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 org.apache.kafka.trogdor.common;
  
  import java.util.HashSet;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * Utilities for expanding strings that have range expressions in them.
   *
   * For example, 'foo[1-3]' would be expaneded to foo1, foo2, foo3.
   * Strings that have no range expressions will not be expanded.
   */
  public class StringExpander {
      private static final Pattern NUMERIC_RANGE_PATTERN =
          Pattern.compile("(.*)\\[([0-9]*)\\-([0-9]*)\\](.*)");
  
      public static HashSet<String> expand(String val) {
          HashSet<String> set = new HashSet<>();
          Matcher matcher = NUMERIC_RANGE_PATTERN.matcher(val);
          if (!matcher.matches()) {
              set.add(val);
              return set;
          }
          String prequel = matcher.group(1);
          String rangeStart = matcher.group(2);
          String rangeEnd = matcher.group(3);
          String epilog = matcher.group(4);
          int rangeStartInt = Integer.parseInt(rangeStart);
          int rangeEndInt = Integer.parseInt(rangeEnd);
          if (rangeEndInt < rangeStartInt) {
              throw new RuntimeException("Invalid range: start " + rangeStartInt +
                      " is higher than end " + rangeEndInt);
          }
          for (int i = rangeStartInt; i <= rangeEndInt; i++) {
              set.add(String.format("%s%d%s", prequel, i, epilog));
          }
          return set;
      }
  }
  