/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.drill.exec.planner.fragment;
import org.apache.drill.exec.exception.FragmentSetupException;
import org.apache.drill.exec.physical.base.AbstractPhysicalVisitor;
import org.apache.drill.exec.physical.base.Exchange;
import org.apache.drill.exec.physical.base.PhysicalOperator;
import org.apache.drill.exec.physical.base.SubScan;
/**
* Responsible for breaking a plan into its constituent Fragments.
*/
public class MakeFragmentsVisitor extends AbstractPhysicalVisitor<Fragment, Fragment, FragmentSetupException> {
static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(MakeFragmentsVisitor.class);
public MakeFragmentsVisitor(){
}
@Override
public Fragment visitExchange(Exchange exchange, Fragment value) throws FragmentSetupException {
// logger.debug("Visiting Exchange {}", exchange);
if(value == null) throw new FragmentSetupException("The simple fragmenter was called without a FragmentBuilder value. This will only happen if the initial call to SimpleFragmenter is by a Exchange node. This should never happen since an Exchange node should never be the root node of a plan.");
Fragment next = getNextBuilder();
value.addReceiveExchange(exchange, next);
next.addSendExchange(exchange);
exchange.getChild().accept(this, next);
return value;
}
@Override
public Fragment visitSubScan(SubScan subScan, Fragment value) throws FragmentSetupException {
// TODO - implement this
return super.visitOp(subScan, value);
}
@Override
public Fragment visitOp(PhysicalOperator op, Fragment value) throws FragmentSetupException{
// logger.debug("Visiting Other {}", op);
value = ensureBuilder(value);
value.addOperator(op);
for(PhysicalOperator child : op){
child.accept(this, value);
}
return value;
}
private Fragment ensureBuilder(Fragment value) throws FragmentSetupException{
if(value != null){
return value;
}else{
return getNextBuilder();
}
}
public Fragment getNextBuilder(){
return new Fragment();
}
}