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
18 package org.apache.commons.jxpath.servlet;
19
20 import org.apache.commons.jxpath.Variables;
21
22 /**
23 * Implementation of the Variables interface that provides access to a single object using a reserved name (keyword).
24 */
25 public class KeywordVariables implements Variables {
26
27 private static final long serialVersionUID = 894145608741325442L;
28
29 /**
30 * The keyword.
31 */
32 private final String keyword;
33
34 /**
35 * The value.
36 */
37 private final Object value;
38
39 /**
40 * Constructs a new KeywordVariables.
41 *
42 * @param keyword The keyword.
43 * @param value The value.
44 */
45 public KeywordVariables(final String keyword, final Object value) {
46 if (keyword == null) {
47 throw new IllegalArgumentException("keyword cannot be null");
48 }
49 this.keyword = keyword;
50 this.value = value;
51 }
52
53 @Override
54 public void declareVariable(final String variable, final Object value) {
55 throw new UnsupportedOperationException("Cannot declare new keyword variables.");
56 }
57
58 @Override
59 public Object getVariable(final String variable) {
60 return isDeclaredVariable(variable) ? value : null;
61 }
62
63 @Override
64 public boolean isDeclaredVariable(final String variable) {
65 return variable.equals(keyword);
66 }
67
68 @Override
69 public void undeclareVariable(final String variable) {
70 throw new UnsupportedOperationException("Cannot undeclare keyword variables.");
71 }
72 }