/**
    * Copyright (c) 2004-2011 QOS.ch
    * All rights reserved.
    *
    * Permission is hereby granted, free  of charge, to any person obtaining
    * a  copy  of this  software  and  associated  documentation files  (the
    * "Software"), to  deal in  the Software without  restriction, including
    * without limitation  the rights to  use, copy, modify,  merge, publish,
    * distribute,  sublicense, and/or sell  copies of  the Software,  and to
   * permit persons to whom the Software  is furnished to do so, subject to
   * the following conditions:
   *
   * The  above  copyright  notice  and  this permission  notice  shall  be
   * included in all copies or substantial portions of the Software.
   *
   * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
   * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
   * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   *
   */
  package org.slf4j.profiler;
  
  /**
   * A very basic {@link TimeInstrument} which can be started and stopped
   * once and only once.
   * 
   * @author Ceki Gülcü
   *
   */
  public class StopWatch implements TimeInstrument {
  
      private String name;
      private long startTime;
      private long stopTime;
      TimeInstrumentStatus status;
  
      public StopWatch(String name) {
          start(name);
      }
  
      StopWatch(StopWatch original) {
          this.name = original.name;
          this.startTime = original.startTime;
          this.stopTime = original.stopTime;
          this.status = original.status;
      }
  
      public void start(String name) {
          this.name = name;
          startTime = System.nanoTime();
          status = TimeInstrumentStatus.STARTED;
      }
  
      public String getName() {
          return name;
      }
  
      public TimeInstrument stop() {
          if (status == TimeInstrumentStatus.STOPPED) {
              return this;
          }
          return stop(System.nanoTime());
      }
  
      public StopWatch stop(long stopTime) {
          this.status = TimeInstrumentStatus.STOPPED;
          this.stopTime = stopTime;
          return this;
      }
  
      @Override
      public String toString() {
          StringBuilder buf = new StringBuilder();
          buf.append("StopWatch [");
          buf.append(name);
          buf.append("] ");
  
          switch (status) {
          case STARTED:
              buf.append("STARTED");
              break;
          case STOPPED:
              buf.append("elapsed time: ");
              buf.append(Util.durationInDurationUnitsAsStr(elapsedTime(), DurationUnit.MICROSECOND));
              break;
          default:
              throw new IllegalStateException("Status " + status + " is not expected");
          }
          return buf.toString();
      }
  
      public final long elapsedTime() {
          if (status == TimeInstrumentStatus.STARTED) {
              return 0;
          } else {
             return stopTime - startTime;
         }
     }
 
     public TimeInstrumentStatus getStatus() {
         return status;
     }
 
     public void print() {
         System.out.println(toString());
     }
 
     public void log() {
         throw new UnsupportedOperationException("A stopwatch instance does not know how to log");
     }
 
 }