Merge branch 'nashorn'

Java 8 removed the Rhino implementation of JavaScript
in favor of the newer, faster, better, shinier, and
backwards-incompatible Nashorn implementation.

Fortunately, Nashorn provides a backwards compatibility
script called mozilla_compat.js which we can source to
regain the most common Mozilla-specific behavior.

Fixes imagej/ImageJ#116.

src/main/java/org/scijava/plugins/scripting/javascript/JavaScriptScriptLanguage.java

@@ -59,18 +59,47 @@ public JavaScriptScriptLanguage() {
 		super("javascript");
 	}
 
+	// -- JavaScriptScriptLanguage methods --
+
+	/**
+	 * Returns true iff this script language is using the <a
+	 * href="http://openjdk.java.net/projects/nashorn/">Nashorn</a> JavaScript
+	 * engine. This is the case for Java 8.
+	 */
+	public boolean isNashorn() {
+		return getEngineName().contains("Nashorn");
+	}
+
+	/**
+	 * Returns true iff this script language is using the <a
+	 * href="https://developer.mozilla.org/en-US/docs/Mozilla/Projects/Rhino"
+	 * >Rhino</a> JavaScript engine. This is the case for Java 6 and Java 7.
+	 */
+	public boolean isRhino() {
+		return getEngineName().contains("Rhino");
+	}
+
+	// -- ScriptEngineFactory methods --
+
 	@Override
 	public ScriptEngine getScriptEngine() {
 		final ScriptEngine engine = super.getScriptEngine();
 		try {
-			engine.eval("function load(path) {\n"
-					+ "  importClass(Packages.sun.org.mozilla.javascript.internal.Context);\n"
-					+ "  importClass(Packages.java.io.FileReader);\n"
-					+ "  var cx = Context.getCurrentContext();\n"
-					+ "  cx.evaluateReader(this, new FileReader(path), path, 1, null);\n"
-					+ "}");
+			if (isNashorn()) {
+				// for Rhino compatibility, importClass and importPackage in particular
+				engine.eval("load(\"nashorn:mozilla_compat.js\");");
+			}
+			if (isRhino()) {
+				// for the load function, which is somehow otherwise unavailable (?)
+				engine.eval("function load(path) {\n" +
+					"  importClass(Packages." + contextClass(engine) + ");\n" +
+					"  importClass(Packages.java.io.FileReader);\n" +
+					"  var cx = Context.getCurrentContext();\n" +
+					"  cx.evaluateReader(this, new FileReader(path), path, 1, null);\n" +
+					"}");
+			}
 		}
-		catch (ScriptException e) {
+		catch (final ScriptException e) {
 			e.printStackTrace();
 		}
 		return engine;
@@ -112,4 +141,24 @@ public Object decode(final Object object) {
 		return null;
 	}
 
+	// -- Helper methods --
+
+	private String contextClass(final ScriptEngine engine) {
+		if (isNashorn()) return "jdk.nashorn.internal.runtime.Context";
+
+		final String engineClassName = engine.getClass().getName();
+
+		if (isRhino()) {
+			if (engineClassName.startsWith("com.sun.")) {
+				// assume JDK-flavored Rhino script engine
+				return "sun.org.mozilla.javascript.internal.Context";
+			}
+			// assume vanilla Mozilla-flavored Rhino script engine
+			return "org.mozilla.javascript.Context";
+		}
+
+		throw new UnsupportedOperationException("Unknown JavaScript flavor: " +
+			engineClassName);
+	}
+
 }

src/test/java/org/scijava/plugins/scripting/javascript/JavaScriptTest.java

@@ -67,10 +67,7 @@ public void testBasic() throws InterruptedException, ExecutionException,
 		final Context context = new Context(ScriptService.class);
 		final ScriptService scriptService = context.getService(ScriptService.class);
 		final String script = "$x = 1 + 2;";
-		// NB: Some JVMs return Integer, others Double. Let's be careful here.
-		final ScriptModule m = scriptService.run("add.js", script, true).get();
-		final Number result = (Number) m.getReturnValue();
-		assertEquals(3.0, result.doubleValue(), 0.0);
+		assertResult(3.0, scriptService.run("add.js", script, true).get());
 	}
 
 	@Test
@@ -80,7 +77,9 @@ public void testLocals() throws ScriptException {
 
 		final ScriptLanguage language = scriptService.getLanguageByExtension("js");
 		final ScriptEngine engine = language.getScriptEngine();
-		assertTrue(engine.getClass().getName().endsWith(".RhinoScriptEngine"));
+		final String engineClassName = engine.getClass().getName();
+		assertTrue(engineClassName.endsWith(".RhinoScriptEngine") ||
+			engineClassName.endsWith(".NashornScriptEngine"));
 		engine.put("$hello", 17);
 		assertEquals("17", engine.eval("$hello").toString());
 		assertEquals("17", engine.get("$hello").toString());
@@ -122,8 +121,32 @@ public void testLoad() throws IOException, InterruptedException, ExecutionExcept
 		final Context context = new Context(ScriptService.class);
 		final ScriptService scriptService = context.getService(ScriptService.class);
 		final String script = "load('" + tmp.getPath() + "'); three();";
-		final Object result = scriptService.run("three.js", script, false).get().getReturnValue();
-		assertEquals(4.0, (Number) result);
+		assertResult(4.0, scriptService.run("three.js", script, false).get());
 		assertTrue(tmp.delete());
 	}
+
+	@Test
+	public void testJavaAPI() throws InterruptedException, ExecutionException,
+		IOException, ScriptException
+	{
+		final Context context = new Context(ScriptService.class);
+		final ScriptService scriptService = context.getService(ScriptService.class);
+		final String script = //
+			"importClass(Packages.java.util.ArrayList);\n" //
+				+ "var list = new ArrayList();\n" //
+				+ "list.add(3);\n" //
+				+ "list.add(5.5);\n" //
+				+ "list.add(7);\n" //
+				+ "list.get(1);\n";
+		assertResult(5.5, scriptService.run("javaAPI.js", script, true).get());
+	}
+
+	// -- Helper methods --
+
+	private void assertResult(final double expected, final ScriptModule m) {
+		// NB: Some JVMs return Integer, others Double. Let's be careful here.
+		final Number result = (Number) m.getReturnValue();
+		assertEquals(expected, result.doubleValue(), 0.0);
+	}
+
 }