diff --git a/statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/internal/statesystem/core/backend/historytree/HistoryTreeBackend.java b/statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/internal/statesystem/core/backend/historytree/HistoryTreeBackend.java
index 5e2ec09..ff30e88 100644
--- a/statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/internal/statesystem/core/backend/historytree/HistoryTreeBackend.java
+++ b/statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/internal/statesystem/core/backend/historytree/HistoryTreeBackend.java
@@ -22,9 +22,7 @@
 import java.io.IOException;
 import java.nio.channels.ClosedChannelException;
 import java.util.ArrayDeque;
-import java.util.Collections;
 import java.util.Deque;
-import java.util.Iterator;
 import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -361,51 +359,7 @@
                 "ssid", getSSID(), //$NON-NLS-1$
                 "quarks", quarks, //$NON-NLS-1$
                 "timeCondition", times).build()) { //$NON-NLS-1$
-            return () -> new Iterator<@NonNull ITmfStateInterval>() {
-                private final Deque<Integer> seqNumberQueue = new ArrayDeque<>(Collections.singleton(getSHT().getRootNode().getSequenceNumber()));
-                private Iterator<@NonNull HTInterval> intervalQueue = Collections.emptyIterator();
-
-                @Override
-                public boolean hasNext() {
-                    while (!intervalQueue.hasNext() && !seqNumberQueue.isEmpty()) {
-                        try {
-                            HTNode currentNode = getSHT().readNode(seqNumberQueue);
-                            /*
-                             * Compute reduced conditions here to reduce complexity in queuing operations.
-                             */
-                            TimeRangeCondition subTimes = times.subCondition(currentNode.getNodeStart(), currentNode.getNodeEnd());
-                            /*
-                             * During the SHT construction, the bounds of the children are not final, so we
-                             * may have queued some nodes which don't overlap the query.
-                             */
-                            if (quarks.intersects(currentNode.getMinQuark(), currentNode.getMaxQuark()) && subTimes != null) {
-                                if (currentNode.getNodeType() == HTNode.NodeType.CORE) {
-                                    // Queue the relevant children nodes for BFS.
-                                    ((ParentNode) currentNode).queueNextChildren2D(quarks, subTimes, seqNumberQueue, reverse);
-                                }
-                                intervalQueue = currentNode.iterable2D(quarks, subTimes).iterator();
-                            }
-                        } catch (ClosedChannelException e) {
-                            try (TraceCompassLogUtils.FlowScopeLog closedChannelLog = new TraceCompassLogUtils.FlowScopeLogBuilder(LOGGER, Level.FINER,
-                                    "HistoryTreeBackend:query2D:channelClosed").setParentScope(log).build()) { //$NON-NLS-1$
-                                return false;
-                            }
-                        }
-                    }
-                    boolean hasNext = intervalQueue.hasNext();
-                    if (!hasNext) {
-                        try (TraceCompassLogUtils.FlowScopeLog noNext = new TraceCompassLogUtils.FlowScopeLogBuilder(LOGGER, Level.FINER,
-                                "HistoryTreeBackend:query2D:iteratorEnd").setParentScope(log).build()) { //$NON-NLS-1$
-                        }
-                    }
-                    return intervalQueue.hasNext();
-                }
-
-                @Override
-                public ITmfStateInterval next() {
-                    return intervalQueue.next();
-                }
-            };
+            return () -> new HistoryTreeBackendIterator(getSHT(), quarks, times, reverse, log);
         }
     }
 
diff --git a/statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/internal/statesystem/core/backend/historytree/HistoryTreeBackendIterator.java b/statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/internal/statesystem/core/backend/historytree/HistoryTreeBackendIterator.java
new file mode 100644
index 0000000..f409b81
--- /dev/null
+++ b/statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/internal/statesystem/core/backend/historytree/HistoryTreeBackendIterator.java
@@ -0,0 +1,99 @@
+/*******************************************************************************
+ * Copyright (c) 2012, 2016, 2022 Ericsson
+ * Copyright (c) 2010, 2011 École Polytechnique de Montréal
+ * Copyright (c) 2010, 2011 Alexandre Montplaisir <alexandre.montplaisir@gmail.com>
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License 2.0 which
+ * accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *   Alexandre Montplaisir - Initial API and implementation
+ *   Patrick Tasse - Add message to exceptions
+ *   Marco Miller - Extract to this class
+ *******************************************************************************/
+
+package org.eclipse.tracecompass.internal.statesystem.core.backend.historytree;
+
+import java.nio.channels.ClosedChannelException;
+import java.util.ArrayDeque;
+import java.util.Collections;
+import java.util.Deque;
+import java.util.Iterator;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.tracecompass.common.core.log.TraceCompassLog;
+import org.eclipse.tracecompass.common.core.log.TraceCompassLogUtils;
+import org.eclipse.tracecompass.internal.provisional.datastore.core.condition.IntegerRangeCondition;
+import org.eclipse.tracecompass.internal.provisional.datastore.core.condition.TimeRangeCondition;
+import org.eclipse.tracecompass.statesystem.core.interval.ITmfStateInterval;
+
+class HistoryTreeBackendIterator implements Iterator<@NonNull ITmfStateInterval> {
+    private static final @NonNull Logger LOGGER = TraceCompassLog.getLogger(HistoryTreeBackendIterator.class);
+
+    private final @NonNull IHistoryTree fSht;
+    private final IntegerRangeCondition fQuarks;
+    private final TimeRangeCondition fTimes;
+    private final boolean fReverse;
+    private final TraceCompassLogUtils.@NonNull FlowScopeLog fParentLog;
+    private final Deque<Integer> fSeqNumberQueue;
+
+    private Iterator<@NonNull HTInterval> intervalQueue = Collections.emptyIterator();
+
+    HistoryTreeBackendIterator(@NonNull IHistoryTree sht, IntegerRangeCondition quarks, TimeRangeCondition times, boolean reverse, TraceCompassLogUtils.@NonNull FlowScopeLog parentLog) {
+        fSht = sht;
+        fQuarks = quarks;
+        fTimes = times;
+        fReverse = reverse;
+        fParentLog = parentLog;
+        fSeqNumberQueue = new ArrayDeque<>(Collections.singleton(fSht.getRootNode().getSequenceNumber()));
+    }
+
+    @Override
+    public boolean hasNext() {
+        while (!intervalQueue.hasNext() && !fSeqNumberQueue.isEmpty()) {
+            try {
+                HTNode currentNode = fSht.readNode(fSeqNumberQueue);
+                /*
+                 * Compute reduced conditions here to reduce complexity in
+                 * queuing operations.
+                 */
+                TimeRangeCondition subTimes = fTimes.subCondition(currentNode.getNodeStart(), currentNode.getNodeEnd());
+                /*
+                 * During the SHT construction, the bounds of the children are
+                 * not final, so we may have queued some nodes which don't
+                 * overlap the query.
+                 */
+                if (fQuarks.intersects(currentNode.getMinQuark(), currentNode.getMaxQuark()) && subTimes != null) {
+                    if (currentNode.getNodeType() == HTNode.NodeType.CORE) {
+                        // Queue the relevant children nodes for BFS.
+                        ((ParentNode) currentNode).queueNextChildren2D(fQuarks, subTimes, fSeqNumberQueue, fReverse);
+                    }
+                    intervalQueue = currentNode.iterable2D(fQuarks, subTimes).iterator();
+                }
+            } catch (ClosedChannelException e) {
+                try (TraceCompassLogUtils.FlowScopeLog closedChannelLog = new TraceCompassLogUtils.FlowScopeLogBuilder(LOGGER, Level.FINER,
+                        "HistoryTreeBackendIterator:query2D:channelClosed").setParentScope(fParentLog).build()) { //$NON-NLS-1$
+                    return false;
+                }
+            }
+        }
+        boolean hasNext = intervalQueue.hasNext();
+        if (!hasNext) {
+            try (TraceCompassLogUtils.FlowScopeLog noNext = new TraceCompassLogUtils.FlowScopeLogBuilder(LOGGER, Level.FINER,
+                    "HistoryTreeBackendIterator:query2D:iteratorEnd").setParentScope(fParentLog).build()) { //$NON-NLS-1$
+            }
+        }
+        return intervalQueue.hasNext();
+    }
+
+    @Override
+    public ITmfStateInterval next() {
+        return intervalQueue.next();
+    }
+}