D-Net

package eu.dnetlib.openaire.exporter;

import java.util.List;

import java.util.concurrent.*;

import javax.annotation.PostConstruct;

import javax.annotation.PreDestroy;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.springframework.stereotype.Component;

@Component

public class OperationManager {

	private static final Log log = LogFactory.getLog(OperationManager.class);

	private static final long SLEEP_TIME = 1000;

	private static final int Q_SIZE = 100;

	private static final int POOL_SIZE = 5;

	private BlockingQueue<Runnable> ops = new ArrayBlockingQueue<>(Q_SIZE);

	private ExecutorService executor;

	@PostConstruct

	public void init() {

		executor = getExecutor();

	}

	public int dropAll() {

		final List<Runnable> lostOperations = executor.shutdownNow();

		log.warn(String.format("discarding %s operations", lostOperations.size()));

		executor = getExecutor();

		return lostOperations.size();

	}

	public int getOpSize() {

		return ops.size();

	}

	public void addOperation(final Runnable op) {

		executor.execute(op);

	}

	@PreDestroy

	public void tearDown() throws InterruptedException {

		executor.shutdown();

		final boolean done = executor.awaitTermination(SLEEP_TIME, TimeUnit.MILLISECONDS);

		log.debug(String.format("All operations were completed so far? %s", done));

	}

	// HELPERS

	private ThreadPoolExecutor getExecutor() {

		return new ThreadPoolExecutor(POOL_SIZE, POOL_SIZE,0L, TimeUnit.MILLISECONDS, ops);

	}

}