Move ordering logic out of AbstractSubtreeManagerRegistryBuilderBuilder

Introduces YangDAG that maintains topological order for yang schema
nodes and can be used by other components to read additional graph edges,
e.g. from file (HONEYCOMB-365).

Change-Id: Ia3046d38ffb4ca222412309f6c4391afc9315bd2
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>

3 files changed, 159 insertions, 43 deletions

diff --git a/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/AbstractSubtreeManagerRegistryBuilderBuilder.java b/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/AbstractSubtreeManagerRegistryBuilderBuilder.java
index 6a19ed220..fe2f1178f 100644
--- a/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/AbstractSubtreeManagerRegistryBuilderBuilder.java
+++ b/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/AbstractSubtreeManagerRegistryBuilderBuilder.java
@@ -18,7 +18,6 @@ package io.fd.honeycomb.translate.util;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Sets;
 import io.fd.honeycomb.translate.ModifiableSubtreeManagerRegistryBuilder;
 import io.fd.honeycomb.translate.SubtreeManager;
 import io.fd.honeycomb.translate.SubtreeManagerRegistryBuilder;
@@ -27,17 +26,18 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 import javax.annotation.Nonnull;
-import org.jgrapht.experimental.dag.DirectedAcyclicGraph;
 import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 
 public abstract class AbstractSubtreeManagerRegistryBuilderBuilder<S extends SubtreeManager<? extends DataObject>, R>
-        implements ModifiableSubtreeManagerRegistryBuilder<S>, SubtreeManagerRegistryBuilder<R>, AutoCloseable {
+        implements ModifiableSubtreeManagerRegistryBuilder<S>, SubtreeManagerRegistryBuilder<R> {
 
-    // Using directed acyclic graph to represent the ordering relationships between writers
-    private final DirectedAcyclicGraph<InstanceIdentifier<?>, Order>
-            handlersRelations = new DirectedAcyclicGraph<>((sourceVertex, targetVertex) -> new Order());
     private final Map<InstanceIdentifier<?>, S> handlersMap = new HashMap<>();
+    private final YangDAG dag;
+
+    protected AbstractSubtreeManagerRegistryBuilderBuilder(@Nonnull final YangDAG yangDAG) {
+        this.dag = Preconditions.checkNotNull(yangDAG, "yangDAG should not be null");
+    }
 
     /**
      * Add handler without any special relationship to any other type.
@@ -49,7 +49,7 @@ public abstract class AbstractSubtreeManagerRegistryBuilderBuilder<S extends Sub
         // not be matched to writers in registry
         final InstanceIdentifier<?> targetType = RWUtils.makeIidWildcarded(handler.getManagedDataObjectType());
         checkWriterNotPresentYet(targetType);
-        handlersRelations.addVertex(targetType);
+        dag.addVertex(targetType);
         handlersMap.put(targetType, handler);
         return this;
     }
@@ -78,9 +78,9 @@ public abstract class AbstractSubtreeManagerRegistryBuilderBuilder<S extends Sub
         final InstanceIdentifier<?> targetType = RWUtils.makeIidWildcarded(handler.getManagedDataObjectType());
         final InstanceIdentifier<?> wildcardedRelatedType = RWUtils.makeIidWildcarded(relatedType);
         checkWriterNotPresentYet(targetType);
-        handlersRelations.addVertex(targetType);
-        handlersRelations.addVertex(wildcardedRelatedType);
-        addEdge(targetType, wildcardedRelatedType);
+        dag.addVertex(targetType);
+        dag.addVertex(wildcardedRelatedType);
+        dag.addEdge(targetType, wildcardedRelatedType);
         handlersMap.put(targetType, handler);
         return this;
     }
@@ -90,13 +90,13 @@ public abstract class AbstractSubtreeManagerRegistryBuilderBuilder<S extends Sub
                                                                         @Nonnull final Collection<InstanceIdentifier<?>> relatedTypes) {
         final InstanceIdentifier<?> targetType = RWUtils.makeIidWildcarded(handler.getManagedDataObjectType());
         checkWriterNotPresentYet(targetType);
-        handlersRelations.addVertex(targetType);
+        dag.addVertex(targetType);
         relatedTypes.stream()
                 .map(RWUtils::makeIidWildcarded)
-                .forEach(handlersRelations::addVertex);
+                .forEach(dag::addVertex);
         relatedTypes.stream()
                 .map(RWUtils::makeIidWildcarded)
-                .forEach(type -> addEdge(targetType, type));
+                .forEach(type -> dag.addEdge(targetType, type));
         handlersMap.put(targetType, handler);
         return this;
     }
@@ -129,10 +129,10 @@ public abstract class AbstractSubtreeManagerRegistryBuilderBuilder<S extends Sub
         final InstanceIdentifier<?> targetType = RWUtils.makeIidWildcarded(handler.getManagedDataObjectType());
         final InstanceIdentifier<?> wildcardedRelatedType = RWUtils.makeIidWildcarded(relatedType);
         checkWriterNotPresentYet(targetType);
-        handlersRelations.addVertex(targetType);
-        handlersRelations.addVertex(wildcardedRelatedType);
+        dag.addVertex(targetType);
+        dag.addVertex(wildcardedRelatedType);
         // set edge to indicate before relationship, just reversed
-        addEdge(wildcardedRelatedType, targetType);
+        dag.addEdge(wildcardedRelatedType, targetType);
         handlersMap.put(targetType, handler);
         return this;
     }
@@ -142,14 +142,14 @@ public abstract class AbstractSubtreeManagerRegistryBuilderBuilder<S extends Sub
                                                                        @Nonnull final Collection<InstanceIdentifier<?>> relatedTypes) {
         final InstanceIdentifier<?> targetType = RWUtils.makeIidWildcarded(handler.getManagedDataObjectType());
         checkWriterNotPresentYet(targetType);
-        handlersRelations.addVertex(targetType);
+        dag.addVertex(targetType);
         relatedTypes.stream()
                 .map(RWUtils::makeIidWildcarded)
-                .forEach(handlersRelations::addVertex);
+                .forEach(dag::addVertex);
         // set edge to indicate before relationship, just reversed
         relatedTypes.stream()
                 .map(RWUtils::makeIidWildcarded)
-                .forEach(type -> addEdge(type, targetType));
+                .forEach(type -> dag.addEdge(type, targetType));
         handlersMap.put(targetType, handler);
         return this;
     }
@@ -170,22 +170,10 @@ public abstract class AbstractSubtreeManagerRegistryBuilderBuilder<S extends Sub
         return addAfter(getSubtreeHandler(handledChildren, handler), relatedTypes);
     }
 
-
-    private void addEdge(final InstanceIdentifier<?> targetType,
-                         final InstanceIdentifier<?> relatedType) {
-        try {
-            handlersRelations.addDagEdge(targetType, relatedType);
-        } catch (DirectedAcyclicGraph.CycleFoundException e) {
-            throw new IllegalArgumentException(String.format(
-                    "Unable to add writer with relation: %s -> %s. Loop detected", targetType, relatedType), e);
-        }
-    }
-
     protected ImmutableMap<InstanceIdentifier<?>, S> getMappedHandlers() {
         final ImmutableMap.Builder<InstanceIdentifier<?>, S> builder = ImmutableMap.builder();
         // Iterate writer types according to their relationships from graph
-        handlersRelations.iterator()
-                .forEachRemaining(handlerType -> {
+        dag.iterator().forEachRemaining(handlerType -> {
                     // There might be types stored just for relationship sake, no real writer, ignoring those
                     if (handlersMap.containsKey(handlerType)) {
                         builder.put(handlerType, handlersMap.get(handlerType));
@@ -199,15 +187,4 @@ public abstract class AbstractSubtreeManagerRegistryBuilderBuilder<S extends Sub
 
         return builder.build();
     }
-
-    @Override
-    public void close() throws Exception {
-        handlersMap.clear();
-        // Wrap sets into another set to avoid concurrent modification ex in graph
-        handlersRelations.removeAllEdges(Sets.newHashSet(handlersRelations.edgeSet()));
-        handlersRelations.removeAllVertices(Sets.newHashSet(handlersRelations.vertexSet()));
-    }
-
-    // Represents edges in graph
-    private class Order {}
 }
diff --git a/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/YangDAG.java b/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/YangDAG.java
new file mode 100644
index 000000000..2269adbff
--- /dev/null
+++ b/infra/translate-utils/src/main/java/io/fd/honeycomb/translate/util/YangDAG.java
@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ *
+ * 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 io.fd.honeycomb.translate.util;
+
+import java.util.Iterator;
+import org.jgrapht.experimental.dag.DirectedAcyclicGraph;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+/**
+ * Directed acyclic graph representing ordering relationships between schema nodes represented as wildcarded
+ * InstanceIdentifiers. Maintains topological order of vertices. Feature is used by translation layer if more nodes are
+ * affected in single read/write transaction.
+ */
+public final class YangDAG {
+
+    private final DirectedAcyclicGraph<InstanceIdentifier<?>, Edge>
+        dag = new DirectedAcyclicGraph<>((sourceVertex, targetVertex) -> new Edge());
+
+    /**
+     * Adds the vertex if it wasn't already in the graph.
+     *
+     * @param vertex vertex to be added
+     */
+    public void addVertex(final InstanceIdentifier<?> vertex) {
+        dag.addVertex(vertex);
+    }
+
+    /**
+     * Adds edge between source and target vertices.
+     *
+     * @param source source vertex of the edge
+     * @param target target vertex of the edge
+     * @throws IllegalArgumentException if the edge would induce a cycle in the graph
+     */
+    public void addEdge(final InstanceIdentifier<?> source, final InstanceIdentifier<?> target) {
+        try {
+            dag.addDagEdge(source, target);
+        } catch (DirectedAcyclicGraph.CycleFoundException e) {
+            throw new IllegalArgumentException(String.format(
+                "Unable to add writer with relation: %s -> %s. Loop detected", source, target), e);
+        }
+    }
+
+    /**
+     * Traverses schema nodes in topological order.
+     *
+     * @return an iterator that will traverse the graph in topological order.
+     */
+    public Iterator<InstanceIdentifier<?>> iterator() {
+        return dag.iterator();
+    }
+
+    private static final class Edge {
+    }
+}
diff --git a/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/YangDAGTest.java b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/YangDAGTest.java
new file mode 100644
index 000000000..1c8fb5442
--- /dev/null
+++ b/infra/translate-utils/src/test/java/io/fd/honeycomb/translate/util/YangDAGTest.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ *
+ * 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 io.fd.honeycomb.translate.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Iterator;
+import org.jgrapht.experimental.dag.DirectedAcyclicGraph;
+import org.junit.Before;
+import org.junit.Test;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+
+public class YangDAGTest {
+
+    private static final InstanceIdentifier<DataObjects.DataObject1> VERTEX_A = DataObjects.DataObject1.IID;
+    private static final InstanceIdentifier<DataObjects.DataObject2> VERTEX_B = DataObjects.DataObject2.IID;
+
+    private YangDAG dag;
+
+    @Before
+    public void setUp() {
+        dag = new YangDAG();
+    }
+    @Test
+    public void testAddVertex() {
+        dag.addVertex(VERTEX_A);
+        final Iterator<InstanceIdentifier<?>> it = dag.iterator();
+        assertEquals(VERTEX_A, it.next());
+        assertFalse(it.hasNext());
+    }
+
+    @Test
+    public void testAddEdge() {
+        dag.addVertex(VERTEX_A);
+        dag.addVertex(VERTEX_B);
+        dag.addEdge(VERTEX_A, VERTEX_B);
+        final Iterator<InstanceIdentifier<?>> it = dag.iterator();
+        assertEquals(VERTEX_A, it.next());
+        assertEquals(VERTEX_B, it.next());
+        assertFalse(it.hasNext());
+    }
+
+    @Test
+    public void testAddCycleFails() {
+        dag.addVertex(VERTEX_A);
+        dag.addVertex(VERTEX_B);
+        dag.addEdge(VERTEX_A, VERTEX_B);
+        try {
+            dag.addEdge(VERTEX_B, VERTEX_A);
+        } catch (IllegalArgumentException e) {
+            assertTrue(e.getCause() instanceof DirectedAcyclicGraph.CycleFoundException);
+        }
+    }
+}
\ No newline at end of file