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diff --git a/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/variable/NodeCache.java b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/variable/NodeCache.java
new file mode 100644
index 000000000..04af10840
--- /dev/null
+++ b/bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/variable/NodeCache.java
@@ -0,0 +1,126 @@
+package org.simantics.db.layer0.variable;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TreeMap;
+
+import gnu.trove.map.hash.TObjectLongHashMap;
+
+/**
+ * @author Antti Villberg
+ *
+ * @param <Node>
+ * @param <Value>
+ * 
+ * @since 1.23
+ */
+public class NodeCache<Node,Value> {
+
+	// Expiration time for items in this cache
+	private long defaultExpirationTimeInNs;
+
+	// Here we hold all nodes with finite expiration times
+	private TreeMap<Long,Node> expirationTimes = new TreeMap<Long,Node>();
+	// Finite expiration times for nodes
+	private TObjectLongHashMap<Node> exp = new TObjectLongHashMap<Node>(10, 0.5f, -1L);
+	
+	// All node values
+	private Map<Node,Value> map = new HashMap<Node,Value>();
+
+	private boolean disposed;
+
+	public NodeCache() {
+		this(1_000_000_000L);
+	}
+
+	public NodeCache(long defaultExpirationTimeInNs) {
+		this.defaultExpirationTimeInNs = defaultExpirationTimeInNs;
+	}
+
+	public synchronized Value get(Node node) {
+		return map.get(node); 
+	}
+	
+	public synchronized void clearExpired() {
+		
+		long now = System.nanoTime();
+		while(!expirationTimes.isEmpty()) {
+			Long first = expirationTimes.firstKey();
+			if(first < now) {
+				Node node = expirationTimes.remove(first);
+				exp.remove(node);
+				map.remove(node);
+			} else {
+				return;
+			}
+		}
+		
+	}
+
+	private long scheduleExpiration(Node node, long expiration) {
+		while(expirationTimes.containsKey(expiration)) expiration++;
+		expirationTimes.put(expiration, node);
+		exp.put(node, expiration);
+		return expiration;
+	}
+	
+	private void refreshExpiration(Node node, long newExpiration, boolean existing) {
+		
+		long current = exp.get(node);
+		if(current == -1) {
+			if(existing) {
+				// We have infinite expiration => do nothing
+			} else {
+				// This is a new value
+				if(newExpiration == 0) {
+					// We require infinite expiration => do nothing
+				} else {
+					scheduleExpiration(node, newExpiration);
+				}
+			}
+			return;
+		}
+		
+		// This node is already under expiration tracking
+		if(newExpiration == 0) {
+			// We now want infinite expiration => remove expiration time info
+			expirationTimes.remove(current);
+			exp.remove(node);
+		} else {
+			if(newExpiration > current) {
+				// Update expiration time
+				expirationTimes.remove(current);
+				scheduleExpiration(node, newExpiration);
+			}
+		}
+		
+	}
+
+	public synchronized void put(Node node, Value value) {
+		if (disposed)
+			return;
+		Value existing = map.put(node, value);
+		refreshExpiration(node, 0, existing != null);
+	}
+
+	public synchronized void put(Node node, Value value, long expiration) {
+		if (disposed)
+			return;
+		Value existing = map.put(node, value);
+		refreshExpiration(node, System.nanoTime() + expiration, existing != null);
+	}
+
+	public synchronized void removeListening(Node node) {
+		if (disposed)
+			return;
+		scheduleExpiration(node, System.nanoTime() + defaultExpirationTimeInNs);
+	}
+
+	public synchronized void dispose() {
+		disposed = true;
+		expirationTimes.clear();
+		exp.clear();
+		map.clear();
+	}
+	
+}