1 files changed, 115 insertions, 0 deletions
diff --git a/framework/src/onos/core/api/src/main/java/org/onosproject/codec/JsonCodec.java b/framework/src/onos/core/api/src/main/java/org/onosproject/codec/JsonCodec.java
new file mode 100644
index 00000000..6df8f117
--- /dev/null
+++ b/framework/src/onos/core/api/src/main/java/org/onosproject/codec/JsonCodec.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * 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 org.onosproject.codec;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Abstraction of a codec capable for encoding/decoding arbitrary objects to/from JSON.
+ */
+public abstract class JsonCodec<T> {
+
+    /**
+     * Encodes the specified entity into JSON.
+     *
+     * @param entity  entity to encode
+     * @param context encoding context
+     * @return JSON node
+     * @throws java.lang.UnsupportedOperationException if the codec does not
+     *                                                 support encode operations
+     */
+    public ObjectNode encode(T entity, CodecContext context) {
+        throw new UnsupportedOperationException("encode() not supported");
+    }
+
+    /**
+     * Decodes the specified entity from JSON.
+     *
+     * @param json    JSON to decode
+     * @param context decoding context
+     * @return decoded entity
+     * @throws java.lang.UnsupportedOperationException if the codec does not
+     *                                                 support decode operations
+     */
+    public T decode(ObjectNode json, CodecContext context) {
+        throw new UnsupportedOperationException("decode() not supported");
+    }
+
+    /**
+     * Encodes the collection of the specified entities.
+     *
+     * @param entities collection of entities to encode
+     * @param context  encoding context
+     * @return JSON array
+     * @throws java.lang.UnsupportedOperationException if the codec does not
+     *                                                 support encode operations
+     */
+    public ArrayNode encode(Iterable<T> entities, CodecContext context) {
+        ArrayNode result = context.mapper().createArrayNode();
+        for (T entity : entities) {
+            result.add(encode(entity, context));
+        }
+        return result;
+    }
+
+    /**
+     * Decodes the specified JSON array into a collection of entities.
+     *
+     * @param json    JSON array to decode
+     * @param context decoding context
+     * @return collection of decoded entities
+     * @throws java.lang.UnsupportedOperationException if the codec does not
+     *                                                 support decode operations
+     */
+    public List<T> decode(ArrayNode json, CodecContext context) {
+        List<T> result = new ArrayList<>();
+        for (JsonNode node : json) {
+            result.add(decode((ObjectNode) node, context));
+        }
+        return result;
+    }
+
+    /**
+     * Gets a child Object Node from a parent by name. If the child is not found
+     * or does nor represent an object, null is returned.
+     *
+     * @param parent parent object
+     * @param childName name of child to query
+     * @return child object if found, null if not found or if not an object
+     */
+    protected static ObjectNode get(ObjectNode parent, String childName) {
+        JsonNode node = parent.path(childName);
+        return node.isObject() && !node.isNull() ? (ObjectNode) node : null;
+    }
+
+    /**
+     * Gets a child Object Node from a parent by index. If the child is not found
+     * or does nor represent an object, null is returned.
+     *
+     * @param parent parent object
+     * @param childIndex index of child to query
+     * @return child object if found, null if not found or if not an object
+     */
+    protected static ObjectNode get(JsonNode parent, int childIndex) {
+        JsonNode node = parent.path(childIndex);
+        return node.isObject() && !node.isNull() ? (ObjectNode) node : null;
+    }
+}