Java tutorial
/** * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * @author Arne Kepp and Gabriel Roldan (OpenGeo) 2010 * */ package org.geowebcache.georss; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import java.net.URL; import java.util.Iterator; import java.util.LinkedList; import java.util.List; import java.util.Map; import javax.imageio.ImageIO; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.geowebcache.GeoWebCacheException; import org.geowebcache.grid.GridSubset; import org.geowebcache.layer.TileLayer; import org.geowebcache.layer.updatesource.GeoRSSFeedDefinition; import org.geowebcache.mime.MimeException; import org.geowebcache.mime.MimeType; import org.geowebcache.seed.GWCTask; import org.geowebcache.seed.GWCTask.STATE; import org.geowebcache.seed.TileBreeder; import org.geowebcache.storage.DiscontinuousTileRange; import org.geowebcache.storage.GeometryRasterMaskBuilder; import org.geowebcache.storage.RasterMask; import org.geowebcache.storage.StorageBroker; /** * A task to run a GeoRSS feed poll and launch the seeding process * <p> * If a poll {@link GeoRSSFeedDefinition#getFeedUrl() URL} is configured with the * <code>${lastUpdate}</code> then the formatted date and time for the last updated entry will be * passed on to the URL. * </p> * <p> * For example, if the URL is configured as * <code>http://some.server.org/georss/gwcupdates?updateSequence=${lastUpdate}</code> and a previous * poll for this resource determined that the most recent <code>updated</code> property of a GeoRSS * entry was <code>2010-01-17T01:05:32Z</code>, the the resulting feed URL will be * <code>http://some.server.org/georss/gwcupdates?updateSequence=2010-01-17T01:05:32Z</code> (or its * equivalent in the server's time zone). * </p> * <p> * By the other hand, if <code>${lastUpdate}</code> parameter is configured but this task is going * to perform the first poll (hence there's no last update history), the parameter will be replaced * by the empty string, resulting in something like * <code>http://some.server.org/georss/gwcupdates?updateSequence=</code> * </p> */ class GeoRSSPollTask implements Runnable { private static final Log logger = LogFactory.getLog(GeoRSSPollTask.class); /** * Layer metadata property under which the lastUpdated entry value is stored * * @see StorageBroker#putLayerMetadata(String, String, String) * @see StorageBroker#getLayerMetadata(String, String) */ private static final String LAST_UPDATED = "GeoRSS.lastUpdated"; private static final String LAST_UPDATE_URL_TEMPLATE = "${lastUpdate}"; private final PollDef poll; private final TileBreeder seeder; private LinkedList<GWCTask> seedTasks = new LinkedList<GWCTask>(); public GeoRSSPollTask(final PollDef poll, final TileBreeder seeder) { this.poll = poll; this.seeder = seeder; } /** * Called by the thread executor when the poll def's interval has elapsed (or as soon as * possible after it elapsed). */ public void run() { /* * This method cannot throw an exception or the thread scheduler will discard the task. * Instead, if an error happens when polling we log the exception and hope for the next run * to work? */ try { runPollAndLaunchSeed(); } catch (Exception e) { logger.error("Error encountered trying to poll the GeoRSS feed " + poll.getPollDef().getFeedUrl() + ". Another attempt will be made after the poll interval of " + poll.getPollDef().getPollIntervalStr(), e); } catch (OutOfMemoryError error) { System.gc(); logger.fatal("Out of memory error processing poll " + poll.getPollDef() + ". Need to reduce the maxMaskLevel param or increase system memory." + " Poll disabled.", error); throw error; } } private void runPollAndLaunchSeed() throws IOException { final String layerName = poll.getLayerName(); final TileLayer layer = poll.getLayer(); final GeoRSSFeedDefinition pollDef = poll.getPollDef(); logger.info("Polling GeoRSS feed for layer " + layerName + ": " + pollDef.toString()); final StorageBroker storageBroker = seeder.getStorageBroker(); final String previousUpdatedEntry = storageBroker.getLayerMetadata(layerName, LAST_UPDATED); final String gridSetId = pollDef.getGridSetId(); final URL feedUrl = new URL(templateFeedUrl(pollDef.getFeedUrl(), previousUpdatedEntry)); final String httpUsername = pollDef.getHttpUsername(); final String httpPassword = pollDef.getHttpUsername(); logger.debug("Getting GeoRSS reader for " + feedUrl.toExternalForm()); final GeoRSSReaderFactory geoRSSReaderFactory = new GeoRSSReaderFactory(); GeoRSSReader geoRSSReader = null; try { geoRSSReader = geoRSSReaderFactory.createReader(feedUrl, httpUsername, httpPassword); } catch (IOException ioe) { logger.error("Failed to fetch RSS feed from " + feedUrl + "\n" + ioe.getMessage()); return; } logger.debug("Got reader for " + pollDef.getFeedUrl() + ". Creating geometry filter matrix for gridset " + gridSetId + " on layer " + layerName); final int maxMaskLevel = pollDef.getMaxMaskLevel(); final GeoRSSTileRangeBuilder matrixBuilder = new GeoRSSTileRangeBuilder(layer, gridSetId, maxMaskLevel); logger.debug("Creating tile range mask based on GeoRSS feed's geometries from " + feedUrl.toExternalForm() + " for " + layerName); final GeometryRasterMaskBuilder tileRangeMask = matrixBuilder.buildTileRangeMask(geoRSSReader, previousUpdatedEntry); if (tileRangeMask == null) { logger.info("Did not create a tileRangeMask, presumably no new entries in feed."); return; } // store last updated entry to persist even after a restart final String lastUpdatedEntry = matrixBuilder.getLastEntryUpdate(); storageBroker.putLayerMetadata(layerName, LAST_UPDATED, lastUpdatedEntry); logger.debug("Created tile range mask based on GeoRSS geometry feed from " + pollDef + " for " + layerName + ". Calculating number of affected tiles..."); _logImagesToDisk(tileRangeMask); final boolean tilesAffected = tileRangeMask.hasTilesSet(); if (tilesAffected) { logger.info("Launching reseed process " + pollDef + " for " + layerName); } else { logger.info(pollDef + " for " + layerName + " did not affect any tile. No need to reseed."); return; } launchSeeding(layer, pollDef, gridSetId, tileRangeMask); logger.info("Seeding process for tiles affected by feed " + feedUrl.toExternalForm() + " successfully launched."); } private String templateFeedUrl(final String feedUrl, final String lastUpdatedEntry) { if (feedUrl == null) { throw new NullPointerException("feedUrl"); } String url = feedUrl; if (feedUrl.indexOf(LAST_UPDATE_URL_TEMPLATE) > -1) { String replaceValue = lastUpdatedEntry == null ? "" : lastUpdatedEntry; url = feedUrl.replace(LAST_UPDATE_URL_TEMPLATE, replaceValue); logger.info("Feed URL templated as '" + url + "'"); } return url; } /** * For debug purposes only, writes down the bitmask images to the directory specified by the * System property (ej, {@code -Dorg.geowebcache.georss.debugToDisk=target/}) * * @param tileRangeMask */ private void _logImagesToDisk(final GeometryRasterMaskBuilder matrix) { if (null == System.getProperty("org.geowebcache.georss.debugToDisk")) { return; } File target = new File(System.getProperty("org.geowebcache.georss.debugToDisk")); if (!target.isDirectory() || !target.canWrite()) { throw new IllegalStateException( "Can't access debug directory for " + "dumping mask images: " + target.getAbsolutePath()); } logger.warn("\n!!!!!!!!!!!\n REMEMBER NOT TO SET THE org.geowebcache.georss.debugToDisk" + " SYSTEM PROPERTY ON A PRODUCTION ENVIRONMENT \n!!!!!!!!!!!"); BufferedImage[] byLevelMasks = matrix.getByLevelMasks(); for (int i = 0; i < byLevelMasks.length; i++) { File output = new File(target, poll.getLayerName() + "_level_" + i + ".tiff"); System.out.println("--- writing " + output.getAbsolutePath() + "---"); try { ImageIO.write(byLevelMasks[i], "TIFF", output); } catch (IOException e) { e.printStackTrace(); } } } private void launchSeeding(final TileLayer layer, final GeoRSSFeedDefinition pollDef, final String gridSetId, final GeometryRasterMaskBuilder tileRangeMask) { GridSubset gridSub = layer.getGridSubset(gridSetId); long[][] fullCoverage = gridSub.getCoverages(); long[][] coveredBounds = tileRangeMask.getCoveredBounds(); BufferedImage[] byLevelMasks = tileRangeMask.getByLevelMasks(); RasterMask rasterMask = new RasterMask(byLevelMasks, fullCoverage, coveredBounds); List<MimeType> mimeList = null; if (pollDef.getFormat() != null) { MimeType mime; try { mime = MimeType.createFromFormat(pollDef.getFormat()); mimeList = new LinkedList<MimeType>(); mimeList.add(mime); } catch (MimeException e) { logger.error(e.getMessage()); } } if (mimeList == null) { mimeList = layer.getMimeTypes(); } Iterator<MimeType> mimeIter = mimeList.iterator(); // Ask any existing seed jobs started by this feed to terminate stopSeeding(true); // We do the truncate synchronously to get rid of stale data as quickly as we can while (mimeIter.hasNext()) { DiscontinuousTileRange dtr = new DiscontinuousTileRange(layer.getName(), gridSetId, gridSub.getZoomStart(), gridSub.getZoomStop(), rasterMask, mimeIter.next(), (Map<String, String>) null); try { GWCTask[] tasks = seeder.createTasks(dtr, layer, GWCTask.TYPE.TRUNCATE, 1, false); tasks[0].doAction(); } catch (GeoWebCacheException e) { logger.error("Problem truncating based on GeoRSS feed: " + e.getMessage()); } catch (InterruptedException e) { logger.info("Task abruptly interrupted."); return; } } // If truncate was all that was needed, we can quit now if (pollDef.getOperation() == GWCTask.TYPE.TRUNCATE) { logger.info("Truncation succeeded, won't seed as stated by poll def: " + pollDef); return; } // ... else we seed mimeIter = mimeList.iterator(); while (mimeIter.hasNext()) { DiscontinuousTileRange dtr = new DiscontinuousTileRange(layer.getName(), gridSetId, gridSub.getZoomStart(), gridSub.getZoomStop(), rasterMask, mimeIter.next(), (Map<String, String>) null); final int seedingThreads = pollDef.getSeedingThreads(); GWCTask[] tasks; try { tasks = seeder.createTasks(dtr, layer, GWCTask.TYPE.SEED, seedingThreads, false); } catch (GeoWebCacheException e) { throw (RuntimeException) new RuntimeException(e.getMessage()).initCause(e); } seeder.dispatchTasks(tasks); // Save the handles so we can stop them for (GWCTask task : tasks) { seedTasks.add(task); } } } protected void stopSeeding(boolean checkLiveCount) { if (this.seedTasks != null) { int liveCount = 0; for (GWCTask task : seedTasks) { if (task.getState() != STATE.DEAD && task.getState() != STATE.DONE) { task.terminateNicely(); liveCount++; } } Thread.yield(); for (GWCTask task : seedTasks) { if (task.getState() != STATE.DEAD && task.getState() != STATE.DONE) { liveCount++; } } if (!checkLiveCount || liveCount == 0) { return; } try { logger.debug("Found " + liveCount + " running seed threads. Waiting 3s for them to terminate."); Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } liveCount = 0; Iterator<GWCTask> iter = seedTasks.iterator(); while (iter.hasNext()) { GWCTask task = iter.next(); if (task.getState() != STATE.DEAD && task.getState() != STATE.DONE) { liveCount++; } else { iter.remove(); } } if (liveCount > 0) { logger.info(liveCount + " seed jobs are still waiting to terminate, proceeding anyway."); } } else { logger.debug("Found no running seed jobs"); } } }