Fix extensions dangling terminal references

commons/src/main/java/com/powsybl/commons/extensions/AbstractExtension.java

@@ -32,15 +32,11 @@ public void setExtendable(T extendable) {
         if (extendable != null && this.extendable != null && this.extendable != extendable) {
             throw new PowsyblException("Extension is already associated to the extendable " + this.extendable);
         }
-        if (extendable == null) {
-            cleanup();
-        }
         this.extendable = extendable;
     }
 
-    /**
-     * Method called when the extension is removed from its holder.
-     * Can be used for e.g. resource cleanup.
-     */
-    protected void cleanup() { }
+    @Override
+    public void cleanup() {
+        // nothing by default
+    }
 }

commons/src/main/java/com/powsybl/commons/extensions/Extension.java

@@ -33,4 +33,11 @@ public interface Extension<T> {
      * @throws com.powsybl.commons.PowsyblException if this extension is already held.
      */
     void setExtendable(T extendable);
+
+    /**
+     * Method called just before the extension is removed from its holder.
+     * Can be used for e.g. resource cleanup.
+     */
+    default void cleanup() {
+    }
 }

contingency/contingency-api/src/test/java/com/powsybl/contingency/json/ContingencyJsonTest.java

@@ -14,7 +14,7 @@
 import com.fasterxml.jackson.databind.ObjectWriter;
 import com.fasterxml.jackson.databind.SerializerProvider;
 import com.google.auto.service.AutoService;
-import com.powsybl.commons.extensions.Extension;
+import com.powsybl.commons.extensions.AbstractExtension;
 import com.powsybl.commons.extensions.ExtensionJsonSerializer;
 import com.powsybl.commons.json.JsonUtil;
 import com.powsybl.commons.test.AbstractSerDeTest;
@@ -249,7 +249,7 @@ void readJsonListContingenciesWithOptionalName() throws IOException {
         roundTripTest(contingencyList, ContingencyJsonTest::write, ContingencyJsonTest::readContingencyList, "/contingenciesWithOptionalName.json");
     }
 
-    static class DummyExtension implements Extension<Contingency> {
+    static class DummyExtension extends AbstractExtension<Contingency> {
 
         private Contingency contingency;
 

iidm/iidm-api/src/main/java/com/powsybl/iidm/network/Terminal.java

@@ -11,6 +11,7 @@
 import com.powsybl.math.graph.TraversalType;
 import com.powsybl.math.graph.TraverseResult;
 
+import java.util.List;
 import java.util.Optional;
 import java.util.function.Predicate;
 
@@ -252,4 +253,11 @@ static Terminal getTerminal(Identifiable<?> identifiable, ThreeSides side) {
     }
 
     ThreeSides getSide();
+
+    /**
+     * Retrieves a list of objects that refer to the terminal.
+     *
+     * @return a list of referrer objects.
+     */
+    List<Object> getReferrers();
 }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractConnectable.java

@@ -70,7 +70,7 @@ public void remove() {
 
         network.getIndex().remove(this);
         for (TerminalExt terminal : terminals) {
-            terminal.removeAsRegulationPoint();
+            terminal.getReferrerManager().notifyOfRemoval();
             VoltageLevelExt vl = terminal.getVoltageLevel();
             vl.getTopologyModel().detach(terminal);
         }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractIdentifiable.java

@@ -260,10 +260,17 @@ public void allocateVariantArrayElement(int[] indexes, int sourceIndex) {
 
     @Override
     public <E extends Extension<I>> boolean removeExtension(Class<E> type) {
+        return removeExtension(type, true);
+    }
+
+    public <E extends Extension<I>> boolean removeExtension(Class<E> type, boolean cleanup) {
         E extension = getExtension(type);
         NetworkListenerList listeners = getNetwork().getListeners();
         if (extension != null) {
             listeners.notifyExtensionBeforeRemoval(extension);
+            if (cleanup) {
+                extension.cleanup();
+            }
             removeExtension(type, extension);
             listeners.notifyExtensionAfterRemoval(this, extension.getName());
             return true;

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractIidmExtension.java

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) 2024, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+package com.powsybl.iidm.network.impl;
+
+import com.powsybl.commons.extensions.AbstractExtension;
+import com.powsybl.iidm.network.Identifiable;
+import com.powsybl.iidm.network.Terminal;
+
+/**
+ * @author Geoffroy Jamgotchian {@literal <geoffroy.jamgotchian at rte-france.com>}
+ */
+public abstract class AbstractIidmExtension<I extends Identifiable<I>> extends AbstractExtension<I> implements Referrer<Terminal> {
+
+    protected AbstractIidmExtension(I extendable) {
+        super(extendable);
+    }
+
+    @Override
+    public void onReferencedRemoval(Terminal removedTerminal) {
+        // nothing by default
+        // this is the place for terminal reference cleanup
+    }
+}

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractMultiVariantIdentifiableExtension.java

@@ -8,14 +8,13 @@
 package com.powsybl.iidm.network.impl;
 
 import com.powsybl.commons.exceptions.UncheckedClassCastExceptionException;
-import com.powsybl.commons.extensions.AbstractExtension;
 import com.powsybl.iidm.network.Identifiable;
 import com.powsybl.iidm.network.Network;
 
 /**
  * @author Florian Dupuy {@literal <florian.dupuy at rte-france.com>}
  */
-public abstract class AbstractMultiVariantIdentifiableExtension<T extends Identifiable<T>> extends AbstractExtension<T> implements MultiVariantObject {
+public abstract class AbstractMultiVariantIdentifiableExtension<T extends Identifiable<T>> extends AbstractIidmExtension<T> implements MultiVariantObject {
 
     public AbstractMultiVariantIdentifiableExtension(T extendable) {
         super(extendable);

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractNetwork.java

@@ -104,7 +104,7 @@ protected static void transferExtensions(Network from, Network to, boolean ignor
                                             "an extension of this same class already exists in the destination network.",
                                     clazz.getName(), from.getId(), to.getId());
                         } else {
-                            from.removeExtension((Class<? extends Extension<Network>>) clazz);
+                            ((AbstractIdentifiable<Network>) from).removeExtension((Class<? extends Extension<Network>>) clazz, false);
                             to.addExtension((Class<? super Extension<Network>>) clazz, (Extension<Network>) e);
                         }
                     })

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractTapChanger.java

@@ -256,4 +256,8 @@ private void throwIncorrectTapPosition(int tapPosition, int highTapPosition) {
             + tapPosition + " [" + lowTapPosition + ", " + highTapPosition
             + "]");
     }
+
+    public void remove() {
+        regulatingPoint.remove();
+    }
 }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AbstractTerminal.java

@@ -8,12 +8,11 @@
 package com.powsybl.iidm.network.impl;
 
 import com.powsybl.commons.PowsyblException;
-import com.powsybl.iidm.network.*;
 import com.powsybl.commons.ref.Ref;
+import com.powsybl.iidm.network.*;
 import com.powsybl.iidm.network.util.SwitchPredicates;
 import gnu.trove.list.array.TDoubleArrayList;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Predicate;
 
@@ -33,7 +32,7 @@ abstract class AbstractTerminal implements TerminalExt {
 
     protected VoltageLevelExt voltageLevel;
 
-    protected final List<RegulatingPoint> regulated = new ArrayList<>();
+    protected final ReferrerManager<Terminal> referrerManager = new ReferrerManager<>(this);
 
     // attributes depending on the variant
 
@@ -94,12 +93,6 @@ public void setVoltageLevel(VoltageLevelExt voltageLevel) {
         }
     }
 
-    @Override
-    public void removeAsRegulationPoint() {
-        regulated.forEach(RegulatingPoint::removeRegulatingTerminal);
-        regulated.clear();
-    }
-
     @Override
     public double getP() {
         if (removed) {
@@ -250,12 +243,12 @@ public void remove() {
     }
 
     @Override
-    public void setAsRegulatingPoint(RegulatingPoint rp) {
-        regulated.add(rp);
+    public ReferrerManager<Terminal> getReferrerManager() {
+        return referrerManager;
     }
 
     @Override
-    public void removeRegulatingPoint(RegulatingPoint rp) {
-        regulated.remove(rp);
+    public List<Object> getReferrers() {
+        return referrerManager.getReferrers().stream().map(r -> (Object) r).toList();
     }
 }

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/AreaImpl.java

@@ -34,31 +34,9 @@ public class AreaImpl extends AbstractIdentifiable<Area> implements Area {
 
     private final TDoubleArrayList interchangeTarget;
 
-    private final class AreaListener extends DefaultNetworkListener {
-        @Override
-        public void beforeRemoval(Identifiable<?> identifiable) {
-            if (identifiable instanceof DanglingLine danglingLine) {
-                // if dangling line removed from network, remove its boundary from this extension
-                AreaImpl.this.removeAreaBoundary(danglingLine.getBoundary());
-            } else if (identifiable instanceof Connectable<?> connectable) {
-                // if connectable removed from network, remove its terminals from this extension
-                connectable.getTerminals().forEach(AreaImpl.this::removeAreaBoundary);
-            }
-            // When a VoltageLevel is removed, its areas' voltageLevels attributes are directly updated. This is not managed via this listener.
-        }
-    }
+    private final Referrer<Terminal> terminalReferrer = this::removeAreaBoundary;
 
-    /**
-     * Must be called whenever the Area is moved to a different root Network when merging and detaching.
-     * @param fromNetwork previous root network
-     * @param toNetwork new root network
-     */
-    void moveListener(NetworkImpl fromNetwork, NetworkImpl toNetwork) {
-        fromNetwork.removeListener(this.areaListener);
-        toNetwork.addListener(this.areaListener);
-    }
-
-    private final NetworkListener areaListener;
+    private final Referrer<Boundary> boundaryReferrer = this::removeAreaBoundary;
 
     AreaImpl(Ref<NetworkImpl> ref, Ref<SubnetworkImpl> subnetworkRef, String id, String name, boolean fictitious, String areaType,
                     double interchangeTarget) {
@@ -74,8 +52,6 @@ void moveListener(NetworkImpl fromNetwork, NetworkImpl toNetwork) {
         for (int i = 0; i < variantArraySize; i++) {
             this.interchangeTarget.add(interchangeTarget);
         }
-        this.areaListener = new AreaListener();
-        getNetwork().addListener(this.areaListener);
     }
 
     @Override
@@ -229,8 +205,14 @@ public Stream<AreaBoundary> getAreaBoundaryStream() {
     protected void addAreaBoundary(AreaBoundaryImpl areaBoundary) {
         Optional<Terminal> terminal = areaBoundary.getTerminal();
         Optional<Boundary> boundary = areaBoundary.getBoundary();
-        boundary.ifPresent(b -> checkBoundaryNetwork(b.getDanglingLine().getParentNetwork(), "Boundary of DanglingLine" + b.getDanglingLine().getId()));
-        terminal.ifPresent(t -> checkBoundaryNetwork(t.getConnectable().getParentNetwork(), "Terminal of connectable " + t.getConnectable().getId()));
+        boundary.ifPresent(b -> {
+            checkBoundaryNetwork(b.getDanglingLine().getParentNetwork(), "Boundary of DanglingLine" + b.getDanglingLine().getId());
+            ((DanglingLineBoundaryImplExt) b).getReferrerManager().register(boundaryReferrer);
+        });
+        terminal.ifPresent(t -> {
+            checkBoundaryNetwork(t.getConnectable().getParentNetwork(), "Terminal of connectable " + t.getConnectable().getId());
+            ((TerminalExt) t).getReferrerManager().register(terminalReferrer);
+        });
         areaBoundaries.add(areaBoundary);
     }
 
@@ -248,8 +230,11 @@ public void remove() {
         for (VoltageLevel voltageLevel : new HashSet<>(voltageLevels)) {
             voltageLevel.removeArea(this);
         }
+        for (AreaBoundary areaBoundary : areaBoundaries) {
+            areaBoundary.getTerminal().ifPresent(t -> ((TerminalExt) t).getReferrerManager().unregister(terminalReferrer));
+            areaBoundary.getBoundary().ifPresent(b -> ((DanglingLineBoundaryImplExt) b).getReferrerManager().unregister(boundaryReferrer));
+        }
         network.getListeners().notifyAfterRemoval(id);
-        network.removeListener(this.areaListener);
         removed = true;
     }
 

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/DanglingLineBoundaryImplExt.java

@@ -0,0 +1,32 @@
+/**
+ * Copyright (c) 2024, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ * SPDX-License-Identifier: MPL-2.0
+ */
+package com.powsybl.iidm.network.impl;
+
+import com.powsybl.iidm.network.Boundary;
+import com.powsybl.iidm.network.DanglingLine;
+import com.powsybl.iidm.network.util.DanglingLineBoundaryImpl;
+
+/**
+ * @author Geoffroy Jamgotchian {@literal <geoffroy.jamgotchian at rte-france.com>}
+ */
+public class DanglingLineBoundaryImplExt extends DanglingLineBoundaryImpl {
+
+    protected final ReferrerManager<Boundary> referrerManager = new ReferrerManager<>(this);
+
+    public DanglingLineBoundaryImplExt(DanglingLine parent) {
+        super(parent);
+    }
+
+    public ReferrerManager<Boundary> getReferrerManager() {
+        return referrerManager;
+    }
+
+    void remove() {
+        referrerManager.notifyOfRemoval();
+    }
+}

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/DanglingLineImpl.java

@@ -10,7 +10,6 @@
 import com.powsybl.commons.util.trove.TBooleanArrayList;
 import com.powsybl.iidm.network.*;
 import com.powsybl.commons.ref.Ref;
-import com.powsybl.iidm.network.util.DanglingLineBoundaryImpl;
 import gnu.trove.list.array.TDoubleArrayList;
 
 import java.util.Collection;
@@ -259,7 +258,7 @@ void allocateVariantArrayElement(int[] indexes, int sourceIndex) {
 
     private final TDoubleArrayList q0;
 
-    private final DanglingLineBoundaryImpl boundary;
+    private final DanglingLineBoundaryImplExt boundary;
 
     DanglingLineImpl(Ref<NetworkImpl> network, String id, String name, boolean fictitious, double p0, double q0, double r, double x, double g, double b, String pairingKey, GenerationImpl generation) {
         super(network, id, name, fictitious);
@@ -277,7 +276,7 @@ void allocateVariantArrayElement(int[] indexes, int sourceIndex) {
         this.b = b;
         this.pairingKey = pairingKey;
         this.operationalLimitsGroups = new OperationalLimitsGroupsImpl(this, "limits");
-        this.boundary = new DanglingLineBoundaryImpl(this);
+        this.boundary = new DanglingLineBoundaryImplExt(this);
         this.generation = generation != null ? generation.attach(this) : null;
     }
 
@@ -309,6 +308,7 @@ public void remove() {
             throw new UnsupportedOperationException("Parent tie line " + tieLine.getId() + " should be removed before the child dangling line");
         }
         super.remove();
+        boundary.remove();
     }
 
     void removeTieLine() {

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/GeneratorAdderImpl.java

@@ -127,7 +127,7 @@ public GeneratorImpl add() {
                 = new GeneratorImpl(getNetworkRef(),
                                     id, getName(), isFictitious(), energySource,
                                     minP, maxP,
-                                    voltageRegulatorOn, regulatingTerminal != null ? regulatingTerminal : terminal,
+                                    voltageRegulatorOn, regulatingTerminal,
                                     targetP, targetQ, targetV,
                                     ratedS, isCondenser);
         generator.addTerminal(terminal);

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/GeneratorImpl.java

@@ -54,7 +54,7 @@ class GeneratorImpl extends AbstractConnectable<Generator> implements Generator,
         this.reactiveLimits = new ReactiveLimitsHolderImpl(this, new MinMaxReactiveLimitsImpl(-Double.MAX_VALUE, Double.MAX_VALUE));
         this.ratedS = ratedS;
         int variantArraySize = network.get().getVariantManager().getVariantArraySize();
-        regulatingPoint = new RegulatingPoint(id, this::getTerminal, variantArraySize, voltageRegulatorOn, voltageRegulatorOn);
+        regulatingPoint = new RegulatingPoint(id, this::getTerminal, variantArraySize, voltageRegulatorOn, true);
         regulatingPoint.setRegulatingTerminal(regulatingTerminal);
         this.targetP = new TDoubleArrayList(variantArraySize);
         this.targetQ = new TDoubleArrayList(variantArraySize);
@@ -129,7 +129,6 @@ public GeneratorImpl setVoltageRegulatorOn(boolean voltageRegulatorOn) {
                 voltageRegulatorOn, targetV.get(variantIndex), targetQ.get(variantIndex),
                 n.getMinValidationLevel(), n.getReportNodeContext().getReportNode());
         boolean oldValue = regulatingPoint.setRegulating(variantIndex, voltageRegulatorOn);
-        regulatingPoint.setUseVoltageRegulation(voltageRegulatorOn);
         String variantId = network.get().getVariantManager().getVariantId(variantIndex);
         n.invalidateValidationLevel();
         notifyUpdate("voltageRegulatorOn", variantId, oldValue, voltageRegulatorOn);

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/NetworkImpl.java

@@ -1015,11 +1015,6 @@ private void merge(Network other) {
 
         checkMergeability(otherNetwork);
 
-        otherNetwork.getAreaStream().forEach(a -> {
-            AreaImpl area = (AreaImpl) a;
-            area.moveListener(otherNetwork, this);
-        });
-
         // try to find dangling lines couples
         List<DanglingLinePair> lines = new ArrayList<>();
         Map<String, List<DanglingLine>> dl1byPairingKey = new HashMap<>();

iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/PhaseTapChangerImpl.java

@@ -131,7 +131,7 @@ public PhaseTapChangerImpl setRegulationTerminal(Terminal regulationTerminal) {
 
     @Override
     public void remove() {
-        regulatingPoint.remove();
+        super.remove();
         parent.setPhaseTapChanger(null);
     }