1 files changed, 176 insertions, 0 deletions
diff --git a/v3po/translate-utils/src/main/java/io/fd/honeycomb/v3po/translate/util/write/DelegatingWriterRegistry.java b/v3po/translate-utils/src/main/java/io/fd/honeycomb/v3po/translate/util/write/DelegatingWriterRegistry.java
new file mode 100644
index 000000000..fda289e2b
--- /dev/null
+++ b/v3po/translate-utils/src/main/java/io/fd/honeycomb/v3po/translate/util/write/DelegatingWriterRegistry.java
@@ -0,0 +1,176 @@
+/*
+ * Copyright (c) 2016 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.v3po.translate.util.write;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.base.Function;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import io.fd.honeycomb.v3po.translate.TranslationException;
+import io.fd.honeycomb.v3po.translate.util.RWUtils;
+import io.fd.honeycomb.v3po.translate.write.WriteContext;
+import io.fd.honeycomb.v3po.translate.write.Writer;
+import io.fd.honeycomb.v3po.translate.write.WriterRegistry;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import org.opendaylight.yangtools.yang.binding.DataObject;
+import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Simple writer registry able to perform and aggregated read (ROOT write) on top of all provided writers. Also able to
+ * delegate a specific read to one of the delegate writers.
+ *
+ * This could serve as a utility to hold & hide all available writers in upper layers.
+ */
+public final class DelegatingWriterRegistry implements WriterRegistry {
+
+    private static final Logger LOG = LoggerFactory.getLogger(DelegatingWriterRegistry.class);
+
+    private static final Function<InstanceIdentifier<?>, Class<? extends DataObject>> ID_TO_CLASS =
+            new Function<InstanceIdentifier<?>, Class<? extends DataObject>>() {
+                @Override
+                public Class<? extends DataObject> apply(final InstanceIdentifier<?> input) {
+                    return input.getTargetType();
+                }
+            };
+
+    private final Map<Class<? extends DataObject>, Writer<? extends DataObject>> rootWriters;
+
+    /**
+     * Create new {@link DelegatingWriterRegistry}
+     *
+     * @param rootWriters List of delegate writers
+     */
+    public DelegatingWriterRegistry(@Nonnull final List<Writer<? extends DataObject>> rootWriters) {
+        this.rootWriters = RWUtils.uniqueLinkedIndex(checkNotNull(rootWriters), RWUtils.MANAGER_CLASS_FUNCTION);
+    }
+
+    /**
+     * @throws UnsupportedOperationException This getter is not supported for writer registry since it does not manage a
+     *                                       specific node type
+     */
+    @Nonnull
+    @Override
+    public InstanceIdentifier<DataObject> getManagedDataObjectType() {
+        throw new UnsupportedOperationException("Root registry has no type");
+    }
+
+    @Override
+    public void update(@Nonnull final InstanceIdentifier<? extends DataObject> id,
+                       @Nullable final DataObject dataBefore,
+                       @Nullable final DataObject dataAfter,
+                       @Nonnull final WriteContext ctx) throws TranslationException {
+        final InstanceIdentifier.PathArgument first = checkNotNull(
+                Iterables.getFirst(id.getPathArguments(), null), "Empty id");
+        final Writer<? extends DataObject> writer = rootWriters.get(first.getType());
+        checkNotNull(writer,
+                "Unable to write %s. Missing writer. Current writers for: %s", id, rootWriters.keySet());
+        writer.update(id, dataBefore, dataAfter, ctx);
+    }
+
+    @Override
+    public void update(@Nonnull final Map<InstanceIdentifier<?>, DataObject> nodesBefore,
+                       @Nonnull final Map<InstanceIdentifier<?>, DataObject> nodesAfter,
+                       @Nonnull final WriteContext ctx) throws TranslationException {
+        checkAllWritersPresent(nodesBefore);
+        checkAllWritersPresent(nodesAfter);
+
+        final List<InstanceIdentifier<?>> processedNodes = Lists.newArrayList();
+
+        for (Map.Entry<Class<? extends DataObject>, Writer<? extends DataObject>> rootWriterEntry : rootWriters
+                .entrySet()) {
+
+            final InstanceIdentifier<? extends DataObject> id = rootWriterEntry.getValue().getManagedDataObjectType();
+
+            final DataObject dataBefore = nodesBefore.get(id);
+            final DataObject dataAfter = nodesAfter.get(id);
+
+            // No change to current writer
+            if (dataBefore == null && dataAfter == null) {
+                continue;
+            }
+
+            LOG.debug("ChangesProcessor.applyChanges() processing dataBefore={}, dataAfter={}", dataBefore, dataAfter);
+
+            try {
+                update(id, dataBefore, dataAfter, ctx);
+                processedNodes.add(id);
+            } catch (Exception e) {
+                LOG.error("Error while processing data change of: {} (before={}, after={})",
+                        id, dataBefore, dataAfter, e);
+                throw new BulkUpdateException(
+                        id, new ReverterImpl(this, processedNodes, nodesBefore, nodesAfter, ctx), e);
+            }
+        }
+    }
+
+    private void checkAllWritersPresent(final @Nonnull Map<InstanceIdentifier<?>, DataObject> nodesBefore) {
+        checkArgument(rootWriters.keySet().containsAll(Collections2.transform(nodesBefore.keySet(), ID_TO_CLASS)),
+                "Unable to handle all changes. Missing dedicated writers for: %s",
+                Sets.difference(nodesBefore.keySet(), rootWriters.keySet()));
+    }
+
+    private static final class ReverterImpl implements Reverter {
+        private final WriterRegistry delegatingWriterRegistry;
+        private final List<InstanceIdentifier<?>> processedNodes;
+        private final Map<InstanceIdentifier<?>, DataObject> nodesBefore;
+        private final Map<InstanceIdentifier<?>, DataObject> nodesAfter;
+        private final WriteContext ctx;
+
+        ReverterImpl(final WriterRegistry delegatingWriterRegistry,
+                            final List<InstanceIdentifier<?>> processedNodes,
+                            final Map<InstanceIdentifier<?>, DataObject> nodesBefore,
+                            final Map<InstanceIdentifier<?>, DataObject> nodesAfter, final WriteContext ctx) {
+            this.delegatingWriterRegistry = delegatingWriterRegistry;
+            this.processedNodes = processedNodes;
+            this.nodesBefore = nodesBefore;
+            this.nodesAfter = nodesAfter;
+            this.ctx = ctx;
+        }
+
+        @Override
+        public void revert() throws RevertFailedException {
+            final LinkedList<InstanceIdentifier<?>> notReverted = new LinkedList<>(processedNodes);
+
+            while (notReverted.size() > 0) {
+                final InstanceIdentifier<?> node = notReverted.peekLast();
+                LOG.debug("ChangesProcessor.revertChanges() processing node={}", node);
+
+                final DataObject dataBefore = nodesBefore.get(node);
+                final DataObject dataAfter = nodesAfter.get(node);
+
+                // revert a change by invoking writer with reordered arguments
+                try {
+                    delegatingWriterRegistry.update(node, dataAfter, dataBefore, ctx);
+                    notReverted.removeLast(); // change was successfully reverted
+                } catch (Exception e) {
+                    throw new RevertFailedException(notReverted, e);
+                }
+
+            }
+        }
+    }
+}