[ONOS-5916] Add various MappingAddress impl classes with unit tests

Change-Id: Ie373601d1406d161e8071e78cd584e5cc8b8f5af
diff --git a/apps/mappingmanagement/api/src/main/java/org/onosproject/mapping/addresses/ExtensionMappingAddress.java b/apps/mappingmanagement/api/src/main/java/org/onosproject/mapping/addresses/ExtensionMappingAddress.java
new file mode 100644
index 0000000..853fd97
--- /dev/null
+++ b/apps/mappingmanagement/api/src/main/java/org/onosproject/mapping/addresses/ExtensionMappingAddress.java
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2017-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.mapping.addresses;
+
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.flow.criteria.ExtensionSelector;
+
+import java.util.Objects;
+
+/**
+ * Mapping address for implementing extensions.
+ */
+public final class ExtensionMappingAddress implements MappingAddress {
+
+    private final ExtensionSelector extensionSelector;
+    private final DeviceId deviceId;
+
+    /**
+     * Default constructor of ExtensionMappingAddress.
+     *
+     * @param extensionSelector extension selector
+     * @param deviceId          device identifier
+     */
+    public ExtensionMappingAddress(ExtensionSelector extensionSelector, DeviceId deviceId) {
+        this.extensionSelector = extensionSelector;
+        this.deviceId = deviceId;
+    }
+
+    @Override
+    public Type type() {
+        return Type.EXTENSION;
+    }
+
+    /**
+     * Returns the extension selector.
+     *
+     * @return extension selector
+     */
+    public ExtensionSelector extensionSelector() {
+        return extensionSelector;
+    }
+
+    /**
+     * Returns the device identifier.
+     *
+     * @return the device identifier
+     */
+    public DeviceId deviceId() {
+        return deviceId;
+    }
+
+    @Override
+    public String toString() {
+        return type().toString() + TYPE_SEPARATOR + deviceId + "/" + extensionSelector;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(type().ordinal(), extensionSelector, deviceId);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof ExtensionMappingAddress) {
+            ExtensionMappingAddress that = (ExtensionMappingAddress) obj;
+            return Objects.equals(extensionSelector, that.extensionSelector) &&
+                    Objects.equals(deviceId, that.deviceId);
+        }
+        return false;
+    }
+}