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1   /**
2    * Copyright 2005-2013 The Kuali Foundation
3    *
4    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
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  package edu.samplu.common;
17  
18  import freemarker.template.Configuration;
19  import freemarker.template.Template;
20  import freemarker.template.TemplateException;
21  import org.apache.commons.io.FileUtils;
22  import org.springframework.ui.freemarker.FreeMarkerTemplateUtils;
23  
24  import java.io.File;
25  import java.io.IOException;
26  import java.io.InputStream;
27  import java.util.Enumeration;
28  import java.util.Properties;
29  
30  /**
31   * FreemarkerUtil loads properties from user defined InputStream.  systemPropertiesOverride should be used to override properties
32   * using a given key to identify them from JVM args. (i.e. -Dkey.name to override the name property in the key file.)
33   * TODO setup so the loading and overriding of properties is done for the user rather then them having to call it.
34   * @author Kuali Rice Team (rice.collab@kuali.org)
35   */
36  public class FreemarkerUtil {
37  
38      protected Configuration cfg;
39  
40      /**
41       * Calls ftlWrite that also accepts a key, using the output getName as the key.
42       * @param output
43       * @param template
44       * @return
45       * @throws java.io.IOException
46       * @throws freemarker.template.TemplateException
47       */
48      public File ftlWrite(File output, Template template, InputStream inputStream) throws IOException, TemplateException {
49  
50          return ftlWrite(output.getName(), output, template, inputStream);
51      }
52  
53      /**
54       * Loads properties from user defined properties file, if not available uses resource file
55       *
56       * writes processed template  to file
57       * @param key
58       * @param output
59       * @param template
60       * @throws IOException
61       * @throws TemplateException
62       */
63      public static File ftlWrite(String key, File output, Template template, InputStream inputStream) throws IOException, TemplateException {
64          Properties props = loadProperties(inputStream);
65          systemPropertiesOverride(props, key);
66          File outputFile = writeTemplateToFile(output, template, props);
67  
68          return outputFile;
69      }
70  
71      protected static Properties loadProperties(InputStream inputStream) throws IOException {
72          Properties props = new Properties();
73  
74          if(inputStream != null) {
75              props.load(inputStream);
76          }
77  
78          return props;
79      }
80  
81      /**
82       *
83       * @param file
84       * @param template
85       * @param props
86       * @return
87       * @throws IOException
88       * @throws freemarker.template.TemplateException
89       */
90      protected static File writeTemplateToFile(File file, Template template, Properties props) throws IOException, TemplateException {
91          String output = FreeMarkerTemplateUtils.processTemplateIntoString(template, props);
92          FileUtils.writeStringToFile(file, output);
93  
94          return file;
95      }
96  
97      /**
98       * -Dkey.propertyname= to override the property value for propertyname.
99       * @param props
100      */
101     public static void systemPropertiesOverride(Properties props, String key) {
102         Enumeration<?> names = props.propertyNames();
103         Object nameObject;
104         String name;
105         while (names.hasMoreElements()) {
106             nameObject = names.nextElement();
107             if (nameObject instanceof String) {
108                 name = (String)nameObject;
109                 props.setProperty(name, System.getProperty(key + "." + name, props.getProperty(name)));
110             }
111         }
112     }
113 
114 }