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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* 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,
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package org.apache.hadoop.hbase.codec.prefixtree;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.KeyValue.KVComparator;
import org.apache.hadoop.hbase.KeyValue.MetaComparator;
import org.apache.hadoop.hbase.KeyValue.RawBytesComparator;
import org.apache.hadoop.hbase.KeyValueUtil;
import org.apache.hadoop.hbase.codec.prefixtree.decode.DecoderFactory;
import org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArraySearcher;
import org.apache.hadoop.hbase.codec.prefixtree.encode.EncoderFactory;
import org.apache.hadoop.hbase.codec.prefixtree.encode.PrefixTreeEncoder;
import org.apache.hadoop.hbase.codec.prefixtree.scanner.CellSearcher;
import org.apache.hadoop.hbase.io.encoding.DataBlockEncoder;
import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
import org.apache.hadoop.hbase.io.encoding.EncodingState;
import org.apache.hadoop.hbase.io.encoding.HFileBlockDecodingContext;
import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext;
import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultEncodingContext;
import org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext;
import org.apache.hadoop.hbase.io.hfile.BlockType;
import org.apache.hadoop.hbase.io.hfile.HFileContext;
import org.apache.hadoop.hbase.util.ByteBufferUtils;
import org.apache.hadoop.io.WritableUtils;
/**
* This class is created via reflection in DataBlockEncoding enum. Update the enum if class name or
* package changes.
* <p/>
* PrefixTreeDataBlockEncoder implementation of DataBlockEncoder. This is the primary entry point
* for PrefixTree encoding and decoding. Encoding is delegated to instances of
* {@link PrefixTreeEncoder}, and decoding is delegated to instances of
* {@link org.apache.hadoop.hbase.codec.prefixtree.scanner.CellSearcher}. Encoder and decoder instances are
* created and recycled by static PtEncoderFactory and PtDecoderFactory.
*/
@InterfaceAudience.Private
public class PrefixTreeCodec implements DataBlockEncoder{
/**
* no-arg constructor for reflection
*/
public PrefixTreeCodec() {
}
@Override
public ByteBuffer decodeKeyValues(DataInputStream source, HFileBlockDecodingContext decodingCtx)
throws IOException {
return decodeKeyValues(source, 0, 0, decodingCtx);
}
/**
* I don't think this method is called during normal HBase operation, so efficiency is not
* important.
*/
public ByteBuffer decodeKeyValues(DataInputStream source, int allocateHeaderLength,
int skipLastBytes, HFileBlockDecodingContext decodingCtx) throws IOException {
ByteBuffer sourceAsBuffer = ByteBufferUtils.drainInputStreamToBuffer(source);// waste
sourceAsBuffer.mark();
PrefixTreeBlockMeta blockMeta = new PrefixTreeBlockMeta(sourceAsBuffer);
sourceAsBuffer.rewind();
int numV1BytesWithHeader = allocateHeaderLength + blockMeta.getNumKeyValueBytes();
byte[] keyValueBytesWithHeader = new byte[numV1BytesWithHeader];
ByteBuffer result = ByteBuffer.wrap(keyValueBytesWithHeader);
result.rewind();
CellSearcher searcher = null;
try {
boolean includesMvcc = decodingCtx.getHFileContext().isIncludesMvcc();
searcher = DecoderFactory.checkOut(sourceAsBuffer, includesMvcc);
while (searcher.advance()) {
KeyValue currentCell = KeyValueUtil.copyToNewKeyValue(searcher.current());
// needs to be modified for DirectByteBuffers. no existing methods to
// write VLongs to byte[]
int offset = result.arrayOffset() + result.position();
System.arraycopy(currentCell.getBuffer(), currentCell.getOffset(), result.array(), offset,
currentCell.getLength());
int keyValueLength = KeyValueUtil.length(currentCell);
ByteBufferUtils.skip(result, keyValueLength);
offset += keyValueLength;
if (includesMvcc) {
ByteBufferUtils.writeVLong(result, currentCell.getMvccVersion());
}
}
result.position(result.limit());//make it appear as if we were appending
return result;
} finally {
DecoderFactory.checkIn(searcher);
}
}
@Override
public ByteBuffer getFirstKeyInBlock(ByteBuffer block) {
block.rewind();
PrefixTreeArraySearcher searcher = null;
try {
// should i includeMemstoreTS (second argument)? i think PrefixKeyDeltaEncoder is, so i will
searcher = DecoderFactory.checkOut(block, true);
if (!searcher.positionAtFirstCell()) {
return null;
}
return KeyValueUtil.copyKeyToNewByteBuffer(searcher.current());
} finally {
DecoderFactory.checkIn(searcher);
}
}
@Override
public HFileBlockEncodingContext newDataBlockEncodingContext(
DataBlockEncoding encoding, byte[] header, HFileContext meta) {
if(DataBlockEncoding.PREFIX_TREE != encoding){
//i'm not sure why encoding is in the interface. Each encoder implementation should probably
//know it's encoding type
throw new IllegalArgumentException("only DataBlockEncoding.PREFIX_TREE supported");
}
return new HFileBlockDefaultEncodingContext(encoding, header, meta);
}
@Override
public HFileBlockDecodingContext newDataBlockDecodingContext(HFileContext meta) {
return new HFileBlockDefaultDecodingContext(meta);
}
/**
* Is this the correct handling of an illegal comparator? How to prevent that from getting all
* the way to this point.
*/
@Override
public EncodedSeeker createSeeker(KVComparator comparator, HFileBlockDecodingContext decodingCtx) {
if (comparator instanceof RawBytesComparator){
throw new IllegalArgumentException("comparator must be KeyValue.KeyComparator");
} else if (comparator instanceof MetaComparator){
throw new IllegalArgumentException("DataBlockEncoding.PREFIX_TREE not compatible with hbase:meta "
+"table");
}
return new PrefixTreeSeeker(decodingCtx.getHFileContext().isIncludesMvcc());
}
@Override
public int encode(Cell cell, HFileBlockEncodingContext encodingCtx, DataOutputStream out)
throws IOException {
PrefixTreeEncodingState state = (PrefixTreeEncodingState) encodingCtx.getEncodingState();
PrefixTreeEncoder builder = state.builder;
builder.write(cell);
int size = KeyValueUtil.length(cell);
if (encodingCtx.getHFileContext().isIncludesMvcc()) {
size += WritableUtils.getVIntSize(cell.getSequenceId());
}
return size;
}
private static class PrefixTreeEncodingState extends EncodingState {
PrefixTreeEncoder builder = null;
}
@Override
public void startBlockEncoding(HFileBlockEncodingContext blkEncodingCtx, DataOutputStream out)
throws IOException {
if (blkEncodingCtx.getClass() != HFileBlockDefaultEncodingContext.class) {
throw new IOException(this.getClass().getName() + " only accepts "
+ HFileBlockDefaultEncodingContext.class.getName() + " as the " + "encoding context.");
}
HFileBlockDefaultEncodingContext encodingCtx =
(HFileBlockDefaultEncodingContext) blkEncodingCtx;
encodingCtx.prepareEncoding(out);
PrefixTreeEncoder builder = EncoderFactory.checkOut(out, encodingCtx.getHFileContext()
.isIncludesMvcc());
PrefixTreeEncodingState state = new PrefixTreeEncodingState();
state.builder = builder;
blkEncodingCtx.setEncodingState(state);
}
@Override
public void endBlockEncoding(HFileBlockEncodingContext encodingCtx, DataOutputStream out,
byte[] uncompressedBytesWithHeader) throws IOException {
PrefixTreeEncodingState state = (PrefixTreeEncodingState) encodingCtx.getEncodingState();
PrefixTreeEncoder builder = state.builder;
builder.flush();
EncoderFactory.checkIn(builder);
// do i need to check this, or will it always be DataBlockEncoding.PREFIX_TREE?
if (encodingCtx.getDataBlockEncoding() != DataBlockEncoding.NONE) {
encodingCtx.postEncoding(BlockType.ENCODED_DATA);
} else {
encodingCtx.postEncoding(BlockType.DATA);
}
}
}