/* * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved. * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. * * * * * * * * * * * * * * * * * * * * */ package javax.script; import java.util.List; /** * ScriptEngineFactory is used to describe and instantiate * ScriptEngines. *

* Each class implementing ScriptEngine has a corresponding factory * that exposes metadata describing the engine class. *

The ScriptEngineManager * uses the service provider mechanism described in the Jar File Specification to obtain * instances of all ScriptEngineFactories available in * the current ClassLoader. * * @since 1.6 */ public interface ScriptEngineFactory { /** * Returns the full name of the ScriptEngine. For * instance an implementation based on the Mozilla Rhino Javascript engine * might return Rhino Mozilla Javascript Engine. * @return The name of the engine implementation. */ public String getEngineName(); /** * Returns the version of the ScriptEngine. * @return The ScriptEngine implementation version. */ public String getEngineVersion(); /** * Returns an immutable list of filename extensions, which generally identify scripts * written in the language supported by this ScriptEngine. * The array is used by the ScriptEngineManager to implement its * getEngineByExtension method. * @return The list of extensions. */ public List getExtensions(); /** * Returns an immutable list of mimetypes, associated with scripts that * can be executed by the engine. The list is used by the * ScriptEngineManager class to implement its * getEngineByMimetype method. * @return The list of mime types. */ public List getMimeTypes(); /** * Returns an immutable list of short names for the ScriptEngine, which may be used to * identify the ScriptEngine by the ScriptEngineManager. * For instance, an implementation based on the Mozilla Rhino Javascript engine might * return list containing {"javascript", "rhino"}. */ public List getNames(); /** * Returns the name of the scripting langauge supported by this * ScriptEngine. * @return The name of the supported language. */ public String getLanguageName(); /** * Returns the version of the scripting language supported by this * ScriptEngine. * @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: *
    *
  • ScriptEngine.ENGINE
    • *
  • ScriptEngine.ENGINE_VERSION
    • *
  • ScriptEngine.NAME
    • *
  • ScriptEngine.LANGUAGE
    • *
  • ScriptEngine.LANGUAGE_VERSION
    • *
*

* The values for these keys are the Strings returned by getEngineName, * getEngineVersion, getName, getLanguageName and * getLanguageVersion respectively.

* A reserved key, THREADING, 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 THREADING key are:

*

    *
  • null - The engine implementation is not thread safe, and cannot * be used to execute scripts concurrently on multiple threads. *
  • "MULTITHREADED" - 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. *
  • "THREAD-ISOLATED" - The implementation satisfies the requirements * of "MULTITHREADED", and also, the engine maintains independent values * for symbols in scripts executing on different threads. *
  • "STATELESS" - The implementation satisfies the requirements of *
  • "THREAD-ISOLATED". In addition, script executions do not alter the * mappings in the Bindings which is the engine scope of the * ScriptEngine. In particular, the keys in the Bindings * and their associated values are the same before and after the execution of the script. *
*

* Implementations may define implementation-specific keys. * * @param key The name of the parameter * @return The value for the given parameter. Returns null 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; *

* 

     * 
     * 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;
     * }
     *
     *
*

* * @param obj The name representing the object whose method is to be invoked. The * name is the one used to create bindings using the put method of * ScriptEngine, the put method of an ENGINE_SCOPE * Bindings,or the setAttribute method * of ScriptContext. 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; *

* 


     * public String getOutputStatement(String toDisplay) {
     *      return "print(" + toDisplay + ")";
     * }
     *
* * @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: *

* 


     * public String getProgram(String... statements) {
     *      $retval = "<?\n";
     *      int len = statements.length;
     *      for (int i = 0; i < len; i++) {
     *          $retval += statements[i] + ";\n";
     *      }
     *      $retval += "?>";
     *
     * }
     *
* * @param statements The statements to be executed. May be return values of * calls to the getMethodCallSyntax and getOutputStatement methods. * @return The Program */ public String getProgram(String... statements); /** * Returns an instance of the ScriptEngine associated with this * ScriptEngineFactory. A new ScriptEngine is generally * returned, but implementations may pool, share or reuse engines. * * @return A new ScriptEngine instance. */ public ScriptEngine getScriptEngine(); }