asterixdb/asterix-column/src/main/java/org/apache/asterix/column/values/reader/AbstractColumnValuesReader.java

/*
 * 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.asterix.column.values.reader;

import java.io.IOException;

import org.apache.asterix.column.bytes.decoder.ParquetRunLengthBitPackingHybridDecoder;
import org.apache.asterix.column.bytes.stream.in.AbstractBytesInputStream;
import org.apache.asterix.column.bytes.stream.in.ByteBufferInputStream;
import org.apache.asterix.column.bytes.stream.in.MultiByteBufferInputStream;
import org.apache.asterix.column.util.ColumnValuesUtil;
import org.apache.asterix.column.values.IColumnValuesReader;
import org.apache.asterix.column.values.IColumnValuesWriter;
import org.apache.asterix.column.values.reader.value.AbstractValueReader;
import org.apache.asterix.om.types.ATypeTag;
import org.apache.hyracks.api.exceptions.HyracksDataException;
import org.apache.hyracks.data.std.api.IValueReference;
import org.apache.parquet.bytes.BytesUtils;

import com.fasterxml.jackson.databind.node.ObjectNode;

abstract class AbstractColumnValuesReader implements IColumnValuesReader {
    protected final AbstractValueReader valueReader;
    protected final int columnIndex;
    protected final int maxLevel;
    protected final ParquetRunLengthBitPackingHybridDecoder definitionLevels;
    protected final AbstractBytesInputStream valuesStream;
    protected int level;
    protected int valueCount;
    protected int valueIndex;

    private int nullBitMask;
    private boolean nullLevel;
    private boolean allMissing;

    // Logging members
    private int numberOfEncounteredMissing;
    private int numberOfEncounteredNull;

    AbstractColumnValuesReader(AbstractValueReader valueReader, int columnIndex, int maxLevel, boolean primaryKey) {
        this.valueReader = valueReader;
        this.columnIndex = columnIndex;
        this.maxLevel = maxLevel;
        definitionLevels = new ParquetRunLengthBitPackingHybridDecoder(ColumnValuesUtil.getBitWidth(maxLevel));
        valuesStream = primaryKey ? new ByteBufferInputStream() : new MultiByteBufferInputStream();
    }

    final void nextLevel() throws HyracksDataException {
        if (allMissing) {
            return;
        }

        valueIndex++;
        int actualLevel = definitionLevels.readInt();
        //Check whether the level is for a null value
        nullLevel = ColumnValuesUtil.isNull(nullBitMask, actualLevel);
        //Clear the null bit to allow repeated value readers determine the correct delimiter for null values
        level = ColumnValuesUtil.clearNullBit(nullBitMask, actualLevel);
        numberOfEncounteredMissing += isMissing() ? 1 : 0;
        numberOfEncounteredNull += isNull() ? 1 : 0;
    }

    abstract void resetValues();

    @Override
    public final void reset(AbstractBytesInputStream in, int tupleCount) throws HyracksDataException {
        valueIndex = 0;
        numberOfEncounteredMissing = 0;
        numberOfEncounteredNull = 0;
        if (in.available() == 0) {
            allMissing = true;
            level = 0;
            valueCount = tupleCount;
            return;
        }
        allMissing = false;
        try {
            nullBitMask = ColumnValuesUtil.getNullMask(BytesUtils.readZigZagVarInt(in));
            int defLevelsSize = BytesUtils.readZigZagVarInt(in);
            valueCount = BytesUtils.readZigZagVarInt(in);
            definitionLevels.reset(in);
            valuesStream.resetAt(defLevelsSize, in);
            int valueLength = BytesUtils.readZigZagVarInt(valuesStream);
            if (valueLength > 0) {
                valueReader.init(valuesStream, tupleCount);
            }
        } catch (IOException e) {
            throw HyracksDataException.create(e);
        }
        resetValues();
    }

    @Override
    public final ATypeTag getTypeTag() {
        return valueReader.getTypeTag();
    }

    @Override
    public final int getColumnIndex() {
        return columnIndex;
    }

    @Override
    public int getLevel() {
        return level;
    }

    @Override
    public final boolean isMissing() {
        return !isDelimiter() && level < maxLevel;
    }

    @Override
    public final boolean isNull() {
        return nullLevel;
    }

    @Override
    public final boolean isValue() {
        return !isNull() && level == maxLevel;
    }

    @Override
    public final long getLong() {
        return valueReader.getLong();
    }

    @Override
    public final double getDouble() {
        return valueReader.getDouble();
    }

    @Override
    public final boolean getBoolean() {
        return valueReader.getBoolean();
    }

    @Override
    public final IValueReference getBytes() {
        return valueReader.getBytes();
    }

    @Override
    public final int compareTo(IColumnValuesReader o) {
        return valueReader.compareTo(((AbstractColumnValuesReader) o).valueReader);
    }

    @Override
    public final void write(IColumnValuesWriter writer, int count) throws HyracksDataException {
        for (int i = 0; i < count; i++) {
            write(writer, true);
        }
    }

    @Override
    public void skip(int count) throws HyracksDataException {
        for (int i = 0; i < count; i++) {
            next();
        }
    }

    protected void appendCommon(ObjectNode node) {
        node.put("typeTag", getTypeTag().toString());
        node.put("columnIndex", columnIndex);
        node.put("valueIndex", valueIndex);
        node.put("valueCount", valueCount);
        node.put("allMissing", allMissing);
        node.put("level", level);
        node.put("maxLevel", maxLevel);
        node.put("nullBitMask", nullBitMask);
        node.put("numberOfEncounteredMissing", numberOfEncounteredMissing);
        node.put("numberOfEncounteredNull", numberOfEncounteredNull);
    }
}