content: package act.metric;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * 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.
   * #L%
   */
  
  import org.osgl.util.E;
  import org.osgl.util.S;
  
  enum DurationScale {
      ns("ns", 1),
      ms("ms", 1000L * 1000L),
      second("s", 1000L * 1000L * 1000L),
      minute("min", 1000L * 1000L * 1000L * 60L),
      hour("h", 1000L * 1000L * 1000L * 60L * 60L),
      day("d", 1000L * 1000L * 1000L * 60L * 60L * 24L),
      week(" week(s)", 1000L * 1000L * 1000L * 60L * 60L * 24L * 7L),
      mon(" month(s)", 1000L * 1000L * 1000L * 60L * 60L * 24L * 30L),
      year(" year(s)", 1000L * 1000L * 1000L * 60L * 60L * 24L * 365L)
      ;
      long value;
      String suffix;
      DurationScale(long value) {
          this.value = value;
      }
      DurationScale(String suffix, long value) {
          this.value = value;
          this.suffix = suffix;
      }
      public static String format(long ns) {
          E.illegalArgumentIf(ns < 0, "duration cannot be negative number");
          if (ns == 0) {
              return "0";
          }
          DurationScale last = DurationScale.year;
          for (DurationScale s : DurationScale.values()) {
              if (s.value <= ns) {
                  last = s;
              } else {
                  break;
              }
          }
          String s;
          if (last == DurationScale.ns) {
              if (ns > 1000L * 10) {
                  last = DurationScale.ms;
                  long l = (ns * 100L) / last.value;
                  s = S.str(l).prepend("0").insert(-2, '.').toString();
              } else {
                  s = S.string(ns);
              }
  
          } else {
              long l = ns / (last.value / 100L);
              s = S.str(l).insert(-2, '.').toString();
          }
          if (s.startsWith(".")) {
              s = S.concat("0", s);
          }
          return S.concat(s, last.suffix);
      }
  
      private String suffix() {
          String suffix = this.suffix;
          if (null == suffix) {
              suffix = this.name();
          }
          return suffix;
      }
  
  }
  