/* * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /** * Provides the implementation of Nashorn script engine and * the runtime environment for programs written in ECMAScript 5.1. *

* Nashorn is a runtime environment for programs written in ECMAScript 5.1. *

* *

Usage

* * The recommended way to use Nashorn is through the * JSR-223 * "Scripting for the Java Platform" APIs found in the * {@link javax.script} package. Usually, you'll obtain a * {@link javax.script.ScriptEngine} instance for Nashorn using: *
import javax.script.*;
...
ScriptEngine nashornEngine = new ScriptEngineManager().getEngineByName("nashorn");
* * and then use it just as you would any other JSR-223 script engine. See * * {@code jdk.nashorn.api.scripting} package for details. *

Compatibility

* Nashorn is 100% compliant with the * ECMA-262 Standard, Edition 5.1. * It requires a Java Virtual Machine that implements the * * JSR-292 "Supporting Dynamically Typed Languages on the Java Platform" * specification (often referred to as "invokedynamic"), as well as * the already mentioned JSR-223. * *

Interoperability with the Java platform

* * In addition to being a 100% ECMAScript 5.1 runtime, Nashorn provides features * for interoperability of the ECMAScript programs with the Java platform. * In general, any Java object put into the script engine's context will be * visible from the script. In terms of the standard, such Java objects are not * considered "native objects", but rather "host objects", as defined in * section 4.3.8. This distinction allows certain semantical differences * in handling them compared to native objects. For most purposes, Java objects * behave just as native objects do: you can invoke their methods, get and set * their properties. In most cases, though, you can't add arbitrary properties * to them, nor can you remove existing properties. * *

Java collection handling

* * Native Java arrays and {@link java.util.List}s support indexed access to * their elements through the property accessors, and {@link java.util.Map}s * support both property and element access through both dot and square-bracket * property accessors, with the difference being that dot operator gives * precedence to object properties (its fields and properties defined as * {@code getXxx} and {@code setXxx} methods) while the square bracket * operator gives precedence to map elements. Native Java arrays expose * the {@code length} property. * *

ECMAScript primitive types

* * ECMAScript primitive types for number, string, and boolean are represented * with {@link java.lang.Number}, {@link java.lang.CharSequence}, and * {@link java.lang.Boolean} objects. While the most often used number type * is {@link java.lang.Double} and the most often used string type is * {@link java.lang.String}, don't rely on it as various internal optimizations * cause other subclasses of {@code Number} and internal implementations of * {@code CharSequence} to be used. * *

Type conversions

* * When a method on a Java object is invoked, the arguments are converted to * the formal parameter types of the Java method using all allowed ECMAScript * conversions. This can be surprising, as in general, conversions from string * to number will succeed according to Standard's section 9.3 "ToNumber" * and so on; string to boolean, number to boolean, Object to number, * Object to string all work. Note that if the Java method's declared parameter * type is {@code java.lang.Object}, Nashorn objects are passed without any * conversion whatsoever; specifically if the JavaScript value being passed * is of primitive string type, you can only rely on it being a * {@code java.lang.CharSequence}, and if the value is a number, you can only * rely on it being a {@code java.lang.Number}. If the Java method declared * parameter type is more specific (e.g. {@code java.lang.String} or * {@code java.lang.Double}), then Nashorn will of course ensure * the required type is passed. * *

SAM types

* * As a special extension when invoking Java methods, ECMAScript function * objects can be passed in place of an argument whose Java type is so-called * "single abstract method" or "SAM" type. While this name usually covers * single-method interfaces, Nashorn is a bit more versatile, and it * recognizes a type as a SAM type if all its abstract methods are * overloads of the same name, and it is either an interface, or it is an * abstract class with a no-arg constructor. The type itself must be public, * while the constructor and the methods can be either public or protected. * If there are multiple abstract overloads of the same name, the single * function will serve as the shared implementation for all of them, * and additionally it will also override any non-abstract methods of * the same name. This is done to be consistent with the fact that * ECMAScript does not have the concept of overloaded methods. * *

The {@code Java} object

* * Nashorn exposes a non-standard global object named {@code Java} that is * the primary API entry point into Java platform-specific functionality. * You can use it to create instances of Java classes, convert from Java arrays * to native arrays and back, and so on. * *

Other non-standard built-in objects

* * In addition to {@code Java}, Nashorn also exposes some other * non-standard built-in objects: * {@code JSAdapter}, {@code JavaImporter}, {@code Packages} * * @provides javax.script.ScriptEngineFactory * @moduleGraph * @since 9 */ module jdk.scripting.nashorn { requires java.logging; requires jdk.dynalink; requires transitive java.scripting; exports jdk.nashorn.api.scripting; exports jdk.nashorn.api.tree; exports jdk.nashorn.internal.runtime to jdk.scripting.nashorn.shell; exports jdk.nashorn.internal.objects to jdk.scripting.nashorn.shell; exports jdk.nashorn.tools to jdk.scripting.nashorn.shell; provides javax.script.ScriptEngineFactory with jdk.nashorn.api.scripting.NashornScriptEngineFactory; provides jdk.dynalink.linker.GuardingDynamicLinkerExporter with jdk.nashorn.api.linker.NashornLinkerExporter; }