[488618] Ignore missing image resources

Introduces a SafeAdapterFactoryItemDelegator, which is an
AdapterFactoryItemDelegator that catches MissingResourceExceptions on
calls of getImage(Object) and just returns null if an item provider in
the adapter factory throws such an exception.

Bug 488618
Change-Id: If7efa8f4a5d5d7fe6553e4e9459527ebc69890e1
Also-by: Mathias Schaefer <mschaefer@eclipsesource.com>
Signed-off-by: Philip Langer <planger@eclipsesource.com>
diff --git a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/SafeAdapterFactoryItemDelegator.java b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/SafeAdapterFactoryItemDelegator.java
new file mode 100644
index 0000000..689af2a
--- /dev/null
+++ b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/SafeAdapterFactoryItemDelegator.java
@@ -0,0 +1,54 @@
+/*******************************************************************************
+ * Copyright (c) 2016 EclipseSource Service GmbH and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *     Philip Langer - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.emf.compare.provider;
+
+import java.util.MissingResourceException;
+
+import org.eclipse.emf.common.notify.AdapterFactory;
+import org.eclipse.emf.edit.provider.AdapterFactoryItemDelegator;
+
+/**
+ * A safe {@link AdapterFactoryItemDelegator}.
+ * <p>
+ * This adapter factory item delegator is safe with respect to {@link MissingResourceException missing image
+ * resources} that may occur in the item providers in the adapter factory this delegator delegates to.
+ * </p>
+ * 
+ * @author Philip Langer <planger@eclipsesource.com>
+ */
+public class SafeAdapterFactoryItemDelegator extends AdapterFactoryItemDelegator {
+
+	/**
+	 * Creates a new safe adapter factory item delegator with the given <code>adapterFactory</code>.
+	 * 
+	 * @param adapterFactory
+	 *            The adapter factory to delegate to.
+	 */
+	public SafeAdapterFactoryItemDelegator(AdapterFactory adapterFactory) {
+		super(adapterFactory);
+	}
+
+	/**
+	 * {@inheritDoc} However, this method catches {@link MissingResourceException} potentially thrown in item
+	 * providers of the adapter factories and returns <code>null</code> in case a
+	 * {@link MissingResourceException} was caught.
+	 */
+	@Override
+	public Object getImage(Object object) {
+		try {
+			return super.getImage(object);
+		} catch (MissingResourceException ex) {
+			// be resilient in regard to missing resources
+			EMFCompareEditPlugin.getPlugin().log(ex);
+			return null;
+		}
+	}
+}
diff --git a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/AttributeChangeItemProviderSpec.java b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/AttributeChangeItemProviderSpec.java
index 66330b6..690a12c 100644
--- a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/AttributeChangeItemProviderSpec.java
+++ b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/AttributeChangeItemProviderSpec.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2012, 2015 Obeo.
+ * Copyright (c) 2012, 2016 Obeo.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,7 +7,7 @@
  * 
  * Contributors:
  *     Obeo - initial API and implementation
- *     Philip Langer - fixed bug 461504
+ *     Philip Langer - fixed bugs 461504, 488618
  *******************************************************************************/
 package org.eclipse.emf.compare.provider.spec;
 
@@ -23,6 +23,7 @@
 import org.eclipse.emf.compare.provider.IItemDescriptionProvider;
 import org.eclipse.emf.compare.provider.IItemStyledLabelProvider;
 import org.eclipse.emf.compare.provider.ISemanticObjectLabelProvider;
+import org.eclipse.emf.compare.provider.SafeAdapterFactoryItemDelegator;
 import org.eclipse.emf.compare.provider.utils.ComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString.Style;
@@ -61,7 +62,7 @@
 	 */
 	public AttributeChangeItemProviderSpec(AdapterFactory adapterFactory) {
 		super(adapterFactory);
-		itemDelegator = new AdapterFactoryItemDelegator(getRootAdapterFactory());
+		itemDelegator = new SafeAdapterFactoryItemDelegator(getRootAdapterFactory());
 		overlayProvider = new OverlayImageProvider(getResourceLocator());
 	}
 
@@ -164,6 +165,7 @@
 	 * 
 	 * @see org.eclipse.emf.compare.provider.IItemStyledLabelProvider#getStyledText(java.lang.Object)
 	 */
+	@Override
 	public IStyledString.IComposedStyledString getStyledText(Object object) {
 		final AttributeChange attChange = (AttributeChange)object;
 
diff --git a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/FeatureMapChangeItemProviderSpec.java b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/FeatureMapChangeItemProviderSpec.java
index 31aab33..8de0318 100644
--- a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/FeatureMapChangeItemProviderSpec.java
+++ b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/FeatureMapChangeItemProviderSpec.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2014, 2015 Obeo.
+ * Copyright (c) 2014, 2016 Obeo.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,6 +7,7 @@
  * 
  * Contributors:
  *     Obeo - initial API and implementation
+ *     Philip Langer (EclispeSource) - bug 488618
  *******************************************************************************/
 package org.eclipse.emf.compare.provider.spec;
 
@@ -22,6 +23,7 @@
 import org.eclipse.emf.compare.provider.IItemDescriptionProvider;
 import org.eclipse.emf.compare.provider.IItemStyledLabelProvider;
 import org.eclipse.emf.compare.provider.ISemanticObjectLabelProvider;
+import org.eclipse.emf.compare.provider.SafeAdapterFactoryItemDelegator;
 import org.eclipse.emf.compare.provider.utils.ComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString.Style;
@@ -55,7 +57,7 @@
 	 */
 	public FeatureMapChangeItemProviderSpec(AdapterFactory adapterFactory) {
 		super(adapterFactory);
-		itemDelegator = new AdapterFactoryItemDelegator(getRootAdapterFactory());
+		itemDelegator = new SafeAdapterFactoryItemDelegator(getRootAdapterFactory());
 		overlayProvider = new OverlayImageProvider(getResourceLocator());
 	}
 
@@ -148,6 +150,7 @@
 	 * 
 	 * @see org.eclipse.emf.compare.provider.IItemStyledLabelProvider#getStyledText(java.lang.Object)
 	 */
+	@Override
 	public IStyledString.IComposedStyledString getStyledText(Object object) {
 		final FeatureMapChange featureMapChange = (FeatureMapChange)object;
 
diff --git a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/MatchItemProviderSpec.java b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/MatchItemProviderSpec.java
index c4ec8cc..b3f1f2d 100644
--- a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/MatchItemProviderSpec.java
+++ b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/MatchItemProviderSpec.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2012, 2015 Obeo.
+ * Copyright (c) 2012, 2016 Obeo and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,6 +7,7 @@
  * 
  * Contributors:
  *     Obeo - initial API and implementation
+ *     Philip Langer (EclipseSource) - bug 488618
  *******************************************************************************/
 package org.eclipse.emf.compare.provider.spec;
 
@@ -22,6 +23,7 @@
 import org.eclipse.emf.compare.provider.IItemStyledLabelProvider;
 import org.eclipse.emf.compare.provider.ISemanticObjectLabelProvider;
 import org.eclipse.emf.compare.provider.MatchItemProvider;
+import org.eclipse.emf.compare.provider.SafeAdapterFactoryItemDelegator;
 import org.eclipse.emf.compare.provider.utils.ComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString;
 import org.eclipse.emf.ecore.util.EcoreUtil;
@@ -48,7 +50,7 @@
 	 */
 	public MatchItemProviderSpec(AdapterFactory adapterFactory) {
 		super(adapterFactory);
-		itemDelegator = new AdapterFactoryItemDelegator(getRootAdapterFactory());
+		itemDelegator = new SafeAdapterFactoryItemDelegator(getRootAdapterFactory());
 		overlayProvider = new OverlayImageProvider(getResourceLocator());
 	}
 
@@ -152,6 +154,7 @@
 	 * @see org.eclipse.emf.compare.provider.IItemStyledLabelProvider#getStyledText(java.lang.Object)
 	 * @since 3.0
 	 */
+	@Override
 	public IStyledString.IComposedStyledString getStyledText(Object object) {
 		ComposedStyledString styledString = new ComposedStyledString(getText(object));
 		return styledString;
diff --git a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/MatchResourceItemProviderSpec.java b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/MatchResourceItemProviderSpec.java
index 366e2d6..87a5a31 100644
--- a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/MatchResourceItemProviderSpec.java
+++ b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/MatchResourceItemProviderSpec.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2012, 2013 Obeo.
+ * Copyright (c) 2012, 2016 Obeo.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,6 +7,7 @@
  * 
  * Contributors:
  *     Obeo - initial API and implementation
+ *     Philip Langer (EclipseSource) - bug 488618
  *******************************************************************************/
 package org.eclipse.emf.compare.provider.spec;
 
@@ -21,6 +22,7 @@
 import org.eclipse.emf.compare.provider.IItemDescriptionProvider;
 import org.eclipse.emf.compare.provider.IItemStyledLabelProvider;
 import org.eclipse.emf.compare.provider.MatchResourceItemProvider;
+import org.eclipse.emf.compare.provider.SafeAdapterFactoryItemDelegator;
 import org.eclipse.emf.compare.provider.utils.ComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString;
 import org.eclipse.emf.ecore.resource.Resource;
@@ -45,7 +47,7 @@
 	 */
 	public MatchResourceItemProviderSpec(AdapterFactory adapterFactory) {
 		super(adapterFactory);
-		itemDelegator = new AdapterFactoryItemDelegator(getRootAdapterFactory());
+		itemDelegator = new SafeAdapterFactoryItemDelegator(getRootAdapterFactory());
 	}
 
 	/**
@@ -182,6 +184,7 @@
 	 * 
 	 * @see org.eclipse.emf.compare.provider.IItemStyledLabelProvider#getStyledText(java.lang.Object)
 	 */
+	@Override
 	public IStyledString.IComposedStyledString getStyledText(Object object) {
 		return new ComposedStyledString(getText(object));
 	}
diff --git a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ReferenceChangeItemProviderSpec.java b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ReferenceChangeItemProviderSpec.java
index ac849b6..dd3bf10 100644
--- a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ReferenceChangeItemProviderSpec.java
+++ b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ReferenceChangeItemProviderSpec.java
@@ -7,6 +7,7 @@
  * 
  * Contributors:
  *     Obeo - initial API and implementation
+ *     Philip Langer (EclipseSource) - bug 488618
  *******************************************************************************/
 package org.eclipse.emf.compare.provider.spec;
 
@@ -26,6 +27,7 @@
 import org.eclipse.emf.compare.provider.IItemStyledLabelProvider;
 import org.eclipse.emf.compare.provider.ISemanticObjectLabelProvider;
 import org.eclipse.emf.compare.provider.ReferenceChangeItemProvider;
+import org.eclipse.emf.compare.provider.SafeAdapterFactoryItemDelegator;
 import org.eclipse.emf.compare.provider.utils.ComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString.Style;
@@ -62,7 +64,7 @@
 	 */
 	public ReferenceChangeItemProviderSpec(AdapterFactory adapterFactory) {
 		super(adapterFactory);
-		itemDelegator = new AdapterFactoryItemDelegator(getRootAdapterFactory());
+		itemDelegator = new SafeAdapterFactoryItemDelegator(getRootAdapterFactory());
 		overlayProvider = new OverlayImageProvider(getResourceLocator());
 	}
 
@@ -238,6 +240,7 @@
 	 * 
 	 * @see org.eclipse.emf.compare.provider.IItemStyledLabelProvider#getStyledText(java.lang.Object)
 	 */
+	@Override
 	public IStyledString.IComposedStyledString getStyledText(Object object) {
 		final ReferenceChange refChange = (ReferenceChange)object;
 
diff --git a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ResourceAttachmentChangeItemProviderSpec.java b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ResourceAttachmentChangeItemProviderSpec.java
index 9bb0cdd..5632886 100644
--- a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ResourceAttachmentChangeItemProviderSpec.java
+++ b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ResourceAttachmentChangeItemProviderSpec.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2013, 2015 Obeo.
+ * Copyright (c) 2013, 2016 Obeo.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,6 +7,7 @@
  * 
  * Contributors:
  *     Obeo - initial API and implementation
+ *     Philip Langer (EclipseSource) - bug 488618
  *******************************************************************************/
 package org.eclipse.emf.compare.provider.spec;
 
@@ -22,6 +23,7 @@
 import org.eclipse.emf.compare.provider.IItemStyledLabelProvider;
 import org.eclipse.emf.compare.provider.ISemanticObjectLabelProvider;
 import org.eclipse.emf.compare.provider.ResourceAttachmentChangeItemProvider;
+import org.eclipse.emf.compare.provider.SafeAdapterFactoryItemDelegator;
 import org.eclipse.emf.compare.provider.utils.ComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString.IComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString.Style;
@@ -50,7 +52,7 @@
 	 */
 	public ResourceAttachmentChangeItemProviderSpec(AdapterFactory adapterFactory) {
 		super(adapterFactory);
-		itemDelegator = new AdapterFactoryItemDelegator(getRootAdapterFactory());
+		itemDelegator = new SafeAdapterFactoryItemDelegator(getRootAdapterFactory());
 		overlayProvider = new OverlayImageProvider(getResourceLocator());
 	}
 
@@ -95,6 +97,7 @@
 	 * 
 	 * @see org.eclipse.emf.compare.provider.IItemStyledLabelProvider#getStyledText(java.lang.Object)
 	 */
+	@Override
 	public IComposedStyledString getStyledText(Object object) {
 		final ResourceAttachmentChange resourceAttachmentChange = (ResourceAttachmentChange)object;
 		String value = doGetSemanticObjectLabel(resourceAttachmentChange, object);
diff --git a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ResourceLocationChangeItemProviderSpec.java b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ResourceLocationChangeItemProviderSpec.java
index 67ac57f..c97d7de 100644
--- a/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ResourceLocationChangeItemProviderSpec.java
+++ b/plugins/org.eclipse.emf.compare.edit/src/org/eclipse/emf/compare/provider/spec/ResourceLocationChangeItemProviderSpec.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2015 Obeo.
+ * Copyright (c) 2015, 2016 Obeo.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,6 +7,7 @@
  * 
  * Contributors:
  *     Obeo - initial API and implementation
+ *     Philip Langer (EclipseSource) - bug 488618
  *******************************************************************************/
 package org.eclipse.emf.compare.provider.spec;
 
@@ -19,6 +20,7 @@
 import org.eclipse.emf.compare.provider.IItemStyledLabelProvider;
 import org.eclipse.emf.compare.provider.ISemanticObjectLabelProvider;
 import org.eclipse.emf.compare.provider.ResourceLocationChangeItemProvider;
+import org.eclipse.emf.compare.provider.SafeAdapterFactoryItemDelegator;
 import org.eclipse.emf.compare.provider.utils.ComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString.IComposedStyledString;
 import org.eclipse.emf.compare.provider.utils.IStyledString.Style;
@@ -50,7 +52,7 @@
 	 */
 	public ResourceLocationChangeItemProviderSpec(AdapterFactory adapterFactory) {
 		super(adapterFactory);
-		itemDelegator = new AdapterFactoryItemDelegator(getRootAdapterFactory());
+		itemDelegator = new SafeAdapterFactoryItemDelegator(getRootAdapterFactory());
 		overlayProvider = new OverlayImageProvider(getResourceLocator());
 	}
 
@@ -89,6 +91,7 @@
 	 * 
 	 * @see org.eclipse.emf.compare.provider.IItemStyledLabelProvider#getStyledText(java.lang.Object)
 	 */
+	@Override
 	public IComposedStyledString getStyledText(Object object) {
 		final ResourceLocationChange resourceLocationChange = (ResourceLocationChange)object;
 		final String baseLocation = resourceLocationChange.getBaseLocation();