Minor code and doc improvements in jface.resource

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/AbstractResourceManager.java

@@ -13,9 +13,8 @@
  *******************************************************************************/
 package org.eclipse.jface.resource;
 
-import java.util.Collection;
 import java.util.HashMap;
-import java.util.Map.Entry;
+import java.util.Map;
 
 /**
  * Abstract implementation of ResourceManager. Maintains reference counts for all previously
@@ -30,13 +29,13 @@ abstract class AbstractResourceManager extends ResourceManager {
 	/**
 	 * Map of ResourceDescriptor onto RefCount. (null when empty)
 	 */
-	private HashMap<DeviceResourceDescriptor, RefCount> map = null;
+	private Map<DeviceResourceDescriptor, RefCount> map = null;
 
 	/**
 	 * Holds a reference count for a previously-allocated resource
 	 */
 	private static class RefCount {
-		Object resource;
+		final Object resource;
 		int count = 1;
 
 		RefCount(Object resource) {
@@ -131,16 +130,7 @@ public void dispose() {
 		if (map == null) {
 			return;
 		}
-
-		Collection<Entry<DeviceResourceDescriptor, RefCount>> entries = map.entrySet();
-
-		for (Entry<DeviceResourceDescriptor, RefCount> next : entries) {
-			Object key = next.getKey();
-			RefCount val = next.getValue();
-
-			deallocate(val.resource, (DeviceResourceDescriptor)key);
-		}
-
+		map.forEach((key, val) -> deallocate(val.resource, key));
 		map = null;
 	}
 
@@ -150,8 +140,9 @@ public Object find(DeviceResourceDescriptor descriptor) {
 			return null;
 		}
 		RefCount refCount = map.get(descriptor);
-		if (refCount == null)
+		if (refCount == null) {
 			return null;
+		}
 		return refCount.resource;
 	}
 }

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/DerivedImageDescriptor.java

@@ -66,13 +66,7 @@ public int hashCode() {
 
 	@Override
 	public boolean equals(Object arg0) {
-		if (arg0 instanceof DerivedImageDescriptor) {
-			DerivedImageDescriptor desc = (DerivedImageDescriptor)arg0;
-
-			return desc.original.equals(original) && flags == desc.flags;
-		}
-
-		return false;
+		return arg0 instanceof DerivedImageDescriptor desc && desc.original.equals(original) && flags == desc.flags;
 	}
 
 	/**

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/DeviceResourceManager.java

@@ -33,7 +33,7 @@
  */
 public final class DeviceResourceManager extends AbstractResourceManager {
 
-	private Device device;
+	private final Device device;
 	private Image missingImage;
 
 	@Override

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/ImageDataImageDescriptor.java

@@ -24,21 +24,21 @@
  */
 class ImageDataImageDescriptor extends ImageDescriptor {
 
-	private ImageDataProvider dataProvider;
+	private final ImageDataProvider dataProvider;
 
 	/**
 	 * Original image being described, or null if this image is described
 	 * completely using its ImageData
 	 */
-	private Image originalImage = null;
+	private final Image originalImage;
 
 	/**
 	 * Creates an image descriptor, given an image and the device it was created on.
 	 *
 	 * @param originalImage
 	 */
 	ImageDataImageDescriptor(Image originalImage) {
-		this(originalImage::getImageData);
+		this.dataProvider = originalImage::getImageData;
 		this.originalImage = originalImage;
 	}
 
@@ -60,30 +60,26 @@ class ImageDataImageDescriptor extends ImageDescriptor {
 	 */
 	ImageDataImageDescriptor(ImageDataProvider provider) {
 		dataProvider = provider;
+		originalImage = null;
 	}
 
 	@Override
 	public Object createResource(Device device) throws DeviceResourceException {
 
 		// If this descriptor is based on an existing image, then we can return the original image
 		// if this is the same device.
-		if (originalImage != null) {
+		if (originalImage != null && originalImage.getDevice() == device) {
 			// If we're allocating on the same device as the original image, return the original.
-			if (originalImage.getDevice() == device) {
-				return originalImage;
-			}
+			return originalImage;
 		}
-
 		return super.createResource(device);
 	}
 
 	@Override
 	public void destroyResource(Object previouslyCreatedObject) {
-		if (previouslyCreatedObject == originalImage) {
-			return;
+		if (previouslyCreatedObject != originalImage) {
+			super.destroyResource(previouslyCreatedObject);
 		}
-
-		super.destroyResource(previouslyCreatedObject);
 	}
 
 	@Override
@@ -101,20 +97,16 @@ public int hashCode() {
 
 	@Override
 	public boolean equals(Object obj) {
-		if (!(obj instanceof ImageDataImageDescriptor)) {
+		if (!(obj instanceof ImageDataImageDescriptor imgWrap)) {
 			return false;
 		}
-
-		ImageDataImageDescriptor imgWrap = (ImageDataImageDescriptor) obj;
-
 		//Intentionally using == instead of equals() as Image.hashCode() changes
 		//when the image is disposed and so leaks may occur with equals()
 
 		if (originalImage != null) {
 			return imgWrap.originalImage == originalImage;
 		}
-
-		return (imgWrap.originalImage == null && dataProvider.equals(imgWrap.dataProvider));
+		return imgWrap.originalImage == null && dataProvider.equals(imgWrap.dataProvider);
 	}
 
 }

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/JFaceResources.java

@@ -21,7 +21,6 @@
 import java.util.MissingResourceException;
 import java.util.Objects;
 import java.util.ResourceBundle;
-import java.util.function.Supplier;
 
 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.FileLocator;
@@ -199,7 +198,7 @@ public static ColorRegistry getColorRegistry() {
 	 * 300 is big enough to cache common images of eclipse IDE, and small enough to
 	 * not blow OS.
 	 */
-	private static final int cacheSize = Integer.getInteger("org.eclipse.jface.resource.cacheSize", 300).intValue(); //$NON-NLS-1$
+	private static final int CACHE_SIZE = Integer.getInteger("org.eclipse.jface.resource.cacheSize", 300).intValue(); //$NON-NLS-1$
 
 	/**
 	 * Returns the global resource manager for the given display
@@ -214,20 +213,18 @@ public static ResourceManager getResources(final Display toQuery) {
 		ResourceManager reg = registries.get(toQuery);
 
 		if (reg == null) {
-			final ResourceManager mgr;
-			if (cacheSize == 0) {
-				mgr = new DeviceResourceManager(toQuery);
+			if (CACHE_SIZE == 0) {
+				reg = new DeviceResourceManager(toQuery);
 			} else {
-				mgr = new LazyResourceManager(cacheSize, new DeviceResourceManager(toQuery));
+				reg = new LazyResourceManager(CACHE_SIZE, new DeviceResourceManager(toQuery));
 			}
-			reg = mgr;
-			registries.put(toQuery, mgr);
+			registries.put(toQuery, reg);
+			final ResourceManager mgr = reg;
 			toQuery.disposeExec(() -> {
 				mgr.dispose();
 				registries.remove(toQuery);
 			});
 		}
-
 		return reg;
 	}
 
@@ -482,17 +479,15 @@ private static void initializeDefaultImages() {
 	private static final void declareImage(Object bundle, String key, String path, Class<?> fallback,
 			String fallbackPath) {
 
-		Supplier<URL> supplier = () -> {
+		imageRegistry.put(key, ImageDescriptor.createFromURLSupplier(false, () -> {
 			if (bundle != null) {
 				URL url = FileLocator.find((Bundle) bundle, new Path(path), null);
-				if (url != null)
+				if (url != null) {
 					return url;
+				}
 			}
-			URL url = fallback.getResource(fallbackPath);
-			return url;
-		};
-
-		imageRegistry.put(key, ImageDescriptor.createFromURLSupplier(false, supplier));
+			return fallback.getResource(fallbackPath);
+		}));
 	}
 
 	/**

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/LazyResourceManager.java

@@ -83,20 +83,13 @@ protected Image getDefaultImage() {
 		return parent.getDefaultImage();
 	}
 
-	private static Integer createOrIncrease(@SuppressWarnings("unused") DeviceResourceDescriptor key, Integer refs) {
-		return Integer.valueOf(refs == null ? 1 : refs.intValue() + 1);
-	}
-
-	private static Integer decreaseOrRemove(@SuppressWarnings("unused") DeviceResourceDescriptor key, Integer refs) {
-		return refs.intValue() == 1 ? null : Integer.valueOf(refs.intValue() - 1);
-
-	}
 	@Override
 	public Object create(DeviceResourceDescriptor descriptor) {
 		if (!shouldBeCached(descriptor)) {
 			return parent.create(descriptor);
 		}
-		int updatedRefs = refCount.compute(descriptor, LazyResourceManager::createOrIncrease).intValue();
+		@SuppressWarnings("boxing")
+		int updatedRefs = refCount.compute(descriptor, (k, refs) -> refs == null ? 1 : refs + 1);
 		if (updatedRefs == 1) {
 			ResourceManager cached = unreferenced.remove(descriptor);
 			if (cached == null) {
@@ -115,7 +108,8 @@ public void destroy(DeviceResourceDescriptor descriptor) {
 			parent.destroy(descriptor);
 			return;
 		}
-		Integer refsLeft = refCount.computeIfPresent(descriptor, LazyResourceManager::decreaseOrRemove);
+		@SuppressWarnings("boxing")
+		Integer refsLeft = refCount.computeIfPresent(descriptor, (k, refs) -> refs == 1 ? null : (refs - 1));
 		if (refsLeft == null) {
 			// defer destroy:
 			ResourceManager old = unreferenced.put(descriptor, parent);

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/LocalResourceManager.java

@@ -67,15 +67,12 @@ public Device getDevice() {
 	}
 
 	@Override
-	protected Object allocate(DeviceResourceDescriptor descriptor)
-			throws DeviceResourceException {
+	protected Object allocate(DeviceResourceDescriptor descriptor) throws DeviceResourceException {
 		return parentRegistry.create(descriptor);
 	}
 
 	@Override
-	protected void deallocate(Object resource,
-			DeviceResourceDescriptor descriptor) {
-
+	protected void deallocate(Object resource, DeviceResourceDescriptor descriptor) {
 		parentRegistry.destroy(descriptor);
 	}
 

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/RGBColorDescriptor.java

@@ -24,12 +24,12 @@
  */
 class RGBColorDescriptor extends ColorDescriptor {
 
-	private RGB color;
+	private final RGB color;
 
 	/**
 	 * Color being copied, or null if none
 	 */
-	private Color originalColor = null;
+	private final Color originalColor;
 
 	/**
 	 * Creates a new RGBColorDescriptor given some RGB values
@@ -38,6 +38,7 @@ class RGBColorDescriptor extends ColorDescriptor {
 	 */
 	public RGBColorDescriptor(RGB color) {
 		this.color = color;
+		this.originalColor = null;
 	}
 
 	/**
@@ -48,19 +49,14 @@ public RGBColorDescriptor(RGB color) {
 	 * @param originalColor a color to describe
 	 */
 	public RGBColorDescriptor(Color originalColor) {
-		this(originalColor.getRGB());
+		this.color = originalColor.getRGB();
 		this.originalColor = originalColor;
 	}
 
 	@Override
 	public boolean equals(Object obj) {
-		if (obj instanceof RGBColorDescriptor) {
-			RGBColorDescriptor other = (RGBColorDescriptor) obj;
-
-			return other.color.equals(color) && other.originalColor == originalColor;
-		}
-
-		return false;
+		return obj instanceof RGBColorDescriptor other //
+				&& other.color.equals(color) && other.originalColor == originalColor;
 	}
 
 	@Override
@@ -72,13 +68,10 @@ public int hashCode() {
 	public Color createColor(Device device) {
 		// If this descriptor is wrapping an existing color, then we can return the original color
 		// if this is the same device.
-		if (originalColor != null) {
+		if (originalColor != null && originalColor.getDevice() == device) {
 			// If we're allocating on the same device as the original color, return the original.
-			if (originalColor.getDevice() == device) {
-				return originalColor;
-			}
+			return originalColor;
 		}
-
 		return new Color(device, color);
 	}
 }