/**
 * 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.hadoop.fs.slive;

/**
 * Simple timer class that abstracts time access
 */
class Timer {

  // no construction allowed
  private Timer() {

  }

  /**
   * The current time in milliseconds
   * 
   * @return long (milliseconds)
   */
  static long now() {
    return System.currentTimeMillis();
  }

  /**
   * Calculates how much time in milliseconds elapsed from given start time to
   * the current time in milliseconds
   * 
   * @param startTime
   * @return elapsed time (milliseconds)
   */
  static long elapsed(long startTime) {
    long elapsedTime = now() - startTime;
    if (elapsedTime < 0) {
      elapsedTime = 0;
    }
    return elapsedTime;
  }

}
