Add OCCURRENCES_CONTRIBUTOR_EXTENSION_POINT_ID.

R=brianwilkerson@google.com
BUG=

Review URL: https://codereview.chromium.org//1337143002 .

pkg/analysis_server/lib/analysis/navigation_core.dart

@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-library analysis_server.analysis.navigation.navigation_core;
+library analysis_server.analysis.navigation_core;
 
 import 'package:analysis_server/src/protocol.dart'
     show ElementKind, Location, NavigationRegion, NavigationTarget;

pkg/analysis_server/lib/analysis/occurrences_core.dart

@@ -0,0 +1,35 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library analysis_server.analysis.occurrences_core;
+
+import 'package:analysis_server/src/protocol.dart' show Element, Occurrences;
+import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
+import 'package:analyzer/src/generated/source.dart' show Source;
+
+/**
+ * An object used to produce occurrences.
+ *
+ * Clients are expected to subtype this class when implementing plugins.
+ */
+abstract class OccurrencesContributor {
+  /**
+   * Contribute occurrences into the given [collector].
+   * The [context] can be used to get analysis results.
+   */
+  void computeOccurrences(
+      OccurrencesCollector collector, AnalysisContext context, Source source);
+}
+
+/**
+ * An object that [OccurrencesContributor]s use to record occurrences into.
+ *
+ * Clients are not expected to subtype this class.
+ */
+abstract class OccurrencesCollector {
+  /**
+   * Record a new element occurrences.
+   */
+  void addOccurrences(Occurrences occurrences);
+}

pkg/analysis_server/lib/plugin/navigation.dart

@@ -8,7 +8,7 @@
  */
 library analysis_server.plugin.navigation;
 
-import 'package:analysis_server/analysis/navigation/navigation_core.dart';
+import 'package:analysis_server/analysis/navigation_core.dart';
 import 'package:analysis_server/src/plugin/server_plugin.dart';
 import 'package:plugin/plugin.dart';
 

pkg/analysis_server/lib/plugin/occurrences.dart

@@ -0,0 +1,22 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/**
+ * Support for client code that extends the analysis server by adding new
+ * occurrences contributors.
+ */
+library analysis_server.plugin.occurrences;
+
+import 'package:analysis_server/analysis/occurrences_core.dart';
+import 'package:analysis_server/src/plugin/server_plugin.dart';
+import 'package:plugin/plugin.dart';
+
+/**
+ * The identifier of the extension point that allows plugins to register
+ * element occurrences. The object used as an extension must be
+ * a [OccurrencesContributor].
+ */
+final String OCCURRENCES_CONTRIBUTOR_EXTENSION_POINT_ID = Plugin.join(
+    ServerPlugin.UNIQUE_IDENTIFIER,
+    ServerPlugin.OCCURRENCES_CONTRIBUTOR_EXTENSION_POINT);

pkg/analysis_server/lib/src/analysis_server.dart

@@ -975,7 +975,7 @@ class AnalysisServer {
                 sendAnalysisNotificationNavigation(this, context, source);
                 break;
               case AnalysisService.OCCURRENCES:
-                sendAnalysisNotificationOccurrences(this, file, dartUnit);
+                sendAnalysisNotificationOccurrences(this, context, source);
                 break;
               case AnalysisService.OUTLINE:
                 AnalysisContext context = dartUnit.element.context;

pkg/analysis_server/lib/src/computer/computer_occurrences.dart

@@ -1,78 +0,0 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library computer.occurrences;
-
-import 'dart:collection';
-
-import 'package:analysis_server/src/protocol_server.dart' as protocol;
-import 'package:analyzer/src/generated/ast.dart';
-import 'package:analyzer/src/generated/element.dart';
-
-/**
- * A computer for elements occurrences in a Dart [CompilationUnit].
- */
-class DartUnitOccurrencesComputer {
-  final CompilationUnit _unit;
-
-  final Map<Element, List<int>> _elementsOffsets =
-      new HashMap<Element, List<int>>();
-
-  DartUnitOccurrencesComputer(this._unit);
-
-  /**
-   * Returns the computed occurrences, not `null`.
-   */
-  List<protocol.Occurrences> compute() {
-    _unit.accept(new _DartUnitOccurrencesComputerVisitor(this));
-    List<protocol.Occurrences> occurrences = <protocol.Occurrences>[];
-    _elementsOffsets.forEach((engineElement, offsets) {
-      var serverElement = protocol.newElement_fromEngine(engineElement);
-      var length = engineElement.displayName.length;
-      occurrences.add(new protocol.Occurrences(serverElement, offsets, length));
-    });
-    return occurrences;
-  }
-
-  void _addOccurrence(Element element, int offset) {
-    element = _canonicalizeElement(element);
-    if (element == null || element == DynamicElementImpl.instance) {
-      return;
-    }
-    List<int> offsets = _elementsOffsets[element];
-    if (offsets == null) {
-      offsets = <int>[];
-      _elementsOffsets[element] = offsets;
-    }
-    offsets.add(offset);
-  }
-
-  Element _canonicalizeElement(Element element) {
-    if (element is FieldFormalParameterElement) {
-      element = (element as FieldFormalParameterElement).field;
-    }
-    if (element is PropertyAccessorElement) {
-      element = (element as PropertyAccessorElement).variable;
-    }
-    if (element is Member) {
-      element = (element as Member).baseElement;
-    }
-    return element;
-  }
-}
-
-class _DartUnitOccurrencesComputerVisitor extends RecursiveAstVisitor {
-  final DartUnitOccurrencesComputer computer;
-
-  _DartUnitOccurrencesComputerVisitor(this.computer);
-
-  @override
-  visitSimpleIdentifier(SimpleIdentifier node) {
-    Element element = node.bestElement;
-    if (element != null) {
-      computer._addOccurrence(element, node.offset);
-    }
-    return super.visitSimpleIdentifier(node);
-  }
-}

pkg/analysis_server/lib/src/domain_analysis.dart

@@ -14,7 +14,10 @@ import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/context_manager.dart';
 import 'package:analysis_server/src/domains/analysis/navigation.dart';
 import 'package:analysis_server/src/operation/operation_analysis.dart'
-    show NavigationOperation, sendAnalysisNotificationNavigation;
+    show
+        NavigationOperation,
+        OccurrencesOperation,
+        sendAnalysisNotificationNavigation;
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/dependencies/library_dependencies.dart';
 import 'package:analyzer/file_system/file_system.dart';
@@ -352,6 +355,9 @@ class AnalysisDomainImpl implements AnalysisDomain {
       if (service == AnalysisService.NAVIGATION) {
         server.scheduleOperation(new NavigationOperation(context, source));
       }
+      if (service == AnalysisService.OCCURRENCES) {
+        server.scheduleOperation(new OccurrencesOperation(context, source));
+      }
     }
   }
 

pkg/analysis_server/lib/src/domains/analysis/navigation.dart

@@ -1,4 +1,4 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -6,7 +6,7 @@ library domains.analysis.navigation;
 
 import 'dart:collection';
 
-import 'package:analysis_server/analysis/navigation/navigation_core.dart';
+import 'package:analysis_server/analysis/navigation_core.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;

pkg/analysis_server/lib/src/domains/analysis/navigation_dart.dart

@@ -1,10 +1,10 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library domains.analysis.navigation_dart;
 
-import 'package:analysis_server/analysis/navigation/navigation_core.dart';
+import 'package:analysis_server/analysis/navigation_core.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';

pkg/analysis_server/lib/src/domains/analysis/occurrences.dart

@@ -0,0 +1,45 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library domains.analysis.occurrences;
+
+import 'package:analysis_server/analysis/occurrences_core.dart';
+import 'package:analysis_server/src/analysis_server.dart';
+import 'package:analysis_server/src/protocol_server.dart' as protocol;
+import 'package:analyzer/src/generated/engine.dart'
+    show AnalysisContext, AnalysisEngine;
+import 'package:analyzer/src/generated/java_engine.dart' show CaughtException;
+import 'package:analyzer/src/generated/source.dart' show Source;
+
+/**
+ * Compute all known occurrences for the given [source].
+ */
+OccurrencesCollectorImpl computeOccurrences(
+    AnalysisServer server, AnalysisContext context, Source source) {
+  OccurrencesCollectorImpl collector = new OccurrencesCollectorImpl();
+  List<OccurrencesContributor> contributors =
+      server.serverPlugin.occurrencesContributors;
+  for (OccurrencesContributor contributor in contributors) {
+    try {
+      contributor.computeOccurrences(collector, context, source);
+    } catch (exception, stackTrace) {
+      AnalysisEngine.instance.logger.logError(
+          'Exception from occurrences contributor: ${contributor.runtimeType}',
+          new CaughtException(exception, stackTrace));
+    }
+  }
+  return collector;
+}
+
+/**
+ * A concrete implementation of [OccurrencesCollector].
+ */
+class OccurrencesCollectorImpl implements OccurrencesCollector {
+  final List<protocol.Occurrences> allOccurrences = <protocol.Occurrences>[];
+
+  @override
+  void addOccurrences(protocol.Occurrences occurrences) {
+    allOccurrences.add(occurrences);
+  }
+}

pkg/analysis_server/lib/src/domains/analysis/occurrences_dart.dart

@@ -0,0 +1,79 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library domains.analysis.occurrences_dart;
+
+import 'package:analysis_server/analysis/occurrences_core.dart';
+import 'package:analysis_server/src/protocol_server.dart' as protocol;
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/element.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/source.dart';
+
+/**
+ * A computer for occurrences in a Dart [CompilationUnit].
+ */
+class DartOccurrencesComputer implements OccurrencesContributor {
+  @override
+  void computeOccurrences(
+      OccurrencesCollector collector, AnalysisContext context, Source source) {
+    List<Source> libraries = context.getLibrariesContaining(source);
+    if (libraries.isNotEmpty) {
+      CompilationUnit unit =
+          context.getResolvedCompilationUnit2(source, libraries.first);
+      if (unit != null) {
+        _DartUnitOccurrencesComputerVisitor visitor =
+            new _DartUnitOccurrencesComputerVisitor();
+        unit.accept(visitor);
+        visitor.elementsOffsets.forEach((engineElement, offsets) {
+          int length = engineElement.displayName.length;
+          protocol.Element serverElement =
+              protocol.newElement_fromEngine(engineElement);
+          protocol.Occurrences occurrences =
+              new protocol.Occurrences(serverElement, offsets, length);
+          collector.addOccurrences(occurrences);
+        });
+      }
+    }
+  }
+}
+
+class _DartUnitOccurrencesComputerVisitor extends RecursiveAstVisitor {
+  final Map<Element, List<int>> elementsOffsets = <Element, List<int>>{};
+
+  @override
+  visitSimpleIdentifier(SimpleIdentifier node) {
+    Element element = node.bestElement;
+    if (element != null) {
+      _addOccurrence(element, node.offset);
+    }
+    return super.visitSimpleIdentifier(node);
+  }
+
+  void _addOccurrence(Element element, int offset) {
+    element = _canonicalizeElement(element);
+    if (element == null || element == DynamicElementImpl.instance) {
+      return;
+    }
+    List<int> offsets = elementsOffsets[element];
+    if (offsets == null) {
+      offsets = <int>[];
+      elementsOffsets[element] = offsets;
+    }
+    offsets.add(offset);
+  }
+
+  Element _canonicalizeElement(Element element) {
+    if (element is FieldFormalParameterElement) {
+      element = (element as FieldFormalParameterElement).field;
+    }
+    if (element is PropertyAccessorElement) {
+      element = (element as PropertyAccessorElement).variable;
+    }
+    if (element is Member) {
+      element = (element as Member).baseElement;
+    }
+    return element;
+  }
+}

pkg/analysis_server/lib/src/operation/operation_analysis.dart

@@ -7,10 +7,10 @@ library operation.analysis;
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/computer/computer_highlights.dart';
 import 'package:analysis_server/src/computer/computer_highlights2.dart';
-import 'package:analysis_server/src/computer/computer_occurrences.dart';
 import 'package:analysis_server/src/computer/computer_outline.dart';
 import 'package:analysis_server/src/computer/computer_overrides.dart';
 import 'package:analysis_server/src/domains/analysis/navigation.dart';
+import 'package:analysis_server/src/domains/analysis/occurrences.dart';
 import 'package:analysis_server/src/operation/operation.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analysis_server/src/services/dependencies/library_dependencies.dart';
@@ -82,8 +82,8 @@ void scheduleNotificationOperations(
     }
     if (server.hasAnalysisSubscription(
         protocol.AnalysisService.OCCURRENCES, file)) {
-      server.scheduleOperation(
-          new _DartOccurrencesOperation(context, file, resolvedDartUnit));
+      Source source = resolvedDartUnit.element.source;
+      server.scheduleOperation(new OccurrencesOperation(context, source));
     }
     if (server.hasAnalysisSubscription(
         protocol.AnalysisService.OVERRIDES, file)) {
@@ -179,10 +179,13 @@ void sendAnalysisNotificationNavigation(
 }
 
 void sendAnalysisNotificationOccurrences(
-    AnalysisServer server, String file, CompilationUnit dartUnit) {
+    AnalysisServer server, AnalysisContext context, Source source) {
   _sendNotification(server, () {
-    var occurrences = new DartUnitOccurrencesComputer(dartUnit).compute();
-    var params = new protocol.AnalysisOccurrencesParams(file, occurrences);
+    OccurrencesCollectorImpl collector =
+        computeOccurrences(server, context, source);
+    String file = source.fullName;
+    var params =
+        new protocol.AnalysisOccurrencesParams(file, collector.allOccurrences);
     server.sendNotification(params.toNotification());
   });
 }
@@ -234,17 +237,35 @@ class NavigationOperation extends _NotificationOperation
   NavigationOperation(AnalysisContext context, Source source)
       : super(context, source);
 
-  @override
-  void perform(AnalysisServer server) {
-    sendAnalysisNotificationNavigation(server, context, source);
-  }
-
   @override
   bool merge(ServerOperation other) {
     return other is NavigationOperation &&
         other.context == context &&
         other.source == source;
   }
+
+  @override
+  void perform(AnalysisServer server) {
+    sendAnalysisNotificationNavigation(server, context, source);
+  }
+}
+
+class OccurrencesOperation extends _NotificationOperation
+    implements MergeableOperation {
+  OccurrencesOperation(AnalysisContext context, Source source)
+      : super(context, source);
+
+  @override
+  bool merge(ServerOperation other) {
+    return other is OccurrencesOperation &&
+        other.context == context &&
+        other.source == source;
+  }
+
+  @override
+  void perform(AnalysisServer server) {
+    sendAnalysisNotificationOccurrences(server, context, source);
+  }
 }
 
 /**
@@ -410,17 +431,6 @@ abstract class _DartNotificationOperation extends _SingleFileOperation {
   }
 }
 
-class _DartOccurrencesOperation extends _DartNotificationOperation {
-  _DartOccurrencesOperation(
-      AnalysisContext context, String file, CompilationUnit unit)
-      : super(context, file, unit);
-
-  @override
-  void perform(AnalysisServer server) {
-    sendAnalysisNotificationOccurrences(server, file, unit);
-  }
-}
-
 class _DartOutlineOperation extends _DartNotificationOperation {
   final LineInfo lineInfo;
 

pkg/analysis_server/lib/src/plugin/server_plugin.dart

@@ -6,7 +6,8 @@ library analysis_server.src.plugin.server_plugin;
 
 import 'package:analysis_server/analysis/analysis_domain.dart';
 import 'package:analysis_server/analysis/index/index_core.dart';
-import 'package:analysis_server/analysis/navigation/navigation_core.dart';
+import 'package:analysis_server/analysis/navigation_core.dart';
+import 'package:analysis_server/analysis/occurrences_core.dart';
 import 'package:analysis_server/completion/completion_core.dart';
 import 'package:analysis_server/edit/assist/assist_core.dart';
 import 'package:analysis_server/edit/fix/fix_core.dart';
@@ -14,12 +15,14 @@ import 'package:analysis_server/plugin/analyzed_files.dart';
 import 'package:analysis_server/plugin/assist.dart';
 import 'package:analysis_server/plugin/fix.dart';
 import 'package:analysis_server/plugin/navigation.dart';
+import 'package:analysis_server/plugin/occurrences.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:analysis_server/src/domain_completion.dart';
 import 'package:analysis_server/src/domain_execution.dart';
 import 'package:analysis_server/src/domain_server.dart';
 import 'package:analysis_server/src/domains/analysis/navigation_dart.dart';
+import 'package:analysis_server/src/domains/analysis/occurrences_dart.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/search/search_domain.dart';
@@ -84,6 +87,13 @@ class ServerPlugin implements Plugin {
   static const String NAVIGATION_CONTRIBUTOR_EXTENSION_POINT =
       'navigationContributor';
 
+  /**
+   * The simple identifier of the extension point that allows plugins to
+   * register element occurrences.
+   */
+  static const String OCCURRENCES_CONTRIBUTOR_EXTENSION_POINT =
+      'occurrencesContributor';
+
   /**
    * The simple identifier of the extension point that allows plugins to
    * register analysis result listeners.
@@ -130,10 +140,17 @@ class ServerPlugin implements Plugin {
   ExtensionPoint indexContributorExtensionPoint;
 
   /**
-   * The extension point that allows plugins to register navigation contributors.
+   * The extension point that allows plugins to register navigation
+   * contributors.
    */
   ExtensionPoint navigationContributorExtensionPoint;
 
+  /**
+   * The extension point that allows plugins to register occurrences
+   * contributors.
+   */
+  ExtensionPoint occurrencesContributorExtensionPoint;
+
   /**
    * The extension point that allows plugins to get access to the `analysis`
    * domain.
@@ -186,6 +203,13 @@ class ServerPlugin implements Plugin {
   List<NavigationContributor> get navigationContributors =>
       navigationContributorExtensionPoint.extensions;
 
+  /**
+   * Return a list containing all of the occurrences contributors that were
+   * contributed.
+   */
+  List<OccurrencesContributor> get occurrencesContributors =>
+      occurrencesContributorExtensionPoint.extensions;
+
   /**
    * Return a list containing all of the receivers of the `analysis` domain
    * instance.
@@ -231,6 +255,9 @@ class ServerPlugin implements Plugin {
     navigationContributorExtensionPoint = registerExtensionPoint(
         NAVIGATION_CONTRIBUTOR_EXTENSION_POINT,
         _validateNavigationContributorExtension);
+    occurrencesContributorExtensionPoint = registerExtensionPoint(
+        OCCURRENCES_CONTRIBUTOR_EXTENSION_POINT,
+        _validateOccurrencesContributorExtension);
   }
 
   @override
@@ -253,10 +280,12 @@ class ServerPlugin implements Plugin {
     // TODO(brianwilkerson) Register the completion contributors.
 //    registerExtension(COMPLETION_CONTRIBUTOR_EXTENSION_POINT_ID, ???);
     //
-    // Register navigation contributors.
+    // Register analysis contributors.
     //
     registerExtension(NAVIGATION_CONTRIBUTOR_EXTENSION_POINT_ID,
         new DartNavigationComputer());
+    registerExtension(OCCURRENCES_CONTRIBUTOR_EXTENSION_POINT_ID,
+        new DartOccurrencesComputer());
     //
     // Register domains.
     //
@@ -367,6 +396,18 @@ class ServerPlugin implements Plugin {
     }
   }
 
+  /**
+   * Validate the given extension by throwing an [ExtensionError] if it is not a
+   * valid occurrences contributor.
+   */
+  void _validateOccurrencesContributorExtension(Object extension) {
+    if (extension is! OccurrencesContributor) {
+      String id = occurrencesContributorExtensionPoint.uniqueIdentifier;
+      throw new ExtensionError(
+          'Extensions to $id must be an OccurrencesContributor');
+    }
+  }
+
   /**
    * Validate the given extension by throwing an [ExtensionError] if it is not a
    * valid analysis domain receiver.

pkg/analysis_server/test/plugin/set_analysis_domain_test.dart

@@ -7,8 +7,10 @@ library test.plugin.analysis_contributor;
 import 'dart:async';
 
 import 'package:analysis_server/analysis/analysis_domain.dart';
-import 'package:analysis_server/analysis/navigation/navigation_core.dart';
+import 'package:analysis_server/analysis/navigation_core.dart';
+import 'package:analysis_server/analysis/occurrences_core.dart';
 import 'package:analysis_server/plugin/navigation.dart';
+import 'package:analysis_server/plugin/occurrences.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analyzer/src/generated/engine.dart';
@@ -38,9 +40,8 @@ main() {
 class SetAnalysisDomainTest extends AbstractAnalysisTest {
   final Set<String> parsedUnitFiles = new Set<String>();
 
-  List<NavigationRegion> regions;
-  List<NavigationTarget> targets;
-  List<String> targetFiles;
+  AnalysisNavigationParams navigationParams;
+  AnalysisOccurrencesParams occurrencesParams;
 
   @override
   void addServerPlugins(List<Plugin> plugins) {
@@ -53,9 +54,13 @@ class SetAnalysisDomainTest extends AbstractAnalysisTest {
     if (notification.event == ANALYSIS_NAVIGATION) {
       var params = new AnalysisNavigationParams.fromNotification(notification);
       if (params.file == testFile) {
-        regions = params.regions;
-        targets = params.targets;
-        targetFiles = params.files;
+        navigationParams = params;
+      }
+    }
+    if (notification.event == ANALYSIS_OCCURRENCES) {
+      var params = new AnalysisOccurrencesParams.fromNotification(notification);
+      if (params.file == testFile) {
+        occurrencesParams = params;
       }
     }
   }
@@ -63,27 +68,38 @@ class SetAnalysisDomainTest extends AbstractAnalysisTest {
   Future test_contributorIsInvoked() async {
     createProject();
     addAnalysisSubscription(AnalysisService.NAVIGATION, testFile);
+    addAnalysisSubscription(AnalysisService.OCCURRENCES, testFile);
     addTestFile('// usually no navigation');
     await server.onAnalysisComplete;
     // we have PARSED_UNIT
     expect(parsedUnitFiles, contains(testFile));
     // we have an additional navigation region/target
-    expect(regions, hasLength(1));
     {
-      NavigationRegion region = regions.single;
-      expect(region.offset, 1);
-      expect(region.length, 5);
-      expect(region.targets.single, 0);
+      expect(navigationParams.regions, hasLength(1));
+      {
+        NavigationRegion region = navigationParams.regions.single;
+        expect(region.offset, 1);
+        expect(region.length, 5);
+        expect(region.targets.single, 0);
+      }
+      {
+        NavigationTarget target = navigationParams.targets.single;
+        expect(target.fileIndex, 0);
+        expect(target.offset, 1);
+        expect(target.length, 2);
+        expect(target.startLine, 3);
+        expect(target.startColumn, 4);
+      }
+      expect(navigationParams.files.single, '/testLocation.dart');
     }
+    // we have additional occurrences
     {
-      NavigationTarget target = targets.single;
-      expect(target.fileIndex, 0);
-      expect(target.offset, 1);
-      expect(target.length, 2);
-      expect(target.startLine, 3);
-      expect(target.startColumn, 4);
+      expect(occurrencesParams.occurrences, hasLength(1));
+      Occurrences occurrences = occurrencesParams.occurrences.single;
+      expect(occurrences.element.name, 'TestElement');
+      expect(occurrences.length, 5);
+      expect(occurrences.offsets, unorderedEquals([1, 2, 3]));
     }
-    expect(targetFiles.single, '/testLocation.dart');
   }
 }
 
@@ -100,6 +116,19 @@ class TestNavigationContributor implements NavigationContributor {
   }
 }
 
+class TestOccurrencesContributor implements OccurrencesContributor {
+  final SetAnalysisDomainTest test;
+
+  TestOccurrencesContributor(this.test);
+
+  @override
+  void computeOccurrences(
+      OccurrencesCollector collector, AnalysisContext context, Source source) {
+    collector.addOccurrences(new Occurrences(
+        new Element(ElementKind.UNKNOWN, 'TestElement', 0), <int>[1, 2, 3], 5));
+  }
+}
+
 class TestSetAnalysisDomainPlugin implements Plugin {
   final SetAnalysisDomainTest test;
 
@@ -116,6 +145,8 @@ class TestSetAnalysisDomainPlugin implements Plugin {
     register(SET_ANALYSIS_DOMAIN_EXTENSION_POINT_ID, _setAnalysisDomain);
     register(NAVIGATION_CONTRIBUTOR_EXTENSION_POINT_ID,
         new TestNavigationContributor(test));
+    register(OCCURRENCES_CONTRIBUTOR_EXTENSION_POINT_ID,
+        new TestOccurrencesContributor(test));
   }
 
   void _setAnalysisDomain(AnalysisDomain domain) {
@@ -127,6 +158,8 @@ class TestSetAnalysisDomainPlugin implements Plugin {
       test.parsedUnitFiles.add(source.fullName);
       domain.scheduleNotification(
           result.context, source, AnalysisService.NAVIGATION);
+      domain.scheduleNotification(
+          result.context, source, AnalysisService.OCCURRENCES);
     });
   }
 }