AbstractBUGModuleActivator.java

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package com.buglabs.bug.bmi.api;

import java.util.Dictionary;
import java.util.Hashtable;

import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceRegistration;
import org.osgi.service.log.LogService;

import com.buglabs.bug.bmi.sysfs.BMIDevice;
import com.buglabs.util.osgi.BUGBundleConstants;
import com.buglabs.util.osgi.LogServiceUtil;

/**
 * Common abstract BundleActivator for bundles that contribute IModletFactories, ie
 * bundles that provide API and service code for BUG modules.
 * 
 * @author kgilmer
 * 
 */
public abstract class AbstractBUGModuleActivator implements BundleActivator, IModletFactory {

	private static BundleContext context;
	private ServiceRegistration sr;
	private Dictionary headers;
	private static LogService log;
	
	/**
	 * @return an instance of LogService or null if bundle has not been started or has been stopped.
	 */
	public static LogService getLog() {
		return log;
	}
	
	/**
	 * @return an instance of local BundleContext or null if bundle has not been started or has been stopped.
	 */
	public static BundleContext getContext() {
		return context;
	}

	public void start(BundleContext context) throws Exception {
		AbstractBUGModuleActivator.context = context;
		AbstractBUGModuleActivator.log = LogServiceUtil.getLogService(context);
		this.headers = context.getBundle().getHeaders();
		
		sr = context.registerService(IModletFactory.class.getName(), this, getModletProperties());		
	}

	/* (non-Javadoc)
	 * @see org.osgi.framework.BundleActivator#stop(org.osgi.framework.BundleContext)
	 */
	public void stop(BundleContext context) throws Exception {
		sr.unregister();
		sr = null;
		context = null;
		log = null;
	}

	/* (non-Javadoc)
	 * @see com.buglabs.bug.bmi.api.IModletFactory#getModuleId()
	 */
	public String getModuleId() {
		return headers.get("Bug-Module-Id").toString();
	}

	/* (non-Javadoc)
	 * @see com.buglabs.bug.bmi.api.IModletFactory#getName()
	 */
	public String getName() {
		return headers.get("Bundle-SymbolicName").toString();
	}

	/* (non-Javadoc)
	 * @see com.buglabs.bug.bmi.api.IModletFactory#getVersion()
	 */
	public String getVersion() {
		return headers.get("Bundle-Version").toString();
	}

	/**
	 * @return driver id
	 */
	public String getModuleDriver() {
		return headers.get("Bug-Module-Driver-Id").toString();
	}
	
	/**
	 * Get the service properties associated with the IModletFactory registration in the OSGi service registry.
	 * 
	 * Clients can override this to provide custom/additional properties.
	 * 
	 * @return A dictionary with some default values.  
	 */
	public Dictionary getModletProperties() {
		Dictionary d = new Hashtable();
		
		d.put(BUGBundleConstants.MODLET_FACTORY_PROVIDER, getName());
		d.put(BUGBundleConstants.MODLET_FACTORY_SOURCE, this.getClass().getName());
		d.put(BUGBundleConstants.MODLET_FACTORY_ID, getModuleId());
		
		return d;
	}

	public abstract IModlet createModlet(BundleContext context, int slotId, BMIDevice device);
}