/**
* 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.expr.fn.impl;
import com.google.common.base.Charsets;
import org.apache.drill.common.exceptions.DrillRuntimeException;
import org.apache.drill.common.types.TypeProtos;
import org.apache.drill.exec.expr.holders.VarCharHolder;
import org.apache.drill.exec.vector.complex.MapUtility;
import org.apache.drill.exec.vector.complex.impl.SingleMapReaderImpl;
import org.apache.drill.exec.vector.complex.reader.FieldReader;
import org.apache.drill.exec.vector.complex.writer.BaseWriter;
import io.netty.buffer.DrillBuf;
import java.util.Iterator;
public class MappifyUtility {
// Default names used in the map.
public static final String fieldKey = "key";
public static final String fieldValue = "value";
public static void mappify(FieldReader reader, BaseWriter.ComplexWriter writer, DrillBuf buffer) {
// Currently we expect single map as input
if (!(reader instanceof SingleMapReaderImpl)) {
throw new DrillRuntimeException("kvgen function only supports Simple maps as input");
}
BaseWriter.ListWriter listWriter = writer.rootAsList();
listWriter.start();
BaseWriter.MapWriter mapWriter = listWriter.map();
// Iterate over the fields in the map
Iterator<String> fieldIterator = reader.iterator();
while (fieldIterator.hasNext()) {
String str = fieldIterator.next();
FieldReader fieldReader = reader.reader(str);
// Skip the field if its null
if (fieldReader.isSet() == false) {
mapWriter.end();
continue;
}
// Check if the value field is not repeated
if (fieldReader.getType().getMode() == TypeProtos.DataMode.REPEATED) {
throw new DrillRuntimeException("kvgen function does not support repeated type values");
}
// writing a new field, start a new map
mapWriter.start();
// write "key":"columnname" into the map
VarCharHolder vh = new VarCharHolder();
byte[] b = str.getBytes(Charsets.UTF_8);
buffer.reallocIfNeeded(b.length);
buffer.setBytes(0, b);
vh.start = 0;
vh.end = b.length;
vh.buffer = buffer;
mapWriter.varChar(fieldKey).write(vh);
// Write the value to the map
MapUtility.writeToMapFromReader(fieldReader, mapWriter, buffer);
mapWriter.end();
}
listWriter.end();
}
}