Java tutorial
/* * Copyright (c) 2005, 2013, 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. * * @param scope The scope * @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. If the scope is <code>GLOBAL_SCOPE</code> * and no Bindings is set for <code>GLOBAL_SCOPE</code>, then setAttribute call is a no-op. * * @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 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(); }