Here you can find the source of isUrn(String value)
public static boolean isUrn(String value)
//package com.java2s; /*//from w ww . j a v a2 s.c o m * Copyright 2012 Lev Khomich * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.util.regex.Pattern; public class Main { private static final Pattern URN_PATTERN = Pattern .compile("urn:[a-zA-Z0-9][a-zA-Z0-9-]{1,31}:.+"); public static boolean isUrn(String value) { return URN_PATTERN.matcher(value).matches(); } }