001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.reef.runtime.common.driver.idle;
020
021import org.apache.reef.tang.InjectionFuture;
022import org.apache.reef.wake.EventHandler;
023import org.apache.reef.wake.time.Clock;
024import org.apache.reef.wake.time.runtime.event.IdleClock;
025
026import javax.inject.Inject;
027
028/**
029 * Informs the DriverIdleManager of clock idleness.
030 */
031public final class ClockIdlenessSource implements DriverIdlenessSource, EventHandler<IdleClock> {
032  private static final String COMPONENT_NAME = "Clock";
033  private static final String IDLE_REASON = "The clock reported idle.";
034  private static final IdleMessage IDLE_MESSAGE = new IdleMessage(COMPONENT_NAME, IDLE_REASON, true);
035  private static final String NOT_IDLE_REASON = "The clock reported not idle.";
036  private static final IdleMessage NOT_IDLE_MESSAGE = new IdleMessage(COMPONENT_NAME, NOT_IDLE_REASON, false);
037
038  private final InjectionFuture<DriverIdleManager> driverIdleManager;
039  private final Clock clock;
040
041  @Inject
042  ClockIdlenessSource(final InjectionFuture<DriverIdleManager> driverIdleManager, final Clock clock) {
043    this.driverIdleManager = driverIdleManager;
044    this.clock = clock;
045  }
046
047  @Override
048  public synchronized IdleMessage getIdleStatus() {
049    if (this.clock.isIdle()) {
050      return IDLE_MESSAGE;
051    } else {
052      return NOT_IDLE_MESSAGE;
053    }
054  }
055
056  @Override
057  public synchronized void onNext(final IdleClock idleClock) {
058    this.driverIdleManager.get().onPotentiallyIdle(IDLE_MESSAGE);
059  }
060}