    001    /*
    002     * Copyright (c) 2007-2014 Concurrent, 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
    021    package cascading.cascade.planner;
    022
    023    import java.util.Comparator;
    024    import java.util.HashSet;
    025    import java.util.List;
    026    import java.util.PriorityQueue;
    027    import java.util.Set;
    028
    029    import cascading.cascade.CascadeException;
    030    import cascading.flow.BaseFlow;
    031    import cascading.flow.Flow;
    032    import org.jgrapht.Graphs;
    033    import org.jgrapht.graph.SimpleDirectedGraph;
    034    import org.jgrapht.traverse.TopologicalOrderIterator;
    035    import org.slf4j.Logger;
    036    import org.slf4j.LoggerFactory;
    037
    038    /**
    039     *
    040     */
    041    public class FlowGraph extends SimpleDirectedGraph<Flow, Integer>
    042      {
    043      private static final Logger LOG = LoggerFactory.getLogger( FlowGraph.class );
    044
    045      public FlowGraph( IdentifierGraph identifierGraph )
    046        {
    047        super( Integer.class );
    048
    049        makeGraph( identifierGraph );
    050
    051        verifyNoCycles();
    052        }
    053
    054      public TopologicalOrderIterator<Flow, Integer> getTopologicalIterator()
    055        {
    056        return new TopologicalOrderIterator<Flow, Integer>( this, new PriorityQueue<Flow>( 10, new Comparator<Flow>()
    057        {
    058        @Override
    059        public int compare( Flow lhs, Flow rhs )
    060          {
    061          return Integer.valueOf( lhs.getSubmitPriority() ).compareTo( rhs.getSubmitPriority() );
    062          }
    063        } ) );
    064        }
    065
    066      private void verifyNoCycles()
    067        {
    068        Set<Flow> flows = new HashSet<Flow>();
    069
    070        TopologicalOrderIterator<Flow, Integer> topoIterator = new TopologicalOrderIterator<Flow, Integer>( this );
    071
    072        while( topoIterator.hasNext() )
    073          flows.add( topoIterator.next() );
    074
    075        if( flows.size() != vertexSet().size() )
    076          throw new CascadeException( "there are likely cycles in the set of given flows, topological iterator cannot traverse flows with cycles" );
    077        }
    078
    079      private void makeGraph( IdentifierGraph identifierGraph )
    080        {
    081        Set<String> identifiers = identifierGraph.vertexSet();
    082
    083        int count = 0;
    084
    085        for( String source : identifiers )
    086          {
    087          if( LOG.isDebugEnabled() )
    088            LOG.debug( "handling flow source: {}", source );
    089
    090          List<String> sinks = Graphs.successorListOf( identifierGraph, source );
    091
    092          for( String sink : sinks )
    093            {
    094            if( LOG.isDebugEnabled() )
    095              LOG.debug( "handling flow path: {} -> {}", source, sink );
    096
    097            Flow flow = identifierGraph.getEdge( source, sink ).flow;
    098
    099            addVertex( flow );
    100
    101            Set<BaseFlow.FlowHolder> previous = identifierGraph.incomingEdgesOf( source );
    102
    103            for( BaseFlow.FlowHolder previousFlow : previous )
    104              {
    105              addVertex( previousFlow.flow );
    106
    107              if( getEdge( previousFlow.flow, flow ) != null )
    108                continue;
    109
    110              if( !addEdge( previousFlow.flow, flow, count++ ) )
    111                throw new CascadeException( "unable to add path between: " + previousFlow.flow.getName() + " and: " + flow.getName() );
    112              }
    113            }
    114          }
    115        }
    116      }