Using Unicode in Java .property files

Using multi-byte characters in Java .property files? Forget the Sun's native2ascii application. Rather than doing the irritating conversions, create UTF-8 encoded .property files, edit them directly and use Utf8ResourceBundle to access them. The code:

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1. package com.varaneckas.utils;  
2.   
3. import java.io.UnsupportedEncodingException;  
4. import java.util.Enumeration;  
5. import java.util.PropertyResourceBundle;  
6. import java.util.ResourceBundle;  
7.   
8. /** 
9.  * UTF-8 friendly ResourceBundle support 
10.  *  
11.  * Utility that allows having multi-byte characters inside java .property files. 
12.  * It removes the need for Sun's native2ascii application, you can simply have 
13.  * UTF-8 encoded editable .property files. 
14.  *  
15.  * Use:  
16.  * ResourceBundle bundle = Utf8ResourceBundle.getBundle("bundle_name"); 
17.  *  
18.  * @author Tomas Varaneckas <tomas.varaneckas@gmail.com> 
19.  */  
20. public abstract class Utf8ResourceBundle {  
21.       
22.     /** 
23.      * Gets the unicode friendly resource bundle 
24.      *  
25.      * @param baseName 
26.      * @see ResourceBundle#getBundle(String) 
27.      * @return Unicode friendly resource bundle 
28.      */  
29.     public static final ResourceBundle getBundle(final String baseName) {  
30.         return createUtf8PropertyResourceBundle(  
31.                 ResourceBundle.getBundle(baseName));  
32.     }  
33.   
34.     /** 
35.      * Creates unicode friendly {@link PropertyResourceBundle} if possible. 
36.      *  
37.      * @param bundle  
38.      * @return Unicode friendly property resource bundle 
39.      */  
40.     private static ResourceBundle createUtf8PropertyResourceBundle(  
41.             final ResourceBundle bundle) {  
42.         if (!(bundle instanceof PropertyResourceBundle)) {  
43.             return bundle;  
44.         }  
45.         return new Utf8PropertyResourceBundle((PropertyResourceBundle) bundle);  
46.     }  
47.   
48.     /** 
49.      * Resource Bundle that does the hard work 
50.      */  
51.     private static class Utf8PropertyResourceBundle extends ResourceBundle {  
52.   
53.         /** 
54.          * Bundle with unicode data 
55.          */  
56.         private final PropertyResourceBundle bundle;  
57.   
58.         /** 
59.          * Initializing constructor 
60.          *  
61.          * @param bundle 
62.          */  
63.         private Utf8PropertyResourceBundle(final PropertyResourceBundle bundle) {  
64.             this.bundle = bundle;  
65.         }  
66.   
67.         @Override  
68.         @SuppressWarnings("unchecked")  
69.         public Enumeration getKeys() {  
70.             return bundle.getKeys();  
71.         }  
72.   
73.         @Override  
74.         protected Object handleGetObject(final String key) {  
75.             final String value = bundle.getString(key);  
76.             if (value == null)  
77.                 return null;  
78.             try {  
79.                 return new String(value.getBytes("ISO-8859-1"), "UTF-8");  
80.             } catch (final UnsupportedEncodingException e) {  
81.                 throw new RuntimeException("Encoding not supported", e);  
82.             }  
83.         }  
84.     }  
85. }  

package com.varaneckas.utils;

import java.io.UnsupportedEncodingException;
import java.util.Enumeration;
import java.util.PropertyResourceBundle;
import java.util.ResourceBundle;

/**
 * UTF-8 friendly ResourceBundle support
 * 
 * Utility that allows having multi-byte characters inside java .property files.
 * It removes the need for Sun's native2ascii application, you can simply have
 * UTF-8 encoded editable .property files.
 * 
 * Use: 
 * ResourceBundle bundle = Utf8ResourceBundle.getBundle("bundle_name");
 * 
 * @author Tomas Varaneckas <tomas.varaneckas@gmail.com>
 */
public abstract class Utf8ResourceBundle {
    
    /**
     * Gets the unicode friendly resource bundle
     * 
     * @param baseName
     * @see ResourceBundle#getBundle(String)
     * @return Unicode friendly resource bundle
     */
    public static final ResourceBundle getBundle(final String baseName) {
        return createUtf8PropertyResourceBundle(
                ResourceBundle.getBundle(baseName));
    }

    /**
     * Creates unicode friendly {@link PropertyResourceBundle} if possible.
     * 
     * @param bundle 
     * @return Unicode friendly property resource bundle
     */
    private static ResourceBundle createUtf8PropertyResourceBundle(
            final ResourceBundle bundle) {
        if (!(bundle instanceof PropertyResourceBundle)) {
            return bundle;
        }
        return new Utf8PropertyResourceBundle((PropertyResourceBundle) bundle);
    }

    /**
     * Resource Bundle that does the hard work
     */
    private static class Utf8PropertyResourceBundle extends ResourceBundle {

        /**
         * Bundle with unicode data
         */
        private final PropertyResourceBundle bundle;

        /**
         * Initializing constructor
         * 
         * @param bundle
         */
        private Utf8PropertyResourceBundle(final PropertyResourceBundle bundle) {
            this.bundle = bundle;
        }

        @Override
        @SuppressWarnings("unchecked")
        public Enumeration getKeys() {
            return bundle.getKeys();
        }

        @Override
        protected Object handleGetObject(final String key) {
            final String value = bundle.getString(key);
            if (value == null)
                return null;
            try {
                return new String(value.getBytes("ISO-8859-1"), "UTF-8");
            } catch (final UnsupportedEncodingException e) {
                throw new RuntimeException("Encoding not supported", e);
            }
        }
    }
}