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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 java.util.Enumeration;
21  
22  import javax.servlet.jsp.PageContext;
23  
24  /**
25   * A lightweight wrapper for {@link PageContext} that restricts access to attributes of the "page" scope. This object is needed so that XPath "foo" would lookup
26   * the attribute "foo" in all scopes, while "$page/foo" would only look in the "page" scope.
27   */
28  public class PageScopeContext {
29  
30      private final PageContext pageContext;
31  
32      /**
33       * Constructs a new PageScopeContext.
34       *
35       * @param pageContext base
36       */
37      public PageScopeContext(final PageContext pageContext) {
38          this.pageContext = pageContext;
39      }
40  
41      /**
42       * Gets the value of the specified attribute.
43       *
44       * @param attribute name
45       * @return Object
46       */
47      public Object getAttribute(final String attribute) {
48          return pageContext.getAttribute(attribute, PageContext.PAGE_SCOPE);
49      }
50  
51      /**
52       * Returns attributes of the pageContext declared in the "page" scope.
53       *
54       * @return Enumeration of attribute names
55       */
56      public Enumeration<String> getAttributeNames() {
57          return pageContext.getAttributeNamesInScope(PageContext.PAGE_SCOPE);
58      }
59  
60      /**
61       * Sets the specified attribute.
62       *
63       * @param attribute to set
64       * @param value     to set
65       */
66      public void setAttribute(final String attribute, final Object value) {
67          pageContext.setAttribute(attribute, value, PageContext.PAGE_SCOPE);
68      }
69  }