D-Net

package eu.dnetlib.data.download.rmi;

import java.util.List;

import java.util.concurrent.BlockingQueue;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Future;

import javax.annotation.Resource;

import com.google.common.base.Function;

import com.google.common.base.Joiner;

import com.google.common.collect.Lists;

import com.google.common.collect.Queues;

import eu.dnetlib.data.download.DownloadPluginEnumeratorImpl;

import eu.dnetlib.data.download.DownloadReport;

import eu.dnetlib.data.download.DownloadReportMap;

import eu.dnetlib.data.download.DownloadServiceImpl;

import eu.dnetlib.data.download.worker.DownloadWorker;

import eu.dnetlib.data.objectstore.modular.connector.ObjectStore;

import eu.dnetlib.data.objectstore.modular.connector.ObjectStoreDao;

import eu.dnetlib.data.objectstore.rmi.ObjectStoreServiceException;

import eu.dnetlib.data.objectstore.rmi.Protocols;

import eu.dnetlib.enabling.resultset.client.ResultSetClientFactory;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.annotation.Autowired;

/**

 * The Class DownloadServiceFeeder.

 */

public class DownloadServiceFeeder {

	/** The Constant log. */

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

	private static final int MAX_NUM_FOUND = 10;

	/** The download plugin enumerator. */

	@Resource

	DownloadPluginEnumeratorImpl downloadPluginEnumerator;

	/** The result set client factory. */

	@Resource

	private ResultSetClientFactory resultSetClientFactory;

	/** The object store dao. */

	@Autowired

	private ObjectStoreDao objectStoreDao;

	public static void reportException(final DownloadReportMap report, final DownloadItem di, final Throwable e) {

		final String className = e.getClass().getName();

		if (!report.containsKey(className)) {

			final DownloadReport dr = new DownloadReport();

			dr.setStackTrace(Joiner.on("\tat ").join(e.getStackTrace()));

			if (di != null) {

				dr.setDownloadItem(di);

			}

			report.put(className, dr);

		} else {

			report.get(className).incrementError();

		}

	}

	/**

	 * Download and feed file into the objectStore .

	 *

	 * @param epr

	 *            the end-point reference of the result-set of Serialized DownloadItem

	 * @param plugin

	 *            the plugin used to retrieve the correct URL

	 * @param objectStoreID

	 *            the object store id to store the data

	 * @param protocol

	 *            the protocol used to download the file

	 * @param mimeType

	 *            the mime type of the Files

	 * @param numberOfThreads

	 *            the number of threads to use for download at the same time

	 * @throws DownloadServiceException

	 *             the download service exception

	 * @throws ObjectStoreServiceException

	 */

	public DownloadReportMap download(final String epr,

			final String plugin,

			final String objectStoreID,

			final String protocol,

			final String mimeType,

			final int numberOfThreads,

			final String basePath,

			final List<String> regularExpression,

			final int connectTimeoutMs,

			final int readTimeoutMs, final int sleepTimeMs) throws DownloadServiceException, ObjectStoreServiceException {

		final DownloadPlugin downloadPlugin = downloadPluginEnumerator.get(plugin);

		if ((basePath != null) && (basePath.isEmpty() == false)) {

			downloadPlugin.setBasePath(basePath);

		}

		final Iterable<String> urlInfo = resultSetClientFactory.getClient(epr);

		final BlockingQueue<String> itemsQueue = Queues.newArrayBlockingQueue(1024);

		final ExecutorService executor = Executors.newFixedThreadPool(numberOfThreads);

		final ObjectStore objStore = objectStoreDao.getObjectStore(objectStoreID);

		final List<Future<DownloadReportMap>> responses = Lists.newArrayList();

		final DownloadReportMap pluginReport = new DownloadReportMap();

		pluginReport.setStatus(true);

		if (regularExpression != null) {

			downloadPlugin.setRegularExpression(regularExpression);

		}

		for (int i = 0; i < numberOfThreads; i++) {

			responses.add(executor

					.submit(new DownloadWorker(itemsQueue, objStore, Protocols.valueOf(protocol), mimeType, connectTimeoutMs, readTimeoutMs, sleepTimeMs,

					new Function<String, DownloadItem>() {

				@Override

				public DownloadItem apply(final String input) {

					if (input == null) {

						log.error("Input is null");

						return null;

					}

					if (input.equals(DownloadServiceImpl.END_QUEUE_STRING)) return DownloadServiceImpl.END_QUEUE;

					DownloadItem di = null;

					try {

						di = DownloadItem.newObjectfromJSON(input);

						if (downloadPlugin.retrieveUrl(di) == null) {

							di.setUrl(null);

							di.setOriginalUrl(null);

						}

						return di;

					} catch (Throwable e) {

						reportException(pluginReport, di, e);

						log.error("Exception on transform item :" + input, e);

						return null;

					}

				}

			})));

		}

		int i = 0;

		int null_found = 0;

		if (urlInfo != null) {

			for (final String downloadItem : urlInfo) {

				if (downloadItem != null) {

					null_found = 0;

					if ((i++ % 1000) == 0) {

						log.debug("Read " + i);

					}

					try {

						itemsQueue.put(downloadItem);

					} catch (final Exception e) {

						log.error("An error occurred while populating the download items queue: " + Joiner.on("\tat ").join(e.getStackTrace()));

					}

				} else {

					if (null_found++ > MAX_NUM_FOUND) {

						break;

					}

				}

			}

		}

		try {

			itemsQueue.put(DownloadServiceImpl.END_QUEUE_STRING);

		} catch (final InterruptedException e) {

			log.error("An error occurred adding the loop terminator: " + Joiner.on("\tat ").join(e.getStackTrace()));

		}

		final DownloadReportMap resultMap = getDownloadReportMap(responses, pluginReport);

		executor.shutdown();

		return resultMap;

	}

	private DownloadReportMap getDownloadReportMap(final List<Future<DownloadReportMap>> responses, final DownloadReportMap pluginReport) {

		final DownloadReportMap resultMap = new DownloadReportMap();

		resultMap.setStatus(true);

		for (final Future<DownloadReportMap> currentResponse : responses) {

			try {

				final DownloadReportMap currentMap = currentResponse.get();

				mergeReport(resultMap, currentMap);

				log.info("Status " + currentMap.getStatus());

				resultMap.setStatus(resultMap.getStatus() && currentMap.getStatus());

				resultMap.setTotalDownloaded(currentMap.getTotalDownloaded() + resultMap.getTotalDownloaded());

			} catch (final Exception e) {

				log.error(e);

				resultMap.setStatus(false);

			}

		}

		mergeReport(resultMap, pluginReport);

		return resultMap;

	}

	private void mergeReport(final DownloadReportMap resultMap, final DownloadReportMap currentMap) {

		for (final String key : currentMap.keySet()) {

			if (!resultMap.containsKey(key)) {

				resultMap.put(key, currentMap.get(key));

			} else {

				final DownloadReport currentReport = currentMap.get(key);

				resultMap.get(key).incrementError(currentReport.getNumberOfOccurrences());

			}

			resultMap.setTotalDownloaded(resultMap.getTotalDownloaded() + currentMap.getTotalDownloaded());

			resultMap.setStatus(resultMap.getStatus() & currentMap.getStatus());

		}

	}

}