code: /**
   * Copyright 2013 Alexey Ragozin
   *
   * 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.
   */
  package org.gridkit.jvmtool.cli;
  
  import java.math.BigInteger;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.TimeUnit;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import com.beust.jcommander.IStringConverter;
  
  /**
   * @author Alexey Ragozin (alexey.ragozin@gmail.com)
   */
  public class TimeIntervalConverter implements IStringConverter<Long> {
  
      private static int DURATION_GROUP = 1;
      private static int TIME_UNIT_GROUP = 2;
  
      private static final String TI_REGEX = "(\\d+)\\s*(\\w+)";
      private static final Pattern TI_PATTERN = Pattern.compile(TI_REGEX);
  
      private static final String MTI_REGEX = String.format("(%s\\s+)+", TI_REGEX);
      private static final Pattern MTI_PATTERN = Pattern.compile(MTI_REGEX);
  
      private static final BigInteger LONG_MAX = BigInteger.valueOf(Long.MAX_VALUE);
  
      private static final Map<String, TimeUnit> timeUnitAlias = new HashMap<String, TimeUnit>();
  
      static {
          timeUnitAlias.put("ms", TimeUnit.MILLISECONDS);
          timeUnitAlias.put("s",  TimeUnit.SECONDS);
          timeUnitAlias.put("m",  TimeUnit.MINUTES);
          timeUnitAlias.put("h",  TimeUnit.HOURS);
          timeUnitAlias.put("d",  TimeUnit.DAYS);
      }
  
      public static long toMillis(String rawStr) {
          if (rawStr == null)
              throw new NullPointerException("Null argument is not allowed");
  
          String str = rawStr.trim() + " ";
          Matcher matcher = MTI_PATTERN.matcher(str);
  
          if (!matcher.matches())
              throw new IllegalArgumentException(String.format("'%s' doesn't match duration pattern", rawStr));
  
          matcher = TI_PATTERN.matcher(str);
  
          BigInteger result = BigInteger.ZERO;
  
          while (matcher.find()) {
              String unitAlias = matcher.group(TIME_UNIT_GROUP).toLowerCase();
              TimeUnit timeUnit = timeUnitAlias.get(unitAlias);
  
              if (timeUnit == null) {
                  throw new IllegalArgumentException(String.format("Unknown time unit alias '%s' in '%s'", unitAlias, rawStr));
              }
  
              long summand;
              try {
                  summand = Long.valueOf(matcher.group(DURATION_GROUP));
              } catch (NumberFormatException e) {
                  throw new IllegalArgumentException("Number overflow for duration '" + rawStr + "'", e);
              }
  
              result = result.add(BigInteger.valueOf(timeUnit.toMillis(summand)));
          }
  
          if (result.compareTo(LONG_MAX) == 1)
              throw new IllegalArgumentException("Number overflow for duration '" + rawStr + "'");
  
          return result.longValue();
      }
  
      @Override
      public Long convert(String value) {
          return toMillis(value);
      }
  }
  