/*
* 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.impl.logicalLayer;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.ArrayList;
import java.util.Set;
import org.apache.pig.PigException;
import org.apache.pig.impl.logicalLayer.schema.Schema;
import org.apache.pig.impl.plan.Operator;
import org.apache.pig.impl.plan.OperatorKey;
import org.apache.pig.impl.plan.PlanException;
import org.apache.pig.impl.plan.PlanVisitor;
import org.apache.pig.impl.plan.ProjectionMap;
import org.apache.pig.impl.plan.RequiredFields;
import org.apache.pig.impl.plan.VisitorException;
import org.apache.pig.impl.util.Pair;
import org.apache.pig.data.DataType;
import org.apache.pig.impl.logicalLayer.optimizer.SchemaRemover;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class LOFilter extends RelationalOperator {
private static final long serialVersionUID = 2L;
private LogicalPlan mComparisonPlan;
private static Log log = LogFactory.getLog(LOFilter.class);
/**
*
* @param plan
* Logical plan this operator is a part of.
* @param k
* Operator key to assign to this node.
* @param comparisonPlan
* the filter condition
*/
public LOFilter(LogicalPlan plan, OperatorKey k,
LogicalPlan comparisonPlan) {
super(plan, k);
mComparisonPlan = comparisonPlan;
}
public LogicalOperator getInput() {
return mPlan.getPredecessors(this).get(0);
}
public LogicalPlan getComparisonPlan() {
return mComparisonPlan;
}
@Override
public Schema getSchema() throws FrontendException {
if (!mIsSchemaComputed) {
LogicalOperator input = mPlan.getPredecessors(this).get(0);
ArrayList<Schema.FieldSchema> fss = new ArrayList<Schema.FieldSchema>();
try {
if(input instanceof ExpressionOperator) {
Schema.FieldSchema fs = Schema.FieldSchema.copyAndLink(((ExpressionOperator)input).getFieldSchema(), input);
if(DataType.isSchemaType(fs.type)) {
mSchema = fs.schema;
} else {
fss.add(fs);
mSchema = new Schema(fss);
}
} else {
if (getInput().getSchema()!=null) {
mSchema = Schema.copyAndLink( input.getSchema(), input );
}
else
mSchema = null;
}
mIsSchemaComputed = true;
} catch (FrontendException ioe) {
mSchema = null;
mIsSchemaComputed = false;
throw ioe;
}
}
return mSchema;
}
@Override
public String name() {
return getAliasString() + "Filter " + mKey.scope + "-" + mKey.id;
}
@Override
public boolean supportsMultipleInputs() {
return false;
}
@Override
public void visit(LOVisitor v) throws VisitorException {
v.visit(this);
}
@Override
public byte getType() {
return DataType.BAG ;
}
public void unsetSchema() throws VisitorException{
SchemaRemover sr = new SchemaRemover(mComparisonPlan);
sr.visit();
super.unsetSchema();
}
/**
* @see org.apache.pig.impl.plan.Operator#clone()
* Do not use the clone method directly. Operators are cloned when logical plans
* are cloned using {@link LogicalPlanCloner}
*/
@Override
protected Object clone() throws CloneNotSupportedException {
LOFilter filterClone = (LOFilter)super.clone();
LogicalPlanCloneHelper lpCloner = new LogicalPlanCloneHelper(mComparisonPlan);
filterClone.mComparisonPlan = lpCloner.getClonedPlan();
return filterClone;
}
@Override
public ProjectionMap getProjectionMap() {
if(mIsProjectionMapComputed) return mProjectionMap;
mIsProjectionMapComputed = true;
Schema outputSchema;
try {
outputSchema = getSchema();
} catch (FrontendException fee) {
mProjectionMap = null;
return mProjectionMap;
}
Schema inputSchema = null;
List<LogicalOperator> predecessors = (ArrayList<LogicalOperator>)mPlan.getPredecessors(this);
if(predecessors != null) {
try {
inputSchema = predecessors.get(0).getSchema();
} catch (FrontendException fee) {
mProjectionMap = null;
return mProjectionMap;
}
} else {
mProjectionMap = null;
return mProjectionMap;
}
if(Schema.equals(inputSchema, outputSchema, false, true)) {
//there is a one is to one mapping between input and output schemas
mProjectionMap = new ProjectionMap(false);
return mProjectionMap;
} else {
//problem - input and output schemas for a filter have to match!
mProjectionMap = null;
return mProjectionMap;
}
}
@Override
public List<RequiredFields> getRequiredFields() {
List<RequiredFields> requiredFields = new ArrayList<RequiredFields>();
Set<Pair<Integer, Integer>> fields = new HashSet<Pair<Integer, Integer>>();
TopLevelProjectFinder projectFinder = new TopLevelProjectFinder(
mComparisonPlan);
try {
projectFinder.visit();
} catch (VisitorException ve) {
requiredFields.clear();
requiredFields.add(null);
return requiredFields;
}
Set<LOProject> projectStarSet = projectFinder.getProjectStarSet();
if (projectStarSet != null) {
requiredFields.add(new RequiredFields(true));
return requiredFields;
} else {
for (LOProject project : projectFinder.getProjectSet()) {
for (int inputColumn : project.getProjection()) {
fields.add(new Pair<Integer, Integer>(0,
inputColumn));
}
}
if(fields.size() == 0) {
requiredFields.add(new RequiredFields(false, true));
} else {
requiredFields.add(new RequiredFields(new ArrayList<Pair<Integer, Integer>>(fields)));
}
return (requiredFields.size() == 0? null: requiredFields);
}
}
/* (non-Javadoc)
* @see org.apache.pig.impl.plan.Operator#rewire(org.apache.pig.impl.plan.Operator, org.apache.pig.impl.plan.Operator)
*/
@Override
public void rewire(Operator<LOVisitor> oldPred, int oldPredIndex, Operator<LOVisitor> newPred, boolean useOldPred) throws PlanException {
super.rewire(oldPred, oldPredIndex, newPred, useOldPred);
LogicalOperator previous = (LogicalOperator) oldPred;
LogicalOperator current = (LogicalOperator) newPred;
try {
ProjectFixerUpper projectFixer = new ProjectFixerUpper(
mComparisonPlan, previous, oldPredIndex, current, useOldPred, this);
projectFixer.visit();
} catch (VisitorException ve) {
int errCode = 2144;
String msg = "Problem while fixing project inputs during rewiring.";
throw new PlanException(msg, errCode, PigException.BUG, ve);
}
}
@Override
public List<RequiredFields> getRelevantInputs(int output, int column) throws FrontendException {
if (!mIsSchemaComputed)
getSchema();
if (output!=0)
return null;
if (column<0)
return null;
// if we have schema information, check if output column is valid
if (mSchema!=null)
{
if (column >= mSchema.size())
return null;
}
ArrayList<Pair<Integer, Integer>> inputList = new ArrayList<Pair<Integer, Integer>>();
inputList.add(new Pair<Integer, Integer>(0, column));
List<RequiredFields> result = new ArrayList<RequiredFields>();
result.add(new RequiredFields(inputList));
return result;
}
@Override
public boolean pruneColumns(List<Pair<Integer, Integer>> columns)
throws FrontendException {
if (!mIsSchemaComputed)
getSchema();
if (mSchema == null) {
log
.warn("Cannot prune columns in filter, no schema information found");
return false;
}
for (int i=columns.size()-1;i>=0;i--) {
Pair<Integer, Integer> column = columns.get(i);
if (column.first != 0) {
int errCode = 2191;
throw new FrontendException(
"Filter only take 1 input, cannot prune input with index "
+ column.first, errCode, PigException.BUG);
}
if (column.second < 0) {
int errCode = 2192;
throw new FrontendException("Column to prune does not exist", errCode,
PigException.BUG);
}
pruneColumnInPlan(mComparisonPlan, column.second);
}
super.pruneColumns(columns);
return true;
}
}