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* 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.
*
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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();
}