/* * Copyright (c) 2005, 2011, 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.util.List; /** * <code>ScriptEngineFactory</code> is used to describe and instantiate * <code>ScriptEngines</code>. * <br><br> * Each class implementing <code>ScriptEngine</code> has a corresponding factory * that exposes metadata describing the engine class. * <br><br>The <code>ScriptEngineManager</code> * uses the service provider mechanism described in the <i>Jar File Specification</i> to obtain * instances of all <code>ScriptEngineFactories</code> available in * the current ClassLoader. * * @since 1.6 */public interface ScriptEngineFactory {    /**     * Returns the full  name of the <code>ScriptEngine</code>.  For     * instance an implementation based on the Mozilla Rhino Javascript engine     * might return <i>Rhino Mozilla Javascript Engine</i>.     * @return The name of the engine implementation.     */    public String getEngineName();     /**     * Returns the version of the <code>ScriptEngine</code>.     * @return The <code>ScriptEngine</code> implementation version.     */    public String getEngineVersion();      /**     * Returns an immutable list of filename extensions, which generally identify scripts     * written in the language supported by this <code>ScriptEngine</code>.     * The array is used by the <code>ScriptEngineManager</code> to implement its     * <code>getEngineByExtension</code> method.     * @return The list of extensions.     */    public List<String> getExtensions();      /**     * Returns an immutable list of mimetypes, associated with scripts that     * can be executed by the engine.  The list is used by the     * <code>ScriptEngineManager</code> class to implement its     * <code>getEngineByMimetype</code> method.     * @return The list of mime types.     */    public List<String> getMimeTypes();     /**     * Returns an immutable list of  short names for the <code>ScriptEngine</code>, which may be used to     * identify the <code>ScriptEngine</code> by the <code>ScriptEngineManager</code>.     * For instance, an implementation based on the Mozilla Rhino Javascript engine might     * return list containing {&quot;javascript&quot;, &quot;rhino&quot;}.     */    public List<String> getNames();     /**     * Returns the name of the scripting langauge supported by this     * <code>ScriptEngine</code>.     * @return The name of the supported language.     */    public String getLanguageName();     /**     * Returns the version of the scripting language supported by this     * <code>ScriptEngine</code>.     * @return The version of the supported language.     */    public String getLanguageVersion();     /**     * Returns the value of an attribute whose meaning may be implementation-specific.     * Keys for which the value is defined in all implementations are:     * <ul>     * <li>ScriptEngine.ENGINE</li>     * <li>ScriptEngine.ENGINE_VERSION</li>     * <li>ScriptEngine.NAME</li>     * <li>ScriptEngine.LANGUAGE</li>     * <li>ScriptEngine.LANGUAGE_VERSION</li>     * </ul>     * <p>     * The values for these keys are the Strings returned by <code>getEngineName</code>,     * <code>getEngineVersion</code>, <code>getName</code>, <code>getLanguageName</code> and     * <code>getLanguageVersion</code> respectively.<br><br>     * A reserved key, <code><b>THREADING</b></code>, whose value describes the behavior of the engine     * with respect to concurrent execution of scripts and maintenance of state is also defined.     * These values for the <code><b>THREADING</b></code> key are:<br><br>     * <ul>     * <li><code>null</code> - The engine implementation is not thread safe, and cannot     * be used to execute scripts concurrently on multiple threads.     * <li><code>&quot;MULTITHREADED&quot;</code> - The engine implementation is internally     * thread-safe and scripts may execute concurrently although effects of script execution     * on one thread may be visible to scripts on other threads.     * <li><code>&quot;THREAD-ISOLATED&quot;</code> - The implementation satisfies the requirements     * of &quot;MULTITHREADED&quot;, and also, the engine maintains independent values     * for symbols in scripts executing on different threads.     * <li><code>&quot;STATELESS&quot;</code> - The implementation satisfies the requirements of     * <li><code>&quot;THREAD-ISOLATED&quot;</code>.  In addition, script executions do not alter the     * mappings in the <code>Bindings</code> which is the engine scope of the     * <code>ScriptEngine</code>.  In particular, the keys in the <code>Bindings</code>     * and their associated values are the same before and after the execution of the script.     * </ul>     * <br><br>     * Implementations may define implementation-specific keys.     *     * @param key The name of the parameter     * @return The value for the given parameter. Returns <code>null</code> if no     * value is assigned to the key.     *     */    public Object getParameter(String key);     /**     * Returns a String which can be used to invoke a method of a  Java object using the syntax     * of the supported scripting language.  For instance, an implementaton for a Javascript     * engine might be;     * <p>     * <pre>     * <code>     * public String getMethodCallSyntax(String obj,     *                                   String m, String... args) {     *      String ret = obj;     *      ret += "." + m + "(";     *      for (int i = 0; i < args.length; i++) {     *          ret += args[i];     *          if (i < args.length - 1) {     *              ret += ",";     *          }     *      }     *      ret += ")";     *      return ret;     * }     *</code>     *</pre>     * <p>     *     * @param obj The name representing the object whose method is to be invoked. The     * name is the one used to create bindings using the <code>put</code> method of     * <code>ScriptEngine</code>, the <code>put</code> method of an <code>ENGINE_SCOPE</code>     * <code>Bindings</code>,or the <code>setAttribute</code> method     * of <code>ScriptContext</code>.  The identifier used in scripts may be a decorated form of the     * specified one.     *     * @param m The name of the method to invoke.     * @param args names of the arguments in the method call.     *     * @return The String used to invoke the method in the syntax of the scripting language.     */    public String getMethodCallSyntax(String obj, String m, String... args);     /**     * Returns a String that can be used as a statement to display the specified String  using     * the syntax of the supported scripting language.  For instance, the implementaton for a Perl     * engine might be;     * <p>     * <pre><code>     * public String getOutputStatement(String toDisplay) {     *      return "print(" + toDisplay + ")";     * }     * </code></pre>     *     * @param toDisplay The String to be displayed by the returned statement.     * @return The string used to display the String in the syntax of the scripting language.     *     *     */    public String getOutputStatement(String toDisplay);      /**     * Returns A valid scripting language executable progam with given statements.     * For instance an implementation for a PHP engine might be:     * <p>     * <pre><code>     * public String getProgram(String... statements) {     *      $retval = "&lt;?\n";     *      int len = statements.length;     *      for (int i = 0; i < len; i++) {     *          $retval += statements[i] + ";\n";     *      }     *      $retval += "?&gt;";     *     * }     * </code></pre>     *     *  @param statements The statements to be executed.  May be return values of     *  calls to the <code>getMethodCallSyntax</code> and <code>getOutputStatement</code> methods.     *  @return The Program     */     public String getProgram(String... statements);     /**     * Returns an instance of the <code>ScriptEngine</code> associated with this     * <code>ScriptEngineFactory</code>. A new ScriptEngine is generally     * returned, but implementations may pool, share or reuse engines.     *     * @return A new <code>ScriptEngine</code> instance.     */    public  ScriptEngine getScriptEngine();}