content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.
   */
  package com.alibaba.metrics;
  
  import java.util.regex.Pattern;
  
  public class StringUtils {
  
      /**
       * According to Opentsdb specification, only the following characters are allowed:
       * a to z, A to Z, 0 to 9, -, _, ., / or Unicode letters (as per the specification)
       */
      private static final String ILLEGAL_CHARS = "[^a-zA-Z0-9-_./\\p{L}]";
  
      /**
       * \p{L} means to match the unicode letters
       * see http://www.regular-expressions.info/unicode.html#prop
       */
      private static final Pattern ILLEGAL_CHARS_PATTERN = Pattern.compile(ILLEGAL_CHARS);
  
      /**
       * check if there is any illegal character in given metric name
       * Focus on metric key and tag value
       * @param name the metric name to check
       */
      public static void checkMetricName(MetricName name) {
          if (name == null) return;
  
          if (ILLEGAL_CHARS_PATTERN.matcher(name.getKey()).find()) {
              throw new IllegalArgumentException("Illegal metric key: " + name.getKey());
          }
  
          for (String tagV: name.getTags().values()) {
              checkTagValue(tagV);
          }
      }
  
  
      /**
       * check if there is any illegal character in tag value
       * @param tagValue the tag value to check
       */
      public static void checkTagValue(String tagValue) {
          if (tagValue == null) return;
  
          if (ILLEGAL_CHARS_PATTERN.matcher(tagValue).find()) {
              throw new IllegalArgumentException("Illegal tag value: " + tagValue);
          }
      }
  
      /**
       * When output to metrics.log, all the illegal chars will be replaced by "_"
       * @param input the input string
       * @return a string with all the illegal chars replaced by "_"
       */
      @Deprecated
      public static String removeIllegalOpentsdbChars(String input) {
          if (input == null) return null;
          return input.replaceAll(ILLEGAL_CHARS, "_");
      }
  
      public static boolean equals(String s1, String s2) {
  
          if (s1 == null && s2 == null) {
              return true;
          }
  
          if (s1 == null || s2 == null) {
              return false;
          }
  
          return s1.equals(s2);
      }
  
      public static boolean isNotBlank(String s) {
  
          if (s != null && !"".equals(s)) {
              return true;
          }
  
          return false;
      }
  
      public static boolean isBlank(String s) {
  
          if (s == null || "".equals(s)) {
              return true;
          }
  
          return false;
      }
  
  }
  