Some nullability and documentation cleanup in package io.flutter.dart

flutter-idea/src/io/flutter/dart/DartPlugin.java

@@ -19,7 +19,14 @@
 import org.jetbrains.annotations.Nullable;
 
 /**
- * Provides access to the Dart Plugin for IntelliJ.
+ * A service component that manages Dart plugin functionality within IntelliJ IDEA.
+ * <p>
+ * This class provides project-level services for Dart integration, including version
+ * management and feature compatibility checks. It acts as a central point for
+ * accessing Dart plugin capabilities and configurations within a project.
+ * <p>
+ * The service is automatically instantiated by the IntelliJ Platform on a per-project
+ * basis and can be accessed via getInstance(Project).
  */
 public class DartPlugin {
 
@@ -64,9 +71,13 @@ public static boolean isDartTestConfiguration(@NotNull ConfigurationType type) {
     return type.getId().equals("DartTestRunConfigurationType");
   }
 
+  /**
+   * Returns the version of the Dart plugin installed in the IDE.
+   */
+  @NotNull
   public static DartPluginVersion getDartPluginVersion() {
     final IdeaPluginDescriptor dartPlugin = PluginManagerCore.getPlugin(PluginId.getId("Dart"));
-    final String versionString = dartPlugin.getVersion();
+    final String versionString = dartPlugin != null ? dartPlugin.getVersion() : null;
     return new DartPluginVersion(versionString);
   }
 

flutter-idea/src/io/flutter/dart/DartPluginVersion.java

@@ -9,6 +9,15 @@
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+/**
+ * Represents and manages Dart plugin version information.
+ * This class provides functionality to parse, compare, and check compatibility
+ * of different Dart plugin versions. It supports version-specific feature
+ * detection, such as determining if a particular version supports the property editor.
+ * <p>
+ * Versions can be compared using standard comparison operators through the
+ * {@link Comparable} interface implementation.
+ */
 public class DartPluginVersion implements Comparable<DartPluginVersion> {
 
   @Nullable
@@ -19,28 +28,27 @@ public class DartPluginVersion implements Comparable<DartPluginVersion> {
 
   public DartPluginVersion(@Nullable String versionString) {
     rawVersionString = versionString;
-    version = Version.parseVersion(versionString);
+    version = versionString == null ? null : Version.parseVersion(versionString);
   }
 
   @Override
   public int compareTo(@NotNull DartPluginVersion otherVersion) {
-    if (rawVersionString == null) return -1;
-    if (otherVersion.rawVersionString == null) return 1;
+    if (rawVersionString == null || version == null) return -1;
+    if (otherVersion.rawVersionString == null || otherVersion.version == null) return 1;
     return version.compareTo(otherVersion.version);
   }
 
   public boolean supportsPropertyEditor() {
-    if (version == null) return false;
+    if (version == null) {
+      return false;
+    }
     final int major = version.major;
-
     if (major == 243) {
       return this.compareTo(new DartPluginVersion("243.26753.1")) >= 0;
-    }
-
-    if (major == 251) {
+    } else if (major == 251) {
       return this.compareTo(new DartPluginVersion("251.23774.318")) >= 0;
+    } else {
+      return major >= 244;
     }
-
-    return major >= 244;
   }
 }

flutter-idea/src/io/flutter/dart/DartPsiUtil.java

@@ -17,8 +17,26 @@
 
 import java.util.List;
 
+/**
+ * Utility class for working with Dart PSI (Program Structure Interface) elements.
+ * <p>
+ * This class provides helper methods for analyzing and manipulating the PSI tree
+ * of Dart files. It contains utility functions for common operations on Dart
+ * language constructs, making it easier to work with the syntactic and semantic
+ * structure of Dart code.
+ * <p>
+ * PSI elements represent the structure of the source code in the IntelliJ Platform,
+ * and this utility class helps plugin developers interact with Dart-specific PSI
+ * elements in a more convenient way.
+ * <p>
+ * All methods in this class are static as this is a utility class.
+ */
 public class DartPsiUtil {
 
+  private DartPsiUtil() {
+    throw new AssertionError("No instances.");
+  }
+
   public static int parseLiteralNumber(@NotNull String val) throws NumberFormatException {
     return val.startsWith("0x") || val.startsWith("0X")
            ? Integer.parseUnsignedInt(val.substring(2), 16)

flutter-idea/src/io/flutter/dart/DartSyntax.java

@@ -17,10 +17,26 @@
 import java.util.regex.Pattern;
 
 /**
- * Finds Dart PSI elements in IntelliJ's syntax tree.
+ * Constants and utility methods for working with Dart language syntax.
+ * <p>
+ * This class provides a collection of common Dart syntax elements, patterns,
+ * and keywords used throughout the plugin. It serves as a central repository
+ * for syntax-related constants and helper methods to ensure consistency in
+ * Dart code analysis and manipulation.
+ * <p>
+ * The class includes regular expressions, common syntax patterns, and utility
+ * methods for identifying and working with various Dart language constructs.
+ * This helps maintain consistency across the plugin when dealing with Dart
+ * syntax elements.
+ * <p>
+ * All members in this class are static as this is a utility class.
  */
 public class DartSyntax {
 
+  private DartSyntax() {
+    throw new AssertionError("No instances.");
+  }
+
   /**
    * Finds the enclosing function call where the function being called has the given name.
    * <p>

flutter-idea/src/io/flutter/dart/FlutterDartAnalysisServer.java

@@ -81,7 +81,7 @@ public FlutterDartAnalysisServer(@NotNull Project project) {
 
       @Override
       public void serverConnected(String s) {
-        // If the server reconnected we need to let it know that we still care
+        // If the server reconnected, we need to let it know that we still care
         // about our subscriptions.
         if (!subscriptions.isEmpty()) {
           sendSubscriptions();
@@ -233,7 +233,7 @@ private void processResponse(@Nullable JsonObject response) {
    */
   @SuppressWarnings("DataFlowIssue") // Ignore for de-marshalling JSON objects.
   private void processNotification(JsonObject response, @NotNull JsonElement eventName) {
-    // If we add code to handle more event types below, update the filter in processString().
+    // If we add code to handle the more event types below, update the filter in processString().
     final String event = eventName.getAsString();
     if (Objects.equals(event, FLUTTER_NOTIFICATION_OUTLINE)) {
       final JsonObject paramsObject = response.get("params").getAsJsonObject();

flutter-idea/src/io/flutter/dart/FlutterRequestUtilities.java

@@ -17,7 +17,7 @@
 import java.util.Map;
 
 /**
- * A utilities class for generating analysis server json requests.
+ * Utility class for generating analysis server json requests.
  */
 public class FlutterRequestUtilities {
   private static final String FILE = "file";
@@ -34,6 +34,7 @@ public class FlutterRequestUtilities {
   private static final String METHOD_FLUTTER_SET_WIDGET_PROPERTY_VALUE = "flutter.setWidgetPropertyValue";
 
   private FlutterRequestUtilities() {
+    throw new AssertionError("No instances.");
   }
 
   public static JsonObject generateFlutterGetWidgetDescription(String id, String file, int offset) {
@@ -130,9 +131,10 @@ private static JsonObject buildJsonObjectRequest(String idValue, String methodVa
   }
 
   /**
-   * Return the name of the given object, may be {@code "null"} string.
+   * Return the name of the given object, may be {@code "null"} String.
    */
+  @NotNull
   private static String getClassName(Object object) {
-    return object != null ? object.getClass().getName() : "null";
+    return object != null && object.getClass().getName() != null ? object.getClass().getName() : "null";
   }
 }

flutter-idea/src/io/flutter/propertyeditor/PropertyEditorViewFactory.java

@@ -45,8 +45,8 @@ public void createToolWindowContent(@NotNull Project project, @NotNull ToolWindo
     FlutterSdk sdk = FlutterSdk.getFlutterSdk(project);
     FlutterSdkVersion sdkVersion = sdk == null ? null : sdk.getVersion();
 
-    DartPluginVersion dartPluginVersion = DartPlugin.getDartPluginVersion();
-    if (!dartPluginVersion.supportsPropertyEditor()) {
+    final DartPluginVersion dartPluginVersion = DartPlugin.getDartPluginVersion();
+    if (dartPluginVersion == null || !dartPluginVersion.supportsPropertyEditor()) {
       viewUtils.presentLabel(toolWindow, "Flutter Property Editor requires a newer version of the Dart plugin.");
       return;
     }