Refactor to separate api from implementation

Change-Id: Ia3ff3eab719cd380f502d359367e65835693ce12
diff --git a/app/src/main/java/org/opencord/cordmcast/impl/OsgiPropertyConstants.java b/app/src/main/java/org/opencord/cordmcast/impl/OsgiPropertyConstants.java
new file mode 100644
index 0000000..dcd5077
--- /dev/null
+++ b/app/src/main/java/org/opencord/cordmcast/impl/OsgiPropertyConstants.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2019-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.opencord.cordmcast.impl;
+
+/**
+ * Constants for default values of configurable properties.
+ */
+public final class OsgiPropertyConstants {
+
+    private OsgiPropertyConstants() {
+    }
+
+    public static final String VLAN_ENABLED = "vlanEnabled";
+    public static final boolean DEFAULT_VLAN_ENABLED = true;
+
+    public static final String PRIORITY = "priority";
+    public static final int DEFAULT_PRIORITY = 500;
+
+    public static final String EVENT_GENERATION_PERIOD = "eventGenerationPeriodInSeconds";
+    public static final int EVENT_GENERATION_PERIOD_DEFAULT = 30;
+}