/*
 * @(#)ScriptEngine.java	1.5 06/06/19 20:53:06
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTAIL. Use is subject to license terms.
 */

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
 * @version 1.0
 * @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