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parquet.column.impl.ColumnReaderImpl Maven / Gradle / Ivy
/**
* Copyright 2012 Twitter, Inc.
*
* Licensed 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 parquet.column.impl;
import static java.lang.String.format;
import static parquet.Log.DEBUG;
import static parquet.Preconditions.checkNotNull;
import java.io.IOException;
import parquet.Log;
import parquet.column.ColumnDescriptor;
import parquet.column.ColumnReader;
import parquet.column.Dictionary;
import parquet.column.ValuesType;
import parquet.column.page.DictionaryPage;
import parquet.column.page.Page;
import parquet.column.page.PageReader;
import parquet.column.values.ValuesReader;
import parquet.io.ParquetDecodingException;
import parquet.io.api.Binary;
import parquet.io.api.PrimitiveConverter;
import parquet.schema.PrimitiveType.PrimitiveTypeName;
import parquet.schema.PrimitiveType.PrimitiveTypeNameConverter;
/**
* ColumnReader implementation
*
* @author Julien Le Dem
*
*/
class ColumnReaderImpl implements ColumnReader {
private static final Log LOG = Log.getLog(ColumnReaderImpl.class);
/**
* binds the lower level page decoder to the record converter materializing the records
*
* @author Julien Le Dem
*
*/
private static abstract class Binding {
/**
* read one value from the underlying page
*/
abstract void read();
/**
* skip one value from the underlying page
*/
abstract void skip();
/**
* write current value to converter
*/
abstract void writeValue();
/**
* @return current value
*/
public int getDictionaryId() {
throw new UnsupportedOperationException();
}
/**
* @return current value
*/
public int getInteger() {
throw new UnsupportedOperationException();
}
/**
* @return current value
*/
public boolean getBoolean() {
throw new UnsupportedOperationException();
}
/**
* @return current value
*/
public long getLong() {
throw new UnsupportedOperationException();
}
/**
* @return current value
*/
public Binary getBinary() {
throw new UnsupportedOperationException();
}
/**
* @return current value
*/
public float getFloat() {
throw new UnsupportedOperationException();
}
/**
* @return current value
*/
public double getDouble() {
throw new UnsupportedOperationException();
}
}
private final ColumnDescriptor path;
private final long totalValueCount;
private final PageReader pageReader;
private final Dictionary dictionary;
private ValuesReader repetitionLevelColumn;
private ValuesReader definitionLevelColumn;
protected ValuesReader dataColumn;
private int repetitionLevel;
private int definitionLevel;
private int dictionaryId;
private long endOfPageValueCount;
private int readValues;
private int pageValueCount;
private final PrimitiveConverter converter;
private Binding binding;
// this is needed because we will attempt to read the value twice when filtering
// TODO: rework that
private boolean valueRead;
private void bindToDictionary(final Dictionary dictionary) {
binding =
new Binding() {
void read() {
dictionaryId = dataColumn.readValueDictionaryId();
}
public void skip() {
dataColumn.skip();
}
public int getDictionaryId() {
return dictionaryId;
}
void writeValue() {
converter.addValueFromDictionary(dictionaryId);
}
public int getInteger() {
return dictionary.decodeToInt(dictionaryId);
}
public boolean getBoolean() {
return dictionary.decodeToBoolean(dictionaryId);
}
public long getLong() {
return dictionary.decodeToLong(dictionaryId);
}
public Binary getBinary() {
return dictionary.decodeToBinary(dictionaryId);
}
public float getFloat() {
return dictionary.decodeToFloat(dictionaryId);
}
public double getDouble() {
return dictionary.decodeToDouble(dictionaryId);
}
};
}
private void bind(PrimitiveTypeName type) {
binding = type.convert(new PrimitiveTypeNameConverter() {
@Override
public Binding convertFLOAT(PrimitiveTypeName primitiveTypeName) throws RuntimeException {
return new Binding() {
float current;
void read() {
current = dataColumn.readFloat();
}
public void skip() {
current = 0;
dataColumn.skip();
}
public float getFloat() {
return current;
}
void writeValue() {
converter.addFloat(current);
}
};
}
@Override
public Binding convertDOUBLE(PrimitiveTypeName primitiveTypeName) throws RuntimeException {
return new Binding() {
double current;
void read() {
current = dataColumn.readDouble();
}
public void skip() {
current = 0;
dataColumn.skip();
}
public double getDouble() {
return current;
}
void writeValue() {
converter.addDouble(current);
}
};
}
@Override
public Binding convertINT32(PrimitiveTypeName primitiveTypeName) throws RuntimeException {
return new Binding() {
int current;
void read() {
current = dataColumn.readInteger();
}
public void skip() {
current = 0;
dataColumn.skip();
}
@Override
public int getInteger() {
return current;
}
void writeValue() {
converter.addInt(current);
}
};
}
@Override
public Binding convertINT64(PrimitiveTypeName primitiveTypeName) throws RuntimeException {
return new Binding() {
long current;
void read() {
current = dataColumn.readLong();
}
public void skip() {
current = 0;
dataColumn.skip();
}
@Override
public long getLong() {
return current;
}
void writeValue() {
converter.addLong(current);
}
};
}
@Override
public Binding convertINT96(PrimitiveTypeName primitiveTypeName) throws RuntimeException {
return this.convertBINARY(primitiveTypeName);
}
@Override
public Binding convertFIXED_LEN_BYTE_ARRAY(
PrimitiveTypeName primitiveTypeName) throws RuntimeException {
return this.convertBINARY(primitiveTypeName);
}
@Override
public Binding convertBOOLEAN(PrimitiveTypeName primitiveTypeName) throws RuntimeException {
return new Binding() {
boolean current;
void read() {
current = dataColumn.readBoolean();
}
public void skip() {
current = false;
dataColumn.skip();
}
@Override
public boolean getBoolean() {
return current;
}
void writeValue() {
converter.addBoolean(current);
}
};
}
@Override
public Binding convertBINARY(PrimitiveTypeName primitiveTypeName) throws RuntimeException {
return new Binding() {
Binary current;
void read() {
current = dataColumn.readBytes();
}
public void skip() {
current = null;
dataColumn.skip();
}
@Override
public Binary getBinary() {
return current;
}
void writeValue() {
converter.addBinary(current);
}
};
}
});
}
/**
* creates a reader for triplets
* @param path the descriptor for the corresponding column
* @param pageReader the underlying store to read from
*/
public ColumnReaderImpl(ColumnDescriptor path, PageReader pageReader, PrimitiveConverter converter) {
this.path = checkNotNull(path, "path");
this.pageReader = checkNotNull(pageReader, "pageReader");
this.converter = checkNotNull(converter, "converter");
DictionaryPage dictionaryPage = pageReader.readDictionaryPage();
if (dictionaryPage != null) {
try {
this.dictionary = dictionaryPage.getEncoding().initDictionary(path, dictionaryPage);
if (converter.hasDictionarySupport()) {
converter.setDictionary(dictionary);
}
} catch (IOException e) {
throw new ParquetDecodingException("could not decode the dictionary for " + path, e);
}
} else {
this.dictionary = null;
}
this.totalValueCount = pageReader.getTotalValueCount();
if (totalValueCount == 0) {
throw new ParquetDecodingException("totalValueCount == 0");
}
consume();
}
private boolean isFullyConsumed() {
return readValues >= totalValueCount;
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#writeCurrentValueToConverter()
*/
@Override
public void writeCurrentValueToConverter() {
readValue();
this.binding.writeValue();
}
@Override
public int getCurrentValueDictionaryID() {
readValue();
return binding.getDictionaryId();
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getInteger()
*/
@Override
public int getInteger() {
readValue();
return this.binding.getInteger();
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getBoolean()
*/
@Override
public boolean getBoolean() {
readValue();
return this.binding.getBoolean();
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getLong()
*/
@Override
public long getLong() {
readValue();
return this.binding.getLong();
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getBinary()
*/
@Override
public Binary getBinary() {
readValue();
return this.binding.getBinary();
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getFloat()
*/
@Override
public float getFloat() {
readValue();
return this.binding.getFloat();
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getDouble()
*/
@Override
public double getDouble() {
readValue();
return this.binding.getDouble();
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getCurrentRepetitionLevel()
*/
@Override
public int getCurrentRepetitionLevel() {
return repetitionLevel;
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getDescriptor()
*/
@Override
public ColumnDescriptor getDescriptor() {
return path;
}
/**
* Reads the value into the binding.
*/
public void readValue() {
try {
if (!valueRead) {
binding.read();
valueRead = true;
}
} catch (RuntimeException e) {
throw new ParquetDecodingException(
format(
"Can't read value in column %s at value %d out of %d, %d out of %d in currentPage. repetition level: %d, definition level: %d",
path, readValues, totalValueCount, readValues - (endOfPageValueCount - pageValueCount), pageValueCount, repetitionLevel, definitionLevel),
e);
}
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#skip()
*/
@Override
public void skip() {
if (!valueRead) {
binding.skip();
valueRead = true;
}
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getCurrentDefinitionLevel()
*/
@Override
public int getCurrentDefinitionLevel() {
return definitionLevel;
}
// TODO: change the logic around read() to not tie together reading from the 3 columns
private void readRepetitionAndDefinitionLevels() {
repetitionLevel = repetitionLevelColumn.readInteger();
definitionLevel = definitionLevelColumn.readInteger();
++readValues;
}
private void checkRead() {
if (isPageFullyConsumed()) {
if (isFullyConsumed()) {
if (DEBUG) LOG.debug("end reached");
repetitionLevel = 0; // the next repetition level
return;
}
readPage();
}
readRepetitionAndDefinitionLevels();
}
private void readPage() {
if (DEBUG) LOG.debug("loading page");
Page page = pageReader.readPage();
this.repetitionLevelColumn = page.getRlEncoding().getValuesReader(path, ValuesType.REPETITION_LEVEL);
this.definitionLevelColumn = page.getDlEncoding().getValuesReader(path, ValuesType.DEFINITION_LEVEL);
if (page.getValueEncoding().usesDictionary()) {
if (dictionary == null) {
throw new ParquetDecodingException(
"could not read page " + page + " in col " + path + " as the dictionary was missing for encoding " + page.getValueEncoding());
}
this.dataColumn = page.getValueEncoding().getDictionaryBasedValuesReader(path, ValuesType.VALUES, dictionary);
} else {
this.dataColumn = page.getValueEncoding().getValuesReader(path, ValuesType.VALUES);
}
if (page.getValueEncoding().usesDictionary() && converter.hasDictionarySupport()) {
bindToDictionary(dictionary);
} else {
bind(path.getType());
}
this.pageValueCount = page.getValueCount();
this.endOfPageValueCount = readValues + pageValueCount;
try {
byte[] bytes = page.getBytes().toByteArray();
if (DEBUG) LOG.debug("page size " + bytes.length + " bytes and " + pageValueCount + " records");
if (DEBUG) LOG.debug("reading repetition levels at 0");
repetitionLevelColumn.initFromPage(pageValueCount, bytes, 0);
int next = repetitionLevelColumn.getNextOffset();
if (DEBUG) LOG.debug("reading definition levels at " + next);
definitionLevelColumn.initFromPage(pageValueCount, bytes, next);
next = definitionLevelColumn.getNextOffset();
if (DEBUG) LOG.debug("reading data at " + next);
dataColumn.initFromPage(pageValueCount, bytes, next);
} catch (IOException e) {
throw new ParquetDecodingException("could not read page " + page + " in col " + path, e);
}
}
private boolean isPageFullyConsumed() {
return readValues >= endOfPageValueCount;
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#consume()
*/
@Override
public void consume() {
checkRead();
valueRead = false;
}
/**
* {@inheritDoc}
* @see parquet.column.ColumnReader#getTotalValueCount()
*/
@Override
public long getTotalValueCount() {
return totalValueCount;
}
}
