Implements [CORD-546]

Changes:
- Adds new l2 tunnel and l2 tunnel policy;
- Extends cfg of the apps;
- Implements CRUD interfaces through netcfg;

Change-Id: I1a295da605e2496f4883f63fa5f6eca16e627d43
diff --git a/src/main/java/org/onosproject/segmentrouting/pwaas/DefaultL2TunnelDescription.java b/src/main/java/org/onosproject/segmentrouting/pwaas/DefaultL2TunnelDescription.java
new file mode 100644
index 0000000..f3fa5ab
--- /dev/null
+++ b/src/main/java/org/onosproject/segmentrouting/pwaas/DefaultL2TunnelDescription.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2016-present 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.segmentrouting.pwaas;
+
+import com.google.common.base.MoreObjects;
+
+import java.util.Objects;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Helper class to carry the l2 tunnel
+ * and its policy.
+ */
+public class DefaultL2TunnelDescription {
+
+    /**
+     * The l2 tunnel.
+     */
+    private DefaultL2Tunnel l2Tunnel;
+
+    /**
+     * The l2 tunnel policy.
+     */
+    private DefaultL2TunnelPolicy l2TunnelPolicy;
+
+    /**
+     * Creates a l2 tunnel description using the given info.
+     *
+     * @param l2Tunnel the l2 tunnel
+     * @param l2TunnelPolicy the l2 tunnel description
+     */
+    public DefaultL2TunnelDescription(DefaultL2Tunnel l2Tunnel,
+                                      DefaultL2TunnelPolicy l2TunnelPolicy) {
+        checkNotNull(l2Tunnel);
+        checkNotNull(l2TunnelPolicy);
+
+        this.l2Tunnel = l2Tunnel;
+        this.l2TunnelPolicy = l2TunnelPolicy;
+    }
+
+    /**
+     * Creates an empty l2 tunnel description.
+     */
+    public DefaultL2TunnelDescription() {
+        this.l2Tunnel = null;
+        this.l2TunnelPolicy = null;
+    }
+
+    /**
+     * Returns the l2 tunnel.
+     *
+     * @return the l2 tunnel
+     */
+    public DefaultL2Tunnel l2Tunnel() {
+        return l2Tunnel;
+    }
+
+    /**
+     * Returns the l2 tunnel policy.
+     *
+     * @return the l2 tunnel policy.
+     */
+    public DefaultL2TunnelPolicy l2TunnelPolicy() {
+        return l2TunnelPolicy;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.l2Tunnel, this.l2TunnelPolicy);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+
+        if (getClass() != o.getClass()) {
+            return false;
+        }
+
+        if (o instanceof DefaultL2TunnelDescription) {
+            DefaultL2TunnelDescription that = (DefaultL2TunnelDescription) o;
+            // Equality is based on tunnel id and pw label
+            // which is always the last label.
+            return this.l2Tunnel.equals(that.l2Tunnel) &&
+                    this.l2TunnelPolicy.equals(that.l2TunnelPolicy);
+        }
+
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("l2Tunnel", l2Tunnel())
+                .add("l2TunnelPolicy", l2TunnelPolicy())
+                .toString();
+    }
+}