/*
    * 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.giraph.time;
  
  import java.util.concurrent.TimeUnit;
  
  /**
   * Utility methods for Time classes.
   */
  public class Times {
    /** Do not instantiate */
    private Times() { }
  
    /**
     * Convenience method to measure time in a given TimeUnit.
     *
     * @param time Time instance to use
     * @param timeUnit TimeUnit to measure in
     * @return long measured time in TimeUnit dimension
     */
    public static long get(Time time, TimeUnit timeUnit) {
      return timeUnit.convert(time.getNanoseconds(), TimeUnit.NANOSECONDS);
    }
  
    /**
     * Convenience method to get time since the beginning of an event in a given
     * TimeUnit.
     *
     * @param time Time object used for measuring.
     * @param timeUnit TimeUnit to use for dimension.
     * @param startTime beginning time to diff against
     * @return time elapsed since startTime in TimeUnit dimension.
     */
    public static long getDiff(Time time, TimeUnit timeUnit, long startTime) {
      return get(time, timeUnit) - startTime;
    }
  
    /**
     * Convenience method to get milliseconds since a previous milliseconds
     * point.
     *
     * @param time Time instance to use
     * @param previousMilliseconds Previous milliseconds
     * @return Milliseconds elapsed since the previous milliseconds
     */
    public static long getMillisecondsSince(Time time,
                                            long previousMilliseconds) {
      return time.getMilliseconds() - previousMilliseconds;
    }
  
    /**
     * Convenience method to get milliseconds since a previous milliseconds
     * point.
     *
     * @param time Time instance to use
     * @param previousMs Previous milliseconds
     * @return Milliseconds elapsed since the previous milliseconds
     */
    public static long getMsSince(Time time, long previousMs) {
      return getMillisecondsSince(time, previousMs);
    }
  
    /**
     * Convenience method to get microseconds since a previous microseconds point.
     *
     * @param time Time instance to use
     * @param previousMicros Previous microseconds
     * @return Microseconds elapsed since the previous microseconds
     */
    public static long getMicrosSince(Time time, long previousMicros) {
      return time.getMicroseconds() - previousMicros;
    }
  
    /**
     * Convenience method to get nanoseconds since a previous nanoseconds
     * point.
     *
     * @param time Time instance to use
     * @param previousNanoseconds Previous nanoseconds
     * @return Nanoseconds elapsed since the previous nanoseconds
     */
    public static long getNanosecondsSince(Time time, long previousNanoseconds) {
      return time.getNanoseconds() - previousNanoseconds;
   }
 
   /**
    * Convenience method to get nanoseconds since a previous nanoseconds
    * point.
    *
    * @param time Time instance to use
    * @param previousNanos Previous nanoseconds
    * @return Nanoseconds elapsed since the previous nanoseconds
    */
   public static long getNanosSince(Time time, long previousNanos) {
     return getNanosecondsSince(time, previousNanos);
   }
 
   /**
    * Convenience method to get seconds since a previous seconds
    * point.
    *
    * @param time Time instance to use
    * @param previousSeconds Previous seconds
    * @return Seconds elapsed since the previous seconds
    */
   public static int getSecondsSince(Time time, int previousSeconds) {
     return time.getSeconds() - previousSeconds;
   }
 
   /**
    * Convenience method to get seconds since a previous seconds
    * point.
    *
    * @param time Time instance to use
    * @param previousSec Previous seconds
    * @return Seconds elapsed since the previous seconds
    */
   public static int getSecSince(Time time, int previousSec) {
     return getSecondsSince(time, previousSec);
   }
 }