HONEYCOMB-61: Restore configuration and context from persisted files

Change-Id: I6edce127f8895f5d65998b4be71a0a111ca2e8bb
Signed-off-by: Maros Marsalek <mmarsale@cisco.com>

1 files changed, 102 insertions, 0 deletions

diff --git a/v3po/translate-utils/src/main/java/io/fd/honeycomb/v3po/translate/util/JsonUtils.java b/v3po/translate-utils/src/main/java/io/fd/honeycomb/v3po/translate/util/JsonUtils.java
new file mode 100644
index 000000000..be6ffa235
--- /dev/null
+++ b/v3po/translate-utils/src/main/java/io/fd/honeycomb/v3po/translate/util/JsonUtils.java
@@ -0,0 +1,102 @@
+/*
+ * 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;
+
+import com.google.common.base.Charsets;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import javax.annotation.Nonnull;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.ContainerNode;
+import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter;
+import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeWriter;
+import org.opendaylight.yangtools.yang.data.codec.gson.JSONCodecFactory;
+import org.opendaylight.yangtools.yang.data.codec.gson.JSONNormalizedNodeStreamWriter;
+import org.opendaylight.yangtools.yang.data.codec.gson.JsonParserStream;
+import org.opendaylight.yangtools.yang.data.codec.gson.JsonWriterFactory;
+import org.opendaylight.yangtools.yang.data.impl.schema.Builders;
+import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNormalizedNodeStreamWriter;
+import org.opendaylight.yangtools.yang.data.impl.schema.builder.api.DataContainerNodeAttrBuilder;
+import org.opendaylight.yangtools.yang.model.api.SchemaContext;
+import org.opendaylight.yangtools.yang.model.api.SchemaPath;
+
+public class JsonUtils {
+
+    private JsonUtils() {}
+
+    /**
+     * Serialize normalized node root structure into provided output stream
+     *
+     * @throws IOException if serialized data cannot be written into provided output stream
+     */
+    public static void writeJsonRoot(@Nonnull final NormalizedNode<?, ?> rootData,
+                                     @Nonnull final SchemaContext schemaContext,
+                                     @Nonnull final OutputStream outputStream) throws IOException {
+        final JsonWriter
+            jsonWriter = createJsonWriter(outputStream, true);
+        final NormalizedNodeStreamWriter streamWriter = JSONNormalizedNodeStreamWriter
+            .createNestedWriter(JSONCodecFactory.create(schemaContext), SchemaPath.ROOT, null, jsonWriter);
+        final NormalizedNodeWriter normalizedNodeWriter =
+            NormalizedNodeWriter.forStreamWriter(streamWriter, true);
+        jsonWriter.beginObject();
+        writeChildren(normalizedNodeWriter,(ContainerNode) rootData);
+        jsonWriter.endObject();
+        jsonWriter.flush();
+    }
+
+    /**
+     * Read json serialized normalized node root structure and parse them into normalized nodes
+     *
+     * @return artificial normalized node holding all the top level nodes from provided stream as children. In case
+     *         the stream is empty, empty artificial normalized node is returned
+     *
+     * @throws IllegalArgumentException if content in the provided input stream is not restore-able
+     */
+    public static ContainerNode readJsonRoot(@Nonnull final SchemaContext schemaContext,
+                                             @Nonnull final InputStream stream) {
+        final DataContainerNodeAttrBuilder<YangInstanceIdentifier.NodeIdentifier, ContainerNode> builder =
+            Builders.containerBuilder().withNodeIdentifier(new YangInstanceIdentifier.NodeIdentifier(schemaContext.getQName()));
+        final NormalizedNodeStreamWriter writer = ImmutableNormalizedNodeStreamWriter.from(builder);
+
+        final JsonParserStream jsonParser = JsonParserStream.create(writer, schemaContext);
+        final JsonReader reader = new JsonReader(new InputStreamReader(stream));
+        jsonParser.parse(reader);
+
+        return builder.build();
+    }
+
+    private static void writeChildren(final NormalizedNodeWriter nnWriter, final ContainerNode data) throws IOException {
+        for(final DataContainerChild<? extends YangInstanceIdentifier.PathArgument, ?> child : data.getValue()) {
+            nnWriter.write(child);
+        }
+    }
+
+    private static JsonWriter createJsonWriter(final OutputStream entityStream, boolean prettyPrint) {
+        if (prettyPrint) {
+            return JsonWriterFactory.createJsonWriter(new OutputStreamWriter(entityStream, Charsets.UTF_8), 2);
+        } else {
+            return JsonWriterFactory.createJsonWriter(new OutputStreamWriter(entityStream, Charsets.UTF_8));
+        }
+    }
+}