1 files changed, 729 insertions, 0 deletions
diff --git a/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/network/ReteContainer.java b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/network/ReteContainer.java
new file mode 100644
index 00000000..16e290fd
--- /dev/null
+++ b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/network/ReteContainer.java
@@ -0,0 +1,729 @@
+/*******************************************************************************
+ * 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.network;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Deque;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.LinkedList;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Function;
+import org.apache.log4j.Logger;
+import tools.refinery.viatra.runtime.matchers.context.IQueryBackendContext;
+import tools.refinery.viatra.runtime.matchers.tuple.Tuple;
+import tools.refinery.viatra.runtime.matchers.util.Clearable;
+import tools.refinery.viatra.runtime.matchers.util.CollectionsFactory;
+import tools.refinery.viatra.runtime.matchers.util.Direction;
+import tools.refinery.viatra.runtime.matchers.util.timeline.Timeline;
+import tools.refinery.viatra.runtime.rete.boundary.InputConnector;
+import tools.refinery.viatra.runtime.rete.matcher.TimelyConfiguration;
+import tools.refinery.viatra.runtime.rete.network.communication.CommunicationGroup;
+import tools.refinery.viatra.runtime.rete.network.communication.CommunicationTracker;
+import tools.refinery.viatra.runtime.rete.network.communication.Timestamp;
+import tools.refinery.viatra.runtime.rete.network.communication.timeless.TimelessCommunicationTracker;
+import tools.refinery.viatra.runtime.rete.network.communication.timely.TimelyCommunicationTracker;
+import tools.refinery.viatra.runtime.rete.network.delayed.DelayedCommand;
+import tools.refinery.viatra.runtime.rete.network.delayed.DelayedConnectCommand;
+import tools.refinery.viatra.runtime.rete.network.delayed.DelayedDisconnectCommand;
+import tools.refinery.viatra.runtime.rete.remote.Address;
+import tools.refinery.viatra.runtime.rete.single.SingleInputNode;
+import tools.refinery.viatra.runtime.rete.single.TrimmerNode;
+import tools.refinery.viatra.runtime.rete.util.Options;
+/**
+ * @author Gabor Bergmann
+ *
+ *         Mutexes: externalMessageLock - enlisting messages into and retrieving from the external message queue
+ * @since 2.2
+ */
+public final class ReteContainer {
+    protected Thread consumerThread = null;
+    protected boolean killed = false;
+    protected Network network;
+    protected LinkedList<Clearable> clearables;
+    protected Map<Long, Node> nodesById;
+    protected long nextId = 0;
+    protected ConnectionFactory connectionFactory;
+    protected NodeProvisioner nodeProvisioner;
+    protected Deque<UpdateMessage> internalMessageQueue = new ArrayDeque<UpdateMessage>();
+    protected/* volatile */Deque<UpdateMessage> externalMessageQueue = new ArrayDeque<UpdateMessage>();
+    protected Object externalMessageLock = new Object();
+    protected Long clock = 1L; // even: steady state, odd: active queue; access
+                               // ONLY with messageQueue locked!
+    protected Map<ReteContainer, Long> terminationCriteria = null;
+    protected final Logger logger;
+    protected final CommunicationTracker tracker;
+    protected final IQueryBackendContext backendContext;
+    protected Set<DelayedCommand> delayedCommandQueue;
+    protected Set<DelayedCommand> delayedCommandBuffer;
+    protected boolean executingDelayedCommands;
+    protected final TimelyConfiguration timelyConfiguration;
+    /**
+     * @param threaded
+     *            false if operating in a single-threaded environment
+     */
+    public ReteContainer(Network network, boolean threaded) {
+        super();
+        this.network = network;
+        this.backendContext = network.getEngine().getBackendContext();
+        this.timelyConfiguration = network.getEngine().getTimelyConfiguration();
+        this.delayedCommandQueue = new LinkedHashSet<DelayedCommand>();
+        this.delayedCommandBuffer = new LinkedHashSet<DelayedCommand>();
+        this.executingDelayedCommands = false;
+        if (this.isTimelyEvaluation()) {
+            this.tracker = new TimelyCommunicationTracker(this.getTimelyConfiguration());
+        } else {
+            this.tracker = new TimelessCommunicationTracker();
+        }
+        this.nodesById = CollectionsFactory.createMap();
+        this.clearables = new LinkedList<Clearable>();
+        this.logger = network.getEngine().getLogger();
+        this.connectionFactory = new ConnectionFactory(this);
+        this.nodeProvisioner = new NodeProvisioner(this);
+        if (threaded) {
+            this.terminationCriteria = CollectionsFactory.createMap();
+            this.consumerThread = new Thread("Rete thread of " + ReteContainer.super.toString()) {
+                @Override
+                public void run() {
+                    messageConsumptionCycle();
+                }
+            };
+            this.consumerThread.start();
+        }
+    }
+    /**
+     * @since 2.4
+     */
+    public boolean isTimelyEvaluation() {
+        return this.timelyConfiguration != null;
+    }
+    /**
+     * @since 2.4
+     */
+    public TimelyConfiguration getTimelyConfiguration() {
+        return this.timelyConfiguration;
+    }
+    /**
+     * @since 1.6
+     * @return the communication graph of the nodes, incl. message scheduling
+     */
+    public CommunicationTracker getCommunicationTracker() {
+        return tracker;
+    }
+    /**
+     * Stops this container. To be called by Network.kill()
+     */
+    public void kill() {
+        killed = true;
+        if (consumerThread != null)
+            consumerThread.interrupt();
+    }
+    /**
+     * Establishes connection between a supplier and a receiver node, regardless which container they are in. Assumption
+     * is that this container is the home of the receiver, but it is not strictly necessary.
+     *
+     * @param synchronise
+     *            indicates whether the receiver should be synchronised to the current contents of the supplier
+     */
+    public void connectRemoteNodes(Address<? extends Supplier> supplier, Address<? extends Receiver> receiver,
+            boolean synchronise) {
+        if (!isLocal(receiver))
+            receiver.getContainer().connectRemoteNodes(supplier, receiver, synchronise);
+        else {
+            Receiver child = resolveLocal(receiver);
+            connectRemoteSupplier(supplier, child, synchronise);
+        }
+    }
+    /**
+     * Severs connection between a supplier and a receiver node, regardless which container they are in. Assumption is
+     * that this container is the home of the receiver, but it is not strictly necessary.
+     *
+     * @param desynchronise
+     *            indicates whether the current contents of the supplier should be subtracted from the receiver
+     */
+    public void disconnectRemoteNodes(Address<? extends Supplier> supplier, Address<? extends Receiver> receiver,
+            boolean desynchronise) {
+        if (!isLocal(receiver))
+            receiver.getContainer().disconnectRemoteNodes(supplier, receiver, desynchronise);
+        else {
+            Receiver child = resolveLocal(receiver);
+            disconnectRemoteSupplier(supplier, child, desynchronise);
+        }
+    }
+    /**
+     * Establishes connection between a remote supplier and a local receiver node.
+     *
+     * @param synchronise
+     *            indicates whether the receiver should be synchronised to the current contents of the supplier
+     */
+    public void connectRemoteSupplier(Address<? extends Supplier> supplier, Receiver receiver, boolean synchronise) {
+        Supplier parent = nodeProvisioner.asSupplier(supplier);
+        if (synchronise)
+            connectAndSynchronize(parent, receiver);
+        else
+            connect(parent, receiver);
+    }
+    /**
+     * Severs connection between a remote supplier and a local receiver node.
+     *
+     * @param desynchronise
+     *            indicates whether the current contents of the supplier should be subtracted from the receiver
+     */
+    public void disconnectRemoteSupplier(Address<? extends Supplier> supplier, Receiver receiver,
+            boolean desynchronise) {
+        Supplier parent = nodeProvisioner.asSupplier(supplier);
+        if (desynchronise)
+            disconnectAndDesynchronize(parent, receiver);
+        else
+            disconnect(parent, receiver);
+    }
+    /**
+     * Connects a receiver to a supplier
+     */
+    public void connect(Supplier supplier, Receiver receiver) {
+        supplier.appendChild(receiver);
+        receiver.appendParent(supplier);
+        tracker.registerDependency(supplier, receiver);
+    }
+    /**
+     * Disconnects a receiver from a supplier
+     */
+    public void disconnect(Supplier supplier, Receiver receiver) {
+        supplier.removeChild(receiver);
+        receiver.removeParent(supplier);
+        tracker.unregisterDependency(supplier, receiver);
+    }
+    /**
+     * @since 2.3
+     */
+    public boolean isExecutingDelayedCommands() {
+        return this.executingDelayedCommands;
+    }
+    /**
+     * @since 2.3
+     */
+    public Set<DelayedCommand> getDelayedCommandQueue() {
+        if (this.executingDelayedCommands) {
+            return this.delayedCommandBuffer;
+        } else {
+            return this.delayedCommandQueue;
+        }
+    }
+    /**
+     * Connects a receiver to a remote supplier, and synchronizes it to the current contents of the supplier
+     */
+    public void connectAndSynchronize(Supplier supplier, Receiver receiver) {
+        supplier.appendChild(receiver);
+        receiver.appendParent(supplier);
+        tracker.registerDependency(supplier, receiver);
+        getDelayedCommandQueue().add(new DelayedConnectCommand(supplier, receiver, this));
+    }
+    /**
+     * Disconnects a receiver from a supplier
+     */
+    public void disconnectAndDesynchronize(Supplier supplier, Receiver receiver) {
+        final boolean wasInSameSCC = this.isTimelyEvaluation() && this.tracker.areInSameGroup(supplier, receiver);
+        supplier.removeChild(receiver);
+        receiver.removeParent(supplier);
+        tracker.unregisterDependency(supplier, receiver);
+        getDelayedCommandQueue().add(new DelayedDisconnectCommand(supplier, receiver, this, wasInSameSCC));
+    }
+    /**
+     * @since 2.3
+     */
+    public void executeDelayedCommands() {
+        if (!this.delayedCommandQueue.isEmpty()) {
+            flushUpdates();
+            this.executingDelayedCommands = true;
+            for (final DelayedCommand command : this.delayedCommandQueue) {
+                command.run();
+            }
+            this.delayedCommandQueue = this.delayedCommandBuffer;
+            this.delayedCommandBuffer = new LinkedHashSet<DelayedCommand>();
+            flushUpdates();
+            this.executingDelayedCommands = false;
+        }
+    }
+    /**
+     * Sends an update message to the receiver node, indicating a newly found or lost partial matching. The receiver is
+     * indicated by the Address. Designed to be called by the Network, DO NOT use in any other way. @pre:
+     * address.container == this, e.g. address MUST be local
+     *
+     * @return the value of the container's clock at the time when the message was accepted into the local message queue
+     */
+    long sendUpdateToLocalAddress(Address<? extends Receiver> address, Direction direction, Tuple updateElement) {
+        long timestamp;
+        Receiver receiver = resolveLocal(address);
+        UpdateMessage message = new UpdateMessage(receiver, direction, updateElement);
+        synchronized (externalMessageLock) {
+            externalMessageQueue.add(message);
+            timestamp = clock;
+            externalMessageLock.notifyAll();
+        }
+        return timestamp;
+    }
+    /**
+     * Sends multiple update messages atomically to the receiver node, indicating a newly found or lost partial
+     * matching. The receiver is indicated by the Address. Designed to be called by the Network, DO NOT use in any other
+     * way. @pre: address.container == this, e.g. address MUST be local @pre: updateElements is nonempty!
+     *
+     * @return the value of the container's clock at the time when the message was accepted into the local message queue
+     */
+    long sendUpdatesToLocalAddress(Address<? extends Receiver> address, Direction direction,
+            Collection<Tuple> updateElements) {
+        long timestamp;
+        Receiver receiver = resolveLocal(address);
+        // UpdateMessage message = new UpdateMessage(receiver, direction,
+        // updateElement);
+        synchronized (externalMessageLock) {
+            for (Tuple ps : updateElements)
+                externalMessageQueue.add(new UpdateMessage(receiver, direction, ps));
+            // messageQueue.add(new UpdateMessage(resolveLocal(address),
+            // direction, updateElement));
+            // this.sendUpdateInternal(resolveLocal(address), direction,
+            // updateElement);
+            timestamp = clock;
+            externalMessageLock.notifyAll();
+        }
+        return timestamp;
+    }
+    /**
+     * Sends an update message to the receiver node, indicating a newly found or lost partial matching. The receiver is
+     * indicated by the Address. Designed to be called by the Network in single-threaded operation, DO NOT use in any
+     * other way.
+     */
+    void sendUpdateToLocalAddressSingleThreaded(Address<? extends Receiver> address, Direction direction,
+            Tuple updateElement) {
+        Receiver receiver = resolveLocal(address);
+        UpdateMessage message = new UpdateMessage(receiver, direction, updateElement);
+        internalMessageQueue.add(message);
+    }
+    /**
+     * Sends multiple update messages to the receiver node, indicating a newly found or lost partial matching. The
+     * receiver is indicated by the Address. Designed to be called by the Network in single-threaded operation, DO NOT
+     * use in any other way.
+     *
+     * @pre: address.container == this, e.g. address MUST be local
+     */
+    void sendUpdatesToLocalAddressSingleThreaded(Address<? extends Receiver> address, Direction direction,
+            Collection<Tuple> updateElements) {
+        Receiver receiver = resolveLocal(address);
+        for (Tuple ps : updateElements)
+            internalMessageQueue.add(new UpdateMessage(receiver, direction, ps));
+    }
+    /**
+     * Sends an update message to a node in a different container. The receiver is indicated by the Address. Designed to
+     * be called by RemoteReceivers, DO NOT use in any other way.
+     *
+     * @since 2.4
+     */
+    public void sendUpdateToRemoteAddress(Address<? extends Receiver> address, Direction direction,
+            Tuple updateElement) {
+        ReteContainer otherContainer = address.getContainer();
+        long otherClock = otherContainer.sendUpdateToLocalAddress(address, direction, updateElement);
+        // Long criterion = terminationCriteria.get(otherContainer);
+        // if (criterion==null || otherClock > criterion)
+        terminationCriteria.put(otherContainer, otherClock);
+    }
+    /**
+     * Finalises all update sequences and returns. To be called from user threads (e.g. network construction).
+     */
+    public void flushUpdates() {
+        network.waitForReteTermination();
+        // synchronized (messageQueue)
+        // {
+        // while (!messageQueue.isEmpty())
+        // {
+        // try {
+        // UpdateMessage message = messageQueue.take();
+        // message.receiver.update(message.direction, message.updateElement);
+        // } catch (InterruptedException e) {}
+        // }
+        // }
+    }
+    /**
+     * Retrieves a safe copy of the contents of a supplier.
+     * 
+     * <p> Note that there may be multiple copies of a Tuple in case of a {@link TrimmerNode}, so the result is not always a set.
+     * 
+     * @param flush if true, a flush is performed before pulling the contents 
+     * @since 2.3
+     */
+    public Collection<Tuple> pullContents(final Supplier supplier, final boolean flush) {
+        if (flush) {
+            flushUpdates();
+        }
+        final Collection<Tuple> collector = new ArrayList<Tuple>();
+        supplier.pullInto(collector, flush);
+        return collector;
+    }
+    /**
+     * @since 2.4
+     */
+    public Map<Tuple, Timeline<Timestamp>> pullContentsWithTimeline(final Supplier supplier, final boolean flush) {
+        if (flush) {
+            flushUpdates();
+        }
+        final Map<Tuple, Timeline<Timestamp>> collector = CollectionsFactory.createMap();
+        supplier.pullIntoWithTimeline(collector, flush);
+        return collector;
+    }
+    /**
+     * Retrieves the contents of a SingleInputNode's parentage.
+     * 
+     * @since 2.3
+     */
+    public Collection<Tuple> pullPropagatedContents(final SingleInputNode supplier, final boolean flush) {
+        if (flush) {
+            flushUpdates();
+        }
+        final Collection<Tuple> collector = new LinkedList<Tuple>();
+        supplier.propagatePullInto(collector, flush);
+        return collector;
+    }
+    /**
+     * Retrieves the timestamp-aware contents of a SingleInputNode's parentage.
+     * 
+     * @since 2.3
+     */
+    public Map<Tuple, Timeline<Timestamp>> pullPropagatedContentsWithTimestamp(final SingleInputNode supplier,
+            final boolean flush) {
+        if (flush) {
+            flushUpdates();
+        }
+        final Map<Tuple, Timeline<Timestamp>> collector = CollectionsFactory.createMap();
+        supplier.propagatePullIntoWithTimestamp(collector, flush);
+        return collector;
+    }
+    /**
+     * Retrieves the contents of a supplier for a remote caller. Assumption is that this container is the home of the
+     * supplier, but it is not strictly necessary.
+     *
+     * @param supplier
+     *            the address of the supplier to be pulled.
+     * @since 2.3
+     */
+    public Collection<Tuple> remotePull(Address<? extends Supplier> supplier, boolean flush) {
+        if (!isLocal(supplier))
+            return supplier.getContainer().remotePull(supplier, flush);
+        return pullContents(resolveLocal(supplier), flush);
+    }
+    /**
+     * Proxies for the getPosMapping() of Production nodes. Retrieves the posmapping of a remote or local Production to
+     * a remote or local caller.
+     */
+    public Map<String, Integer> remotePosMapping(Address<? extends ProductionNode> production) {
+        if (!isLocal(production))
+            return production.getContainer().remotePosMapping(production);
+        return resolveLocal(production).getPosMapping();
+    }
+    /**
+     * Continually consumes update messages. Should be run on a dedicated thread.
+     */
+    void messageConsumptionCycle() {
+        while (!killed) // deliver messages on and on and on....
+        {
+            long incrementedClock = 0;
+            UpdateMessage message = null;
+            if (!internalMessageQueue.isEmpty()) // take internal messages first
+                message = internalMessageQueue.removeFirst();
+            else
+                // no internal message, take an incoming message
+                synchronized (externalMessageLock) { // no sleeping allowed,
+                                                     // because external
+                                                     // queue is locked for
+                                                     // precise clocking of
+                                                     // termination point!
+                    if (!externalMessageQueue.isEmpty()) { // if external queue
+                                                           // is non-empty,
+                                                           // retrieve the next
+                                                           // message instantly
+                        message = takeExternalMessage();
+                    } else { // if external queue is found empty (and this is
+                             // the first time in a row)
+                        incrementedClock = ++clock; // local termination point
+                        // synchronized(clock){incrementedClock = ++clock;}
+                    }
+                }
+            if (message == null) // both queues were empty
+            {
+                localUpdateTermination(incrementedClock); // report local
+                                                          // termination point
+                while (message == null) // wait for a message while external
+                                        // queue is still empty
+                {
+                    synchronized (externalMessageLock) {
+                        while (externalMessageQueue.isEmpty()) {
+                            try {
+                                externalMessageLock.wait();
+                            } catch (InterruptedException e) {
+                                if (killed)
+                                    return;
+                            }
+                        }
+                        message = takeExternalMessage();
+                    }
+                }
+            }
+            // now we have a message to deliver
+            // NOTE: this method is not compatible with differential dataflow
+            message.receiver.update(message.direction, message.updateElement, Timestamp.ZERO);
+        }
+    }
+    /**
+     * @since 1.6
+     */
+    public static final Function<Node, String> NAME_MAPPER = input -> input.toString().substring(0,
+            Math.min(30, input.toString().length()));
+    /**
+     * Sends out all pending messages to their receivers. The delivery is governed by the communication tracker.
+     * 
+     * @since 1.6
+     */
+    public void deliverMessagesSingleThreaded() {
+        if (!backendContext.areUpdatesDelayed()) {
+            if (Options.MONITOR_VIOLATION_OF_RETE_NODEGROUP_TOPOLOGICAL_SORTING) {
+                // known unreachable; enable for debugging only
+                CommunicationGroup lastGroup = null;
+                Set<CommunicationGroup> seenInThisCycle = new HashSet<>();
+                while (!tracker.isEmpty()) {
+                    final CommunicationGroup group = tracker.getAndRemoveFirstGroup();
+                    /**
+                     * The current group does not violate the communication schema iff (1) it was not seen before OR (2)
+                     * the last one that was seen is exactly the same as the current one this can happen if the group
+                     * was added back because of in-group message passing
+                     */
+                    boolean okGroup = (group == lastGroup) || seenInThisCycle.add(group);
+                    if (!okGroup) {
+                        logger.error(
+                                "[INTERNAL ERROR] Violation of communication schema! The communication component with representative "
+                                        + group.getRepresentative() + " has already been processed!");
+                    }
+                    group.deliverMessages();
+                    lastGroup = group;
+                }
+            } else {
+                while (!tracker.isEmpty()) {
+                    final CommunicationGroup group = tracker.getAndRemoveFirstGroup();
+                    group.deliverMessages();
+                }
+            }
+        }
+    }
+    private void localUpdateTermination(long incrementedClock) {
+        network.reportLocalUpdateTermination(this, incrementedClock, terminationCriteria);
+        terminationCriteria.clear();
+        // synchronized(clock){++clock;} // +1 incrementing for parity and easy
+        // comparison
+    }
+    // @pre: externalMessageQueue synchronized && nonempty
+    private UpdateMessage takeExternalMessage() {
+        UpdateMessage message = externalMessageQueue.removeFirst();
+        if (!externalMessageQueue.isEmpty()) { // copy the whole queue over
+                                               // for speedup
+            Deque<UpdateMessage> temp = externalMessageQueue;
+            externalMessageQueue = internalMessageQueue;
+            internalMessageQueue = temp;
+        }
+        return message;
+    }
+    /**
+     * Provides an external address for the selected node.
+     *
+     * @pre node belongs to this container.
+     */
+    public <N extends Node> Address<N> makeAddress(N node) {
+        return new Address<N>(node);
+    }
+    /**
+     * Checks whether a certain address points to a node at this container.
+     */
+    public boolean isLocal(Address<? extends Node> address) {
+        return address.getContainer() == this;
+    }
+    /**
+     * Returns an addressed node at this container.
+     * 
+     * @pre: address.container == this, e.g. address MUST be local
+     * @throws IllegalArgumentException
+     *             if address is non-local
+     */
+    @SuppressWarnings("unchecked")
+    public <N extends Node> N resolveLocal(Address<N> address) {
+        if (this != address.getContainer())
+            throw new IllegalArgumentException(String.format("Address %s non-local at container %s", address, this));
+        N cached = address.getNodeCache();
+        if (cached != null)
+            return cached;
+        else {
+            N node = (N) nodesById.get(address.getNodeId());
+            address.setNodeCache(node);
+            return node;
+        }
+    }
+    /**
+     * Registers a node into the rete network (should be called by constructor). Every node MUST be registered by its
+     * constructor.
+     *
+     * @return the unique nodeId issued to the node.
+     */
+    public long registerNode(Node n) {
+        long id = nextId++;
+        nodesById.put(id, n);
+        return id;
+    }
+    /**
+     * Unregisters a node from the rete network. Do NOT call if node is still connected to other Nodes, or Adressed or
+     * otherwise referenced.
+     */
+    public void unregisterNode(Node n) {
+        nodesById.remove(n.getNodeId());
+    }
+    /**
+     * Registers a pattern memory into the rete network. Every memory MUST be registered by its owner node.
+     */
+    public void registerClearable(Clearable c) {
+        clearables.addFirst(c);
+    }
+    /**
+     * Unregisters a pattern memory from the rete network.
+     */
+    public void unregisterClearable(Clearable c) {
+        clearables.remove(c);
+    }
+    /**
+     * Clears all memory contents in the network. Reverts to initial state.
+     */
+    public void clearAll() {
+        for (Clearable c : clearables) {
+            c.clear();
+        }
+    }
+    public NodeFactory getNodeFactory() {
+        return network.getNodeFactory();
+    }
+    public ConnectionFactory getConnectionFactory() {
+        return connectionFactory;
+    }
+    public NodeProvisioner getProvisioner() {
+        return nodeProvisioner;
+    }
+    public Network getNetwork() {
+        return network;
+    }
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        String separator = System.getProperty("line.separator");
+        sb.append(super.toString() + "[[[" + separator);
+        java.util.List<Long> keys = new java.util.ArrayList<Long>(nodesById.keySet());
+        java.util.Collections.sort(keys);
+        for (Long key : keys) {
+            sb.append(key + " -> " + nodesById.get(key) + separator);
+        }
+        sb.append("]]] of " + network);
+        return sb.toString();
+    }
+    /**
+     * Access all the Rete nodes inside this container.
+     *
+     * @return the collection of {@link Node} instances
+     */
+    public Collection<Node> getAllNodes() {
+        return nodesById.values();
+    }
+    public InputConnector getInputConnectionFactory() {
+        return network.getInputConnector();
+    }
+}