1 /*
2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.script;
27 import java.util.List;
28 import java.io.Writer;
29 import java.io.Reader;
30
31 /**
32 * The interface whose implementing classes are used to connect Script Engines
33 * with objects, such as scoped Bindings, in hosting applications. Each scope is a set
34 * of named attributes whose values can be set and retrieved using the
35 * <code>ScriptContext</code> methods. ScriptContexts also expose Readers and Writers
36 * that can be used by the ScriptEngines for input and output.
37 *
38 * @author Mike Grogan
39 * @since 1.6
40 */
41 public interface ScriptContext {
42
43
44 /**
45 * EngineScope attributes are visible during the lifetime of a single
46 * <code>ScriptEngine</code> and a set of attributes is maintained for each
47 * engine.
48 */
49 public static final int ENGINE_SCOPE = 100;
50
51 /**
52 * GlobalScope attributes are visible to all engines created by same ScriptEngineFactory.
53 */
54 public static final int GLOBAL_SCOPE = 200;
55
56
57 /**
58 * Associates a <code>Bindings</code> instance with a particular scope in this
59 * <code>ScriptContext</code>. Calls to the <code>getAttribute</code> and
60 * <code>setAttribute</code> methods must map to the <code>get</code> and
61 * <code>put</code> methods of the <code>Bindings</code> for the specified scope.
62 *
63 * @param bindings The <code>Bindings</code> to associate with the given scope
64 * @param scope The scope
65 *
66 * @throws IllegalArgumentException If no <code>Bindings</code> is defined for the
67 * specified scope value in ScriptContexts of this type.
68 * @throws NullPointerException if value of scope is <code>ENGINE_SCOPE</code> and
69 * the specified <code>Bindings</code> is null.
70 *
71 */
72 public void setBindings(Bindings bindings, int scope);
73
74 /**
75 * Gets the <code>Bindings</code> associated with the given scope in this
76 * <code>ScriptContext</code>.
77 *
78 * @return The associated <code>Bindings</code>. Returns <code>null</code> if it has not
79 * been set.
80 *
81 * @param scope The scope
82 * @throws IllegalArgumentException If no <code>Bindings</code> is defined for the
83 * specified scope value in <code>ScriptContext</code> of this type.
84 */
85 public Bindings getBindings(int scope);
86
87 /**
88 * Sets the value of an attribute in a given scope.
89 *
90 * @param name The name of the attribute to set
91 * @param value The value of the attribute
92 * @param scope The scope in which to set the attribute
93 *
94 * @throws IllegalArgumentException
95 * if the name is empty or if the scope is invalid.
96 * @throws NullPointerException if the name is null.
97 */
98 public void setAttribute(String name, Object value, int scope);
99
100 /**
101 * Gets the value of an attribute in a given scope.
102 *
103 * @param name The name of the attribute to retrieve.
104 * @param scope The scope in which to retrieve the attribute.
105 * @return The value of the attribute. Returns <code>null</code> is the name
106 * does not exist in the given scope.
107 *
108 * @throws IllegalArgumentException
109 * if the name is empty or if the value of scope is invalid.
110 * @throws NullPointerException if the name is null.
111 */
112 public Object getAttribute(String name, int scope);
113
114 /**
115 * Remove an attribute in a given scope.
116 *
117 * @param name The name of the attribute to remove
118 * @param scope The scope in which to remove the attribute
119 *
120 * @return The removed value.
121 * @throws IllegalArgumentException
122 * if the name is empty or if the scope is invalid.
123 * @throws NullPointerException if the name is null.
124 */
125 public Object removeAttribute(String name, int scope);
126
127 /**
128 * Retrieves the value of the attribute with the given name in
129 * the scope occurring earliest in the search order. The order
130 * is determined by the numeric value of the scope parameter (lowest
131 * scope values first.)
132 *
133 * @param name The name of the attribute to retrieve.
134 * @return The value of the attribute in the lowest scope for
135 * which an attribute with the given name is defined. Returns
136 * null if no attribute with the name exists in any scope.
137 * @throws NullPointerException if the name is null.
138 * @throws IllegalArgumentException if the name is empty.
139 */
140 public Object getAttribute(String name);
141
142
143 /**
144 * Get the lowest scope in which an attribute is defined.
145 * @param name Name of the attribute
146 * .
147 * @return The lowest scope. Returns -1 if no attribute with the given
148 * name is defined in any scope.
149 * @throws NullPointerException if name is null.
150 * @throws IllegalArgumentException if name is empty.
151 */
152 public int getAttributesScope(String name);
153
154 /**
155 * Returns the <code>Writer</code> for scripts to use when displaying output.
156 *
157 * @return The <code>Writer</code>.
158 */
159 public Writer getWriter();
160
161
162 /**
163 * Returns the <code>Writer</code> used to display error output.
164 *
165 * @return The <code>Writer</code>
166 */
167 public Writer getErrorWriter();
168
169 /**
170 * Sets the <code>Writer</code> for scripts to use when displaying output.
171 *
172 * @param writer The new <code>Writer</code>.
173 */
174 public void setWriter(Writer writer);
175
176
177 /**
178 * Sets the <code>Writer</code> used to display error output.
179 *
180 * @param writer The <code>Writer</code>.
181 */
182 public void setErrorWriter(Writer writer);
183
184 /**
185 * Returns a <code>Reader</code> to be used by the script to read
186 * input.
187 *
188 * @return The <code>Reader</code>.
189 */
190 public Reader getReader();
191
192
193 /**
194 * Sets the <code>Reader</code> for scripts to read input
195 * .
196 * @param reader The new <code>Reader</code>.
197 */
198 public void setReader(Reader reader);
199
200 /**
201 * Returns immutable <code>List</code> of all the valid values for
202 * scope in the ScriptContext.
203 *
204 * @return list of scope values
205 */
206 public List<Integer> getScopes();
207 }