130 lines
3.3 KiB
Java
130 lines
3.3 KiB
Java
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package org.gcube.data.analysis.wps.repository;
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import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;
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import static java.nio.file.StandardWatchEventKinds.OVERFLOW;
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import java.io.IOException;
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import java.lang.reflect.Method;
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import java.net.URL;
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import java.net.URLClassLoader;
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import java.nio.file.FileSystems;
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import java.nio.file.Path;
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import java.nio.file.Paths;
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import java.nio.file.WatchEvent;
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import java.nio.file.WatchKey;
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import java.nio.file.WatchService;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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public final class AlgorithmUpdater {
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private static final Logger log = LoggerFactory.getLogger(AlgorithmUpdater.class);
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private String algorithmDirectory;
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private boolean mustUpdate = false;
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private WatcherThread watcherThread = null;
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public AlgorithmUpdater(String algorithmDirectory) {
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super();
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this.algorithmDirectory = algorithmDirectory;
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}
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protected synchronized boolean mustUpdate(){
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return mustUpdate;
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}
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protected synchronized void reset(){
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mustUpdate = false;
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}
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public boolean isStarted(){
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return watcherThread!=null;
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}
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protected void startWhatcher(){
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watcherThread = new WatcherThread(Thread.currentThread().getContextClassLoader(), algorithmDirectory);
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watcherThread.start();
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}
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private class WatcherThread extends Thread {
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private WatchService watcher;
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private ClassLoader loader;
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private Path dir;
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public WatcherThread(ClassLoader loader, String algorithmDirectory) {
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super();
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try {
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watcher = FileSystems.getDefault().newWatchService();
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this.loader = loader;
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//TODO: change with something from configuration
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dir = Paths.get(algorithmDirectory);
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dir.register(watcher, ENTRY_CREATE);
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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}
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@SuppressWarnings("unchecked")
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public void run(){
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for (;;) {
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// wait for key to be signaled
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WatchKey key;
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try {
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key = watcher.take();
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} catch (InterruptedException x) {
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return;
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}
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for (WatchEvent<?> event: key.pollEvents()) {
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WatchEvent.Kind<?> kind = event.kind();
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// This key is registered only
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// for ENTRY_CREATE events,
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// but an OVERFLOW event can
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// occur regardless if events
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// are lost or discarded.
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if (kind == OVERFLOW) {
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continue;
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}
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// The filename is the
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// context of the event.
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WatchEvent<Path> ev = (WatchEvent<Path>)event;
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Path filename = ev.context();
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if (filename.toString().endsWith(".jar")){
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try{
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final Class<URLClassLoader> sysclass = URLClassLoader.class;
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// TODO some kind of a hack. Need to invent better solution.
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final Method method = sysclass.getDeclaredMethod("addURL", new Class[] { URL.class });
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method.setAccessible(true);
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method.invoke(loader, new URL[] { dir.resolve(filename).toFile().toURI().toURL() });
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log.info("filename added is {} in loader {}",filename, loader.getClass().getName());
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mustUpdate = true;
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}catch(Exception e){
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log.error("filename {} cannot be added to classpath",e,filename);
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}
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} else log.info("filename {} is not a jar",filename);
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}
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boolean valid = key.reset();
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if (!valid) {
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break;
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}
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}
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}
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}
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protected void shutdown(){
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if (isStarted()){
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//TODO : kill the watcherThread
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watcherThread = null;
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}
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}
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}
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