Move ComponentService from incubator into core

Change-Id: I23f22fde87f689d2ff54888b43139f32c3d182f0
diff --git a/core/net/src/main/java/org/onosproject/component/impl/ComponentManager.java b/core/net/src/main/java/org/onosproject/component/impl/ComponentManager.java
new file mode 100644
index 0000000..29ae1ad
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/component/impl/ComponentManager.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright 2015-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.component.impl;
+
+import org.apache.felix.scr.ScrService;
+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;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.component.ComponentService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import static org.onlab.util.Tools.groupedThreads;
+
+/**
+ * Manages OSGi components.
+ */
+@Service
+@Component(immediate = true)
+public class ComponentManager implements ComponentService {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private static final int POLLING_PERIOD_MS = 500;
+
+    private static final int NUM_THREADS = 1;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ScrService scrService;
+
+    private Set<String> components;
+
+    private ScheduledExecutorService executor;
+
+    @Activate
+    private void activate() {
+        components = Collections.newSetFromMap(new ConcurrentHashMap<>());
+
+        executor = Executors.newScheduledThreadPool(NUM_THREADS,
+                groupedThreads("onos/component", "%d", log));
+
+        executor.scheduleAtFixedRate(() -> components.forEach(this::enableComponent),
+                0, POLLING_PERIOD_MS, TimeUnit.MILLISECONDS);
+
+        log.info("Started");
+    }
+
+    @Deactivate
+    private void deactivate() {
+        executor.shutdownNow();
+
+        log.info("Stopped");
+    }
+
+    @Override
+    public void activate(ApplicationId appId, String name) {
+        components.add(name);
+        enableComponent(name);
+    }
+
+    @Override
+    public void deactivate(ApplicationId appId, String name) {
+        components.remove(name);
+        disableComponent(name);
+    }
+
+    private void enableComponent(String name) {
+        org.apache.felix.scr.Component[] components = scrService.getComponents(name);
+
+        if (components == null || components.length == 0) {
+            return;
+        }
+
+        org.apache.felix.scr.Component component = components[0];
+
+        if (component.getState() == org.apache.felix.scr.Component.STATE_DISABLED) {
+            log.info("Enabling component {}", name);
+            component.enable();
+        }
+    }
+
+    private void disableComponent(String name) {
+        org.apache.felix.scr.Component[] components = scrService.getComponents(name);
+
+        if (components == null || components.length == 0) {
+            return;
+        }
+
+        log.info("Disabling component {}", name);
+
+        components[0].disable();
+    }
+}