1 files changed, 127 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/index/StandardIndexer.java b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/index/StandardIndexer.java
new file mode 100644
index 00000000..9847a8dd
--- /dev/null
+++ b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/index/StandardIndexer.java
@@ -0,0 +1,127 @@
+/*******************************************************************************
+ * Copyright (c) 2004-2008 Gabor Bergmann and Daniel Varro
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-v20.html.
+ * 
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+
+package tools.refinery.viatra.runtime.rete.index;
+
+import java.util.Collection;
+import java.util.List;
+
+import tools.refinery.viatra.runtime.matchers.tuple.Tuple;
+import tools.refinery.viatra.runtime.matchers.tuple.TupleMask;
+import tools.refinery.viatra.runtime.matchers.util.CollectionsFactory;
+import tools.refinery.viatra.runtime.matchers.util.Direction;
+import tools.refinery.viatra.runtime.rete.network.BaseNode;
+import tools.refinery.viatra.runtime.rete.network.NetworkStructureChangeSensitiveNode;
+import tools.refinery.viatra.runtime.rete.network.ReteContainer;
+import tools.refinery.viatra.runtime.rete.network.Supplier;
+import tools.refinery.viatra.runtime.rete.network.communication.Timestamp;
+import tools.refinery.viatra.runtime.rete.traceability.TraceInfo;
+
+/**
+ * An abstract standard implementation of the Indexer interface, providing common bookkeeping functionality.
+ * 
+ * @author Gabor Bergmann
+ * 
+ */
+public abstract class StandardIndexer extends BaseNode implements Indexer, NetworkStructureChangeSensitiveNode {
+
+    protected Supplier parent;
+    private final List<IndexerListener> originalListeners;
+    private final List<IndexerListener> proxyListeners;
+    protected TupleMask mask;
+
+    public StandardIndexer(ReteContainer reteContainer, TupleMask mask) {
+        super(reteContainer);
+        this.parent = null;
+        this.mask = mask;
+        this.originalListeners = CollectionsFactory.createObserverList();
+        this.proxyListeners = CollectionsFactory.createObserverList();
+    }
+
+    /**
+     * @since 2.4
+     */
+    protected void propagate(Direction direction, Tuple updateElement, Tuple signature, boolean change, Timestamp timestamp) {
+        for (IndexerListener listener : proxyListeners) {
+            listener.notifyIndexerUpdate(direction, updateElement, signature, change, timestamp);
+        }
+    }
+
+    @Override
+    public TupleMask getMask() {
+        return mask;
+    }
+
+    @Override
+    public Supplier getParent() {
+        return parent;
+    }
+
+    @Override
+    public void attachListener(IndexerListener listener) {
+        this.getCommunicationTracker().registerDependency(this, listener.getOwner());
+        // obtain the proxy after registering the dependency because then the proxy reflects the new SCC structure
+        final IndexerListener proxy = this.getCommunicationTracker().proxifyIndexerListener(this, listener);
+        // See Bug 518434
+        // Must add to the first position, so that the later listeners are notified earlier.
+        // Thus if the beta node added as listener is also an indirect descendant of the same indexer on its opposite slot, 
+        // then the beta node is connected later than its ancestor's listener, therefore it will be notified earlier,
+        // eliminating duplicate insertions and lost deletions that would result from fall-through update propagation
+        this.originalListeners.add(0, listener);
+        this.proxyListeners.add(0, proxy);
+    }
+
+    @Override
+    public void detachListener(IndexerListener listener) {
+        this.originalListeners.remove(listener);
+        IndexerListener listenerToRemove = null;
+        for (final IndexerListener proxyListener : this.proxyListeners) {
+            if (proxyListener.getOwner() == listener.getOwner()) {
+                listenerToRemove = proxyListener;
+                break;
+            }
+        }
+        assert listenerToRemove != null;
+        this.proxyListeners.remove(listenerToRemove);
+        this.getCommunicationTracker().unregisterDependency(this, listener.getOwner());
+    }
+    
+    @Override
+    public void networkStructureChanged() {
+        this.proxyListeners.clear();
+        for (final IndexerListener original : this.originalListeners) {
+            this.proxyListeners.add(this.getCommunicationTracker().proxifyIndexerListener(this, original));
+        }
+    }
+
+    @Override
+    public Collection<IndexerListener> getListeners() {
+        return proxyListeners;
+    }
+
+    @Override
+    public ReteContainer getContainer() {
+        return reteContainer;
+    }
+
+    @Override
+    protected String toStringCore() {
+        return super.toStringCore() + "(" + parent + "/" + mask + ")";
+    }
+    
+    @Override
+    public void assignTraceInfo(TraceInfo traceInfo) {
+        super.assignTraceInfo(traceInfo);
+        if (traceInfo.propagateFromIndexerToSupplierParent())
+            if (parent != null)
+                parent.acceptPropagatedTraceInfo(traceInfo);
+    }
+
+    
+}