/* * Copyright (c) 2005, 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;import java.io.Writer;import java.io.Reader; /** * The interface whose implementing classes are used to connect Script Engines * with objects, such as scoped Bindings, in hosting applications.  Each scope is a set * of named attributes whose values can be set and retrieved using the * <code>ScriptContext</code> methods. ScriptContexts also expose Readers and Writers * that can be used by the ScriptEngines for input and output. * * @author Mike Grogan * @since 1.6 */public interface ScriptContext {      /**     * EngineScope attributes are visible during the lifetime of a single     * <code>ScriptEngine</code> and a set of attributes is maintained for each     * engine.     */    public static final int ENGINE_SCOPE = 100;     /**     * GlobalScope attributes are visible to all engines created by same ScriptEngineFactory.     */    public static final int GLOBAL_SCOPE = 200;      /**     * Associates a <code>Bindings</code> instance with a particular scope in this     * <code>ScriptContext</code>.  Calls to the <code>getAttribute</code> and     * <code>setAttribute</code> methods must map to the <code>get</code> and     * <code>put</code> methods of the <code>Bindings</code> for the specified scope.     *     * @param  bindings The <code>Bindings</code> to associate with the given scope     * @param scope The scope     *     * @throws IllegalArgumentException If no <code>Bindings</code> is defined for the     * specified scope value in ScriptContexts of this type.     * @throws NullPointerException if value of scope is <code>ENGINE_SCOPE</code> and     * the specified <code>Bindings</code> is null.     *     */    public void setBindings(Bindings bindings, int scope);     /**     * Gets the <code>Bindings</code>  associated with the given scope in this     * <code>ScriptContext</code>.     *     * @return The associated <code>Bindings</code>.  Returns <code>null</code> if it has not     * been set.     *     * @throws IllegalArgumentException If no <code>Bindings</code> is defined for the     * specified scope value in <code>ScriptContext</code> of this type.     */    public Bindings getBindings(int scope);     /**     * Sets the value of an attribute in a given scope.     *     * @param name The name of the attribute to set     * @param value The value of the attribute     * @param scope The scope in which to set the attribute     *     * @throws IllegalArgumentException     *         if the name is empty or if the scope is invalid.     * @throws NullPointerException if the name is null.     */    public void setAttribute(String name, Object value, int scope);     /**     * Gets the value of an attribute in a given scope.     *     * @param name The name of the attribute to retrieve.     * @param scope The scope in which to retrieve the attribute.     * @return The value of the attribute. Returns <code>null</code> is the name     * does not exist in the given scope.     *     * @throws IllegalArgumentException     *         if the name is empty or if the value of scope is invalid.     * @throws NullPointerException if the name is null.     */    public Object getAttribute(String name, int scope);     /**     * Remove an attribute in a given scope.     *     * @param name The name of the attribute to remove     * @param scope The scope in which to remove the attribute     *     * @return The removed value.     * @throws IllegalArgumentException     *         if the name is empty or if the scope is invalid.     * @throws NullPointerException if the name is null.     */    public Object removeAttribute(String name, int scope);     /**     * Retrieves the value of the attribute with the given name in     * the scope occurring earliest in the search order.  The order     * is determined by the numeric value of the scope parameter (lowest     * scope values first.)     *     * @param name The name of the the attribute to retrieve.     * @return The value of the attribute in the lowest scope for     * which an attribute with the given name is defined.  Returns     * null if no attribute with the name exists in any scope.     * @throws NullPointerException if the name is null.     * @throws IllegalArgumentException if the name is empty.     */    public Object getAttribute(String name);      /**     * Get the lowest scope in which an attribute is defined.     * @param name Name of the attribute     * .     * @return The lowest scope.  Returns -1 if no attribute with the given     * name is defined in any scope.     * @throws NullPointerException if name is null.     * @throws IllegalArgumentException if name is empty.     */    public int getAttributesScope(String name);     /**     * Returns the <code>Writer</code> for scripts to use when displaying output.     *     * @return The <code>Writer</code>.     */    public Writer getWriter();      /**     * Returns the <code>Writer</code> used to display error output.     *     * @return The <code>Writer</code>     */    public Writer getErrorWriter();     /**     * Sets the <code>Writer</code> for scripts to use when displaying output.     *     * @param writer The new <code>Writer</code>.     */    public void setWriter(Writer writer);      /**     * Sets the <code>Writer</code> used to display error output.     *     * @param writer The <code>Writer</code>.     */    public void setErrorWriter(Writer writer);     /**     * Returns a <code>Reader</code> to be used by the script to read     * input.     *     * @return The <code>Reader</code>.     */    public Reader getReader();      /**     * Sets the <code>Reader</code> for scripts to read input     * .     * @param reader The new <code>Reader</code>.     */    public void setReader(Reader reader);     /**     * Returns immutable <code>List</code> of all the valid values for     * scope in the ScriptContext.     *     * @return list of scope values     */    public List<Integer> getScopes();}