1 files changed, 124 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/network/communication/Timestamp.java b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/network/communication/Timestamp.java
new file mode 100644
index 00000000..a50a63a8
--- /dev/null
+++ b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/network/communication/Timestamp.java
@@ -0,0 +1,124 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2018, Tamas Szabo, Istvan Rath 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.communication;
+
+import java.util.AbstractMap;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Set;
+
+import tools.refinery.viatra.runtime.matchers.util.timeline.Timeline;
+import tools.refinery.viatra.runtime.matchers.util.timeline.Timelines;
+
+/**
+ * A timestamp associated with update messages in timely evaluation.
+ * 
+ * @author Tamas Szabo
+ * @since 2.3
+ */
+public class Timestamp implements Comparable<Timestamp>, MessageSelector {
+
+    protected final int value;
+    public static final Timestamp ZERO = new Timestamp(0);
+    /**
+     * @since 2.4
+     */
+    public static final Timeline<Timestamp> INSERT_AT_ZERO_TIMELINE = Timelines.createFrom(Timestamp.ZERO);
+
+    public Timestamp(final int value) {
+        this.value = value;
+    }
+
+    public int getValue() {
+        return value;
+    }
+
+    public Timestamp max(final Timestamp that) {
+        if (this.value >= that.value) {
+            return this;
+        } else {
+            return that;
+        }
+    }
+    
+    /**
+     * @since 2.4
+     */
+    public Timestamp min(final Timestamp that) {
+        if (this.value <= that.value) {
+            return this;
+        } else {
+            return that;
+        }
+    }
+
+    @Override
+    public int compareTo(final Timestamp that) {
+        return this.value - that.value;
+    }
+
+    @Override
+    public boolean equals(final Object obj) {
+        if (obj == null || !(obj instanceof Timestamp)) {
+            return false;
+        } else {
+            return this.value == ((Timestamp) obj).value;
+        }
+    }
+
+    @Override
+    public int hashCode() {
+        return this.value;
+    }
+
+    @Override
+    public String toString() {
+        return Integer.toString(this.value);
+    }
+    
+    /**
+     * A {@link Map} implementation that associates the zero timestamp with every key. There is no suppor for
+     * {@link Map#entrySet()} due to performance reasons.
+     * 
+     * @author Tamas Szabo
+     */
+    public static final class AllZeroMap<T> extends AbstractMap<T, Timeline<Timestamp>> {
+
+        private final Collection<T> wrapped;
+
+        public AllZeroMap(Set<T> wrapped) {
+            this.wrapped = wrapped;
+        }
+
+        @Override
+        public Set<Entry<T, Timeline<Timestamp>>> entrySet() {
+            throw new UnsupportedOperationException("Use the combination of keySet() and get()!");
+        }
+
+        /**
+         * @since 2.4
+         */
+        @Override
+        public Timeline<Timestamp> get(final Object key) {
+            return INSERT_AT_ZERO_TIMELINE;
+        }
+
+        @Override
+        public Set<T> keySet() {
+            return (Set<T>) this.wrapped;
+        }
+
+        @Override
+        public String toString() {
+            return this.getClass().getSimpleName() + ": " + this.keySet().toString();
+        }
+
+    }
+
+}