Implement REST APIs for flows:

- get all flows
- get all flows for a device
- get all flows for a device with a given ID

Change-Id: Ifb1541e4ae4a7e49f1347b34bef2fe788902368d
diff --git a/web/api/src/main/java/org/onosproject/codec/impl/TrafficTreatmentCodec.java b/web/api/src/main/java/org/onosproject/codec/impl/TrafficTreatmentCodec.java
new file mode 100644
index 0000000..c2a9a78
--- /dev/null
+++ b/web/api/src/main/java/org/onosproject/codec/impl/TrafficTreatmentCodec.java
@@ -0,0 +1,48 @@
+/*
+ * 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.impl;
+
+import org.onosproject.codec.CodecContext;
+import org.onosproject.codec.JsonCodec;
+import org.onosproject.net.flow.TrafficTreatment;
+import org.onosproject.net.flow.instructions.Instruction;
+
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Traffic treatment codec.
+ */
+public class TrafficTreatmentCodec extends JsonCodec<TrafficTreatment> {
+    @Override
+    public ObjectNode encode(TrafficTreatment treatment, CodecContext context) {
+        checkNotNull(treatment, "Traffic treatment cannot be null");
+
+        final ObjectNode result = context.mapper().createObjectNode();
+        final ArrayNode jsonInstructions = result.putArray("instructions");
+
+        if (treatment.instructions() != null) {
+            for (final Instruction instruction : treatment.instructions()) {
+                // TODO: would be better to have a codec that understands instructions
+                jsonInstructions.add(instruction.toString());
+            }
+        }
+
+        return result;
+    }
+}