Source code

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.io.data.loading.api;
020
021import org.apache.reef.driver.evaluator.EvaluatorRequest;
022import org.apache.reef.driver.evaluator.EvaluatorRequestor;
023import org.apache.reef.wake.EventHandler;
024
025import java.util.concurrent.CountDownLatch;
026import java.util.logging.Level;
027import java.util.logging.Logger;
028
029public class ResourceRequestHandler implements EventHandler<EvaluatorRequest> {
030
031  private static final Logger LOG = Logger.getLogger(ResourceRequestHandler.class.getName());
032
033  private final EvaluatorRequestor requestor;
034
035  private CountDownLatch resourceRequestGate = new CountDownLatch(1);
036
037  public ResourceRequestHandler(final EvaluatorRequestor requestor) {
038    this.requestor = requestor;
039  }
040
041  public void releaseResourceRequestGate() {
042    LOG.log(Level.FINE, "Releasing Gate");
043    this.resourceRequestGate.countDown();
044  }
045
046  @Override
047  public void onNext(final EvaluatorRequest request) {
048    try {
049
050      LOG.log(Level.FINE,
051          "Processing a request with count: {0} - Waiting for gate to be released",
052          request.getNumber());
053
054      this.resourceRequestGate.await();
055
056      LOG.log(Level.FINE, "Gate released. Submitting request: {0}", request);
057      this.resourceRequestGate = new CountDownLatch(1);
058      this.requestor.submit(request);
059
060    } catch (final InterruptedException ex) {
061      LOG.log(Level.FINEST, "Interrupted", ex);
062    }
063  }
064}