ListLiteral


1   /*
2    * Copyright 1999,2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */ 
16  
17  package org.apache.taglibs.standard.lang.jpath.expression;
18  
19  import java.util.ArrayList  ;
20  import java.util.Collection  ;
21  
22  import javax.servlet.jsp.PageContext  ;
23  
24  import org.apache.taglibs.standard.lang.jpath.adapter.IterationContext;
25  
26  /**
27   * The ListLiteral class
28   *
29   *
30   * @author <a HREF='mailto:scott.hasse@isthmusgroup.com'>Scott Hasse</a>
31   * @version
32   */
33  public class ListLiteral extends SimpleNode {
34  
35      /**
36       * Used to create an instance of the ListLiteral class
37       *
38       *
39       * @param id
40       *
41       */
42      public ListLiteral(int id) {
43          super(id);
44      }
45  
46      /**
47       * Used to create an instance of the ListLiteral class
48       *
49       *
50       * @param p
51       * @param id
52       *
53       */
54      public ListLiteral(Parser p, int id) {
55          super(p, id);
56      }
57  
58      /**
59       * Provides a method to print a normalized version of the original
60       * expression.  The normalized version has standardized spacing and
61       * parenthesis, and can be used to compare expressions formatted
62       * in different ways to see if they are actually the same expression.
63       *
64       *
65       * @return The normalized version of the original expression
66       *
67       */
68      public String   toNormalizedString() {
69  
70          boolean first = true;
71          String   normalized;
72  
73          normalized = "{";
74  
75          if (children != null) {
76              for (int i = 0; i < children.length; ++i) {
77                  if (!first) {
78                      normalized = normalized + ",";
79                  }
80  
81                  first = false;
82  
83                  SimpleNode n = (SimpleNode) children[i];
84  
85                  if (n != null) {
86                      normalized = normalized + n.toNormalizedString();
87                  }
88              }
89          }
90  
91          normalized = normalized + "}";
92  
93          return normalized;
94      }
95  
96      /**
97       * This method evaluates this node of the expression and all child nodes.
98       * It returns the result of the
99       * evaluation as an <tt>Object</tt>.  If any problems are encountered
100      * during the evaluation, an <tt>EvaluationException</tt> is thrown.
101      *
102      *
103      * @param pageContext the current JSP PageContext
104      *
105      * @param icontext the Iteration Context of the expression.  If there is
106      *         no interation context, this should be null.
107      *
108      * @return the result of the expression evaluation as an object
109      *
110      * @throws EvaluationException if a problem is encountered during the
111      *         evaluation
112      */
113     public Object   evaluate(PageContext   pageContext, IterationContext icontext)
114             throws EvaluationException {
115 
116         Collection   c = new ArrayList  ();
117 
118         for (int i = 0; i < jjtGetNumChildren(); i++) {
119             c.add(jjtGetChild(i).evaluate(pageContext, icontext));
120         }
121 
122         return c;
123     }
124 }
125
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