First attempt at having the app poll the plugins directory to dynamic…

…ally reload plugins. Class unloading occurs when threadpools are shutdown and the correct hooks are triggered, now just a matter of making sure the correct triggers happen at the correct time.

src/main/java/org/netmelody/cieye/core/observation/ForeignAgencies.java

@@ -0,0 +1,8 @@
+package org.netmelody.cieye.core.observation;
+
+import org.netmelody.cieye.core.domain.CiServerType;
+
+public interface ForeignAgencies {
+    ObservationAgency agencyFor(CiServerType type);
+    boolean hasChanged();
+}

src/main/java/org/netmelody/cieye/server/CiSpyHandler.java

@@ -10,4 +10,6 @@ public interface CiSpyHandler {
     long millisecondsUntilNextUpdate(Feature feature);
 
     boolean takeNoteOf(String targetId, String note);
+
+    void endMission();
 }

src/main/java/org/netmelody/cieye/server/configuration/PluginDirectory.java

@@ -0,0 +1,31 @@
+package org.netmelody.cieye.server.configuration;
+
+import java.io.File;
+import java.io.FileFilter;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Date;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.filefilter.SuffixFileFilter;
+
+public final class PluginDirectory {
+
+    private final File directory;
+    private Date lastReadDate = new Date(0L); 
+
+    public PluginDirectory(File directory) {
+        this.directory = directory;
+    }
+
+    public Iterable<File> jars() {
+        lastReadDate = new Date();
+        File[] jarFiles = directory.listFiles((FileFilter)new SuffixFileFilter(".jar"));
+        return jarFiles == null ? Collections.<File>emptySet() : Arrays.asList(jarFiles);
+    }
+
+    public boolean updateAvailable() {
+        return FileUtils.isFileNewer(directory, lastReadDate);
+    }
+
+}

src/main/java/org/netmelody/cieye/server/observation/ResourceBundleObservationAgencyConfiguration.java → src/main/java/org/netmelody/cieye/server/configuration/ResourceBundleObservationAgencyConfiguration.java

@@ -1,11 +1,12 @@
-package org.netmelody.cieye.server.observation;
+package org.netmelody.cieye.server.configuration;
 
 import java.util.ResourceBundle;
 
 import org.netmelody.cieye.core.domain.CiServerType;
+import org.netmelody.cieye.core.observation.ForeignAgencies;
 import org.netmelody.cieye.core.observation.ObservationAgency;
 
-public final class ResourceBundleObservationAgencyConfiguration implements ObservationAgencyConfiguration {
+public final class ResourceBundleObservationAgencyConfiguration implements ForeignAgencies {
 
     private static final ResourceBundle AGENCY_CONFIGURATION = ResourceBundle.getBundle(ResourceBundleObservationAgencyConfiguration.class.getName());
 
@@ -25,4 +26,9 @@ public ObservationAgency agencyFor(CiServerType type) {
             throw new IllegalStateException("Failed to load CI Observation Module for " + typeName, e);
         }
     }
+
+    @Override
+    public boolean hasChanged() {
+        return false;
+    }
 }

src/main/java/org/netmelody/cieye/server/configuration/ServerConfiguration.java

@@ -4,7 +4,7 @@
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
-import org.netmelody.cieye.core.observation.ForeignAgents;
+import org.netmelody.cieye.core.observation.ForeignAgencies;
 import org.netmelody.cieye.core.observation.KnownOffendersDirectory;
 import org.netmelody.cieye.server.CiEyeServerInformationFetcher;
 import org.netmelody.cieye.server.LandscapeFetcher;
@@ -17,7 +17,7 @@ public final class ServerConfiguration {
     private final ServerInformation information = new ServerInformation(settings.settingsLocation());
     private final RecordedKnownOffenders detective = new RecordedKnownOffenders(settings.picturesFile());
     private final RecordedObservationTargets targets = new RecordedObservationTargets(settings.viewsFile());
-    private final RecordedForeignAgents foreignAgents = new RecordedForeignAgents(settings.pluginDirectory());
+    private final ServiceLoadingRecordedForeignAgencies foreignAgencies = new ServiceLoadingRecordedForeignAgencies(settings.pluginDirectory());
     private final Album album = new Album(settings.picturesDirectory());
 
     private static final class Refresher implements Runnable {
@@ -32,9 +32,10 @@ public void run() {
     }
 
     public ServerConfiguration() {
-        final ScheduledExecutorService executor = Executors.newScheduledThreadPool(2);
+        final ScheduledExecutorService executor = Executors.newScheduledThreadPool(3);
         executor.scheduleWithFixedDelay(new Refresher(detective), 1L, 10L, TimeUnit.SECONDS);
         executor.scheduleWithFixedDelay(new Refresher(targets), 1L, 10L, TimeUnit.SECONDS);
+        executor.scheduleWithFixedDelay(new Refresher(foreignAgencies), 1L, 10L, TimeUnit.SECONDS);
     }
 
     public KnownOffendersDirectory detective() {
@@ -53,7 +54,7 @@ public PictureFetcher album() {
         return album;
     }
 
-    public ForeignAgents foreignAgents() {
-        return foreignAgents;
+    public ForeignAgencies foreignAgents() {
+        return foreignAgencies;
     }
 }

src/main/java/org/netmelody/cieye/server/configuration/ServiceLoadingRecordedForeignAgencies.java

@@ -0,0 +1,106 @@
+package org.netmelody.cieye.server.configuration;
+
+import java.io.File;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.Date;
+import java.util.Iterator;
+import java.util.ServiceLoader;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.netmelody.cieye.core.domain.CiServerType;
+import org.netmelody.cieye.core.logging.LogKeeper;
+import org.netmelody.cieye.core.logging.Logbook;
+import org.netmelody.cieye.core.observation.ForeignAgencies;
+import org.netmelody.cieye.core.observation.ObservationAgency;
+
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+
+public final class ServiceLoadingRecordedForeignAgencies implements ForeignAgencies, Refreshable {
+    private final static Logbook LOGBOOK = LogKeeper.logbookFor(ServiceLoadingRecordedForeignAgencies.class);
+
+    private final PluginDirectory pluginDirectory;
+
+    private final AtomicReference<Date> lastUpdate = new AtomicReference<Date>(new Date(0L));
+    private final AtomicReference<Date> lastAsked = new AtomicReference<Date>(new Date(0L));
+
+    private final AtomicReference<ServiceLoader<ObservationAgency>> services;
+
+    public ServiceLoadingRecordedForeignAgencies(PluginDirectory pluginDirectory) {
+        this.pluginDirectory = pluginDirectory;
+        this.services = new AtomicReference<ServiceLoader<ObservationAgency>>(newServiceLoader());
+    }
+
+    @Override
+    public ObservationAgency agencyFor(CiServerType type) {
+        final String typeName = type.name();
+        Iterator<ObservationAgency> agencies = available();
+
+        while (agencies.hasNext()) {
+            ObservationAgency agency = agencies.next();
+            if (agency.canProvideSpyFor(type)) {
+                return agency;
+            }
+        }
+
+        throw new IllegalStateException("No CI Observation Module for " + typeName);
+    }
+
+    private ServiceLoader<ObservationAgency> newServiceLoader() {
+        return ServiceLoader.load(ObservationAgency.class, pluginsClassLoader());
+    }
+
+    private Iterator<ObservationAgency> available() {
+        return services.get().iterator();
+    }
+
+    private ClassLoader pluginsClassLoader() {
+        Iterable<File> jarFiles = pluginDirectory.jars();
+        return new URLClassLoader(FluentIterable.from(urlsOf(jarFiles)).toArray(URL.class));
+    }
+
+    private Set<URL> urlsOf(Iterable<File> jarFiles) {
+        Set<URL> urls = Sets.newHashSet();
+        Set<Throwable> problems = Sets.newHashSet();
+        for (File file : jarFiles) {
+            try {
+                urls.add(file.toURI().toURL());
+            } catch (MalformedURLException e) {
+                problems.add(e);
+            }
+        }
+
+        if (!problems.isEmpty()) {
+            logProblems(problems);
+        }
+
+        return ImmutableSet.copyOf(urls);
+    }
+
+    private static void logProblems(Set<Throwable> problems) {
+        System.out.printf("Found [%d] problems obtaining plugin jars. See logs for more details.%n", problems.size());
+        for (Throwable throwable : problems) {
+            LOGBOOK.error("Error loading plugin.", throwable);
+        }
+    }
+
+    @Override
+    public void refresh() {
+        if (pluginDirectory.updateAvailable()) {
+            services.set(newServiceLoader());
+            lastUpdate.set(new Date());
+        }
+    }
+
+
+    @Override
+    public boolean hasChanged() {
+        Date lastAskedDate = lastAsked.getAndSet(new Date());
+        return lastUpdate.get().after(lastAskedDate);
+    }
+
+}

src/main/java/org/netmelody/cieye/server/configuration/SettingsInitialiser.java

@@ -113,7 +113,7 @@ public String settingsLocation() {
         }
     }
 
-    public File pluginDirectory() {
-        return pluginsDir;
+    public PluginDirectory pluginDirectory() {
+        return new PluginDirectory(pluginsDir);
     }
 }

src/main/java/org/netmelody/cieye/server/observation/IntelligenceAgency.java

@@ -5,7 +5,7 @@
 import org.netmelody.cieye.core.domain.Feature;
 import org.netmelody.cieye.core.observation.CiSpy;
 import org.netmelody.cieye.core.observation.CommunicationNetwork;
-import org.netmelody.cieye.core.observation.ForeignAgents;
+import org.netmelody.cieye.core.observation.ForeignAgencies;
 import org.netmelody.cieye.core.observation.KnownOffendersDirectory;
 import org.netmelody.cieye.server.CiSpyAllocator;
 import org.netmelody.cieye.server.CiSpyHandler;
@@ -16,9 +16,9 @@
 
 public final class IntelligenceAgency implements CiSpyAllocator {
 
-    private final ObservationAgencyConfiguration agencyConfiguration;
     private final LoadingCache<Feature, CiSpyHandler> handlers =
-            CacheBuilder.newBuilder().build(from(new Function<Feature, CiSpyHandler>() {
+            CacheBuilder.newBuilder()
+                .build(from(new Function<Feature, CiSpyHandler>() {
                 @Override
                 public CiSpyHandler apply(Feature feature) {
                     return createSpyFor(feature);
@@ -27,20 +27,31 @@ public CiSpyHandler apply(Feature feature) {
 
     private final CommunicationNetwork network;
     private final KnownOffendersDirectory directory;
+    private final ForeignAgencies foreignAgencies;
 
-    public IntelligenceAgency(CommunicationNetwork network, KnownOffendersDirectory directory, ForeignAgents foreignAgents) {
+    public IntelligenceAgency(CommunicationNetwork network, KnownOffendersDirectory directory, ForeignAgencies foreignAgencies) {
         this.network = network;
         this.directory = directory;
-        this.agencyConfiguration = new ServiceLoaderObservationAgencyConfiguration(foreignAgents);
+        this.foreignAgencies = foreignAgencies;
     }
 
     @Override
     public CiSpyHandler spyFor(Feature feature) {
+    	if (foreignAgencies.hasChanged()) {
+    		recallSpies();
+    	}
         return handlers.getUnchecked(feature);
     }
 
+    private void recallSpies() {
+        for (CiSpyHandler ciSpyHandler : handlers.asMap().values()) {
+            ciSpyHandler.endMission();
+        }
+        handlers.invalidateAll();
+    }
+
     private CiSpyHandler createSpyFor(Feature feature) {
-        final CiSpy spy = agencyConfiguration.agencyFor(feature.type()).provideSpyFor(feature, network, directory);
-        return new PollingSpyHandler(spy);
+        final CiSpy spy = foreignAgencies.agencyFor(feature.type()).provideSpyFor(feature, network, directory);
+        return new PollingSpyHandler(spy, feature);
     }
 }