Merge pull request #246 from JLLeitschuh/fix/invalidSourceLoading

Fixes invalid sources preventing saves from being loaded

Author: ThomasJClark

core/src/main/java/edu/wpi/grip/core/Main.java

@@ -4,6 +4,8 @@
 import com.google.common.eventbus.Subscribe;
 import com.google.inject.Guice;
 import com.google.inject.Injector;
+import edu.wpi.grip.core.events.ExceptionClearedEvent;
+import edu.wpi.grip.core.events.ExceptionEvent;
 import edu.wpi.grip.core.events.UnexpectedThrowableEvent;
 import edu.wpi.grip.core.operations.Operations;
 import edu.wpi.grip.core.serialization.Project;
@@ -78,6 +80,21 @@ public void start(String[] args) throws IOException, InterruptedException {
         }
     }
 
+    @Subscribe
+    public final void onExceptionEvent(ExceptionEvent event) {
+        Logger.getLogger(event.getOrigin().getClass().getName()).log(
+                Level.SEVERE,
+                event.getMessage(),
+                // The throwable can be null
+                event.getException().orElse(null)
+        );
+    }
+
+    @Subscribe
+    public final void onExceptionClearedEvent(ExceptionClearedEvent event) {
+        Logger.getLogger(event.getOrigin().getClass().getName()).log(Level.INFO, "Exception Cleared Event");
+    }
+
     /**
      * When an unexpected error happens in headless mode, print a stack trace and exit.
      */

core/src/main/java/edu/wpi/grip/core/Source.java

@@ -4,15 +4,20 @@
 import edu.wpi.grip.core.sources.CameraSource;
 import edu.wpi.grip.core.sources.ImageFileSource;
 import edu.wpi.grip.core.sources.MultiImageFileSource;
+import edu.wpi.grip.core.util.ExceptionWitness;
 
 import java.io.IOException;
 import java.util.Optional;
 import java.util.Properties;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 /**
  * Base class for an input into the pipeline.
  */
 public abstract class Source {
+    private final Logger logger = Logger.getLogger(getClass().getName());
+    private final ExceptionWitness exceptionWitness;
 
     public static class SourceFactoryImpl implements SourceFactory {
         @Inject
@@ -35,6 +40,13 @@ public interface SourceFactory {
         Source create(Class<?> type, Properties properties) throws IOException;
     }
 
+    /**
+     * @param exceptionWitnessFactory Factory to create the exceptionWitness
+     */
+    protected Source(ExceptionWitness.Factory exceptionWitnessFactory) {
+        this.exceptionWitness = exceptionWitnessFactory.create(this);
+    }
+
     /**
      * @return The name of this source.  This is used by the GUI to distinguish different sources.  For example,
      * {@link edu.wpi.grip.core.sources.ImageFileSource} returns the filename of the image.
@@ -62,4 +74,33 @@ public final OutputSocket[] getOutputSockets() {
      * serialization/deserialization.
      */
     public abstract Properties getProperties();
+
+    protected ExceptionWitness getExceptionWitness() {
+        return this.exceptionWitness;
+    }
+
+    /**
+     * Initializes the source. This should not try to handle initialization exceptions. Instead, the
+     * {@link #initializeSafely()} should report the problem with initializing to the exception witness.
+     *
+     * @throws IOException
+     */
+    public abstract void initialize() throws IOException;
+
+    /**
+     * Initializes the source in a safe way such that the exception caused by initializing will be reported to
+     * the {@link ExceptionWitness}.
+     * This method should be used by the deserializer to ensure that a source that is invalid can display
+     * this info to the UI and allow the user to modify the save file.
+     */
+    public final void initializeSafely() {
+        try {
+            initialize();
+        } catch (IOException e) {
+            final String message = "Failed to initialize " + getClass().getSimpleName();
+            logger.log(Level.WARNING, message, e);
+            getExceptionWitness().flagException(e, message);
+        }
+    }
+
 }

core/src/main/java/edu/wpi/grip/core/serialization/SourceConverter.java

@@ -9,7 +9,6 @@
 import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
 import edu.wpi.grip.core.Source;
 import edu.wpi.grip.core.events.SourceAddedEvent;
-import edu.wpi.grip.core.sources.LoadableSource;
 
 import javax.inject.Inject;
 import java.io.IOException;
@@ -50,13 +49,16 @@ public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext co
             // ensure that other objects being deserialized (such as connections) don't try to access sources that
             // are in the process of loading.
             final Source source = sourceFactory.create(sourceClass, properties);
-            if (source instanceof LoadableSource) {
-                ((LoadableSource) source).load();
-            }
 
             // Instead of returning the source, post it to the event bus so both the core and GUI classes know it
             // exists.
             eventBus.post(new SourceAddedEvent(source));
+
+            // Now that the source has been added it needs to be initialized
+            // We do it safely here in case the source has changed in some way out
+            // of our control. For example, if a webcam is no longer available.
+            source.initializeSafely();
+
             return null;
         } catch (IOException | RuntimeException e) {
             throw new ConversionException("Error deserializing source", e);

core/src/main/java/edu/wpi/grip/core/sources/CameraSource.java

@@ -11,6 +11,7 @@
 import edu.wpi.grip.core.events.SourceRemovedEvent;
 import edu.wpi.grip.core.events.StartedStoppedEvent;
 import edu.wpi.grip.core.events.UnexpectedThrowableEvent;
+import edu.wpi.grip.core.util.ExceptionWitness;
 import org.bytedeco.javacpp.opencv_core.Mat;
 import org.bytedeco.javacv.*;
 
@@ -39,7 +40,7 @@ public class CameraSource extends Source implements StartStoppable {
 
     private final static String DEVICE_NUMBER_PROPERTY = "deviceNumber";
     private final static String ADDRESS_PROPERTY = "address";
-    private static Logger logger =  Logger.getLogger(CameraSource.class.getName());
+    private static Logger logger = Logger.getLogger(CameraSource.class.getName());
 
     private final EventBus eventBus;
     private final String name;
@@ -98,8 +99,12 @@ public FrameGrabber create(String addressProperty) throws MalformedURLException
      * @param deviceNumber The device number of the webcam
      */
     @AssistedInject
-    CameraSource(EventBus eventBus, FrameGrabberFactory grabberFactory, @Assisted int deviceNumber) throws IOException {
-        this(eventBus, grabberFactory, createProperties(deviceNumber));
+    CameraSource(
+            final EventBus eventBus,
+            final FrameGrabberFactory grabberFactory,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            @Assisted final int deviceNumber) throws IOException {
+        this(eventBus, grabberFactory, exceptionWitnessFactory, createProperties(deviceNumber));
     }
 
     /**
@@ -109,15 +114,24 @@ public FrameGrabber create(String addressProperty) throws MalformedURLException
      * @param address  A URL to stream video from an IP camera
      */
     @AssistedInject
-    CameraSource(EventBus eventBus, FrameGrabberFactory grabberFactory, @Assisted String address) throws IOException {
-        this(eventBus, grabberFactory, createProperties(address));
+    CameraSource(
+            final EventBus eventBus,
+            final FrameGrabberFactory grabberFactory,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            @Assisted final String address) throws IOException {
+        this(eventBus, grabberFactory, exceptionWitnessFactory, createProperties(address));
     }
 
     /**
      * Used for serialization
      */
     @AssistedInject
-    CameraSource(EventBus eventBus, FrameGrabberFactory grabberFactory, @Assisted Properties properties) throws MalformedURLException {
+    CameraSource(
+            final EventBus eventBus,
+            final FrameGrabberFactory grabberFactory,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            @Assisted final Properties properties) throws MalformedURLException {
+        super(exceptionWitnessFactory);
         this.frameThread = Optional.empty();
         this.eventBus = eventBus;
         this.frameOutputSocket = new OutputSocket<>(eventBus, imageOutputHint);
@@ -155,6 +169,11 @@ public Properties getProperties() {
         return this.properties;
     }
 
+    @Override
+    public void initialize() throws IOException {
+        start();
+    }
+
     /**
      * Starts the video capture from this frame grabber.
      */
@@ -196,6 +215,7 @@ public void start() throws IOException, IllegalStateException {
                     final long elapsedTime = thisMoment - lastFrame;
                     if (elapsedTime != 0) frameRateOutputSocket.setValue(1e9 / elapsedTime);
                     lastFrame = thisMoment;
+                    getExceptionWitness().clearException();
                 }
             }, "Camera");
 

core/src/main/java/edu/wpi/grip/core/sources/ImageFileSource.java

@@ -8,6 +8,8 @@
 import edu.wpi.grip.core.OutputSocket;
 import edu.wpi.grip.core.SocketHint;
 import edu.wpi.grip.core.SocketHints;
+import edu.wpi.grip.core.Source;
+import edu.wpi.grip.core.util.ExceptionWitness;
 import edu.wpi.grip.core.util.ImageLoadingUtility;
 import org.bytedeco.javacpp.opencv_core.Mat;
 import org.bytedeco.javacpp.opencv_imgcodecs;
@@ -25,7 +27,7 @@
  * Provides a way to generate a {@link Mat} from an image on the filesystem.
  */
 @XStreamAlias(value = "grip:ImageFile")
-public final class ImageFileSource extends LoadableSource {
+public final class ImageFileSource extends Source {
 
     private static final String PATH_PROPERTY = "path";
 
@@ -38,25 +40,37 @@ public final class ImageFileSource extends LoadableSource {
 
     public interface Factory {
         ImageFileSource create(File file);
+
         ImageFileSource create(Properties properties);
     }
 
     /**
-     * @param eventBus The event bus for the pipeline.
-     * @param file     The location on the file system where the image exists.
+     * @param eventBus                The event bus for the pipeline.
+     * @param exceptionWitnessFactory Factory to create the exceptionWitness
+     * @param file                    The location on the file system where the image exists.
      */
     @AssistedInject
-    ImageFileSource(EventBus eventBus, @Assisted File file) {
-        this(eventBus, URLDecoder.decode(Paths.get(file.toURI()).toString()));
+    ImageFileSource(
+            final EventBus eventBus,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            @Assisted final File file) {
+        this(eventBus, exceptionWitnessFactory, URLDecoder.decode(Paths.get(file.toURI()).toString()));
     }
 
 
     @AssistedInject
-    ImageFileSource(EventBus eventBus, @Assisted Properties properties) {
-        this(eventBus, properties.getProperty(PATH_PROPERTY));
+    ImageFileSource(
+            final EventBus eventBus,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            @Assisted final Properties properties) {
+        this(eventBus, exceptionWitnessFactory, properties.getProperty(PATH_PROPERTY));
     }
 
-    private ImageFileSource(EventBus eventBus, String path) {
+    private ImageFileSource(
+            final EventBus eventBus,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            final String path) {
+        super(exceptionWitnessFactory);
         this.eventBus = checkNotNull(eventBus, "Event Bus was null.");
         this.path = checkNotNull(path, "Path can not be null");
         this.name = Files.getNameWithoutExtension(this.path);
@@ -65,10 +79,11 @@ private ImageFileSource(EventBus eventBus, String path) {
 
     /**
      * Performs the loading of the image from the file system
+     *
      * @throws IOException If the image fails to load from the filesystem
      */
     @Override
-    public void load() throws IOException {
+    public void initialize() throws IOException {
         this.loadImage(path);
         this.loaded = true;
     }
@@ -81,7 +96,7 @@ public String getName() {
 
     @Override
     public OutputSocket[] createOutputSockets() {
-        if(!loaded) {
+        if (!loaded) {
             throw new IllegalStateException("The images were never loaded from the filesystem. Must call `loadImage` first.");
         }
         return new OutputSocket[]{this.outputSocket};

core/src/main/java/edu/wpi/grip/core/sources/LoadableSource.java

@@ -7,6 +7,7 @@
 import com.google.inject.assistedinject.AssistedInject;
 import com.thoughtworks.xstream.annotations.XStreamAlias;
 import edu.wpi.grip.core.*;
+import edu.wpi.grip.core.util.ExceptionWitness;
 import edu.wpi.grip.core.util.ImageLoadingUtility;
 import org.bytedeco.javacpp.opencv_core.Mat;
 
@@ -27,7 +28,7 @@
  * {@link MultiImageFileSource#previous()}
  */
 @XStreamAlias(value = "grip:MultiImageFile")
-public final class MultiImageFileSource extends LoadableSource implements PreviousNext {
+public final class MultiImageFileSource extends Source implements PreviousNext {
     private static final String INDEX_PROPERTY = "index";
     private static final String SIZE_PROPERTY = "numImages";
 
@@ -47,39 +48,53 @@ public interface Factory {
     }
 
     /**
-     * @param eventBus The event bus.
-     * @param files    A list of files to be loaded.
-     * @param index    The index to use as the first file that is in the socket.
-     * @throws IOException If the source fails to load any of the images
+     * @param eventBus                The event bus.
+     * @param exceptionWitnessFactory Factory to create the exceptionWitness
+     * @param files                   A list of files to be loaded.
+     * @param index                   The index to use as the first file that is in the socket.
      */
     @AssistedInject
-    MultiImageFileSource(final EventBus eventBus, @Assisted final List<File> files, @Assisted int index) throws IOException {
-        this(eventBus, files.stream()
-                        .map(file -> URLDecoder.decode(Paths.get(file.toURI()).toString()))
-                        .collect(Collectors.toList()).toArray(new String[files.size()]), index);
+    MultiImageFileSource(
+            final EventBus eventBus,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            @Assisted final List<File> files,
+            @Assisted final int index) {
+        this(eventBus, exceptionWitnessFactory, files.stream()
+                .map(file -> URLDecoder.decode(Paths.get(file.toURI()).toString()))
+                .collect(Collectors.toList()).toArray(new String[files.size()]), index);
     }
 
     @AssistedInject
-    MultiImageFileSource(final EventBus eventBus, @Assisted final List<File> files) throws IOException {
-        this(eventBus, files, 0);
+    MultiImageFileSource(
+            final EventBus eventBus,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            @Assisted final List<File> files) {
+        this(eventBus, exceptionWitnessFactory, files, 0);
     }
 
     /**
      * Used only for serialization
      */
     @AssistedInject
-    MultiImageFileSource(final EventBus eventBus, @Assisted Properties properties) throws IOException {
-        this(eventBus, pathsFromProperties(properties), indexFromProperties(properties));
-    }
-
-    private MultiImageFileSource(final EventBus eventBus, final String[] paths, int index) throws IOException {
+    MultiImageFileSource(final EventBus eventBus,
+                         final ExceptionWitness.Factory exceptionWitnessFactory,
+                         @Assisted final Properties properties) {
+        this(eventBus, exceptionWitnessFactory, pathsFromProperties(properties), indexFromProperties(properties));
+    }
+
+    private MultiImageFileSource(
+            final EventBus eventBus,
+            final ExceptionWitness.Factory exceptionWitnessFactory,
+            final String[] paths,
+            final int index) {
+        super(exceptionWitnessFactory);
         this.outputSocket = new OutputSocket(eventBus, imageOutputHint);
         this.index = new AtomicInteger(checkElementIndex(index, paths.length, "File List Index"));
         this.paths = Arrays.asList(paths);
     }
 
     @Override
-    public void load() throws IOException {
+    public void initialize() throws IOException {
         this.images = createImagesArray(this.paths);
         this.outputSocket.setValue(addIndexAndGetImageByOffset(0));
     }