/*
 * Copyright 2017, OpenCensus Authors
 *
 * 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.
 */

package io.opencensus.common;

/**
 * Interface for getting the current time.
 *
 * @since 0.5
 */
public abstract class Clock {

  /**
   * Obtains the current instant from this clock.
   *
   * @return the current instant.
   * @since 0.5
   */
  public abstract Timestamp now();

  /**
   * Returns a time measurement with nanosecond precision that can only be used to calculate elapsed
   * time.
   *
   * @return a time measurement with nanosecond precision that can only be used to calculate elapsed
   *     time.
   * @since 0.5
   */
  public abstract long nowNanos();
}