services/druid/src/main/java/org/apache/whirr/service/druid/osgi/Activator.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.whirr.service.druid.osgi;

import org.apache.whirr.service.ClusterActionHandler;
import org.apache.whirr.service.druid.DruidBrokerClusterActionHandler;
import org.apache.whirr.service.druid.DruidComputeClusterActionHandler;
import org.apache.whirr.service.druid.DruidMasterClusterActionHandler;
import org.apache.whirr.service.druid.DruidMySQLClusterActionHandler;
import org.apache.whirr.service.druid.DruidRealtimeClusterActionHandler;
import org.jclouds.scriptbuilder.functionloader.osgi.BundleFunctionLoader;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceRegistration;

import java.util.Properties;

public class Activator implements BundleActivator {

    private BundleFunctionLoader functionLoader;

    private final ClusterActionHandler druidBrokerClusterActionHandler = new
            DruidBrokerClusterActionHandler();
    private ServiceRegistration druidBrokerRegistration;

    private final ClusterActionHandler druidMasterClusterActionHandler = new
            DruidMasterClusterActionHandler();
    private ServiceRegistration druidMasterRegistration;

    private final ClusterActionHandler druidComputeClusterActionHandler = new
            DruidComputeClusterActionHandler();
    private ServiceRegistration druidComputeRegistration;

    private final ClusterActionHandler druidRealtimeClusterActionHandler = new
            DruidRealtimeClusterActionHandler();
    private ServiceRegistration druidRealtimeRegistration;

    private final ClusterActionHandler druidMySQLClusterActionHandler = new
            DruidMySQLClusterActionHandler();
    private ServiceRegistration druidMySQLRegistration;

    /**
     * Called when this bundle is started so the Framework can perform the
     * bundle-specific activities necessary to start this bundle. This method
     * can be used to register services or to allocate any resources that this
     * bundle needs.
     * <p/>
     * <p/>
     * This method must complete and return to its caller in a timely manner.
     *
     * @param context The execution context of the bundle being started.
     * @throws Exception If this method throws an exception, this
     *         bundle is marked as stopped and the Framework will remove this
     *         bundle's listeners, unregister all services registered by this
     *         bundle, and release all services used by this bundle.
     */
    @Override
    public void start(BundleContext context) throws Exception {
        //Initialize OSGi based FunctionLoader
        functionLoader = new BundleFunctionLoader(context);
        functionLoader.start();

        Properties brokerProps = new Properties();
        brokerProps.put("name", "druid-broker");
        druidBrokerRegistration = context.registerService(
                ClusterActionHandler.class.getName(),
                druidBrokerClusterActionHandler,
                brokerProps
        );

        Properties masterProps = new Properties();
        masterProps.put("name", "druid-master");
        druidMasterRegistration = context.registerService(
                ClusterActionHandler.class.getName(),
                druidMasterClusterActionHandler, masterProps
        );

        Properties computeProps = new Properties();
        computeProps.put("name", "druid-compute");
        druidComputeRegistration = context.registerService(
                ClusterActionHandler.class.getName(),
                druidComputeClusterActionHandler,
                computeProps
        );

        Properties realtimeProps = new Properties();
        realtimeProps.put("name", "druid-realtime");
        druidRealtimeRegistration = context.registerService(
                ClusterActionHandler.class.getName(),
                druidRealtimeClusterActionHandler,
                realtimeProps
        );

        Properties mysqlProps = new Properties();
        realtimeProps.put("name", "druid-mysql");
        druidRealtimeRegistration = context.registerService(
                ClusterActionHandler.class.getName(),
                druidRealtimeClusterActionHandler,
                mysqlProps
        );

    }

    /**
     * Called when this bundle is stopped so the Framework can perform the
     * bundle-specific activities necessary to stop the bundle. In general, this
     * method should undo the work that the <code>BundleActivator.start</code>
     * method started. There should be no active threads that were started by
     * this bundle when this bundle returns. A stopped bundle must not call any
     * Framework objects.
     * <p/>
     * <p/>
     * This method must complete and return to its caller in a timely manner.
     *
     * @param context The execution context of the bundle being stopped.
     * @throws Exception If this method throws an exception, the
     *         bundle is still marked as stopped, and the Framework will remove
     *         the bundle's listeners, unregister all services registered by the
     *         bundle, and release all services used by the bundle.
     */
    @Override
    public void stop(BundleContext context) throws Exception {
        if (druidBrokerRegistration != null) {
            druidBrokerRegistration.unregister();
        }
        if (druidMasterRegistration != null) {
            druidMasterRegistration.unregister();
        }
        if (druidComputeRegistration != null) {
            druidComputeRegistration.unregister();
        }
        if (druidRealtimeRegistration != null) {
            druidRealtimeRegistration.unregister();
        }
        if (druidMySQLRegistration != null) {
            druidMySQLRegistration.unregister();
        }
        if (functionLoader != null) {
            functionLoader.stop();
        }
    }
}