triggerClass)
void	reloadClasses() Reload the triggers which is already loaded, Invoking this will update the class loader so new jars can be loaded.

Methods inherited from class java.lang.Object

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

Field Detail

instance

public static final TriggerExecutor instance

Method Detail

reloadClasses

public void reloadClasses()

Reload the triggers which is already loaded, Invoking this will update the class loader so new jars can be loaded.

execute

public PartitionUpdate execute(PartitionUpdate updates)
                        throws InvalidRequestException

Augment a partition update by executing triggers to generate an intermediate set of mutations, then merging the update from each mutation with those supplied. This is called from @{link org.apache.cassandra.service.StorageProxy#cas} which is scoped for a single partition. For that reason, any mutations generated by triggers are checked to ensure that they are for the same table and partition key as the primary update; if not, InvalidRequestException is thrown. If no additional mutations are generated, the original updates are returned unmodified.

Parameters:

updates - partition update to be applied, contains the merge of the original update and any generated mutations

Returns:

the final update to be applied, the original update merged with any additional mutations generated by configured triggers

Throws:

InvalidRequestException - if any mutation generated by a trigger does not apply to the exact same partition as the initial update

execute

public java.util.Collection<Mutation> execute(java.util.Collection<? extends IMutation> mutations)
                                       throws InvalidRequestException

Takes a collection of mutations and possibly augments it by adding extra mutations generated by configured triggers. If no additional mutations are created this returns null, signalling to the caller that only the initial set of mutations should be applied. If additional mutations are generated, the total set (i.e. the original plus the additional mutations) are applied together in a logged batch. Should this not be possible because the initial mutations contain counter updates, InvalidRequestException is thrown.

Parameters:

mutations - initial collection of mutations

Returns:

augmented mutations. Either the union of the initial and additional mutations or null if no additional mutations were generated

Throws:

InvalidRequestException - if additional mutations were generated, but the initial mutations contains counter updates

loadTriggerInstance

public ITrigger loadTriggerInstance(java.lang.String triggerClass)
                             throws java.lang.Exception

Throws:

java.lang.Exception