org.motechproject.server.decisiontree.Activator.java Source code

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Here is the source code for org.motechproject.server.decisiontree.Activator.java

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/**
 * MOTECH PLATFORM OPENSOURCE LICENSE AGREEMENT
 *
 * Copyright (c) 2011 Grameen Foundation USA.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of Grameen Foundation USA, nor its respective contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY GRAMEEN FOUNDATION USA AND ITS CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL GRAMEEN FOUNDATION USA OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 */
package org.motechproject.server.decisiontree;

import org.motechproject.context.Context;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.http.HttpService;
import org.osgi.util.tracker.ServiceTracker;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.DispatcherServlet;

/**
 * 
 * @author Igor (iopushnyev@2paths.com)
 * 
 */
public class Activator implements BundleActivator {
    private static Logger logger = LoggerFactory.getLogger(Activator.class);
    private static final String CONTEXT_CONFIG_LOCATION = "applicationDecisionTree.xml";
    private static final String SERVLET_URL_MAPPING = "/tree";
    private ServiceTracker tracker;

    @Override
    public void start(BundleContext context) throws Exception {
        this.tracker = new ServiceTracker(context, HttpService.class.getName(), null) {

            @Override
            public Object addingService(ServiceReference ref) {
                Object service = super.addingService(ref);
                serviceAdded((HttpService) service);
                return service;
            }

            @Override
            public void removedService(ServiceReference ref, Object service) {
                serviceRemoved((HttpService) service);
                super.removedService(ref, service);
            }
        };
        this.tracker.open();
    }

    public void stop(BundleContext context) throws Exception {
        this.tracker.close();
    }

    private void serviceAdded(HttpService service) {
        try {
            DispatcherServlet dispatcherServlet = new DispatcherServlet();
            dispatcherServlet.setContextConfigLocation(CONTEXT_CONFIG_LOCATION);
            ClassLoader old = Thread.currentThread().getContextClassLoader();
            try {
                Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
                service.registerServlet(SERVLET_URL_MAPPING, dispatcherServlet, null, null);
                logger.debug("Servlet registered");
            } finally {
                Thread.currentThread().setContextClassLoader(old);
            }

            // I need to access Context so maven-bundle-plugin lists it in my manifest.
            // If I don't actually need to reference it then this access should be removed and we should
            // explicitly list the dependency in the bundle plugin config
            Context context = Context.getInstance();
            logger.info("Using Context: " + context.toString());

        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private void serviceRemoved(HttpService service) {
        service.unregister(SERVLET_URL_MAPPING);
        logger.debug("Servlet unregistered");
    }
}