osgi.enroute.executor.simple.provider.ExecutorImplementation Maven / Gradle / Ivy

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package osgi.enroute.executor.simple.provider;

import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import org.osgi.annotation.bundle.Capability;
import org.osgi.namespace.implementation.ImplementationNamespace;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.ConfigurationPolicy;
import org.osgi.service.component.annotations.Deactivate;
import org.osgi.service.component.annotations.ServiceScope;
import org.osgi.service.metatype.annotations.Designate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import osgi.enroute.executor.capabilities.ExecutorConstants;

/**
 * This bundle provides a java.util.concurrent.Executor service that can be
 * configured and is shared between all bundles.
 */
@Capability(namespace = ImplementationNamespace.IMPLEMENTATION_NAMESPACE, name = ExecutorConstants.EXECUTOR_SPECIFICATION_NAME, version = ExecutorConstants.EXECUTOR_SPECIFICATION_VERSION)
@Designate(ocd = Configuration.class, factory = true)
@Component(name = "osgi.executor.provider", configurationPolicy = ConfigurationPolicy.OPTIONAL, scope = ServiceScope.BUNDLE)
public class ExecutorImplementation implements Executor {
	ExecutorService			es;
	BlockingQueue	queue	= new LinkedBlockingQueue();
	static Logger			log		= LoggerFactory.getLogger(ExecutorImplementation.class);

	/*
	 * Creates a new instance of the underlying implementation of the executor
	 * service (depending on the configuration parameters) if needed, or returns
	 * a pre-existing instance of this service, shared by all bundles.
	 * @param properties Configuration parameters, passed by the framework
	 */
	@Activate
	void activate(Configuration config) {
		int coreSize = config.coreSize();
		int maxSize = config.maximumPoolSize();
		long keepAlive = config.keepAliveTime();
		int cores = Runtime.getRuntime()
			.availableProcessors();

		if (coreSize < 10 * cores)
			coreSize = 30;

		if (maxSize <= coreSize)
			maxSize = coreSize * 4;

		if (keepAlive < 10 || keepAlive > 1000)
			keepAlive = 300;

		es = new ThreadPoolExecutor(coreSize, maxSize, keepAlive, TimeUnit.SECONDS, queue, //
			new ThreadPoolExecutor.CallerRunsPolicy());
	}

	/*
	 * Cancels the tasks submitted by the exiting bundle, shutting down the
	 * executor service if no more bundle is using it
	 */
	@Deactivate
	void deactivate() {
		List running = es.shutdownNow();
		if (!running.isEmpty())
			log.warn("Shutting down while tasks %s are running", running);
	}

	/*
	 * Execute a runnable
	 */
	@Override
	public void execute(Runnable command) {
		es.submit(command);
	}

}