/**
* 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.ref.rops;
import org.apache.drill.common.expression.SchemaPath;
import org.apache.drill.common.logical.data.Flatten;
import org.apache.drill.common.types.TypeProtos.DataMode;
import org.apache.drill.exec.ref.RecordIterator;
import org.apache.drill.exec.ref.RecordPointer;
import org.apache.drill.exec.ref.UnbackedRecord;
import org.apache.drill.exec.ref.eval.EvaluatorFactory;
import org.apache.drill.exec.ref.eval.EvaluatorTypes.BasicEvaluator;
import org.apache.drill.exec.ref.values.BaseArrayValue;
import org.apache.drill.exec.ref.values.DataValue;
import org.apache.drill.exec.ref.values.SimpleArrayValue;
public class FlattenROP extends SingleInputROPBase<Flatten> {
static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(FlattenROP.class);
private RecordPointer outputRecord = new UnbackedRecord();
private BasicEvaluator evaluator;
private RecordIterator iter;
public FlattenROP(Flatten config) {
super(config);
}
@Override
protected void setInput(RecordIterator incoming) {
this.iter = new FlattenIterator(incoming);
}
@Override
protected RecordIterator getIteratorInternal() {
return iter;
}
@Override
protected void setupEvals(EvaluatorFactory builder) {
evaluator = builder.getBasicEvaluator(record, config.getExpr());
}
private class ArrayValueIterator {
private BaseArrayValue arrayValue;
private int currentIndex = 0;
public ArrayValueIterator(BaseArrayValue arrayValue) {
this.arrayValue = arrayValue;
}
public ArrayValueIterator() {
this(new SimpleArrayValue());
}
public DataValue next() {
DataValue v = null;
if (currentIndex < arrayValue.size()) {
v = arrayValue.getByArrayIndex(currentIndex);
}
currentIndex++;
return v;
}
}
private class FlattenIterator implements RecordIterator {
RecordIterator incoming;
NextOutcome currentOutcome;
int currentIndex = 0;
ArrayValueIterator arrayValueIterator = new ArrayValueIterator();
public FlattenIterator(RecordIterator incoming) {
super();
this.incoming = incoming;
}
@Override
public RecordPointer getRecordPointer() {
return outputRecord;
}
@Override
public NextOutcome next() {
DataValue v;
if ((v = arrayValueIterator.next()) != null) //if we are already iterating through a sub-array, keep going
return mergeValue(v);
else //otherwise, get the next record
currentOutcome = incoming.next();
if (currentOutcome != NextOutcome.NONE_LEFT) {
if (evaluator.eval().getDataType().getMode() == DataMode.REPEATED) {
arrayValueIterator = new ArrayValueIterator(evaluator.eval().getAsContainer().getAsArray());
while ((v = arrayValueIterator.next()) != null) {
return mergeValue(v);
}
} else {
outputRecord.copyFrom(record);
outputRecord.addField(config.getName(), evaluator.eval());
if(config.isDrop())
outputRecord.removeField((SchemaPath)config.getExpr());
}
}
return currentOutcome;
}
// helper function to merge one of the values from a sub array into the parent record
private NextOutcome mergeValue(DataValue v) {
outputRecord.copyFrom(record);
outputRecord.addField(config.getName(), v);
if(config.isDrop())
outputRecord.removeField((SchemaPath)config.getExpr());
return NextOutcome.INCREMENTED_SCHEMA_CHANGED;
}
@Override
public ROP getParent() {
return FlattenROP.this;
}
}
}