+
+ public static String getVideoId(final String alterId) {
+ final int startIdIdx = alterId.lastIndexOf("/") + 1;
+ final String altId = alterId.substring(startIdIdx);
+ final Pattern idPattern = Pattern.compile("([a-z]*\\d+)");
+ final Matcher idMatcher = idPattern.matcher(altId);
+ if (!idMatcher.find()) {
+ throw new IllegalArgumentException("URL/IDの指定が不正です: " + alterId);
+ }
+
+ return idMatcher.group(1);
+ }