/*
* 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.pig.newplan.logical.optimizer;
import java.util.Collection;
import org.apache.pig.impl.logicalLayer.FrontendException;
import org.apache.pig.impl.util.MultiMap;
import org.apache.pig.newplan.OperatorPlan;
import org.apache.pig.newplan.PlanWalker;
import org.apache.pig.newplan.logical.expression.LogicalExpressionPlan;
import org.apache.pig.newplan.logical.expression.LogicalExpressionVisitor;
import org.apache.pig.newplan.logical.relational.LOCogroup;
import org.apache.pig.newplan.logical.relational.LOCube;
import org.apache.pig.newplan.logical.relational.LOFilter;
import org.apache.pig.newplan.logical.relational.LOForEach;
import org.apache.pig.newplan.logical.relational.LOGenerate;
import org.apache.pig.newplan.logical.relational.LOInnerLoad;
import org.apache.pig.newplan.logical.relational.LOJoin;
import org.apache.pig.newplan.logical.relational.LOLimit;
import org.apache.pig.newplan.logical.relational.LORank;
import org.apache.pig.newplan.logical.relational.LOSort;
import org.apache.pig.newplan.logical.relational.LOSplitOutput;
import org.apache.pig.newplan.logical.relational.LogicalRelationalNodesVisitor;
import org.apache.pig.newplan.logical.relational.LogicalRelationalOperator;
/**
* A visitor that walks a logical plan and then applies a given
* LogicalExpressionVisitor to all expressions it encounters.
*
*/
public abstract class AllExpressionVisitor extends LogicalRelationalNodesVisitor {
protected LogicalRelationalOperator currentOp;
/**
* @param plan LogicalPlan to visit
* @param walker Walker to use to visit the plan.
*/
public AllExpressionVisitor(OperatorPlan plan,
PlanWalker walker) throws FrontendException {
super(plan, walker);
}
/**
* Get a new instance of the expression visitor to apply to
* a given expression.
* @param expr LogicalExpressionPlan that will be visited
* @return a new LogicalExpressionVisitor for that expression
*/
abstract protected LogicalExpressionVisitor getVisitor(LogicalExpressionPlan expr) throws FrontendException;
private void visitAll(Collection<LogicalExpressionPlan> lexpPlans) throws FrontendException {
for (LogicalExpressionPlan plan : lexpPlans) {
LogicalExpressionVisitor v = getVisitor(plan);
v.visit();
}
}
@Override
public void visit(LOFilter filter) throws FrontendException {
currentOp = filter;
LogicalExpressionVisitor v = getVisitor(filter.getFilterPlan());
v.visit();
}
@Override
public void visit(LOLimit limit) throws FrontendException {
currentOp = limit;
if (limit.getLimitPlan() != null) {
LogicalExpressionVisitor v = getVisitor(limit.getLimitPlan());
v.visit();
}
}
@Override
public void visit(LOJoin join) throws FrontendException {
currentOp = join;
visitAll(join.getExpressionPlanValues());
}
@Override
public void visit(LOCube cu) throws FrontendException {
currentOp = cu;
MultiMap<Integer, LogicalExpressionPlan> expressionPlans = cu.getExpressionPlans();
for (Integer key : expressionPlans.keySet()) {
visitAll(expressionPlans.get(key));
}
}
@Override
public void visit(LOCogroup cg) throws FrontendException {
currentOp = cg;
MultiMap<Integer, LogicalExpressionPlan> expressionPlans = cg.getExpressionPlans();
for( Integer key : expressionPlans.keySet() ) {
visitAll(expressionPlans.get(key));
}
}
@Override
public void visit(LOForEach foreach) throws FrontendException {
currentOp = foreach;
// We have an Inner OperatorPlan in ForEach, so we go ahead
// and work on that plan
OperatorPlan innerPlan = foreach.getInnerPlan();
PlanWalker newWalker = currentWalker.spawnChildWalker(innerPlan);
pushWalker(newWalker);
currentWalker.walk(this);
popWalker();
}
@Override
public void visit(LOGenerate gen ) throws FrontendException {
currentOp = gen;
visitAll(gen.getOutputPlans());
}
@Override
public void visit(LOInnerLoad load) throws FrontendException {
// the expression in LOInnerLoad contains info relative from LOForEach
// so use LOForeach as currentOp
currentOp = load.getLOForEach();
LogicalExpressionPlan exp = (LogicalExpressionPlan)load.getProjection().getPlan();
LogicalExpressionVisitor v = getVisitor(exp);
v.visit();
}
@Override
public void visit(LOSplitOutput splitOutput) throws FrontendException {
currentOp = splitOutput;
LogicalExpressionVisitor v = getVisitor(splitOutput.getFilterPlan());
v.visit();
}
@Override
public void visit(LORank rank) throws FrontendException{
currentOp = rank;
visitAll(rank.getRankColPlans());
}
@Override
public void visit(LOSort sort) throws FrontendException {
currentOp = sort;
visitAll(sort.getSortColPlans());
}
}