/**
 * 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 kafka.utils

import java.util.concurrent._

/**
 * A class used for unit testing things which depend on the Time interface.
 * 
 * This class never manually advances the clock, it only does so when you call
 *   sleep(ms)
 * 
 * It also comes with an associated scheduler instance for managing background tasks in
 * a deterministic way.
 */
class MockTime(@volatile private var currentMs: Long) extends Time {
  
  val scheduler = new MockScheduler(this)
  
  def this() = this(System.currentTimeMillis)
  
  def milliseconds: Long = currentMs

  def nanoseconds: Long = 
    TimeUnit.NANOSECONDS.convert(currentMs, TimeUnit.MILLISECONDS)

  def sleep(ms: Long) {
    this.currentMs += ms
    scheduler.tick()
  }
  
  override def toString() = "MockTime(%d)".format(milliseconds)

}