1 files changed, 111 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/timeline/CompactTimeline.java b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/timeline/CompactTimeline.java
new file mode 100644
index 00000000..0532d094
--- /dev/null
+++ b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/util/timeline/CompactTimeline.java
@@ -0,0 +1,111 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2019, Tamas Szabo, itemis AG, Gabor Bergmann, IncQuery Labs Ltd.
+ * 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.matchers.util.timeline;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import tools.refinery.viatra.runtime.matchers.util.Direction;
+import tools.refinery.viatra.runtime.matchers.util.Signed;
+
+/**
+ * A compact timeline may cosist of an arbitrary amount of moments. 
+ * It is backed by an {@link ArrayList}. 
+ * 
+ * @author Tamas Szabo
+ * @since 2.4
+ */
+public class CompactTimeline<Timestamp extends Comparable<Timestamp>> extends Timeline<Timestamp> {
+
+    protected final List<Timestamp> elements;
+
+    CompactTimeline() {
+        this.elements = new ArrayList<>();
+    }
+    
+    CompactTimeline(final Timestamp timestamp) {
+        this();
+        this.elements.add(timestamp);
+    }
+    
+    CompactTimeline(final List<Timestamp> timestamps) {
+        this.elements = new ArrayList<>(timestamps.size());
+        this.elements.addAll(timestamps);
+    }
+
+    CompactTimeline(final Diff<Timestamp> diff) {
+        this.elements = new ArrayList<>(diff.size());
+        Direction expected = Direction.INSERT;
+        for (Signed<Timestamp> signed : diff) {
+            if (!expected.equals(signed.getDirection())) {
+                throw new IllegalStateException(String.format("Expected direction (%s) constraint violated! %s @%s",
+                        expected, diff, signed.getPayload()));
+            }
+            this.elements.add(signed.getPayload());
+            expected = expected.opposite();
+        }
+    }
+    
+    @Override
+    public Signed<Timestamp> getSigned(final int index) {
+        final Direction direction = index % 2 == 0 ? Direction.INSERT : Direction.DELETE;
+        return new Signed<>(direction, this.getUnsigned(index));
+    }
+
+    @Override
+    public Timestamp getUnsigned(final int index) {
+        if (this.elements.size() <= index) {
+            throw new IllegalArgumentException(
+                    "Timeline size (" + this.size() + ") is smaller than requested index " + index + "!");
+        } else {
+            return this.elements.get(index);
+        }
+    }
+
+    @Override
+    public int size() {
+        return this.elements.size();
+    }
+
+    @Override
+    public boolean isPresentAtInfinity() {
+        // if it has an odd length, then it ends with "INSERT"
+        return this.size() % 2 == 1;
+    }
+
+    @Override
+    public Iterable<Signed<Timestamp>> asChangeSequence() {
+        Iterable<Timestamp> outer = this.elements;
+        return () -> {
+            final Iterator<Timestamp> itr = outer.iterator();
+            return new Iterator<Signed<Timestamp>>() {
+                Direction direction = Direction.INSERT;
+
+                @Override
+                public boolean hasNext() {
+                    return itr.hasNext();
+                }
+
+                @Override
+                public Signed<Timestamp> next() {
+                    final Signed<Timestamp> result = new Signed<Timestamp>(direction, itr.next());
+                    direction = direction.opposite();
+                    return result;
+                }
+            };
+        };
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return this.elements.isEmpty();
+    }
+
+}