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 CountScale {
      nil("", 1L),
      kilo("k", 1000L),
      million("m", 1000L * 1000L),
      billion("b", 1000L * 1000L * 1000L),
      tera("t", 1000L * 1000L * 1000L * 1000L),
      peta("p", 1000L * 1000L * 1000L * 1000L * 1000L),
      exa("e", 1000L * 1000L * 1000L * 1000L * 1000L * 1000L)
      ;
      long value;
      String suffix;
      CountScale(long value) {
          this.value = value;
      }
      CountScale(String suffix, long value) {
          this.value = value;
          this.suffix = suffix;
      }
      public static String format(long count) {
          E.illegalArgumentIf(count < 0, "counts cannot be negative number");
          if (count == 0) {
              return "0";
          }
          CountScale last = CountScale.exa;
          for (CountScale s : CountScale.values()) {
              if (s.value <= count) {
                  last = s;
              } else {
                  break;
              }
          }
          if (last == nil) {
              return S.string(count);
          }
          long l = count / (last.value / 100L);
          String s = S.str(l).insert(-2, '.').toString();
          if (s.endsWith(".00")) {
              s = s.substring(0, s.length() - 3);
          }
          return S.fmt("%s%s", s, last.suffix());
      }
  
      private String suffix() {
          String suffix = this.suffix;
          if (null == suffix) {
              suffix = this.name();
          }
          return suffix;
      }
  
  }
  