Taken into account PR review comments

Author: thboileau

org.restlet.java/org.restlet/src/main/java/org/restlet/data/Reference.java

@@ -2855,52 +2855,36 @@ private void validateAuthority(String authority) {
 			return;
 		}
 
+		authority = validateUserInfoAndReturnRemaining(authority);
+		authority = validateIpV6AndReturnRemaining(authority);
+
+		int portIndex = authority.indexOf(':');
+		if (portIndex != -1) {
+			validateHostPort(authority.substring(portIndex + 1));
+		}
+	}
+
+	/**
+	 * Validate the user info part of the authority, and return the remaining part of the authority.
+	 */
+	private String validateUserInfoAndReturnRemaining(final String authority) {
 		int atIndex = authority.indexOf('@');
-		int ipV6StartIndex = authority.indexOf('[');
 
 		if (atIndex != -1) {
+			final int ipV6StartIndex = authority.indexOf('[');
+
 			if (ipV6StartIndex != -1) {
-				if (atIndex < ipV6StartIndex) {
-					authority = authority.substring(atIndex + 1);
-					ipV6StartIndex -= atIndex + 1;
-				} else {
+				if (atIndex >= ipV6StartIndex) {
 					throw new IllegalArgumentException("Invalid authority format");
 				}
-			} else {
-				authority = authority.substring(atIndex + 1);
 			}
+			return authority.substring(atIndex + 1);
 		}
 
-		if (ipV6StartIndex == -1) {
-			int portIndex = authority.indexOf(':');
-
-			if (portIndex != -1) {
-				validateHostPort(authority.substring(portIndex + 1));
-			}
-		} else if (ipV6StartIndex == 0) {
-			int ipV6EndIndex = authority.indexOf(']');
-
-			if (ipV6EndIndex == -1) {
-				throw new IllegalArgumentException("Invalid IPv6 address format: no closing bracket");
-			}
-
-			validateIpV6(authority.substring(1, ipV6EndIndex)); // trim brackets
-
-			if (ipV6EndIndex + 1 < authority.length()) {
-				if (authority.charAt(ipV6EndIndex + 1) == ':') {
-					validateHostPort(authority.substring(ipV6EndIndex + 2));
-				} else {
-					throw new IllegalArgumentException(
-							"Invalid authority format: unexpected character after closing bracket");
-				}
-			}
-		} else {
-			throw new IllegalArgumentException(
-					"Invalid IPv6 address format: unexpected character before opening bracket");
-		}
+		return authority;
 	}
 
-    /**
+	/**
      * Validate an host port.
      * 
      * @param hostPort The port to validate.
@@ -2915,16 +2899,42 @@ private void validateHostPort(final String hostPort) {
 		}
 	}
 
+	private String validateIpV6AndReturnRemaining(String authority) {
+		int ipV6StartIndex = authority.indexOf('[');
+		int ipV6EndIndex = authority.indexOf(']');
+
+		if (ipV6StartIndex > 0) {
+			throw new IllegalArgumentException(
+					"Invalid IPv6 address format: unexpected character before opening bracket");
+		}
+		if (ipV6StartIndex == -1) {
+			return authority;
+		}
+
+		if (ipV6EndIndex == -1) {
+			throw new IllegalArgumentException("Invalid IPv6 address format: no closing bracket");
+		}
+		validateIpV6(authority.substring(1, ipV6EndIndex)); // trim brackets
+
+		if (ipV6EndIndex + 1 < authority.length()) {
+			if (authority.charAt(ipV6EndIndex + 1) != ':') {
+				throw new IllegalArgumentException(
+						"Invalid authority format: unexpected character after closing bracket");
+			}
+		}
+
+		return authority.substring(ipV6EndIndex + 1);
+	}
+
     /**
      * Validate an IP v6 according to RFC 2373.
-     * 
-     * @param ipV6 The IP v6 to validate.
      */
 	private void validateIpV6(String ipV6) {
 		if (ipV6 == null || ipV6.isEmpty()) {
 			throw new IllegalArgumentException("Invalid IPv6 address");
 		}
 
+
 		// Check for double colon compression (only one allowed)
 		int doubleColonCount = 0;
 		int idx = ipV6.indexOf("::");