Added graalvm native interop example calling dart->jvm->js (#34)

Author: jwill

.gitignore

@@ -82,3 +82,5 @@ yarn.lock
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
 !/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+/graalvm_test/build
+/graalvm_test_native_interop/build

graalvm_test_native_interop/.gitignore

@@ -0,0 +1,3 @@
+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/

graalvm_test_native_interop/README.md

@@ -0,0 +1,53 @@
+# GraalVM Test
+
+This is a sample command-line application demonstrating how to use Dart's Java Native Interface (JNI) packages 
+(`jni` and `jnigen`) to interoperate with Java code, specifically the GraalVM Polyglot API.
+
+The application initializes a Java Virtual Machine (JVM) within a Dart environment, loads the necessary GraalVM JAR 
+files, and then executes a simple JavaScript snippet using GraalVM's polyglot capabilities.
+
+## How it Works
+
+The core logic is in `bin/graalvm_test.dart`. It performs the following steps:
+
+1.  **Spawns a JVM**: It uses `Jni.spawn()` to start a JVM, providing the paths to the required GraalVM JAR files 
+located in the `mvn_jar` directory.
+2.  **Creates a Polyglot Context**: It creates a GraalVM `Context` for the JavaScript language.
+3.  **Executes JavaScript**: It evaluates a JavaScript string that defines a simple function.
+4.  **Interoperates**: It calls the JavaScript function from Dart, passing a string argument ("World") to it. 
+The JavaScript code then prints a message to the console.
+
+The Dart bindings for the GraalVM Polyglot API (`org.graalvm.polyglot.Context` and `org.graalvm.polyglot.Value`) are 
+generated by `jnigen` based on the configuration in `jnigen.yaml` and the Java source files in `mvn_java`.
+
+## Requirements
+
+*   Dart SDK
+*   Java Development Kit (JDK) 17
+
+## Setup
+
+1.  **Get dependencies**:
+    ```bash
+    dart pub get
+    ```
+
+2.  **Generate JNI bindings**:
+    This project uses `jnigen` to generate the Dart code for Java classes. 
+    Run the following command to generate the necessary files:
+    ```bash
+    dart run jni:setup
+    dart run jnigen:setup
+    dart run jnigen --config jnigen.yaml
+    ```
+    The underlying graalvm libraries require OpenJDK 17 or higher. 
+
+## Running the Application
+
+After completing the setup steps, run the application with the following command:
+
+```bash
+dart run bin/graalvm_test.dart
+```
+
+You should see output from both Dart and the executed JavaScript code in your console.

graalvm_test_native_interop/analysis_options.yaml

@@ -0,0 +1,30 @@
+# This file configures the static analysis results for your project (errors,
+# warnings, and lints).
+#
+# This enables the 'recommended' set of lints from `package:lints`.
+# This set helps identify many issues that may lead to problems when running
+# or consuming Dart code, and enforces writing Dart using a single, idiomatic
+# style and format.
+#
+# If you want a smaller set of lints you can change this to specify
+# 'package:lints/core.yaml'. These are just the most critical lints
+# (the recommended set includes the core lints).
+# The core lints are also what is used by pub.dev for scoring packages.
+
+include: package:lints/recommended.yaml
+
+# Uncomment the following section to specify additional rules.
+
+# linter:
+#   rules:
+#     - camel_case_types
+
+# analyzer:
+#   exclude:
+#     - path/to/excluded/files/**
+
+# For more information about the core and recommended set of lints, see
+# https://dart.dev/go/core-lints
+
+# For additional information about configuring this file, see
+# https://dart.dev/guides/language/analysis-options

graalvm_test_native_interop/bin/graalvm_test.dart

@@ -0,0 +1,35 @@
+import 'package:jni/jni.dart';
+import 'package:path/path.dart';
+import 'package:graalvm_test/graal/org/graalvm/polyglot/_package.dart' as graal;
+
+void main(List<String> arguments) {
+  Jni.spawn(
+    dylibDir: join('build', 'jni_libs'),
+    classPath: [
+      './mvn_jar/collections-24.2.2.jar',
+      './mvn_jar/icu4j-24.2.2.jar',
+      './mvn_jar/jniutils-24.2.2.jar',
+      './mvn_jar/js-language-24.2.2.jar',
+      './mvn_jar/nativebridge-24.2.2.jar',
+      './mvn_jar/nativeimage-24.2.2.jar',
+      './mvn_jar/polyglot-24.2.2.jar',
+      './mvn_jar/regex-24.2.2.jar',
+      './mvn_jar/truffle-api-24.2.2.jar',
+      './mvn_jar/truffle-compiler-24.2.2.jar',
+      './mvn_jar/truffle-enterprise-24.2.2.jar',
+      './mvn_jar/truffle-runtime-24.2.2.jar',
+      './mvn_jar/word-24.2.2.jar',
+      './mvn_jar/xz-24.2.2.jar'
+    ],
+  );
+
+  var jsCode = "(function myFun(param){console.log('Hello ' + param + ' from JS');})";
+
+  var langs = JArray.of(JString.type, ["js".toJString()]);
+  var context = graal.Context.create(langs);
+  var value = context?.eval$1("js".toJString(), jsCode.toJString());
+  print(value);
+  value?.execute(JArray.of(JString.type, ["World".toJString()]));
+  return;
+}
+

graalvm_test_native_interop/jnigen.yaml

@@ -0,0 +1,12 @@
+output:
+  dart:
+    path: lib/graal/
+
+classes:
+  - 'org.graalvm.polyglot.Context'
+  - 'org.graalvm.polyglot.Value'
+
+maven_downloads:
+  jar_only_deps:
+    - 'org.graalvm.polyglot:polyglot:24.2.1'
+    - 'org.graalvm.polyglot:js:24.2.2'

graalvm_test_native_interop/lib/graalvm_test.dart

@@ -0,0 +1,3 @@
+int calculate() {
+  return 6 * 7;
+}

graalvm_test_native_interop/pubspec.yaml

@@ -0,0 +1,17 @@
+name: graalvm_test
+description: A sample command-line application.
+version: 1.0.0
+# repository: https://github.com/my_org/my_repo
+
+environment:
+  sdk: ^3.10.0-36.0.dev
+
+# Add regular dependencies here.
+dependencies:
+  path: ^1.9.0
+  jni: ^0.14.2
+  jnigen: ^0.14.2
+
+dev_dependencies:
+  lints: ^6.0.0
+  test: ^1.25.6