CODEC-110 - Add a String version of Base64.isArrayByteBase64()

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/codec/trunk@1063091 13f79535-47bb-0310-9956-ffa450edef68

Author: Julius Davies

src/java/org/apache/commons/codec/binary/Base64.java

@@ -607,6 +607,19 @@ public static boolean isArrayByteBase64(byte[] arrayOctet) {
         return true;
     }
 
+    /**
+     * Tests a given String to see if it contains only valid characters within the Base64 alphabet. Currently the
+     * method treats whitespace as valid.
+     * 
+     * @param base64
+     *            String of (presumably) base64 characters to test
+     * @return <code>true</code> if all characters in the String are valid characters in the Base64 alphabet or if
+     *         the String is empty; false, otherwise
+     */
+    public static boolean isStringBase64(String base64) {
+        return isArrayByteBase64(StringUtils.getBytesUtf8(base64));
+    }
+    
     /**
      * Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
      * 

src/test/org/apache/commons/codec/binary/Base64Test.java

@@ -55,6 +55,27 @@ public Random getRandom() {
         return this._random;
     }
 
+    /**
+     * Test the isStringBase64 method.
+     */
+    public void testIsStringBase64() {
+        String nullString = null;
+        String emptyString = "";
+        String validString = "abc===defg\n\r123456\r789\r\rABC\n\nDEF==GHI\r\nJKL==============";
+        String invalidString = validString + ((char)0); // append null character
+        
+        try {
+            Base64.isStringBase64(nullString);
+            fail("Base64.isStringBase64() should not be null-safe.");
+        } catch (NullPointerException npe) {
+            assertNotNull("Base64.isStringBase64() should not be null-safe.", npe);
+        }
+        
+        assertTrue("Base64.isStringBase64(empty-string) is true", Base64.isStringBase64(emptyString));
+        assertTrue("Base64.isStringBase64(valid-string) is true", Base64.isStringBase64(validString));        
+        assertFalse("Base64.isStringBase64(invalid-string) is false", Base64.isStringBase64(invalidString));        
+    }
+    
     /**
      * Test the Base64 implementation
      */