1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.jxpath.servlet;
18
19 import org.apache.commons.jxpath.Variables;
20
21 /**
22 * Implementation of the Variables interface that provides access
23 * to a single object using a reserved name (keyword).
24 *
25 * @author Dmitri Plotnikov
26 * @version $Revision: 652925 $ $Date: 2008-05-03 00:05:41 +0200 (Sa, 03 Mai 2008) $
27 */
28 public class KeywordVariables implements Variables {
29 private static final long serialVersionUID = 894145608741325442L;
30
31 private String keyword;
32 private Object object;
33
34 /**
35 * Create a new KeywordVariables.
36 * @param keyword String
37 * @param object value
38 */
39 public KeywordVariables(String keyword, Object object) {
40 if (keyword == null) {
41 throw new IllegalArgumentException("keyword cannot be null");
42 }
43 this.keyword = keyword;
44 this.object = object;
45 }
46
47 public boolean isDeclaredVariable(String variable) {
48 return variable.equals(keyword);
49 }
50
51 public Object getVariable(String variable) {
52 return isDeclaredVariable(variable) ? object : null;
53 }
54
55 public void declareVariable(String variable, Object value) {
56 throw new UnsupportedOperationException(
57 "Cannot declare new keyword variables.");
58 }
59
60 public void undeclareVariable(String variable) {
61 throw new UnsupportedOperationException(
62 "Cannot undeclare keyword variables.");
63 }
64 }