Java tutorial
/* * 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 com.facebook.presto.orc.writer; import com.facebook.presto.orc.checkpoint.BooleanStreamCheckpoint; import com.facebook.presto.orc.checkpoint.LongStreamCheckpoint; import com.facebook.presto.orc.metadata.ColumnEncoding; import com.facebook.presto.orc.metadata.CompressionKind; import com.facebook.presto.orc.metadata.MetadataWriter; import com.facebook.presto.orc.metadata.RowGroupIndex; import com.facebook.presto.orc.metadata.Stream; import com.facebook.presto.orc.metadata.Stream.StreamKind; import com.facebook.presto.orc.metadata.statistics.ColumnStatistics; import com.facebook.presto.orc.stream.LongOutputStream; import com.facebook.presto.orc.stream.PresentOutputStream; import com.facebook.presto.spi.block.Block; import com.facebook.presto.spi.block.ColumnarArray; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableMap; import io.airlift.slice.SliceOutput; import org.openjdk.jol.info.ClassLayout; import java.io.IOException; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.Optional; import static com.facebook.presto.orc.metadata.ColumnEncoding.ColumnEncodingKind.DIRECT; import static com.facebook.presto.orc.metadata.ColumnEncoding.ColumnEncodingKind.DIRECT_V2; import static com.facebook.presto.orc.metadata.CompressionKind.NONE; import static com.facebook.presto.orc.stream.LongOutputStream.createLengthOutputStream; import static com.facebook.presto.spi.block.ColumnarArray.toColumnarArray; import static com.google.common.base.Preconditions.checkArgument; import static com.google.common.base.Preconditions.checkState; import static java.util.Objects.requireNonNull; public class ListColumnWriter implements ColumnWriter { private static final int INSTANCE_SIZE = ClassLayout.parseClass(ListColumnWriter.class).instanceSize(); private final int column; private final boolean compressed; private final ColumnEncoding columnEncoding; private final LongOutputStream lengthStream; private final PresentOutputStream presentStream; private final ColumnWriter elementWriter; private final List<ColumnStatistics> rowGroupColumnStatistics = new ArrayList<>(); private int nonNullValueCount; private boolean closed; public ListColumnWriter(int column, CompressionKind compression, int bufferSize, boolean isDwrf, ColumnWriter elementWriter) { checkArgument(column >= 0, "column is negative"); this.column = column; this.compressed = requireNonNull(compression, "compression is null") != NONE; this.columnEncoding = new ColumnEncoding(isDwrf ? DIRECT : DIRECT_V2, 0); this.elementWriter = requireNonNull(elementWriter, "elementWriter is null"); this.lengthStream = createLengthOutputStream(compression, bufferSize, isDwrf); this.presentStream = new PresentOutputStream(compression, bufferSize); } @Override public List<ColumnWriter> getNestedColumnWriters() { return ImmutableList.<ColumnWriter>builder().add(elementWriter) .addAll(elementWriter.getNestedColumnWriters()).build(); } @Override public Map<Integer, ColumnEncoding> getColumnEncodings() { ImmutableMap.Builder<Integer, ColumnEncoding> encodings = ImmutableMap.builder(); encodings.put(column, columnEncoding); encodings.putAll(elementWriter.getColumnEncodings()); return encodings.build(); } @Override public void beginRowGroup() { lengthStream.recordCheckpoint(); presentStream.recordCheckpoint(); elementWriter.beginRowGroup(); } @Override public void writeBlock(Block block) { checkState(!closed); checkArgument(block.getPositionCount() > 0, "Block is empty"); ColumnarArray columnarArray = toColumnarArray(block); writeColumnarArray(columnarArray); } private void writeColumnarArray(ColumnarArray columnarArray) { // write nulls and lengths for (int position = 0; position < columnarArray.getPositionCount(); position++) { boolean present = !columnarArray.isNull(position); presentStream.writeBoolean(present); if (present) { nonNullValueCount++; lengthStream.writeLong(columnarArray.getLength(position)); } } // write element values Block elementsBlock = columnarArray.getElementsBlock(); if (elementsBlock.getPositionCount() > 0) { elementWriter.writeBlock(elementsBlock); } } @Override public Map<Integer, ColumnStatistics> finishRowGroup() { checkState(!closed); ColumnStatistics statistics = new ColumnStatistics((long) nonNullValueCount, 0, null, null, null, null, null, null, null, null); rowGroupColumnStatistics.add(statistics); nonNullValueCount = 0; ImmutableMap.Builder<Integer, ColumnStatistics> columnStatistics = ImmutableMap.builder(); columnStatistics.put(column, statistics); columnStatistics.putAll(elementWriter.finishRowGroup()); return columnStatistics.build(); } @Override public void close() { closed = true; elementWriter.close(); lengthStream.close(); presentStream.close(); } @Override public Map<Integer, ColumnStatistics> getColumnStripeStatistics() { checkState(closed); ImmutableMap.Builder<Integer, ColumnStatistics> columnStatistics = ImmutableMap.builder(); columnStatistics.put(column, ColumnStatistics.mergeColumnStatistics(rowGroupColumnStatistics)); columnStatistics.putAll(elementWriter.getColumnStripeStatistics()); return columnStatistics.build(); } @Override public List<Stream> writeIndexStreams(SliceOutput outputStream, MetadataWriter metadataWriter) throws IOException { checkState(closed); ImmutableList.Builder<RowGroupIndex> rowGroupIndexes = ImmutableList.builder(); List<LongStreamCheckpoint> lengthCheckpoints = lengthStream.getCheckpoints(); Optional<List<BooleanStreamCheckpoint>> presentCheckpoints = presentStream.getCheckpoints(); for (int i = 0; i < rowGroupColumnStatistics.size(); i++) { int groupId = i; ColumnStatistics columnStatistics = rowGroupColumnStatistics.get(groupId); LongStreamCheckpoint lengthCheckpoint = lengthCheckpoints.get(groupId); Optional<BooleanStreamCheckpoint> presentCheckpoint = presentCheckpoints .map(checkpoints -> checkpoints.get(groupId)); List<Integer> positions = createArrayColumnPositionList(compressed, lengthCheckpoint, presentCheckpoint); rowGroupIndexes.add(new RowGroupIndex(positions, columnStatistics)); } int length = metadataWriter.writeRowIndexes(outputStream, rowGroupIndexes.build()); Stream stream = new Stream(column, StreamKind.ROW_INDEX, length, false); ImmutableList.Builder<Stream> indexStreams = ImmutableList.builder(); indexStreams.add(stream); indexStreams.addAll(elementWriter.writeIndexStreams(outputStream, metadataWriter)); return indexStreams.build(); } private static List<Integer> createArrayColumnPositionList(boolean compressed, LongStreamCheckpoint lengthCheckpoint, Optional<BooleanStreamCheckpoint> presentCheckpoint) { ImmutableList.Builder<Integer> positionList = ImmutableList.builder(); presentCheckpoint.ifPresent( booleanStreamCheckpoint -> positionList.addAll(booleanStreamCheckpoint.toPositionList(compressed))); positionList.addAll(lengthCheckpoint.toPositionList(compressed)); return positionList.build(); } @Override public List<Stream> writeDataStreams(SliceOutput outputStream) throws IOException { checkState(closed); ImmutableList.Builder<Stream> dataStreams = ImmutableList.builder(); presentStream.writeDataStreams(column, outputStream).ifPresent(dataStreams::add); lengthStream.writeDataStreams(column, outputStream).ifPresent(dataStreams::add); dataStreams.addAll(elementWriter.writeDataStreams(outputStream)); return dataStreams.build(); } @Override public long getBufferedBytes() { return lengthStream.getBufferedBytes() + presentStream.getBufferedBytes() + elementWriter.getBufferedBytes(); } @Override public long getRetainedBytes() { // NOTE: we do not include stats because they should be small and it would be annoying to calculate the size return INSTANCE_SIZE + lengthStream.getRetainedBytes() + presentStream.getRetainedBytes() + elementWriter.getRetainedBytes(); } @Override public void reset() { closed = false; lengthStream.reset(); presentStream.reset(); elementWriter.reset(); rowGroupColumnStatistics.clear(); nonNullValueCount = 0; } }