Java Code Examples for javax.script.Invocable#getInterface()

public static void main(final String[] args) throws Exception {
    final ScriptEngineManager manager = new ScriptEngineManager();
    final ScriptEngine engine = manager.getEngineByName("nashorn");

    // JavaScript code in a String
    final String script = "function run() { print('run called'); }";

    // evaluate script
    engine.eval(script);

    final Invocable inv = (Invocable) engine;

    // get Runnable interface object from engine. This interface methods
    // are implemented by script functions with the matching name.
    final Runnable r = inv.getInterface(Runnable.class);

    // start a new thread that runs the script implemented
    // runnable interface
    final Thread th = new Thread(r);
    th.start();
    th.join();
}
 

public static void main(final String[] args) throws Exception {
    final ScriptEngineManager manager = new ScriptEngineManager();
    final ScriptEngine engine = manager.getEngineByName("nashorn");

    // JavaScript code in a String
    final String script = "function run() { print('run called'); }";

    // evaluate script
    engine.eval(script);

    final Invocable inv = (Invocable) engine;

    // get Runnable interface object from engine. This interface methods
    // are implemented by script functions with the matching name.
    final Runnable r = inv.getInterface(Runnable.class);

    // start a new thread that runs the script implemented
    // runnable interface
    final Thread th = new Thread(r);
    th.start();
    th.join();
}
 

public static void main(final String[] args) throws Exception {
    final ScriptEngineManager manager = new ScriptEngineManager();
    final ScriptEngine engine = manager.getEngineByName("nashorn");

    // JavaScript code in a String
    final String script = "function run() { print('run called'); }";

    // evaluate script
    engine.eval(script);

    final Invocable inv = (Invocable) engine;

    // get Runnable interface object from engine. This interface methods
    // are implemented by script functions with the matching name.
    final Runnable r = inv.getInterface(Runnable.class);

    // start a new thread that runs the script implemented
    // runnable interface
    final Thread th = new Thread(r);
    th.start();
    th.join();
}
 

public static void main(final String[] args) throws Exception {
    final ScriptEngineManager manager = new ScriptEngineManager();
    final ScriptEngine engine = manager.getEngineByName("nashorn");

    // JavaScript code in a String
    final String script = "function run() { print('run called'); }";

    // evaluate script
    engine.eval(script);

    final Invocable inv = (Invocable) engine;

    // get Runnable interface object from engine. This interface methods
    // are implemented by script functions with the matching name.
    final Runnable r = inv.getInterface(Runnable.class);

    // start a new thread that runs the script implemented
    // runnable interface
    final Thread th = new Thread(r);
    th.start();
    th.join();
}
 

@Test
public void pythonFn() throws Exception {
    ScriptEngine python = Scripting.createManager().getEngineByMimeType("text/x-python");
    assumeNotNull("Need python", python);
    Object rawMul = python.eval(MUL);
    assertNotNull("mul created", rawMul);
    assertTrue("Engines are invocable: " + python, python instanceof Invocable);
    final Invocable inv = (Invocable)python;

    Object res = inv.invokeFunction("mul", 6, 7);
    assertNotNull("Expecting non-null", res);

    assertTrue("Expecting number: " + res + " type: " + res.getClass(), res instanceof Number);
    assertEquals(42, ((Number)res).intValue());

    Mul mul = inv.getInterface(rawMul, Mul.class);
    assertEquals(42, mul.multiplyTwoNumbers(7, 6));
}
 

public static void main(final String[] args) throws Exception {
    final ScriptEngineManager manager = new ScriptEngineManager();
    final ScriptEngine engine = manager.getEngineByName("nashorn");

    // JavaScript code in a String
    final String script = "var obj = new Object(); obj.run = function() { print('run method called'); }";

    // evaluate script
    engine.eval(script);

    // get script object on which we want to implement the interface with
    final Object obj = engine.get("obj");

    final Invocable inv = (Invocable) engine;

    // get Runnable interface object from engine. This interface methods
    // are implemented by script methods of object 'obj'
    final Runnable r = inv.getInterface(obj, Runnable.class);

    // start a new thread that runs the script implemented
    // runnable interface
    final Thread th = new Thread(r);
    th.start();
    th.join();
}
 

public static void main(final String[] args) throws Exception {
    final ScriptEngineManager manager = new ScriptEngineManager();
    final ScriptEngine engine = manager.getEngineByName("nashorn");

    // JavaScript code in a String
    final String script = "function run() { print('run called'); }";

    // evaluate script
    engine.eval(script);

    final Invocable inv = (Invocable) engine;

    // get Runnable interface object from engine. This interface methods
    // are implemented by script functions with the matching name.
    final Runnable r = inv.getInterface(Runnable.class);

    // start a new thread that runs the script implemented
    // runnable interface
    final Thread th = new Thread(r);
    th.start();
    th.join();
}
 

public static void main(final String[] args) throws Exception {
    final ScriptEngineManager manager = new ScriptEngineManager();
    final ScriptEngine engine = manager.getEngineByName("nashorn");

    // JavaScript code in a String
    final String script = "function run() { print('run called'); }";

    // evaluate script
    engine.eval(script);

    final Invocable inv = (Invocable) engine;

    // get Runnable interface object from engine. This interface methods
    // are implemented by script functions with the matching name.
    final Runnable r = inv.getInterface(Runnable.class);

    // start a new thread that runs the script implemented
    // runnable interface
    final Thread th = new Thread(r);
    th.start();
    th.join();
}
 

@Test
public void defaultMethodTest() throws ScriptException {
    final ScriptEngineManager m = new ScriptEngineManager();
    final ScriptEngine e = m.getEngineByName("nashorn");
    final Invocable inv = (Invocable) e;

    final Object obj = e.eval("({ apply: function(arg) { return arg.toUpperCase(); }})");
    @SuppressWarnings("unchecked")
    final Function<String, String> func = inv.getInterface(obj, Function.class);
    assertEquals(func.apply("hello"), "HELLO");
}
 

@Nullable
protected Object adaptToInterfaces(
		@Nullable Object script, ScriptSource scriptSource, Class<?>... actualInterfaces) {

	Class<?> adaptedIfc;
	if (actualInterfaces.length == 1) {
		adaptedIfc = actualInterfaces[0];
	}
	else {
		adaptedIfc = ClassUtils.createCompositeInterface(actualInterfaces, this.beanClassLoader);
	}

	if (adaptedIfc != null) {
		ScriptEngine scriptEngine = this.scriptEngine;
		if (!(scriptEngine instanceof Invocable)) {
			throw new ScriptCompilationException(scriptSource,
					"ScriptEngine must implement Invocable in order to adapt it to an interface: " + scriptEngine);
		}
		Invocable invocable = (Invocable) scriptEngine;
		if (script != null) {
			script = invocable.getInterface(script, adaptedIfc);
		}
		if (script == null) {
			script = invocable.getInterface(adaptedIfc);
			if (script == null) {
				throw new ScriptCompilationException(scriptSource,
						"Could not adapt script to interface [" + adaptedIfc.getName() + "]");
			}
		}
	}

	return script;
}
 

@Test
public void mirrorUnwrapInterfaceMethod() throws Exception {
    final ScriptEngineManager engineManager = new ScriptEngineManager();
    final ScriptEngine engine = engineManager.getEngineByName("nashorn");
    final Invocable invocable = (Invocable)engine;
    engine.eval("function apply(obj) { " +
        " return obj instanceof Packages.jdk.nashorn.api.scripting.ScriptObjectMirror; " +
        "}");
    @SuppressWarnings("unchecked")
    final Function<Object,Object> func = invocable.getInterface(Function.class);
    assertFalse((boolean)func.apply(engine.eval("({ x: 2 })")));
}
 

@Test
public void checkMirrorToObject() throws Exception {
    final ScriptEngineManager engineManager = new ScriptEngineManager();
    final ScriptEngine engine = engineManager.getEngineByName("nashorn");
    final Invocable invocable = (Invocable)engine;

    engine.eval("function test1(arg) { return { arg: arg }; }");
    engine.eval("function test2(arg) { return arg; }");
    engine.eval("function compare(arg1, arg2) { return arg1 == arg2; }");

    final Map<String, Object> map = new HashMap<>();
    map.put("option", true);

    final MirrorCheckExample example = invocable.getInterface(MirrorCheckExample.class);

    final Object value1 = invocable.invokeFunction("test1", map);
    final Object value2 = example.test1(map);
    final Object value3 = invocable.invokeFunction("test2", value2);
    final Object value4 = example.test2(value2);

    // check that Object type argument receives a ScriptObjectMirror
    // when ScriptObject is passed
    assertEquals(ScriptObjectMirror.class, value1.getClass());
    assertEquals(ScriptObjectMirror.class, value2.getClass());
    assertEquals(ScriptObjectMirror.class, value3.getClass());
    assertEquals(ScriptObjectMirror.class, value4.getClass());
    assertTrue((boolean)invocable.invokeFunction("compare", value1, value1));
    assertTrue(example.compare(value1, value1));
    assertTrue((boolean)invocable.invokeFunction("compare", value3, value4));
    assertTrue(example.compare(value3, value4));
}
 

@Test
public void defaultMethodTest() throws ScriptException {
    final ScriptEngineManager m = new ScriptEngineManager();
    final ScriptEngine e = m.getEngineByName("nashorn");
    final Invocable inv = (Invocable) e;

    final Object obj = e.eval("({ apply: function(arg) { return arg.toUpperCase(); }})");
    @SuppressWarnings("unchecked")
    final Function<String, String> func = inv.getInterface(obj, Function.class);
    assertEquals(func.apply("hello"), "HELLO");
}
 

@Test
public void checkMirrorToObject() throws Exception {
    final ScriptEngineManager engineManager = new ScriptEngineManager();
    final ScriptEngine engine = engineManager.getEngineByName("nashorn");
    final Invocable invocable = (Invocable)engine;

    engine.eval("function test1(arg) { return { arg: arg }; }");
    engine.eval("function test2(arg) { return arg; }");
    engine.eval("function compare(arg1, arg2) { return arg1 == arg2; }");

    final Map<String, Object> map = new HashMap<>();
    map.put("option", true);

    final MirrorCheckExample example = invocable.getInterface(MirrorCheckExample.class);

    final Object value1 = invocable.invokeFunction("test1", map);
    final Object value2 = example.test1(map);
    final Object value3 = invocable.invokeFunction("test2", value2);
    final Object value4 = example.test2(value2);

    // check that Object type argument receives a ScriptObjectMirror
    // when ScriptObject is passed
    assertEquals(ScriptObjectMirror.class, value1.getClass());
    assertEquals(ScriptObjectMirror.class, value2.getClass());
    assertEquals(ScriptObjectMirror.class, value3.getClass());
    assertEquals(ScriptObjectMirror.class, value4.getClass());
    assertTrue((boolean)invocable.invokeFunction("compare", value1, value1));
    assertTrue(example.compare(value1, value1));
    assertTrue((boolean)invocable.invokeFunction("compare", value3, value4));
    assertTrue(example.compare(value3, value4));
}
 

@Test
public void mirrorUnwrapInterfaceMethod() throws Exception {
    final ScriptEngineManager engineManager = new ScriptEngineManager();
    final ScriptEngine engine = engineManager.getEngineByName("nashorn");
    final Invocable invocable = (Invocable)engine;
    engine.eval("function apply(obj) { " +
        " return obj instanceof Packages.jdk.nashorn.api.scripting.ScriptObjectMirror; " +
        "}");
    @SuppressWarnings("unchecked")
    final Function<Object,Object> func = invocable.getInterface(Function.class);
    assertFalse((boolean)func.apply(engine.eval("({ x: 2 })")));
}
 

@Test
public void returnArrayInPython() throws Exception {
    ScriptEngine python = Scripting.createManager().getEngineByMimeType("text/x-python");
    assumeNotNull("Need python", python);
    python.eval("\n"
            + "import math\n"
            + "\n"
            + "def arr(x):\n"
            + "  return [ 1, 2, 'a', math.pi, x ]\n"
            + "\n"
    );

    assertTrue("Engines are invocable: " + python, python instanceof Invocable);
    final Invocable inv = (Invocable)python;

    Sum sum = new Sum();
    Object raw = inv.invokeFunction("arr", sum);

    List<?> list = inv.getInterface(raw, List.class);
    assertNotNull("List " + list, list);
    assertEquals("Length of five", 5, list.size());

    List<?> list2 = inv.getInterface(list, List.class);
    assertNotNull("List 2 " + list2, list2);
    assertEquals("Length 2 of five", 5, list2.size());

    assertEquals(1, list.get(0));
    assertEquals(2, list.get(1));
    assertEquals("a", list.get(2));
    assertEquals(Math.PI, list.get(3));
    assertEquals(sum, list.get(4));
}
 

public static HttpHandler instantiate(Path scriptFile) {
    ScriptEngineManager sem = new ScriptEngineManager();
    ScriptEngine engine = sem.getEngineByName("javascript");
    try {
        engine.eval(new FileReader(scriptFile.toFile()));
    } catch (ScriptException | FileNotFoundException ex) {
        throw new IllegalStateException(ex);
    }
    Invocable invocable = (Invocable) engine;
    NanoRequest request = invocable.getInterface(NanoRequest.class);

    return (HttpExchange he) -> {
        final OutputStream responseBody = he.getResponseBody();
        StringBuilder builder = new StringBuilder();
        ResponseWriter writer = builder::append;
        final InputStream requestBody = he.getRequestBody();
        String requestContent;
        try (BufferedReader buffer = new BufferedReader(new InputStreamReader(requestBody))) {
            requestContent = buffer.lines().collect(Collectors.joining("\n"));
        }
        Headers requestHeaders = he.getRequestHeaders();
        Headers responseHeaders = he.getResponseHeaders();
        int statusCode = request.process(he.getRequestMethod(), requestHeaders, responseHeaders, requestContent, writer);
        String content = builder.toString();
        he.sendResponseHeaders(statusCode, content.length());
        responseBody.write(content.getBytes());
        responseBody.flush();
        he.close();
    };
}
 

public ColumnTransformer createFromScript(Reader script) {
    Invocable invocable = (Invocable) engine;
    try {
        if (scriptEngineBindings != null) {
            manager.getBindings().putAll(scriptEngineBindings);
        }
        engine.eval(script);
    } catch (ScriptException ex) {
        throw new IllegalStateException("Cannot evaluate script", ex);
    }
    return invocable.getInterface(ColumnTransformer.class);

}
 

public ColumnTransformer createFromScript(String script) {
    Invocable invocable = (Invocable) engine;
    try {
        if (scriptEngineBindings != null) {
            manager.getBindings().putAll(scriptEngineBindings);
        }
        engine.eval(script);
    } catch (ScriptException ex) {
        throw new IllegalStateException("Cannot evaluate script", ex);
    }
    return invocable.getInterface(ColumnTransformer.class);

}
 

public void callJavaScriptClassFactoryFromJava() throws Exception {
    String src = "\n"
        + "(function() {\n"
        + "  class JSIncrementor {\n"
        + "     constructor(init) {\n"
        + "       this.value = init;\n"
        + "     }\n"
        + "     inc() {\n"
        + "       return ++this.value;\n"
        + "     }\n"
        + "     dec() {\n"
        + "       return --this.value;\n"
        + "     }\n"
        + "  }\n"
        + "  return function(init) {\n"
        + "    return new JSIncrementor(init);\n"
        + "  }\n"
        + "})\n";

    // Evaluate JavaScript function definition
    Object jsFunction = engine.eval(src);

    final Invocable inv = (Invocable) engine;

    // Execute the JavaScript function
    Object jsFactory = inv.invokeMethod(jsFunction, "call");

    // Execute the JavaScript factory to create Java objects
    Incrementor initFive = inv.getInterface(
        inv.invokeMethod(jsFactory, "call", null, 5),
        Incrementor.class
    );
    Incrementor initTen = inv.getInterface(
        inv.invokeMethod(jsFactory, "call", null, 10),
        Incrementor.class
    );

    initFive.inc();
    assertEquals("Now at seven", 7, initFive.inc());

    initTen.dec();
    assertEquals("Now at eight", 8, initTen.dec());
    initTen.dec();

    assertEquals("Values are the same", initFive.value(), initTen.value());
}