Added private helper method to Java QrSegmentAdvanced.

java/io/nayuki/qrcodegen/QrSegmentAdvanced.java

@@ -257,13 +257,18 @@ public final class QrSegmentAdvanced {
 	public static boolean isEncodableAsKanji(String text) {
 		Objects.requireNonNull(text);
 		for (int i = 0; i < text.length(); i++) {
-			if (UNICODE_TO_QR_KANJI[text.charAt(i)] == -1)
+			if (!isKanji(text.charAt(i)))
 				return false;
 		}
 		return true;
 	}
 	
 	
+	private static boolean isKanji(char c) {
+		return UNICODE_TO_QR_KANJI[c] != -1;
+	}
+	
+	
 	// Data derived from ftp://ftp.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/JIS/SHIFTJIS.TXT
 	private static final String PACKED_QR_KANJI_TO_UNICODE =
 		"MAAwATAC/wz/DjD7/xr/G/8f/wEwmzCcALT/QACo/z7/4/8/MP0w/jCdMJ4wA07dMAUwBjAHMPwgFSAQ/w8AXDAcIBb/XCAmICUgGCAZIBwgHf8I/wkwFDAV/zv/Pf9b/10wCDAJMAowCzAMMA0wDjAPMBAwEf8LIhIAsQDX//8A9/8dImD/HP8eImYiZyIeIjQmQiZA" +