com.adobe.cq.social.messaging.osgi.BundleServices Maven / Gradle / Ivy

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 *  Copyright 2014 Adobe Systems Incorporated
 *  All Rights Reserved.
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 * NOTICE:  All information contained herein is, and remains
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package com.adobe.cq.social.messaging.osgi;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.util.tracker.ServiceTracker;

/**
 * Implementation of {@link org.osgi.framework.BundleActivator} for Messaging.
 */
public class BundleServices implements BundleActivator {

    private static BundleContext bundleContext;

    private static Map serviceTrackers = new HashMap();

    @Override
    public void start(final BundleContext context) throws Exception {
        synchronized (BundleServices.class) {
            bundleContext = context;
        }
    }

    @Override
    public synchronized void stop(final BundleContext context) throws Exception {
        synchronized (BundleServices.class) {
            for (final Iterator i = serviceTrackers.values().iterator(); i.hasNext();) {
                i.next().close();
            }
        }
    }

    /**
     * Get the service for the specified class.
     * @param in The class.
     * @param  The type of the service.
     * @return The service.
     */
    public static  T getService(final Class in) {
        if (bundleContext == null) {
            return null;
        }
        final String name = in.getName();
        ServiceTracker t = null;
        synchronized (BundleServices.class) {
            t = serviceTrackers.get(name);
            if (t == null) {
                t = new ServiceTracker(bundleContext, name, null);
                serviceTrackers.put(name, t);
                t.open();
            }
        }
        final T service = (T) t.getService();
        if (service == null) {
            throw new IllegalStateException("Service unavailable: " + name);
        }
        return service;
    }
}