Metacat

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

        return multiThreadUpgrade();

        //return singleThreadUpgrade();

    }

    /**

     * Use this current single thread to process each ID in the list

     * @return

     * @throws AdminException

     * @deprecated use the multithreaded version of this upgrade method

     */

    public boolean singleThreadUpgrade() throws AdminException {

    /**

     * Use multiple threads to process parts of the complete ID list concurrently

     * @return

     * @throws AdminException

     */

    public boolean multiThreadUpgrade() throws AdminException {

        boolean success = true;

        // do not include ORE or data, but can generate SystemMetadata for ALL records

        final boolean includeOre = false;

        final boolean downloadData = false;

        int serverLocation = -1;

        try {

        	// get list of ALL docids at ALL server locations

            List<String> idList = DBUtil.getAllDocidsByType(null, true, serverLocation);

            Collections.sort(idList);

            // executor

            int availableProcessors = Runtime.getRuntime().availableProcessors();

            int nThreads = availableProcessors * 1;

        	log.debug("Using nThreads: " + nThreads);

            ExecutorService executor = Executors.newFixedThreadPool(nThreads);

            // chunk into groups

			int fromIndex = 0;

            int toIndex = 0;

            String prefix = null;

            for (String docid: idList) {

            	// increment the next entry, exclusive

            	toIndex++;

            	// use scope.docid (without revision) to determine groups

            	if (prefix == null || !docid.startsWith(prefix)) {

            		// construct a sublist for this previous group of docids

					final List<String> subList = idList.subList(fromIndex, toIndex);

	            	log.debug("Grouping docid prefix: " + prefix);

					log.debug("subList.size: " + subList.size());

					// add the task for this sublist

					Runnable command = new Runnable() {

						@Override

						public void run() {

							// generate based on this list

				            try {

				            	log.debug("Processing subList.size: " + subList.size());

								SystemMetadataFactory.generateSystemMetadata(subList, includeOre, downloadData);

								log.debug("Done processing subList.size: " + subList.size());

							} catch (Exception e) {

								throw new RuntimeException(e);

							}

						}

					};

					// execute the task 

					executor.execute(command);

					// start at the end of this sublist

					fromIndex = toIndex;

            	}

            	log.debug("docid: " + docid);

            	// get the previous docid prefix

            	String previousId = docid;

            	prefix = previousId.substring(0, previousId.lastIndexOf("."));

            }

            // wait for executor to finish

            executor.shutdown();

		} catch (Exception e) {

			String msg = "Problem generating missing system metadata: " + e.getMessage();

			log.error(msg, e);

			success = false;

			throw new AdminException(msg);

		}

    	return success;

    }