org.eclipse.incquery.runtime.rete.misc

Class DeltaMonitor<MatchType>

java.lang.Object

org.eclipse.incquery.runtime.rete.network.BaseNode

org.eclipse.incquery.runtime.rete.misc.SimpleReceiver

org.eclipse.incquery.runtime.rete.misc.DeltaMonitor<MatchType>

All Implemented Interfaces:

Node, Receiver, Clearable

Direct Known Subclasses:

DefaultDeltaMonitor

public abstract class DeltaMonitor<MatchType>
extends SimpleReceiver
implements Clearable

A monitoring object that connects to the rete network as a receiver to reflect changes since an arbitrary state acknowledged by the client. Match tuples are represented by a type MatchType.

Usage. If a new matching is found, it appears in the matchFoundEvents collection, and disappears when that particular matching cannot be found anymore. If the event of finding a match has been processed by the client, it can be removed manually. In this case, when a previously found matching is lost, the Tuple will appear in the matchLostEvents collection, and disappear upon finding the same matching again. "Matching lost" events can also be acknowledged by removing a Tuple from the collection. If the matching is found once again, it will return to matchFoundEvents.

Technical notes. Does NOT propagate updates! By overriding statelessConvert(), results can be stored to a MatchType. MatchType must provide equals() and hashCode() reflecting its contents. The default implementation (DefaultDeltaMonitor) uses Tuple as MatchType. By overriding statelessFilter(), some tuples can be filtered.

Author:

Gabor Bergmann

Field Summary

Fields

Modifier and Type	Field and Description
java.util.Collection<MatchType>	matchFoundEvents matches that are newly found
java.util.Collection<MatchType>	matchLostEvents matches that are newly lost

Constructor Summary

Constructors

Constructor and Description
DeltaMonitor(ReteContainer reteContainer)

Method Summary

Modifier and Type	Method and Description
void	clear() Clear all partial matchings stored in memory
abstract MatchType	statelessConvert(Tuple tuple)
boolean	statelessFilter(Tuple tuple) Override this method to provide a lightweight, stateless filter on the tuples
void	update(Direction direction, Tuple updateElement) updates the receiver with a newly found or lost partial matching

Methods inherited from class org.eclipse.incquery.runtime.rete.misc.SimpleReceiver

appendParent, assignTraceInfo, disconnectFromNetwork, getParents, removeParent

Methods inherited from class org.eclipse.incquery.runtime.rete.network.BaseNode

acceptPropagatedTraceInfo, getContainer, getNodeId, getTag, getTraceInfos, setTag, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.eclipse.incquery.runtime.rete.network.Node

acceptPropagatedTraceInfo, getContainer, getNodeId, getTag, getTraceInfos, setTag

Field Detail

matchFoundEvents

public java.util.Collection<MatchType> matchFoundEvents

matches that are newly found

matchLostEvents

public java.util.Collection<MatchType> matchLostEvents

matches that are newly lost

Constructor Detail

DeltaMonitor

public DeltaMonitor(ReteContainer reteContainer)

Parameters:

reteContainer -

Method Detail

statelessFilter

public boolean statelessFilter(Tuple tuple)

Override this method to provide a lightweight, stateless filter on the tuples

Parameters:

tuple - the occurrence that is to be filtered

Returns:

true if this tuple should be monitored, false if ignored

statelessConvert

public abstract MatchType statelessConvert(Tuple tuple)

update

public void update(Direction direction,
                   Tuple updateElement)

Description copied from interface: Receiver

updates the receiver with a newly found or lost partial matching

Specified by:

update in interface Receiver

clear

public void clear()

Description copied from interface: Clearable

Clear all partial matchings stored in memory

Specified by:

clear in interface Clearable