[AETHER-599] Implement FabricPipelineTraceable

Core changes supporting fabric traceable implementation.
Includes minor fixes to the OFDPA traceable unit tests

Change-Id: I2f0d1172022a8fc725df9e96526092c59ddc0e0b
diff --git a/core/api/src/main/java/org/onosproject/net/PipelineTraceablePacket.java b/core/api/src/main/java/org/onosproject/net/PipelineTraceablePacket.java
new file mode 100644
index 0000000..ffa2063
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/PipelineTraceablePacket.java
@@ -0,0 +1,96 @@
+/*
+ * Copyright 2020-present Open Networking Foundation
+ *
+ * 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.net;
+
+import org.onosproject.net.flow.TrafficSelector;
+
+import java.util.Objects;
+
+/**
+ * Represents a traceable packet composed by a traffic selector and metadata.
+ */
+public final class PipelineTraceablePacket {
+
+    // stores metadata associated with the packet
+    private PipelineTraceableMetadata metadata;
+    // representation of the packet
+    private TrafficSelector packet;
+
+    /**
+     * Builds a traceable packet without metadata.
+     * Note this can be used for legacy device like ofdpa.
+     *
+     * @param packet the packet selector
+     */
+    public PipelineTraceablePacket(TrafficSelector packet) {
+        this.packet = packet;
+    }
+
+    /**
+     * Builds a traceable packet with metadata.
+     * @param packet the packet selector
+     * @param metadata the packet metadata
+     */
+    public PipelineTraceablePacket(TrafficSelector packet, PipelineTraceableMetadata metadata) {
+        this.packet = packet;
+        this.metadata = metadata;
+    }
+
+    /**
+     * Getter for the metadata.
+     *
+     * @return the packet metadata
+     */
+    public PipelineTraceableMetadata metadata() {
+        return metadata;
+    }
+
+    /**
+     * Getter for the packet selector.
+     *
+     * @return the packet selector
+     */
+    public TrafficSelector packet() {
+        return packet;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(metadata, packet);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof PipelineTraceablePacket) {
+            PipelineTraceablePacket that = (PipelineTraceablePacket) obj;
+            return Objects.equals(this.metadata, that.metadata) &&
+                    Objects.equals(this.packet, that.packet);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return "PipelineTraceablePacket{" +
+                "metadata=" + metadata +
+                ", packet=" + packet +
+                '}';
+    }
+}