Bug 521382 - [generic editor] Default highlighter for generic editorI20171107-2000

Added extension point for highlight reconcilers, when one is added the
default is turned off

Change-Id: Ibbe8d3df69ba5d364c027bd8c8f07aa7b4e71902
Signed-off-by: Lucas Bullen <lbullen@redhat.com>

16 files changed, 816 insertions, 28 deletions

diff --git a/org.eclipse.ui.genericeditor.examples/plugin.xml b/org.eclipse.ui.genericeditor.examples/plugin.xml
index a4fd6f752d5..97238a81750 100644
--- a/org.eclipse.ui.genericeditor.examples/plugin.xml
+++ b/org.eclipse.ui.genericeditor.examples/plugin.xml
@@ -10,6 +10,7 @@
 <!-- Contributors:                                                          -->
 <!--     Sopot Cela & Mickael Istria (Red Hat Inc). -initial implementation -->
 <!--     Lucas Bullen (Red Hat Inc.) - Bug 508829 custom reconciler support -->
+<!--    							 - Bug 521382 default highlighter		-->
 <!-- ====================================================================== -->
 <plugin>
    <extension
@@ -76,4 +77,11 @@
             contentType="org.eclipse.ui.genericeditor.examples.dotproject">
       </autoEditStrategy>
    </extension>
+   <extension
+         point="org.eclipse.ui.genericeditor.highlightReconcilers">
+      <highlightReconciler
+            class="org.eclipse.ui.genericeditor.examples.dotproject.HighlightReconciler"
+            contentType="org.eclipse.ui.genericeditor.examples.dotproject">
+      </highlightReconciler>
+   </extension>
 </plugin>
diff --git a/org.eclipse.ui.genericeditor.examples/src/org/eclipse/ui/genericeditor/examples/dotproject/HighlightReconciler.java b/org.eclipse.ui.genericeditor.examples/src/org/eclipse/ui/genericeditor/examples/dotproject/HighlightReconciler.java
new file mode 100644
index 00000000000..dd520c273a6
--- /dev/null
+++ b/org.eclipse.ui.genericeditor.examples/src/org/eclipse/ui/genericeditor/examples/dotproject/HighlightReconciler.java
@@ -0,0 +1,37 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Red Hat Inc. 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:
+ * - Lucas Bullen (Red Hat Inc.)
+ *******************************************************************************/
+package org.eclipse.ui.genericeditor.examples.dotproject;
+
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jface.text.ITextViewer;
+import org.eclipse.jface.text.reconciler.Reconciler;
+
+public class HighlightReconciler extends Reconciler {
+
+	private HighlightStrategy fStrategy;
+
+	public HighlightReconciler() {
+        fStrategy = new HighlightStrategy();
+        this.setReconcilingStrategy(fStrategy, IDocument.DEFAULT_CONTENT_TYPE);
+    }
+
+	@Override
+	public void install(ITextViewer textViewer) {
+		super.install(textViewer);
+		fStrategy.install(textViewer);
+	}
+
+	@Override
+	public void uninstall() {
+		super.uninstall();
+		fStrategy.uninstall();
+	}
+}
\ No newline at end of file
diff --git a/org.eclipse.ui.genericeditor.examples/src/org/eclipse/ui/genericeditor/examples/dotproject/HighlightStrategy.java b/org.eclipse.ui.genericeditor.examples/src/org/eclipse/ui/genericeditor/examples/dotproject/HighlightStrategy.java
new file mode 100644
index 00000000000..58d1b9060a2
--- /dev/null
+++ b/org.eclipse.ui.genericeditor.examples/src/org/eclipse/ui/genericeditor/examples/dotproject/HighlightStrategy.java
@@ -0,0 +1,209 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Red Hat Inc. 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:
+ * - Lucas Bullen (Red Hat Inc.)
+ *******************************************************************************/
+package org.eclipse.ui.genericeditor.examples.dotproject;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent;
+import org.eclipse.core.runtime.preferences.InstanceScope;
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jface.text.IRegion;
+import org.eclipse.jface.text.ISynchronizable;
+import org.eclipse.jface.text.ITextViewer;
+import org.eclipse.jface.text.ITextViewerExtension5;
+import org.eclipse.jface.text.Position;
+import org.eclipse.jface.text.reconciler.DirtyRegion;
+import org.eclipse.jface.text.reconciler.IReconcilingStrategy;
+import org.eclipse.jface.text.reconciler.IReconcilingStrategyExtension;
+import org.eclipse.jface.text.source.Annotation;
+import org.eclipse.jface.text.source.IAnnotationModel;
+import org.eclipse.jface.text.source.IAnnotationModelExtension;
+import org.eclipse.jface.text.source.ISourceViewer;
+import org.eclipse.swt.custom.CaretEvent;
+import org.eclipse.swt.custom.CaretListener;
+
+/**
+*
+* This Reconciler Strategy is an example for how to override the default highlight strategy.
+* It will highlight closing and opening tag names that match the current word the user is on.
+*
+*/
+public class HighlightStrategy implements IReconcilingStrategy, IReconcilingStrategyExtension, CaretListener, IPreferenceChangeListener {
+
+	private static final String ANNOTATION_TYPE = "org.eclipse.ui.genericeditor.text"; //$NON-NLS-1$
+	public static final String TOGGLE_HIGHLIGHT_PREFERENCE = "org.eclipse.ui.genericeditor.togglehighlight"; //$NON-NLS-1$
+	public static final String GENERIC_EDITOR_BUNDLE_ID = "org.eclipse.ui.genericeditor"; //$NON-NLS-1$
+
+	private boolean enabled;
+	private ISourceViewer sourceViewer;
+	private IDocument document;
+
+	private static final String TAG_NAME_REGEX = "<\\/?\\s*([a-zA-Z]+)"; //$NON-NLS-1$
+	private static final Pattern TAG_NAME_PATTERN = Pattern.compile(TAG_NAME_REGEX);
+
+	private Annotation[] fOccurrenceAnnotations = null;
+
+	private void applyHighlights(int offset) {
+		if (sourceViewer == null || !enabled) {
+			return;
+		}
+		String text = document.get();
+		offset = ((ITextViewerExtension5)sourceViewer).widgetOffset2ModelOffset(offset);
+
+		int wordStartOffset = Math.max(text.lastIndexOf('/',offset),text.lastIndexOf('<',offset))+1;
+		int wordEndOffset = findEndingOffset(text, offset);
+		if(wordEndOffset <= wordStartOffset || wordEndOffset == -1 || wordStartOffset == -1)
+			return;
+		String word = text.substring(wordStartOffset, wordEndOffset);
+		if(word.indexOf('>') != -1 || word.indexOf('<') != -1) {
+			removeOccurrenceAnnotations();
+			return;
+		}
+
+		Matcher m = TAG_NAME_PATTERN.matcher(text);
+		Map<Annotation, Position> annotationMap = new HashMap<>();
+		while(m.find()) {
+			if(m.group(1).equals(word)) {
+				annotationMap.put(new Annotation(ANNOTATION_TYPE, false, null),
+						new Position(m.start(1), m.end(1) - m.start(1)));
+			}
+		}
+
+		if(annotationMap.size() < 2) {
+			removeOccurrenceAnnotations();
+			return;
+		}
+
+		IAnnotationModel annotationModel = sourceViewer.getAnnotationModel();
+		synchronized (getLockObject(annotationModel)) {
+			if (annotationModel instanceof IAnnotationModelExtension) {
+				((IAnnotationModelExtension) annotationModel).replaceAnnotations(fOccurrenceAnnotations, annotationMap);
+			} else {
+				removeOccurrenceAnnotations();
+				Iterator<Entry<Annotation, Position>> iter = annotationMap.entrySet().iterator();
+				while (iter.hasNext()) {
+					Entry<Annotation, Position> mapEntry = iter.next();
+					annotationModel.addAnnotation(mapEntry.getKey(), mapEntry.getValue());
+				}
+			}
+			fOccurrenceAnnotations = annotationMap.keySet().toArray(new Annotation[annotationMap.keySet().size()]);
+		}
+	}
+
+	private static int findEndingOffset(String text, int offset) {
+		String substring = text.substring(offset);
+		String[] split = substring.split("[^a-zA-Z0-9]+");//$NON-NLS-1$
+		if(split.length == 0) {
+			return -1;
+		}
+		return offset + split[0].length();
+	}
+
+	public void install(ITextViewer viewer) {
+		if (!(viewer instanceof ISourceViewer)) {
+			return;
+		}
+		IEclipsePreferences preferences = InstanceScope.INSTANCE.getNode(GENERIC_EDITOR_BUNDLE_ID);
+		preferences.addPreferenceChangeListener(this);
+		this.enabled = preferences.getBoolean(TOGGLE_HIGHLIGHT_PREFERENCE, true);
+		this.sourceViewer = (ISourceViewer) viewer;
+		this.sourceViewer.getTextWidget().addCaretListener(this);
+	}
+
+	public void uninstall() {
+		if (sourceViewer != null) {
+			sourceViewer.getTextWidget().removeCaretListener(this);
+		}
+		IEclipsePreferences preferences = InstanceScope.INSTANCE.getNode(GENERIC_EDITOR_BUNDLE_ID);
+		preferences.removePreferenceChangeListener(this);
+	}
+
+	@Override
+	public void preferenceChange(PreferenceChangeEvent event) {
+		if (event.getKey().equals(TOGGLE_HIGHLIGHT_PREFERENCE)) {
+			this.enabled = Boolean.parseBoolean(event.getNewValue().toString());
+			if (enabled) {
+				initialReconcile();
+			} else {
+				removeOccurrenceAnnotations();
+			}
+		}
+	}
+
+	@Override
+	public void caretMoved(CaretEvent event) {
+		applyHighlights(event.caretOffset);
+	}
+
+	@Override
+	public void initialReconcile() {
+		if (sourceViewer != null) {
+			sourceViewer.getTextWidget().getDisplay().asyncExec(() -> {
+				if (sourceViewer != null) {
+					applyHighlights(sourceViewer.getTextWidget().getCaretOffset());
+				}
+			});
+		}
+	}
+
+	void removeOccurrenceAnnotations() {
+		IAnnotationModel annotationModel = sourceViewer.getAnnotationModel();
+		if (annotationModel == null || fOccurrenceAnnotations == null)
+			return;
+
+		synchronized (getLockObject(annotationModel)) {
+			if (annotationModel instanceof IAnnotationModelExtension) {
+				((IAnnotationModelExtension) annotationModel).replaceAnnotations(fOccurrenceAnnotations, null);
+			} else {
+				for (Annotation fOccurrenceAnnotation : fOccurrenceAnnotations)
+					annotationModel.removeAnnotation(fOccurrenceAnnotation);
+			}
+			fOccurrenceAnnotations = null;
+		}
+	}
+
+	private static Object getLockObject(IAnnotationModel annotationModel) {
+		if (annotationModel instanceof ISynchronizable) {
+			Object lock = ((ISynchronizable) annotationModel).getLockObject();
+			if (lock != null)
+				return lock;
+		}
+		return annotationModel;
+	}
+
+	@Override
+	public void setDocument(IDocument document) {
+		this.document = document;
+	}
+
+	@Override
+	public void reconcile(DirtyRegion dirtyRegion, IRegion subRegion) {
+		// Do nothing
+	}
+
+	@Override
+	public void reconcile(IRegion partition) {
+		// Do nothing
+	}
+
+	@Override
+	public void setProgressMonitor(IProgressMonitor monitor) {
+		// Not used
+	}
+}
diff --git a/org.eclipse.ui.genericeditor/icons/full/dtool16/mark_occurrences.png b/org.eclipse.ui.genericeditor/icons/full/dtool16/mark_occurrences.png
new file mode 100644
index 00000000000..84d023606b2
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/icons/full/dtool16/mark_occurrences.png
diff --git a/org.eclipse.ui.genericeditor/icons/full/dtool16/mark_occurrences@2x.png b/org.eclipse.ui.genericeditor/icons/full/dtool16/mark_occurrences@2x.png
new file mode 100644
index 00000000000..11b09b05236
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/icons/full/dtool16/mark_occurrences@2x.png
diff --git a/org.eclipse.ui.genericeditor/icons/full/etool16/mark_occurrences.png b/org.eclipse.ui.genericeditor/icons/full/etool16/mark_occurrences.png
new file mode 100644
index 00000000000..8bb2361071f
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/icons/full/etool16/mark_occurrences.png
diff --git a/org.eclipse.ui.genericeditor/icons/full/etool16/mark_occurrences@2x.png b/org.eclipse.ui.genericeditor/icons/full/etool16/mark_occurrences@2x.png
new file mode 100644
index 00000000000..ca74b2bb88e
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/icons/full/etool16/mark_occurrences@2x.png
diff --git a/org.eclipse.ui.genericeditor/plugin.properties b/org.eclipse.ui.genericeditor/plugin.properties
index 7670e1e42b0..4905b4f6779 100644
--- a/org.eclipse.ui.genericeditor/plugin.properties
+++ b/org.eclipse.ui.genericeditor/plugin.properties
@@ -8,6 +8,7 @@
 # Contributors:
 #     Sopot Cela & Mickael Istria (Red Hat Inc.) - initial implementation
 #     Lucas Bullen (Red Hat Inc.) - Bug 508829 custom reconciler support
+#                                 - Bug 521382 default highlighter
 ###############################################################################
 genericEditor_name=Generic Text Editor
 ExtPoint.reconciliers=Reconciliers
@@ -15,10 +16,13 @@ ExtPoint.presentationReconciliers=Presentation Reconciliers
 ExtPoint.hoverProviders= Hover Providers
 ExtPoint.contentAssistProcessors=Content Assist Providers
 ExtPoint.autoEditStrategies=Auto Edit Strategies
+ExtPoint.highlightReconcilers=Highlight Reconcilers
 openDeclarationCommand_name=Open Declaration
 context_name=in Generic Code Editor
 context_description=When editing in the Generic Code Editor
 findReferencesCommand_name=Find References
 findReferencesCommand_description=Find other code items referencing the current selected item.
 Bundle-Vendor=Eclipse.org
-Bundle-Name=Generic and Extensible Text Editor
\ No newline at end of file
+Bundle-Name=Generic and Extensible Text Editor
+command.toggle.highlight.label = Toggle Mark Occurences
+command.toggle.highlight.name = Toggle Highlight
\ No newline at end of file
diff --git a/org.eclipse.ui.genericeditor/plugin.xml b/org.eclipse.ui.genericeditor/plugin.xml
index 28e7a1dd96c..f7098c91743 100644
--- a/org.eclipse.ui.genericeditor/plugin.xml
+++ b/org.eclipse.ui.genericeditor/plugin.xml
@@ -10,6 +10,7 @@
 <!-- Contributors:                                                          -->
 <!--     Sopot Cela & Mickael Istria (Red Hat Inc). -initial implementation -->
 <!--     Lucas Bullen (Red Hat Inc.) - Bug 508829 custom reconciler support -->
+<!--                                 - Bug 521382 default highlighter       -->
 <!-- ====================================================================== -->
 <plugin>
    <extension-point id="reconcilers" name="%ExtPoint.reconciliers" schema="schema/reconcilers.exsd"/>
@@ -17,6 +18,7 @@
    <extension-point id="contentAssistProcessors" name="%ExtPoint.contentAssistProcessors" schema="schema/contentAssistProcessors.exsd"/>
    <extension-point id="hoverProviders" name="%ExtPoint.hoverProviders" schema="schema/hoverProviders.exsd"/>
    <extension-point id="autoEditStrategies" name="%ExtPoint.autoEditStrategies" schema="schema/autoEditStrategies.exsd"/>
+   <extension-point id="highlightReconcilers" name="%ExtPoint.highlightReconcilers" schema="schema/highlightReconcilers.exsd"/>
    <extension
          point="org.eclipse.ui.editors">
       <editor
@@ -38,6 +40,14 @@
             id="org.eclipse.ui.genericeditor.findReferences"
             name="%findReferencesCommand_name">
       </command>
+      <command
+            id="org.eclipse.ui.genericeditor.togglehighlight"
+            name="%command.toggle.highlight.name">
+		   <state
+		         class="org.eclipse.ui.handlers.RegistryToggleState:true"
+		         id="org.eclipse.ui.commands.toggleState">
+		   </state>
+      </command>
    </extension>
    <extension
          point="org.eclipse.ui.contexts">
@@ -73,6 +83,23 @@
                style="push">
          </command>
       </menuContribution>
+      <menuContribution
+            allPopups="false"
+            locationURI="toolbar:org.eclipse.ui.genericeditor.GenericEditor">
+         <command
+               commandId="org.eclipse.ui.genericeditor.togglehighlight"
+               label="%command.toggle.highlight.label"
+               style="toggle">
+         </command>
+      </menuContribution>
+   </extension>
+   <extension
+         point="org.eclipse.ui.handlers">
+      <handler
+            commandId="org.eclipse.ui.genericeditor.togglehighlight">
+         <class
+               class="org.eclipse.ui.internal.genericeditor.ToggleHighlight"></class>
+      </handler>
    </extension>
    <extension
          point="org.eclipse.ui.genericeditor.hoverProviders">
@@ -90,5 +117,40 @@
             id="org.eclipse.ui.genericeditor.annotationsHoverProvider">
       </hoverProvider>
    </extension>
-
+   <extension
+         point="org.eclipse.ui.commandImages">
+      <image
+            commandId="org.eclipse.ui.genericeditor.togglehighlight"
+            disabledIcon="icons/full/dtool16/mark_occurrences.png"
+            icon="icons/full/etool16/mark_occurrences.png">
+      </image>
+   </extension>
+   <extension point="org.eclipse.ui.editors.annotationTypes">
+      <type name="org.eclipse.ui.genericeditor.text"></type>
+   </extension>
+   <extension point="org.eclipse.ui.editors.markerAnnotationSpecification">
+		<specification annotationType="org.eclipse.ui.genericeditor.text"
+			label="Text Occurrence"
+			textPreferenceKey="TextOccurrenceIndication" textPreferenceValue="false"
+			highlightPreferenceKey="TextOccurrenceHighlighting"
+			highlightPreferenceValue="true" contributesToHeader="false"
+			overviewRulerPreferenceKey="TextOccurrenceIndicationInOverviewRuler"
+			overviewRulerPreferenceValue="true"
+			verticalRulerPreferenceKey="TextOccurrenceIndicationInVerticalRuler"
+			verticalRulerPreferenceValue="false" colorPreferenceKey="TextOccurrenceIndicationColor"
+			colorPreferenceValue="212,212,212" presentationLayer="4"
+			showInNextPrevDropdownToolbarAction="true"
+			textStylePreferenceKey="TextOccurrenceTextStyle"
+			textStylePreferenceValue="NONE">
+		</specification>
+   </extension>
+   <extension
+         point="org.eclipse.e4.ui.css.swt.theme">
+      <stylesheet
+            uri="resources/css/dark.css">
+         <themeid
+               refid="org.eclipse.e4.ui.css.theme.e4_dark">
+         </themeid>
+      </stylesheet>
+   </extension>
 </plugin>
diff --git a/org.eclipse.ui.genericeditor/resources/css/dark.css b/org.eclipse.ui.genericeditor/resources/css/dark.css
new file mode 100644
index 00000000000..34c46b58c9d
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/resources/css/dark.css
@@ -0,0 +1,16 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Red Hat Inc. 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:
+ *  Lucas Bullen (Red Hat Inc.) - initial implementation
+ *******************************************************************************/
+
+IEclipsePreferences#org-eclipse-ui-editors:org-eclipse-ui-genericeditor {
+  preferences:
+        'TextOccurrenceIndicationColor=27,98,145'
+}
+
diff --git a/org.eclipse.ui.genericeditor/schema/highlightReconcilers.exsd b/org.eclipse.ui.genericeditor/schema/highlightReconcilers.exsd
new file mode 100644
index 00000000000..25c6abf7249
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/schema/highlightReconcilers.exsd
@@ -0,0 +1,116 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!-- Schema file written by PDE -->
+<schema targetNamespace="org.eclipse.ui.genericeditor" xmlns="http://www.w3.org/2001/XMLSchema">
+<annotation>
+      <appinfo>
+         <meta.schema plugin="org.eclipse.ui.genericeditor" id="highlightReconcilers" name="Highlight reconcilers"/>
+      </appinfo>
+      <documentation>
+         This extension point is used to contribute highlight reconcilers for controlling the highlighting on a file with a given content type. Reconcilers attached to this extension point that listen to the preference &quot;org.eclipse.ui.genericeditor.togglehighlight&quot; will be toggled with the &quot;Toggle Mark Occurences&quot; button.
+      </documentation>
+   </annotation>
+
+   <include schemaLocation="schema://org.eclipse.core.expressions/schema/expressionLanguage.exsd"/>
+
+   <element name="extension">
+      <annotation>
+         <appinfo>
+            <meta.element />
+         </appinfo>
+      </annotation>
+      <complexType>
+         <sequence minOccurs="1" maxOccurs="unbounded">
+            <element ref="highlightReconciler"/>
+         </sequence>
+         <attribute name="point" type="string" use="required">
+            <annotation>
+               <documentation>
+                  a fully qualified identifier of the target extension point
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="id" type="string">
+            <annotation>
+               <documentation>
+                  an optional identifier of the extension instance
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="name" type="string">
+            <annotation>
+               <documentation>
+                  an optional name of the extension instance
+               </documentation>
+               <appinfo>
+                  <meta.attribute translatable="true"/>
+               </appinfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="highlightReconciler">
+      <complexType>
+         <attribute name="class" type="string" use="required">
+            <annotation>
+               <documentation>
+                  The fully qualified class name implementing the interface &lt;code&gt;org.eclipse.jface.text.reconciler.IReconciler&lt;/code&gt;
+               </documentation>
+               <appinfo>
+                  <meta.attribute kind="java" basedOn=":org.eclipse.jface.text.reconciler.IReconciler"/>
+               </appinfo>
+            </annotation>
+         </attribute>
+         <attribute name="contentType" type="string" use="required">
+            <annotation>
+               <documentation>
+                  The target content-type for this extension. Content-types are defined as extension to the org.eclipse.core.contenttype.contentTypes extension point.
+               </documentation>
+               <appinfo>
+                  <meta.attribute kind="identifier" basedOn="org.eclipse.core.contenttype.contentTypes/content-type/@id"/>
+               </appinfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <annotation>
+      <appinfo>
+         <meta.section type="since"/>
+      </appinfo>
+      <documentation>
+         1.1
+      </documentation>
+   </annotation>
+
+   <annotation>
+      <appinfo>
+         <meta.section type="examples"/>
+      </appinfo>
+      <documentation>
+         Below is an example of how to use the Highlight Reconciler extension point:
+
+&lt;pre&gt;
+&lt;extension point=&quot;org.eclipse.ui.genericeditor.highlightReconcilers&quot;&gt;
+      &lt;presentationReconciler
+            class=&quot;org.eclipse.ui.genericeditor.examples.TPHighlightReconcilers&quot;
+            contentType=&quot;org.eclipse.pde.targetFile&quot;&gt;
+      &lt;/presentationReconciler&gt;
+&lt;/extension&gt;
+&lt;/pre&gt;
+      </documentation>
+   </annotation>
+
+
+
+   <annotation>
+      <appinfo>
+         <meta.section type="copyright"/>
+      </appinfo>
+      <documentation>
+         Copyright (c) 2017 Red Hat Inc. 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 &lt;a href=&quot;http://www.eclipse.org/legal/epl-v10.html&quot;&gt;http://www.eclipse.org/legal/epl-v10.html&lt;/a&gt;
+      </documentation>
+   </annotation>
+
+</schema>
diff --git a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/DefaultWordHighlightReconciler.java b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/DefaultWordHighlightReconciler.java
new file mode 100644
index 00000000000..ecf027fc924
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/DefaultWordHighlightReconciler.java
@@ -0,0 +1,37 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Red Hat Inc. 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:
+ * - Lucas Bullen (Red Hat Inc.)
+ *******************************************************************************/
+package org.eclipse.ui.internal.genericeditor;
+
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jface.text.ITextViewer;
+import org.eclipse.jface.text.reconciler.Reconciler;
+
+public class DefaultWordHighlightReconciler extends Reconciler {
+
+	private DefaultWordHighlightStrategy fStrategy;
+
+	public DefaultWordHighlightReconciler() {
+        fStrategy = new DefaultWordHighlightStrategy();
+        this.setReconcilingStrategy(fStrategy, IDocument.DEFAULT_CONTENT_TYPE);
+    }
+
+	@Override
+	public void install(ITextViewer textViewer) {
+		super.install(textViewer);
+		fStrategy.install(textViewer);
+	}
+
+	@Override
+	public void uninstall() {
+		super.uninstall();
+		fStrategy.uninstall();
+	}
+}
\ No newline at end of file
diff --git a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/DefaultWordHighlightStrategy.java b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/DefaultWordHighlightStrategy.java
new file mode 100644
index 00000000000..d1aacdfa889
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/DefaultWordHighlightStrategy.java
@@ -0,0 +1,225 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Red Hat Inc. 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:
+ * - Lucas Bullen (Red Hat Inc.)
+ *******************************************************************************/
+package org.eclipse.ui.internal.genericeditor;
+
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent;
+import org.eclipse.core.runtime.preferences.InstanceScope;
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jface.text.IRegion;
+import org.eclipse.jface.text.ISynchronizable;
+import org.eclipse.jface.text.ITextViewer;
+import org.eclipse.jface.text.ITextViewerExtension5;
+import org.eclipse.jface.text.Position;
+import org.eclipse.jface.text.reconciler.DirtyRegion;
+import org.eclipse.jface.text.reconciler.IReconcilingStrategy;
+import org.eclipse.jface.text.reconciler.IReconcilingStrategyExtension;
+import org.eclipse.jface.text.source.Annotation;
+import org.eclipse.jface.text.source.IAnnotationModel;
+import org.eclipse.jface.text.source.IAnnotationModelExtension;
+import org.eclipse.jface.text.source.ISourceViewer;
+import org.eclipse.swt.custom.CaretEvent;
+import org.eclipse.swt.custom.CaretListener;
+
+/**
+*
+* This Reconciler Strategy is a default stategy which will be present if
+* no other highlightReconcilers are registered for a given content-type. It splits
+* the text into 'words' (which are defined as anything in-between
+* non-alphanumeric characters) and searches the document highlighting all like words.
+*
+* E.g. if your file contains "t^he dog in the bog" and you leave your caret at
+* ^ you will get both instances of 'the' highlighted.
+*
+*/
+public class DefaultWordHighlightStrategy implements IReconcilingStrategy, IReconcilingStrategyExtension, CaretListener, IPreferenceChangeListener {
+
+	private static final String ANNOTATION_TYPE = "org.eclipse.ui.genericeditor.text"; //$NON-NLS-1$
+
+	private boolean enabled;
+	private ISourceViewer sourceViewer;
+	private IDocument document;
+
+	private static final String WORD_REGEXP = "[a-zA-Z]+"; //$NON-NLS-1$
+	private static final Pattern WORD_PATTERN = Pattern.compile(WORD_REGEXP);
+
+	private Annotation[] fOccurrenceAnnotations = null;
+
+	private void applyHighlights(int offset) {
+		if (sourceViewer == null || !enabled) {
+			removeOccurrenceAnnotations();
+			return;
+		}
+
+		String text = document.get();
+		offset = ((ITextViewerExtension5)sourceViewer).widgetOffset2ModelOffset(offset);
+
+		int wordStartOffset = findStartingOffset(text, offset);
+		int wordEndOffset = findEndingOffset(text, offset);
+		if(wordEndOffset <= wordStartOffset || wordEndOffset == -1 || wordStartOffset == -1) {
+			removeOccurrenceAnnotations();
+			return;
+		}
+		String word = text.substring(wordStartOffset, wordEndOffset);
+
+		Matcher m = WORD_PATTERN.matcher(text);
+		Map<Annotation, Position> annotationMap = new HashMap<>();
+		while(m.find()) {
+			if(m.group().equals(word)) {
+				annotationMap.put(new Annotation(ANNOTATION_TYPE, false, null),
+						new Position(m.start(), m.end() - m.start()));
+			}
+		}
+
+		if(annotationMap.size() < 2) {
+			removeOccurrenceAnnotations();
+			return;
+		}
+
+		IAnnotationModel annotationModel = sourceViewer.getAnnotationModel();
+		synchronized (getLockObject(annotationModel)) {
+			if (annotationModel instanceof IAnnotationModelExtension) {
+				((IAnnotationModelExtension) annotationModel).replaceAnnotations(fOccurrenceAnnotations, annotationMap);
+			} else {
+				removeOccurrenceAnnotations();
+				Iterator<Entry<Annotation, Position>> iter = annotationMap.entrySet().iterator();
+				while (iter.hasNext()) {
+					Entry<Annotation, Position> mapEntry = iter.next();
+					annotationModel.addAnnotation(mapEntry.getKey(), mapEntry.getValue());
+				}
+			}
+			fOccurrenceAnnotations = annotationMap.keySet().toArray(new Annotation[annotationMap.keySet().size()]);
+		}
+	}
+
+	private static int findStartingOffset(String text, int offset) {
+		final Pattern NON_ALPHANUMERIC_LAST_PATTERN = Pattern.compile("[^\\w](?!.*[^\\w])"); //$NON-NLS-1$
+		String substring = text.substring(0, offset);
+		Matcher m = NON_ALPHANUMERIC_LAST_PATTERN.matcher(substring);
+		if(m.find()) {
+			return m.end();
+		}
+		return -1;
+	}
+
+	private static int findEndingOffset(String text, int offset) {
+		String substring = text.substring(offset);
+		String[] split = substring.split("[^a-zA-Z0-9]+");//$NON-NLS-1$
+		if(split.length == 0) {
+			return -1;
+		}
+		return offset + split[0].length();
+	}
+
+	public void install(ITextViewer viewer) {
+		if (!(viewer instanceof ISourceViewer)) {
+			return;
+		}
+		IEclipsePreferences preferences = InstanceScope.INSTANCE.getNode(GenericEditorPlugin.BUNDLE_ID);
+		preferences.addPreferenceChangeListener(this);
+		this.enabled = preferences.getBoolean(ToggleHighlight.TOGGLE_HIGHLIGHT_PREFERENCE, true);
+		this.sourceViewer = (ISourceViewer) viewer;
+		this.sourceViewer.getTextWidget().addCaretListener(this);
+	}
+
+	public void uninstall() {
+		if (sourceViewer != null) {
+			sourceViewer.getTextWidget().removeCaretListener(this);
+		}
+		IEclipsePreferences preferences = InstanceScope.INSTANCE.getNode(GenericEditorPlugin.BUNDLE_ID);
+		preferences.removePreferenceChangeListener(this);
+	}
+
+	@Override
+	public void preferenceChange(PreferenceChangeEvent event) {
+		if (event.getKey().equals(ToggleHighlight.TOGGLE_HIGHLIGHT_PREFERENCE)) {
+			this.enabled = Boolean.parseBoolean(event.getNewValue().toString());
+			if (enabled) {
+				initialReconcile();
+			} else {
+				removeOccurrenceAnnotations();
+			}
+		}
+	}
+
+	@Override
+	public void caretMoved(CaretEvent event) {
+		applyHighlights(event.caretOffset);
+	}
+
+	@Override
+	public void initialReconcile() {
+		if (sourceViewer != null) {
+			sourceViewer.getTextWidget().getDisplay().asyncExec(() -> {
+				if (sourceViewer != null) {
+					applyHighlights(sourceViewer.getTextWidget().getCaretOffset());
+				}
+			});
+		}
+	}
+
+	void removeOccurrenceAnnotations() {
+		IAnnotationModel annotationModel = sourceViewer.getAnnotationModel();
+		if (annotationModel == null || fOccurrenceAnnotations == null) {
+			return;
+		}
+
+		synchronized (getLockObject(annotationModel)) {
+			if (annotationModel instanceof IAnnotationModelExtension) {
+				((IAnnotationModelExtension) annotationModel).replaceAnnotations(fOccurrenceAnnotations, null);
+			} else {
+				for (Annotation fOccurrenceAnnotation : fOccurrenceAnnotations) {
+					annotationModel.removeAnnotation(fOccurrenceAnnotation);
+				}
+			}
+			fOccurrenceAnnotations = null;
+		}
+	}
+
+	private static Object getLockObject(IAnnotationModel annotationModel) {
+		if (annotationModel instanceof ISynchronizable) {
+			Object lock = ((ISynchronizable) annotationModel).getLockObject();
+			if (lock != null) {
+				return lock;
+			}
+		}
+		return annotationModel;
+	}
+
+	@Override
+	public void setDocument(IDocument document) {
+		this.document = document;
+	}
+
+	@Override
+	public void reconcile(DirtyRegion dirtyRegion, IRegion subRegion) {
+		// Do nothing
+	}
+
+	@Override
+	public void reconcile(IRegion partition) {
+		// Do nothing
+	}
+
+	@Override
+	public void setProgressMonitor(IProgressMonitor monitor) {
+		// Not used
+	}
+}
diff --git a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ExtensionBasedTextViewerConfiguration.java b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ExtensionBasedTextViewerConfiguration.java
index 4e0461fe0b1..be79f1f6f55 100644
--- a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ExtensionBasedTextViewerConfiguration.java
+++ b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ExtensionBasedTextViewerConfiguration.java
@@ -8,6 +8,7 @@
  * Contributors:
  *   Sopot Cela, Mickael Istria (Red Hat Inc.) - initial implementation
  *   Lucas Bullen (Red Hat Inc.) - Bug 508829 custom reconciler support
+ *                               - Bug 521382 default highlight reconciler
  *******************************************************************************/
 package org.eclipse.ui.internal.genericeditor;
 
@@ -27,7 +28,6 @@ import org.eclipse.jface.text.IAutoEditStrategy;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IDocumentPartitioningListener;
 import org.eclipse.jface.text.IInformationControl;
-import org.eclipse.jface.text.IInformationControlCreator;
 import org.eclipse.jface.text.ITextHover;
 import org.eclipse.jface.text.contentassist.ContentAssistant;
 import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
@@ -39,7 +39,6 @@ import org.eclipse.jface.text.reconciler.IReconciler;
 import org.eclipse.jface.text.source.ISourceViewer;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.ui.IEditorPart;
-import org.eclipse.ui.IPropertyListener;
 import org.eclipse.ui.editors.text.TextSourceViewerConfiguration;
 import org.eclipse.ui.internal.editors.text.EditorsPlugin;
 import org.eclipse.ui.internal.genericeditor.hover.CompositeTextHover;
@@ -72,12 +71,9 @@ public final class ExtensionBasedTextViewerConfiguration extends TextSourceViewe
 	public ExtensionBasedTextViewerConfiguration(ITextEditor editor, IPreferenceStore preferenceStore) {
 		super(preferenceStore);
 		this.editor = editor;
-		this.editor.addPropertyListener(new IPropertyListener() {
-			@Override
-			public void propertyChanged(Object source, int propId) {
-				if (propId == IEditorPart.PROP_INPUT) {
-					watchDocument(editor.getDocumentProvider().getDocument(editor.getEditorInput()));
-				}
+		this.editor.addPropertyListener((source, propId) -> {
+			if (propId == IEditorPart.PROP_INPUT) {
+				watchDocument(editor.getDocumentProvider().getDocument(editor.getEditorInput()));
 			}
 		});
 	}
@@ -185,12 +181,7 @@ public final class ExtensionBasedTextViewerConfiguration extends TextSourceViewe
 				));
 		quickAssistAssistant.setQuickAssistProcessor(processor);
 		quickAssistAssistant.setRestoreCompletionProposalSize(EditorsPlugin.getDefault().getDialogSettingsSection("quick_assist_proposal_size")); //$NON-NLS-1$
-		quickAssistAssistant.setInformationControlCreator(new IInformationControlCreator() {
-			@Override
-			public IInformationControl createInformationControl(Shell parent) {
-				return new DefaultInformationControl(parent, EditorsPlugin.getAdditionalInfoAffordanceString());
-			}
-		});
+		quickAssistAssistant.setInformationControlCreator(parent -> new DefaultInformationControl(parent, EditorsPlugin.getAdditionalInfoAffordanceString()));
 		return quickAssistAssistant;
 	}
 
@@ -198,12 +189,20 @@ public final class ExtensionBasedTextViewerConfiguration extends TextSourceViewe
 	public IReconciler getReconciler(ISourceViewer sourceViewer) {
 		ReconcilerRegistry registry = GenericEditorPlugin.getDefault().getReconcilerRegistry();
 		List<IReconciler> reconciliers = registry.getReconcilers(sourceViewer, getContentTypes());
+		List<IReconciler> highlightReconciliers = registry.getHighlightReconcilers(sourceViewer, getContentTypes());
+
+		if(!highlightReconciliers.isEmpty()) {
+			reconciliers.addAll(highlightReconciliers);
+		}else {
+			reconciliers.add(new DefaultWordHighlightReconciler());
+		}
+
 		if (!reconciliers.isEmpty()) {
 			return new CompositeReconciler(reconciliers);
 		}
 		return null;
 	}
-	
+
 	@Override
 	public IAutoEditStrategy[] getAutoEditStrategies(ISourceViewer sourceViewer, String contentType) {
 		AutoEditStrategyRegistry registry = GenericEditorPlugin.getDefault().getAutoEditStrategyRegistry();
@@ -213,5 +212,5 @@ public final class ExtensionBasedTextViewerConfiguration extends TextSourceViewe
 		}
 		return super.getAutoEditStrategies(sourceViewer, contentType);
 	}
-	
+
 }
diff --git a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ReconcilerRegistry.java b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ReconcilerRegistry.java
index 5d52e3cfd65..b31ecadbd17 100644
--- a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ReconcilerRegistry.java
+++ b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ReconcilerRegistry.java
@@ -18,8 +18,6 @@ import java.util.Set;
 import java.util.stream.Collectors;
 
 import org.eclipse.core.runtime.IConfigurationElement;
-import org.eclipse.core.runtime.IRegistryChangeEvent;
-import org.eclipse.core.runtime.IRegistryChangeListener;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.Status;
@@ -28,33 +26,38 @@ import org.eclipse.jface.text.reconciler.IReconciler;
 import org.eclipse.jface.text.source.ISourceViewer;
 
 /**
- * A registry of reconciliers provided by extension <code>org.eclipse.ui.genericeditor.reconcilers</code>.
+ * A registry of reconciliers provided by extensions <code>org.eclipse.ui.genericeditor.reconcilers</code>
+ * and <code>org.eclipse.ui.genericeditor.foldingReconcilers</code>.
  * Those extensions are specific to a given {@link IContentType}.
- * 
+ *
  * @since 1.1
  */
 public class ReconcilerRegistry {
 
 	private static final String EXTENSION_POINT_ID = GenericEditorPlugin.BUNDLE_ID + ".reconcilers"; //$NON-NLS-1$
+	private static final String HIGHLIGHT_EXTENSION_POINT_ID = GenericEditorPlugin.BUNDLE_ID + ".highlightReconcilers"; //$NON-NLS-1$
 
 	private Map<IConfigurationElement, GenericContentTypeRelatedExtension<IReconciler>> extensions = new HashMap<>();
+	private Map<IConfigurationElement, GenericContentTypeRelatedExtension<IReconciler>> highlightExtensions = new HashMap<>();
 	private boolean outOfSync = true;
+	private boolean highlightOutOfSync = true;
 
 	/**
 	 * Creates the registry and binds it to the extension point.
 	 */
 	public ReconcilerRegistry() {
-		Platform.getExtensionRegistry().addRegistryChangeListener(new IRegistryChangeListener() {
-			@Override
-			public void registryChanged(IRegistryChangeEvent event) {
-				outOfSync = true;
-			}
+		Platform.getExtensionRegistry().addRegistryChangeListener(event -> {
+			outOfSync = true;
 		}, EXTENSION_POINT_ID);
+
+		Platform.getExtensionRegistry().addRegistryChangeListener(event -> {
+			highlightOutOfSync = true;
+		}, HIGHLIGHT_EXTENSION_POINT_ID);
 	}
 
 	/**
 	 * Get the contributed {@link IReconciliers}s that are relevant to hook on source viewer according
-	 * to document content types. 
+	 * to document content types.
 	 * @param sourceViewer the source viewer we're hooking completion to.
 	 * @param contentTypes the content types of the document we're editing.
 	 * @return the list of {@link IReconciler} contributed for at least one of the content types,
@@ -72,6 +75,26 @@ public class ReconcilerRegistry {
 		return reconcilers;
 	}
 
+	/**
+	 * Get the contributed highlight {@link IReconciliers}s that are relevant to hook on source viewer according
+	 * to document content types.
+	 * @param sourceViewer the source viewer we're hooking completion to.
+	 * @param contentTypes the content types of the document we're editing.
+	 * @return the list of highlight {@link IReconciler}s contributed for at least one of the content types,
+	 * sorted by most generic content type to most specific.
+	 */
+	public List<IReconciler> getHighlightReconcilers(ISourceViewer sourceViewer, Set<IContentType> contentTypes) {
+		if (this.highlightOutOfSync) {
+			syncHighlight();
+		}
+		List<IReconciler> highlightReconcilers = this.highlightExtensions.values().stream()
+				.filter(ext -> contentTypes.contains(ext.targetContentType))
+				.sorted(new ContentTypeSpecializationComparator<IReconciler>().reversed())
+				.map(GenericContentTypeRelatedExtension<IReconciler>::createDelegate)
+				.collect(Collectors.toList());
+		return highlightReconcilers;
+	}
+
 	private void sync() {
 		Set<IConfigurationElement> toRemoveExtensions = new HashSet<>(this.extensions.keySet());
 		for (IConfigurationElement extension : Platform.getExtensionRegistry().getConfigurationElementsFor(EXTENSION_POINT_ID)) {
@@ -90,4 +113,22 @@ public class ReconcilerRegistry {
 		this.outOfSync = false;
 	}
 
+	private void syncHighlight() {
+		Set<IConfigurationElement> toRemoveExtensions = new HashSet<>(this.extensions.keySet());
+		for (IConfigurationElement extension : Platform.getExtensionRegistry().getConfigurationElementsFor(HIGHLIGHT_EXTENSION_POINT_ID)) {
+			toRemoveExtensions.remove(extension);
+			if (!this.highlightExtensions.containsKey(extension)) {
+				try {
+					this.highlightExtensions.put(extension, new GenericContentTypeRelatedExtension<IReconciler>(extension));
+				} catch (Exception ex) {
+					GenericEditorPlugin.getDefault().getLog().log(new Status(IStatus.ERROR, GenericEditorPlugin.BUNDLE_ID, ex.getMessage(), ex));
+				}
+			}
+		}
+		for (IConfigurationElement toRemove : toRemoveExtensions) {
+			this.highlightExtensions.remove(toRemove);
+		}
+		this.highlightOutOfSync = false;
+	}
+
 }
diff --git a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ToggleHighlight.java b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ToggleHighlight.java
new file mode 100644
index 00000000000..9e9cc8e77dc
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/ToggleHighlight.java
@@ -0,0 +1,34 @@
+/*******************************************************************************
+ * Copyright (c) 2017 Red Hat Inc. 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:
+ *  Lucas Bullen (Red Hat Inc.) - initial implementation
+ *******************************************************************************/
+package org.eclipse.ui.internal.genericeditor;
+
+import org.eclipse.core.commands.AbstractHandler;
+import org.eclipse.core.commands.Command;
+import org.eclipse.core.commands.ExecutionEvent;
+import org.eclipse.core.commands.ExecutionException;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.InstanceScope;
+import org.eclipse.ui.handlers.HandlerUtil;
+
+public class ToggleHighlight extends AbstractHandler {
+
+	public static final String TOGGLE_HIGHLIGHT_PREFERENCE = "org.eclipse.ui.genericeditor.togglehighlight"; //$NON-NLS-1$
+
+	@Override
+	public Object execute(ExecutionEvent event) throws ExecutionException {
+		Command command = event.getCommand();
+		boolean oldValue = HandlerUtil.toggleCommandState(command);
+
+		IEclipsePreferences preferences = InstanceScope.INSTANCE.getNode(GenericEditorPlugin.BUNDLE_ID);
+		preferences.putBoolean(TOGGLE_HIGHLIGHT_PREFERENCE, !oldValue);
+		return null;
+	}
+}