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1   /**
2    * Copyright 2010 The Kuali Foundation Licensed under the
3    * Educational Community License, Version 2.0 (the "License"); you may
4    * not use this file except in compliance with the License. You may
5    * obtain a copy of the License at
6    *
7    * http://www.osedu.org/licenses/ECL-2.0
8    *
9    * Unless required by applicable law or agreed to in writing,
10   * software distributed under the License is distributed on an "AS IS"
11   * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
12   * or implied. See the License for the specific language governing
13   * permissions and limitations under the License.
14   */
15  
16  package org.kuali.student.common.util;
17  
18  import java.util.HashSet;
19  import java.util.Map;
20  import java.util.Set;
21  
22  public class MessageUtils {
23      /**
24       * Interpolates a message based on values contained in the data map, assuming message is formatted using a ${key} syntax.
25       * 
26       * @param message
27       *            the message to be interpolated
28       * @param data
29       *            Map<String, String> containing the data to be used for interpolation
30       * @return the interpolated message
31       */
32      public static String interpolate(String message, String... data) {
33          if (message != null) {
34              for (int i = 0; i < data.length; i++) {
35                  message = message.replaceAll("\\$\\{" + i + "\\}", "" + escape(data[i]));
36              }
37          }
38          return message;
39      }
40  
41      /**
42       * Interpolates a message based on parameter index, assuming message is formatted using a ${0}..${n} syntax
43       * 
44       * @param message
45       *            the message to be interpolated
46       * @param data
47       *            varargs to be used for interpolation
48       * @return the interpolated message
49       */
50      public static String interpolate(String message, Map<String, Object> data) {
51          if (message != null && data != null) {
52              Set<String> fields = findFields(message);
53              for (String s : fields) {
54              	if(data.get(s) != null){
55              		message = message.replaceAll("\\$\\{" + s + "\\}", "" + escape(data.get(s).toString()));
56              	}
57              }
58          }
59          return message;
60      }
61      
62      /**
63       * Interpolates a message which requires only a single property replacement.
64       * 
65       * @param message
66       * @param parameter
67       * @param value
68       * @return the interpolated message
69       */
70      public static String interpolate(String message, String parameter, Object value){
71      	message = message.replaceAll("\\$\\{" + parameter + "\\}", "" + escape(value.toString()));
72      	return message;
73      }
74      
75      /**
76       * Adds an escape to all characters requiring an escape.
77       * 
78       * @param input
79       * @return the input string with characters escaped.
80       */
81      private static String escape(String input) {
82          char[] toEscape = {'\\', '$', '.', '*', '+', '?', '|', '(', ')', '[', ']', '{', '}'};
83          for (char c : toEscape) {
84              input = input.replaceAll("\\" + c, "\\\\\\" + c);
85          }
86          return input;
87      }
88      
89      /**
90       * Returns a Set<String> of all interpolation targets (fields) within a String.
91       * 
92       * @param input
93       *            the String from which to extract the interpolation targets
94       * @return Set<String> containing the field names of the interpolation targets
95       */
96      public static Set<String> findFields(String input) {
97          Set<String> result = new HashSet<String>();
98          int begin = input.indexOf("${");
99          while (begin != -1) {
100             int end = input.indexOf("}", begin);
101             result.add(input.substring(begin + 2, end));
102             begin = input.indexOf("${", end);
103         }
104         return result;
105     }
106 
107 }