Do not create object if it is unnecessary

Change-Id: I8e1664ea0e8828252690209b88a78721d1fa9579

3 files changed, 7 insertions, 26 deletions

diff --git a/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/contentmergeviewer/EMFCompareContentMergeViewer.java b/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/contentmergeviewer/EMFCompareContentMergeViewer.java
index de3fb2f76..af19a2059 100644
--- a/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/contentmergeviewer/EMFCompareContentMergeViewer.java
+++ b/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/contentmergeviewer/EMFCompareContentMergeViewer.java
@@ -14,7 +14,6 @@ import static com.google.common.collect.Iterables.filter;
 
 import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableSet;
 import com.google.common.eventbus.Subscribe;
 
 import java.util.EventObject;
@@ -22,7 +21,6 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.ResourceBundle;
-import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.eclipse.compare.contentmergeviewer.ContentMergeViewer;
@@ -45,7 +43,6 @@ import org.eclipse.emf.compare.rcp.EMFCompareRCPPlugin;
 import org.eclipse.emf.compare.rcp.ui.contentmergeviewer.accessor.ICompareAccessor;
 import org.eclipse.emf.compare.rcp.ui.internal.configuration.IAdapterFactoryChange;
 import org.eclipse.emf.compare.rcp.ui.internal.configuration.ICompareEditingDomainChange;
-import org.eclipse.emf.compare.rcp.ui.internal.mergeviewer.CompareColorImpl;
 import org.eclipse.emf.compare.rcp.ui.internal.mergeviewer.IColorChangeEvent;
 import org.eclipse.emf.compare.rcp.ui.internal.mergeviewer.item.impl.MergeViewerItem;
 import org.eclipse.emf.compare.rcp.ui.internal.util.SWTUtil;
@@ -101,12 +98,6 @@ public abstract class EMFCompareContentMergeViewer extends ContentMergeViewer im
 
 	private static final String HANDLER_SERVICE = "fHandlerService"; //$NON-NLS-1$
 
-	/** List of all color ID that this viewer shall listen. */
-	private static final Set<String> LISTENING_COLOR_IDS = ImmutableSet.of(
-			CompareColorImpl.INCOMING_CHANGE_COLOR_THEME_KEY,
-			CompareColorImpl.OUTGOING_CHANGE_COLOR_THEME_KEY,
-			CompareColorImpl.CONFLICTING_CHANGE_COLOR_THEME_KEY);
-
 	/**
 	 * Width of center bar
 	 */
@@ -170,10 +161,9 @@ public abstract class EMFCompareContentMergeViewer extends ContentMergeViewer im
 	}
 
 	@Subscribe
-	public void refreshNeeded(IColorChangeEvent event) {
-		if (LISTENING_COLOR_IDS.contains(event.getColorID())) {
-			refresh();
-		}
+	public void colorChanged(
+			@SuppressWarnings("unused")/* necessary for @Subscribe */IColorChangeEvent changeColorEvent) {
+		getControl().redraw();
 	}
 
 	/**
diff --git a/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/contentmergeviewer/util/EMFCompareColor.java b/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/contentmergeviewer/util/EMFCompareColor.java
index ad17301b4..76c9e04c3 100644
--- a/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/contentmergeviewer/util/EMFCompareColor.java
+++ b/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/contentmergeviewer/util/EMFCompareColor.java
@@ -78,9 +78,9 @@ public class EMFCompareColor extends CompareColorImpl {
 

 		if (COLOR_IDS.contains(propertyKey)) {

 			updateColors();

-			ColorChangeEvent colorEvent = new ColorChangeEvent(propertyKey);

 			// This event bus may not have been set

 			if (eventBus != null) {

+				ColorChangeEvent colorEvent = new ColorChangeEvent(propertyKey);

 				eventBus.post(colorEvent);

 			}

 		}

diff --git a/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/structuremergeviewer/EMFCompareStructureMergeViewer.java b/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/structuremergeviewer/EMFCompareStructureMergeViewer.java
index 92fe37893..a1e486520 100644
--- a/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/structuremergeviewer/EMFCompareStructureMergeViewer.java
+++ b/plugins/org.eclipse.emf.compare.ide.ui/src/org/eclipse/emf/compare/ide/ui/internal/structuremergeviewer/EMFCompareStructureMergeViewer.java
@@ -20,7 +20,6 @@ import static org.eclipse.emf.compare.utils.EMFComparePredicates.hasConflict;
 import static org.eclipse.emf.compare.utils.EMFComparePredicates.hasState;
 
 import com.google.common.base.Predicate;
-import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.common.eventbus.Subscribe;
 
@@ -74,7 +73,6 @@ import org.eclipse.emf.compare.internal.utils.ComparisonUtil;
 import org.eclipse.emf.compare.rcp.EMFCompareRCPPlugin;
 import org.eclipse.emf.compare.rcp.ui.internal.configuration.ICompareEditingDomainChange;
 import org.eclipse.emf.compare.rcp.ui.internal.configuration.IMergePreviewModeChange;
-import org.eclipse.emf.compare.rcp.ui.internal.mergeviewer.CompareColorImpl;
 import org.eclipse.emf.compare.rcp.ui.internal.mergeviewer.IColorChangeEvent;
 import org.eclipse.emf.compare.rcp.ui.internal.structuremergeviewer.filters.StructureMergeViewerFilter;
 import org.eclipse.emf.compare.rcp.ui.internal.structuremergeviewer.filters.impl.PseudoConflictsFilter;
@@ -138,11 +136,6 @@ public class EMFCompareStructureMergeViewer extends AbstractStructuredViewerWrap
 		}
 	}
 
-	/** List of all color ID that this viewer shall listen. */
-	private static final Set<String> LISTENING_COLOR_IDS = ImmutableSet
-			.of(CompareColorImpl.UNMERGEABLE_DIFF_COLOR_THEME_KEY,
-					CompareColorImpl.REQUIRED_DIFF_COLOR_THEME_KEY);
-
 	private static final Predicate<Diff> UNRESOLVED_AND_WITHOUT_PSEUDO_CONFLICT = and(
 			hasState(DifferenceState.UNRESOLVED), not(hasConflict(ConflictKind.PSEUDO)));
 
@@ -299,11 +292,9 @@ public class EMFCompareStructureMergeViewer extends AbstractStructuredViewerWrap
 	}
 
 	@Subscribe
-	public void refreshNeeded(IColorChangeEvent changeColorEvent) {
-		if (LISTENING_COLOR_IDS.contains(changeColorEvent.getColorID())) {
-			refresh();
-		}
-
+	public void colorChanged(
+			@SuppressWarnings("unused")/* necessary for @Subscribe */IColorChangeEvent changeColorEvent) {
+		internalRedraw();
 	}
 
 	/**