ONOS-2486 Adding swagger-based REST API documentation.

Change-Id: I237d973d73549ad30ddc638c1c201f024d344c70
diff --git a/core/api/src/main/java/org/onosproject/rest/AbstractApiDocRegistrator.java b/core/api/src/main/java/org/onosproject/rest/AbstractApiDocRegistrator.java
new file mode 100644
index 0000000..7349c69
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/rest/AbstractApiDocRegistrator.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2015 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.rest;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+
+/**
+ * Self-registering REST API provider.
+ */
+@Component(immediate = true, componentAbstract = true)
+public abstract class AbstractApiDocRegistrator {
+
+    protected final ApiDocProvider provider;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ApiDocService service;
+
+    /**
+     * Creates registrator for the specified REST API doc provider.
+     *
+     * @param provider REST API provider
+     */
+    protected AbstractApiDocRegistrator(ApiDocProvider provider) {
+        this.provider = provider;
+    }
+
+    @Activate
+    protected void activate() {
+        service.register(provider);
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        service.unregister(provider);
+    }
+}