/*
* Copyright (c) 2007-2014 Concurrent, Inc. All Rights Reserved.
*
* Project and contact information: http://www.cascading.org/
*
* This file is part of the Cascading project.
*
* Licensed 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 cascading.flow.hadoop.planner.rule.scopeexpression;
import java.net.URI;
import cascading.flow.FlowElement;
import cascading.flow.hadoop.planner.HadoopPlanner;
import cascading.flow.planner.PlannerContext;
import cascading.flow.planner.Scope;
import cascading.flow.planner.graph.ElementGraph;
import cascading.flow.planner.iso.expression.ScopeExpression;
import cascading.tap.hadoop.Hfs;
/**
*
*/
public class EquivalentTapsScopeExpression extends ScopeExpression
{
@Override
public boolean applies( PlannerContext plannerContext, ElementGraph elementGraph, Scope scope )
{
FlowElement edgeSource = elementGraph.getEdgeSource( scope );
FlowElement edgeTarget = elementGraph.getEdgeTarget( scope );
if( !( edgeSource instanceof Hfs ) || !( edgeTarget instanceof Hfs ) )
throw new IllegalStateException( "non Hfs Taps matched" );
Hfs predecessor = (Hfs) edgeSource;
Hfs successor = (Hfs) edgeTarget;
// does this scheme source what it sinks
if( !successor.getScheme().isSymmetrical() )
return false;
HadoopPlanner flowPlanner = (HadoopPlanner) plannerContext.getFlowPlanner();
URI tempURIScheme = flowPlanner.getDefaultURIScheme( predecessor ); // temp uses default fs
URI successorURIScheme = flowPlanner.getURIScheme( successor );
if( !tempURIScheme.equals( successorURIScheme ) )
return false;
// safe, both are symmetrical
// should be called after fields are resolved
if( !predecessor.getSourceFields().equals( successor.getSourceFields() ) )
return true;
return true;
}
}