HCOLL-353 Implement nested contexts

src/test/java/net/openhft/chronicle/map/NestedContextsTest.java

@@ -0,0 +1,181 @@
+/*
+ * Copyright 2015 Higher Frequency Trading
+ *
+ *  http://www.higherfrequencytrading.com
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package net.openhft.chronicle.map;
+
+import com.google.common.collect.ImmutableSet;
+import org.jetbrains.annotations.NotNull;
+import org.junit.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.ThreadLocalRandom;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class NestedContextsTest {
+
+    @Test
+    public void nestedContextsTest() throws ExecutionException, InterruptedException {
+        ChronicleMap<Integer, Set<Integer>> graph = ChronicleMapBuilder
+                .of(Integer.class, (Class<Set<Integer>>) (Class) Set.class)
+                .actualSegments(1)
+                .create();
+
+        addEdge(graph, 1, 2);
+        addEdge(graph, 2, 3);
+        addEdge(graph, 1, 3);
+
+        assertEquals(ImmutableSet.of(2, 3), graph.get(1));
+        assertEquals(ImmutableSet.of(1, 3), graph.get(2));
+        assertEquals(ImmutableSet.of(1, 2), graph.get(3));
+
+        verifyGraphConsistent(graph);
+
+        ForkJoinPool pool = new ForkJoinPool(8);
+        try {
+            pool.submit(() -> {
+                ThreadLocalRandom.current().ints().limit(10_000).parallel().forEach(i -> {
+                    int sourceNode = Math.abs(i % 10);
+                    int targetNode;
+                    do {
+                        targetNode = ThreadLocalRandom.current().nextInt(10);
+                    } while (targetNode == sourceNode);
+                    if (i % 2 == 0) {
+                        addEdge(graph, sourceNode, targetNode);
+                    } else {
+                        removeEdge(graph, sourceNode, targetNode);
+                    }
+                });
+            }).get();
+            verifyGraphConsistent(graph);
+        } finally {
+            pool.shutdownNow();
+        }
+    }
+
+    private static void verifyGraphConsistent(ChronicleMap<Integer, Set<Integer>> graph) {
+        graph.forEach((node, neighbours) ->
+                neighbours.forEach(neighbour -> assertTrue(graph.get(neighbour).contains(node))));
+    }
+
+    public static boolean addEdge(
+            ChronicleMap<Integer, Set<Integer>> graph, int source, int target) {
+        if (source == target)
+            throw new IllegalArgumentException("loops are forbidden");
+
+        try (ExternalMapQueryContext<Integer, Set<Integer>, ?> sc = graph.queryContext(source)) {
+            sc.updateLock().lock();
+            try (ExternalMapQueryContext<Integer, Set<Integer>, ?> tc =
+                         graph.queryContext(target)) {
+                tc.updateLock().lock();
+                MapEntry<Integer, Set<Integer>> sEntry = sc.entry();
+                if (sEntry != null) {
+                    MapEntry<Integer, Set<Integer>> tEntry = tc.entry();
+                    if (tEntry != null) {
+                        return addEdgeBothPresent(sc, sEntry, source, tc, tEntry, target);
+                    } else {
+                        addEdgePresentAbsent(sc, sEntry, source, tc, target);
+                        return true;
+                    }
+                } else {
+                    MapEntry<Integer, Set<Integer>> tEntry = tc.entry();
+                    if (tEntry != null) {
+                        addEdgePresentAbsent(tc, tEntry, target, sc, source);
+                    } else {
+                        addEdgeBothAbsent(sc, source, tc, target);
+                    }
+                    return true;
+                }
+            }
+        }
+    }
+
+    private static boolean addEdgeBothPresent(
+            MapQueryContext<Integer, Set<Integer>, ?> sc,
+            @NotNull MapEntry<Integer, Set<Integer>> sEntry, int source,
+            MapQueryContext<Integer, Set<Integer>, ?> tc,
+            @NotNull MapEntry<Integer, Set<Integer>> tEntry, int target) {
+        Set<Integer> sNeighbours = sEntry.value().get();
+        if (sNeighbours.add(target)) {
+            Set<Integer> tNeighbours = tEntry.value().get();
+            boolean added = tNeighbours.add(source);
+            assert added;
+            sEntry.doReplaceValue(sc.wrapValueAsData(sNeighbours));
+            tEntry.doReplaceValue(tc.wrapValueAsData(tNeighbours));
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    private static void addEdgePresentAbsent(
+            MapQueryContext<Integer, Set<Integer>, ?> sc,
+            @NotNull MapEntry<Integer, Set<Integer>> sEntry, int source,
+            MapQueryContext<Integer, Set<Integer>, ?> tc, int target) {
+        Set<Integer> sNeighbours = sEntry.value().get();
+        boolean added = sNeighbours.add(target);
+        assert added;
+        sEntry.doReplaceValue(sc.wrapValueAsData(sNeighbours));
+
+        addEdgeOneSide(tc, source);
+    }
+
+    private static void addEdgeBothAbsent(MapQueryContext<Integer, Set<Integer>, ?> sc, int source,
+            MapQueryContext<Integer, Set<Integer>, ?> tc, int target) {
+        addEdgeOneSide(sc, target);
+        addEdgeOneSide(tc, source);
+    }
+
+    private static void addEdgeOneSide(MapQueryContext<Integer, Set<Integer>, ?> tc, int source) {
+        Set<Integer> tNeighbours = new HashSet<>();
+        tNeighbours.add(source);
+        MapAbsentEntry<Integer, Set<Integer>> tAbsentEntry = tc.absentEntry();
+        assert tAbsentEntry != null;
+        tAbsentEntry.doInsert(tc.wrapValueAsData(tNeighbours));
+    }
+
+    public static boolean removeEdge(
+            ChronicleMap<Integer, Set<Integer>> graph, int source, int target) {
+        try (ExternalMapQueryContext<Integer, Set<Integer>, ?> sc = graph.queryContext(source)) {
+            sc.updateLock().lock();
+            MapEntry<Integer, Set<Integer>> sEntry = sc.entry();
+            if (sEntry == null)
+                return false;
+            Set<Integer> sNeighbours = sEntry.value().get();
+            if (!sNeighbours.remove(target))
+                return false;
+            try (ExternalMapQueryContext<Integer, Set<Integer>, ?> tc =
+                         graph.queryContext(target)) {
+                tc.updateLock().lock();
+                MapEntry<Integer, Set<Integer>> tEntry = tc.entry();
+                if (tEntry == null)
+                    throw new IllegalStateException("target node should be present in the graph");
+                Set<Integer> tNeighbours = tEntry.value().get();
+                if (!tNeighbours.remove(source))
+                    throw new IllegalStateException("the target node have an edge to the source");
+                sEntry.doReplaceValue(sc.wrapValueAsData(sNeighbours));
+                tEntry.doReplaceValue(tc.wrapValueAsData(tNeighbours));
+                return true;
+            }
+        }
+    }
+}