Merge pull request #507 from TNO/440-prevent-the-same-knowledge-base-…

…to-be-contacted-multiple-times-in-a-single-interaction

Fix applying a rule multiple times.

reasoner/src/main/java/eu/knowledge/engine/reasoner/BaseRule.java

@@ -392,6 +392,10 @@ protected void setName(String aName) {
 		this.name = aName;
 	}
 
+	protected String getName() {
+		return name;
+	}
+
 	@Override
 	public int hashCode() {
 		final int prime = 31;

reasoner/src/main/java/eu/knowledge/engine/reasoner/ReasonerPlan.java

@@ -120,9 +120,9 @@ public TaskBoard execute(BindingSet bindingSet) {
 
 				// Ready, and current version of input has not been scheduled on taskboard? ->
 				// Add to taskboard otherwise -> Do not add to taskboard
-				if (current.readyForApplyRule() && !current.isResultBindingSetInputScheduled()) {
+				if (current.readyForApplyRule() && !current.isResultBindingSetInputAlreadyScheduledOrDone()) {
 					this.scheduleOrDoTask(current, taskBoard);
-					current.setResultBindingSetInputScheduled(true);
+					current.setResultBindingSetInputAlreadyScheduledOrDone(true);
 				}
 
 				if (current.shouldPropagateFilterBindingSetOutput()) {
@@ -145,10 +145,18 @@ public TaskBoard execute(BindingSet bindingSet) {
 					((ConsSide) current).getConsequentNeighbours().forEach((n, matches) -> {
 						var translated = toBeResultPropagated.translate(n.getRule().getAntecedent(),
 								Match.invertAll(matches));
+
+						TripleVarBindingSet beforeBindingSet = n.getResultBindingSetInput();
 						boolean itChanged = ((AntSide) n).addResultBindingSetInput(current, translated);
+						TripleVarBindingSet afterBindingSet = n.getResultBindingSetInput();
 						if (itChanged) {
 							changed.add(n);
-							n.setResultBindingSetInputScheduled(false);
+
+							// We should only set this to false if the actual binding set of the
+							// BindngSetStore.get() method changes. Otherwise rules get applied multiple
+							// times with the same binding set.
+							if (!beforeBindingSet.equals(afterBindingSet))
+								n.setResultBindingSetInputAlreadyScheduledOrDone(false);
 						}
 					});
 					current.setResultBindingSetOutputPropagated();
@@ -287,7 +295,6 @@ private RuleNode createOrGetReasonerNode(BaseRule aRule, BaseRule aParent) {
 	private void scheduleOrDoTask(RuleNode current, TaskBoard taskBoard) {
 		if (this.useTaskBoard) {
 			taskBoard.addTask(current);
-			current.setResultBindingSetInputScheduled(true);
 		} else {
 			try {
 				current.applyRule().get();

reasoner/src/main/java/eu/knowledge/engine/reasoner/rulenode/RuleNode.java

@@ -52,11 +52,11 @@ public BaseRule getRule() {
 
 	public abstract Set<RuleNode> getAllSameLoopNeighbors();
 
-	public void setResultBindingSetInputScheduled(boolean b) {
+	public void setResultBindingSetInputAlreadyScheduledOrDone(boolean b) {
 		this.resultBindingSetOutputScheduled = b;
 	}
 
-	public boolean isResultBindingSetInputScheduled() {
+	public boolean isResultBindingSetInputAlreadyScheduledOrDone() {
 		return this.resultBindingSetOutputScheduled;
 	}