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Jadex Rules is a small lightweight rule engine, which currently
employs the well-known Rete algorithm for highly efficient rule
matching. Jadex rules is therefore similar to other rule engines
like JESS and Drools. Despite the similarities there are also
important differences between these systems:
* Jadex Rules is very small and
intended to be used as component
of other software. Even though rules can be specified in a Java
dialect as well as (a small variation of) the CLIPS language
its primary usage is on the API level. Jadex Rules is currently
the core component of the Jadex BDI reasoning engine.
* Jadex Rules cleanly separates between state and rule representation.
This allows the state implementation as well as the matcher to be
flexibly exchanged. Some experiments have e.g. been conducted with
a Jena representation. Regarding the matcher, it is planned to
support also the Treat algorithm, which has a lower memory footprint
than Rete.
* Jadex Rules pays close attention to rule debugging. The state as
well as the rete engine can be observed at runtime. The rule debugger
provides functionalities to execute a rule program stepwise and also
use rule breakpoints to stop the execution at those points.
package jadex.rules.rulesystem.rete.nodes;
import jadex.rules.rulesystem.AbstractAgenda;
import jadex.rules.rulesystem.rete.Tuple;
import jadex.rules.rulesystem.rete.constraints.IConstraintEvaluator;
import jadex.rules.rulesystem.rete.extractors.AttributeSet;
import jadex.rules.state.IOAVState;
import jadex.rules.state.IProfiler;
import jadex.rules.state.OAVAttributeType;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* The purpose of a collect node is to compress a number of tuples to a
* new tuple, which contains a multi slot.
* Example: Incoming tuples are:
* [a, b, d1]
* [a, b, d2]
* [a, c, d3]
* [a, c, d1]
* ->
* [a, b, {d1, d2}]
* [a, c, {d3, d1}]
*/
public class CollectNode extends AbstractNode implements ITupleConsumerNode, ITupleSourceNode
{
//-------- attributes --------
/** The tuple consumers. */
protected ITupleConsumerNode[] tconsumers;
/** The tuple source. */
protected ITupleSourceNode tsource;
/** The constraint evaluator. */
protected IConstraintEvaluator[] evaluators;
/** The set of relevant attributes. */
protected AttributeSet relevants;
/** The set of indirect attributes. */
protected AttributeSet indirects;
/** The tuple index to collect. */
protected int tupleindex;
//-------- constructors --------
/**
* Create a new beta node.
*/
public CollectNode(int nodeid, int tupleindex, IConstraintEvaluator[] evaluators)
{
super(nodeid);
this.tupleindex = tupleindex;
this.evaluators = evaluators;
}
//-------- tuple source interface --------
/**
* Add an tuple consumer node.
* @param node A new consumer node.
*/
public void addTupleConsumer(ITupleConsumerNode node)
{
if(tconsumers==null)
{
tconsumers = new ITupleConsumerNode[]{node};
}
else
{
ITupleConsumerNode[] tmp = new ITupleConsumerNode[tconsumers.length+1];
System.arraycopy(tconsumers, 0, tmp, 0, tconsumers.length);
tmp[tconsumers.length] = node;
tconsumers = tmp;
}
relevants = null; // Will be recalculated on next access;
}
/**
* Remove an tuple consumer.
* @param node The consumer node.
*/
public void removeTupleConsumer(ITupleConsumerNode node)
{
if(tconsumers!=null)
{
for(int i=0; i0)
System.arraycopy(tconsumers, 0, tmp, 0, i);
if(i add
if(!nodemem.resultMemoryContains(resulttuple))
{
nodemem.addResultTuple(resulttuple);
propagateAdditionToTupleConsumers(resulttuple, state, mem, agenda);
}
// If constraints passed and in result -> modify
else
{
// todo:
propagateModificationToTupleConsumers(resulttuple, null, null, resulttuple, state, mem, agenda);
}
}
else
{
// If constraints not passed and in result -> remove
if(nodemem.resultMemoryContains(resulttuple))
{
nodemem.removeResultTuple(resulttuple);
propagateRemovalToTupleConsumers(resulttuple, state, mem, agenda);
}
// If constraints not passed and not in result -> nop
}
state.getProfiler().stop(IProfiler.TYPE_NODEEVENT, IProfiler.NODEEVENT_TUPLEADDED);
state.getProfiler().stop(IProfiler.TYPE_NODE, this);
// System.out.println(nodemem);
}
/**
* Remove a tuple from this node.
* @param tuple The tuple.
*/
public void removeTuple(Tuple left, IOAVState state, ReteMemory mem, AbstractAgenda agenda)
{
// if(getNodeId()==531)
// System.out.println("Remove tuple called: "+this+" "+left);
state.getProfiler().start(IProfiler.TYPE_NODE, this);
state.getProfiler().start(IProfiler.TYPE_NODEEVENT, IProfiler.NODEEVENT_TUPLEREMOVED);
Tuple indextuple = createIndexTuple(state, left, mem);
CollectMemory nodemem = (CollectMemory)mem.getNodeMemory(this);
Tuple resulttuple = nodemem.getWorkingTuple(indextuple);
assert resulttuple!=null: "No working tuple found: "+indextuple;
Object val = left.getObject(tupleindex);
Set vals = (Set)resulttuple.getObject(tupleindex);
boolean removed = vals.remove(val);
// Remove tuple when last element is removed from set.
if(vals.isEmpty())
{
nodemem.removeWorkingTuple(indextuple);
if(nodemem.resultMemoryContains(resulttuple))
{
nodemem.removeResultTuple(resulttuple);
propagateRemovalToTupleConsumers(resulttuple, state, mem, agenda);
}
}
// Check constraints if at least one element.
else
{
assert removed: "Value not found in result tuple: "+val;
if(checkConstraints(resulttuple, state))
{
// If constraints passed and not in result -> add
if(!nodemem.resultMemoryContains(resulttuple))
{
nodemem.addResultTuple(resulttuple);
propagateAdditionToTupleConsumers(resulttuple, state, mem, agenda);
}
// If constraints passed and in result -> modify
else
{
// todo:
propagateModificationToTupleConsumers(resulttuple, null, null, resulttuple, state, mem, agenda);
}
}
else
{
// If constraints not passed and in result -> remove
if(nodemem.resultMemoryContains(resulttuple))
{
nodemem.removeResultTuple(resulttuple);
propagateRemovalToTupleConsumers(resulttuple, state, mem, agenda);
}
// If constraints not passed and not in result -> nop
}
}
state.getProfiler().stop(IProfiler.TYPE_NODEEVENT, IProfiler.NODEEVENT_TUPLEREMOVED);
state.getProfiler().stop(IProfiler.TYPE_NODE, this);
// System.out.println(nodemem);
}
/**
* Modify a tuple in this node.
* @param left The tuple.
*/
public void modifyTuple(Tuple left, int tupleindex, OAVAttributeType type,
Object oldvalue, Object newvalue, IOAVState state, ReteMemory mem, AbstractAgenda agenda)
{
// if(getNodeId()==531)
// System.out.println("Modify tuple called: "+this+" "+left);
if(!getRelevantAttributes().contains(type))
return;
// Problem: changed tuple could produce changed indextuple -> no identification of old value
Tuple indextuple = createIndexTuple(state, left, mem);
CollectMemory nodemem = (CollectMemory)mem.getNodeMemory(this);
Tuple resulttuple = nodemem.getWorkingTuple(indextuple);
assert resulttuple!=null: "No working tuple found: "+indextuple;
// Check if modification changes node memory.
boolean affected = isAffected(type);
if(affected)
{
boolean contains = nodemem.resultMemoryContains(resulttuple);
boolean check = checkConstraints(resulttuple, state);
// Object no longer valid -> remove
if(contains && !check)
{
nodemem.removeResultTuple(resulttuple);
propagateRemovalToTupleConsumers(resulttuple, state, mem, agenda);
}
// Tuple newly valid -> add
else if(!contains && check)
{
nodemem.addResultTuple(resulttuple);
propagateAdditionToTupleConsumers(resulttuple, state, mem, agenda);
}
else if(contains)
{
propagateModificationToTupleConsumers(resulttuple, type, oldvalue, newvalue,
state, mem, agenda);
}
}
else
{
// Tuple changed in memory -> propagate modification
boolean contains = nodemem.resultMemoryContains(resulttuple);
if(contains)
{
propagateModificationToTupleConsumers(resulttuple, type, oldvalue, newvalue,
state, mem, agenda);
}
}
state.getProfiler().start(IProfiler.TYPE_NODE, this);
state.getProfiler().start(IProfiler.TYPE_NODEEVENT, IProfiler.NODEEVENT_TUPLEMODIFIED);
state.getProfiler().stop(IProfiler.TYPE_NODEEVENT, IProfiler.NODEEVENT_TUPLEMODIFIED);
state.getProfiler().stop(IProfiler.TYPE_NODE, this);
// System.out.println(nodemem);
}
/**
* Propagate an indirect object change to this node.
* @param object The changed object.
*/
public void modifyIndirectObject(Object object, OAVAttributeType type, Object oldvalue, Object newvalue, IOAVState state, ReteMemory mem, AbstractAgenda agenda)
{
throw new UnsupportedOperationException("Unsupported method.");
}
/**
* Set the tuple source of this node.
* @param node The tuple source node.
*/
public void setTupleSource(ITupleSourceNode node)
{
this.tsource = node;
}
/**
* Get the tuple source of this node.
* @return The object source node.
*/
public ITupleSourceNode getTupleSource()
{
return tsource;
}
//-------- methods --------
/**
* Create the node memory.
* @param state The state.
* @return The node memory.
*/
public Object createNodeMemory(IOAVState state)
{
return new CollectMemory();
}
/**
* Get the evaluators.
* @return The evaluators.
*/
public IConstraintEvaluator[] getConstraintEvaluators()
{
return evaluators;
}
//-------- methods --------
/**
* Test if the node is affected from a modification.
* @param type The attribute type.
* @return True, if possibly affected.
*/
public boolean isAffected(OAVAttributeType attr)
{
boolean ret = false;
for(int i=0; !ret && evaluators!=null && i