/* * Copyright (c) 2005, 2006, 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. */ package javax.script; import java.io.Reader;import java.util.Map;import java.util.Set; /** * <code>ScriptEngine</code> is the fundamental interface whose methods must be * fully functional in every implementation of this specification. * <br><br> * These methods provide basic scripting functionality.  Applications written to this * simple interface are expected to work with minimal modifications in every implementation. * It includes methods that execute scripts, and ones that set and get values. * <br><br> * The values are key/value pairs of two types.  The first type of pairs consists of * those whose keys are reserved and defined in this specification or  by individual * implementations.  The values in the pairs with reserved keys have specified meanings. * <br><br> * The other type of pairs consists of those that create Java language Bindings, the values are * usually represented in scripts by the corresponding keys or by decorated forms of them. * * @author Mike Grogan * @since 1.6 */ public interface ScriptEngine  {     /**     * Reserved key for a named value that passes     * an array of positional arguments to a script.     */    public static final String ARGV="javax.script.argv";     /**     * Reserved key for a named value that is     * the name of the file being executed.     */    public static final String FILENAME = "javax.script.filename";     /**     * Reserved key for a named value that is     * the name of the <code>ScriptEngine</code> implementation.     */    public static final String ENGINE = "javax.script.engine";     /**     * Reserved key for a named value that identifies     * the version of the <code>ScriptEngine</code> implementation.     */    public static final String ENGINE_VERSION = "javax.script.engine_version";     /**     * Reserved key for a named value that identifies     * the short name of the scripting language.  The name is used by the     * <code>ScriptEngineManager</code> to locate a <code>ScriptEngine</code>     * with a given name in the <code>getEngineByName</code> method.     */    public static final String NAME = "javax.script.name";     /**     * Reserved key for a named value that is     * the full name of Scripting Language supported by the implementation.     */    public static final String LANGUAGE = "javax.script.language";     /**     * Reserved key for the named value that identifies     * the version of the scripting language supported by the implementation.     */    public static final String LANGUAGE_VERSION ="javax.script.language_version";      /**     * Causes the immediate execution of the script whose source is the String     * passed as the first argument.  The script may be reparsed or recompiled before     * execution.  State left in the engine from previous executions, including     * variable values and compiled procedures may be visible during this execution.     *     * @param script The script to be executed by the script engine.     *     * @param context A <code>ScriptContext</code> exposing sets of attributes in     * different scopes.  The meanings of the scopes <code>ScriptContext.GLOBAL_SCOPE</code>,     * and <code>ScriptContext.ENGINE_SCOPE</code> are defined in the specification.     * <br><br>     * The <code>ENGINE_SCOPE</code> <code>Bindings</code> of the <code>ScriptContext</code> contains the     * bindings of scripting variables to application objects to be used during this     * script execution.     *     *     * @return The value returned from the execution of the script.     *     * @throws ScriptException if an error occurrs in script. ScriptEngines should create and throw     * <code>ScriptException</code> wrappers for checked Exceptions thrown by underlying scripting     * implementations.     * @throws NullPointerException if either argument is null.     */    public Object eval(String script, ScriptContext context) throws ScriptException;      /**     * Same as <code>eval(String, ScriptContext)</code> where the source of the script     * is read from a <code>Reader</code>.     *     * @param reader The source of the script to be executed by the script engine.     *     * @param context The <code>ScriptContext</code> passed to the script engine.     *     * @return The value returned from the execution of the script.     *     * @throws ScriptException if an error occurrs in script.     * @throws NullPointerException if either argument is null.     */    public Object eval(Reader reader , ScriptContext context) throws ScriptException;     /**     * Executes the specified script.  The default <code>ScriptContext</code> for the <code>ScriptEngine</code>     * is used.     *     * @param script The script language source to be executed.     *     * @return The value returned from the execution of the script.     *     * @throws ScriptException if error occurrs in script.     * @throws NullPointerException if the argument is null.     */    public Object eval(String script) throws ScriptException;     /**     * Same as <code>eval(String)</code> except that the source of the script is     * provided as a <code>Reader</code>     *     * @param reader The source of the script.     *     * @return The value returned by the script.     *     * @throws ScriptException if an error occurrs in script.     * @throws NullPointerException if the argument is null.     */    public Object eval(Reader reader) throws ScriptException;     /**     * Executes the script using the <code>Bindings</code> argument as the <code>ENGINE_SCOPE</code>     * <code>Bindings</code> of the <code>ScriptEngine</code> during the script execution.  The     * <code>Reader</code>, <code>Writer</code> and non-<code>ENGINE_SCOPE</code> <code>Bindings</code> of the     * default <code>ScriptContext</code> are used. The <code>ENGINE_SCOPE</code>     * <code>Bindings</code> of the <code>ScriptEngine</code> is not changed, and its     * mappings are unaltered by the script execution.     *     * @param script The source for the script.     *     * @param n The <code>Bindings</code> of attributes to be used for script execution.     *     * @return The value returned by the script.     *     * @throws ScriptException if an error occurrs in script.     * @throws NullPointerException if either argument is null.     */    public Object eval(String script, Bindings n) throws ScriptException;     /**     * Same as <code>eval(String, Bindings)</code> except that the source of the script     * is provided as a <code>Reader</code>.     *     * @param reader The source of the script.     * @param n The <code>Bindings</code> of attributes.     *     * @return The value returned by the script.     *     * @throws ScriptException if an error occurrs.     * @throws NullPointerException if either argument is null.     */    public Object eval(Reader reader , Bindings n) throws ScriptException;       /**     * Sets a key/value pair in the state of the ScriptEngine that may either create     * a Java Language Binding to be used in the execution of scripts or be used in some     * other way, depending on whether the key is reserved.  Must have the same effect as     * <code>getBindings(ScriptContext.ENGINE_SCOPE).put</code>.     *     * @param key The name of named value to add     * @param value The value of named value to add.     *     * @throws NullPointerException if key is null.     * @throws IllegalArgumentException if key is empty.     */    public void put(String key, Object value);      /**     * Retrieves a value set in the state of this engine.  The value might be one     * which was set using <code>setValue</code> or some other value in the state     * of the <code>ScriptEngine</code>, depending on the implementation.  Must have the same effect     * as <code>getBindings(ScriptContext.ENGINE_SCOPE).get</code>     *     * @param key The key whose value is to be returned     * @return the value for the given key     *     * @throws NullPointerException if key is null.     * @throws IllegalArgumentException if key is empty.     */    public Object get(String key);      /**     * Returns a scope of named values.  The possible scopes are:     * <br><br>     * <ul>     * <li><code>ScriptContext.GLOBAL_SCOPE</code> - The set of named values representing global     * scope. If this <code>ScriptEngine</code> is created by a <code>ScriptEngineManager</code>,     * then the manager sets global scope bindings. This may be <code>null</code> if no global     * scope is associated with this <code>ScriptEngine</code></li>     * <li><code>ScriptContext.ENGINE_SCOPE</code> - The set of named values representing the state of     * this <code>ScriptEngine</code>.  The values are generally visible in scripts using     * the associated keys as variable names.</li>     * <li>Any other value of scope defined in the default <code>ScriptContext</code> of the <code>ScriptEngine</code>.     * </li>     * </ul>     * <br><br>     * The <code>Bindings</code> instances that are returned must be identical to those returned by the     * <code>getBindings</code> method of <code>ScriptContext</code> called with corresponding arguments on     * the default <code>ScriptContext</code> of the <code>ScriptEngine</code>.     *     * @param scope Either <code>ScriptContext.ENGINE_SCOPE</code> or <code>ScriptContext.GLOBAL_SCOPE</code>     * which specifies the <code>Bindings</code> to return.  Implementations of <code>ScriptContext</code>     * may define additional scopes.  If the default <code>ScriptContext</code> of the <code>ScriptEngine</code>     * defines additional scopes, any of them can be passed to get the corresponding <code>Bindings</code>.     *     * @return The <code>Bindings</code> with the specified scope.     *     * @throws IllegalArgumentException if specified scope is invalid     *     */    public Bindings getBindings(int scope);     /**     * Sets a scope of named values to be used by scripts.  The possible scopes are:     *<br><br>     * <ul>     * <li><code>ScriptContext.ENGINE_SCOPE</code> - The specified <code>Bindings</code> replaces the     * engine scope of the <code>ScriptEngine</code>.     * </li>     * <li><code>ScriptContext.GLOBAL_SCOPE</code> - The specified <code>Bindings</code> must be visible     * as the <code>GLOBAL_SCOPE</code>.     * </li>     * <li>Any other value of scope defined in the default <code>ScriptContext</code> of the <code>ScriptEngine</code>.     *</li>     * </ul>     * <br><br>     * The method must have the same effect as calling the <code>setBindings</code> method of     * <code>ScriptContext</code> with the corresponding value of <code>scope</code> on the default     * <code>ScriptContext</code> of the <code>ScriptEngine</code>.     *     * @param bindings The <code>Bindings</code> for the specified scope.     * @param scope The specified scope.  Either <code>ScriptContext.ENGINE_SCOPE</code>,     * <code>ScriptContext.GLOBAL_SCOPE</code>, or any other valid value of scope.     *     * @throws IllegalArgumentException if the scope is invalid     * @throws NullPointerException if the bindings is null and the scope is     * <code>ScriptContext.ENGINE_SCOPE</code>     */    public void setBindings(Bindings bindings, int scope);      /**     * Returns an uninitialized <code>Bindings</code>.     *     * @return A <code>Bindings</code> that can be used to replace the state of this <code>ScriptEngine</code>.     **/    public Bindings createBindings();      /**     * Returns the default <code>ScriptContext</code> of the <code>ScriptEngine</code> whose Bindings, Reader     * and Writers are used for script executions when no <code>ScriptContext</code> is specified.     *     * @return The default <code>ScriptContext</code> of the <code>ScriptEngine</code>.     */    public ScriptContext getContext();     /**     * Sets the default <code>ScriptContext</code> of the <code>ScriptEngine</code> whose Bindings, Reader     * and Writers are used for script executions when no <code>ScriptContext</code> is specified.     *     * @param context A <code>ScriptContext</code> that will replace the default <code>ScriptContext</code> in     * the <code>ScriptEngine</code>.     * @throws NullPointerException if context is null.     */    public void setContext(ScriptContext context);     /**     * Returns a <code>ScriptEngineFactory</code> for the class to which this <code>ScriptEngine</code> belongs.     *     * @return The <code>ScriptEngineFactory</code>     */    public ScriptEngineFactory getFactory();}