    001/*
    002 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
    003 *
    004 * Project and contact information: http://www.cascading.org/
    005 *
    006 * This file is part of the Cascading project.
    007 *
    008 * Licensed under the Apache License, Version 2.0 (the "License");
    009 * you may not use this file except in compliance with the License.
    010 * You may obtain a copy of the License at
    011 *
    012 *     http://www.apache.org/licenses/LICENSE-2.0
    013 *
    014 * Unless required by applicable law or agreed to in writing, software
    015 * distributed under the License is distributed on an "AS IS" BASIS,
    016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    017 * See the License for the specific language governing permissions and
    018 * limitations under the License.
    019 */
    020
    021package cascading.flow;
    022
    023import java.io.IOException;
    024
    025/**
    026 * Class FlowSkipIfSinkNotStale is a {@link cascading.flow.FlowSkipStrategy} implementation that returns
    027 * {@code true} if the Flow sink exists and is not stale in relation to the Flow sources.
    028 * <p/>
    029 * This is the default Cascading strategy.
    030 *
    031 * @see cascading.flow.FlowSkipIfSinkExists
    032 */
    033public class FlowSkipIfSinkNotStale implements FlowSkipStrategy
    034  {
    035  public boolean skipFlow( Flow flow ) throws IOException
    036    {
    037    long sinkModified = flow.getSinkModified();
    038
    039    return sinkModified > 0 && !flow.areSourcesNewer( sinkModified );
    040    }
    041  }