/*
* 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.hadoop.hbase.io.encoding;
import java.io.IOException;
import java.io.OutputStream;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.util.Bytes;
/**
* Provide access to all data block encoding algorithms. All of the algorithms
* are required to have unique id which should <b>NEVER</b> be changed. If you
* want to add a new algorithm/version, assign it a new id. Announce the new id
* in the HBase mailing list to prevent collisions.
*/
@InterfaceAudience.Public
public enum DataBlockEncoding {
/** Disable data block encoding. */
NONE(0, null),
// id 1 is reserved for the BITSET algorithm to be added later
PREFIX(2, "org.apache.hadoop.hbase.io.encoding.PrefixKeyDeltaEncoder"),
DIFF(3, "org.apache.hadoop.hbase.io.encoding.DiffKeyDeltaEncoder"),
FAST_DIFF(4, "org.apache.hadoop.hbase.io.encoding.FastDiffDeltaEncoder"),
// id 5 is reserved for the COPY_KEY algorithm for benchmarking
// COPY_KEY(5, "org.apache.hadoop.hbase.io.encoding.CopyKeyDataBlockEncoder"),
PREFIX_TREE(6, "org.apache.hadoop.hbase.codec.prefixtree.PrefixTreeCodec"),
ROW_INDEX_V1(7, "org.apache.hadoop.hbase.io.encoding.RowIndexCodecV1");
private final short id;
private final byte[] idInBytes;
private DataBlockEncoder encoder;
private final String encoderCls;
public static final int ID_SIZE = Bytes.SIZEOF_SHORT;
/** Maps data block encoding ids to enum instances. */
private static DataBlockEncoding[] idArray = new DataBlockEncoding[Byte.MAX_VALUE + 1];
static {
for (DataBlockEncoding algo : values()) {
if (idArray[algo.id] != null) {
throw new RuntimeException(String.format(
"Two data block encoder algorithms '%s' and '%s' have " + "the same id %d",
idArray[algo.id].toString(), algo.toString(), (int) algo.id));
}
idArray[algo.id] = algo;
}
}
private DataBlockEncoding(int id, String encoderClsName) {
if (id < 0 || id > Byte.MAX_VALUE) {
throw new AssertionError(
"Data block encoding algorithm id is out of range: " + id);
}
this.id = (short) id;
this.idInBytes = Bytes.toBytes(this.id);
if (idInBytes.length != ID_SIZE) {
// White this may seem redundant, if we accidentally serialize
// the id as e.g. an int instead of a short, all encoders will break.
throw new RuntimeException("Unexpected length of encoder ID byte " +
"representation: " + Bytes.toStringBinary(idInBytes));
}
this.encoderCls = encoderClsName;
}
/**
* @return name converted to bytes.
*/
public byte[] getNameInBytes() {
return Bytes.toBytes(toString());
}
/**
* @return The id of a data block encoder.
*/
public short getId() {
return id;
}
/**
* Writes id in bytes.
* @param stream where the id should be written.
*/
public void writeIdInBytes(OutputStream stream) throws IOException {
stream.write(idInBytes);
}
/**
* Writes id bytes to the given array starting from offset.
*
* @param dest output array
* @param offset starting offset of the output array
* @throws IOException
*/
public void writeIdInBytes(byte[] dest, int offset) throws IOException {
System.arraycopy(idInBytes, 0, dest, offset, ID_SIZE);
}
/**
* Return new data block encoder for given algorithm type.
* @return data block encoder if algorithm is specified, null if none is
* selected.
*/
public DataBlockEncoder getEncoder() {
if (encoder == null && id != 0) {
// lazily create the encoder
encoder = createEncoder(encoderCls);
}
return encoder;
}
/**
* Find and create data block encoder for given id;
* @param encoderId id of data block encoder.
* @return Newly created data block encoder.
*/
public static DataBlockEncoder getDataBlockEncoderById(short encoderId) {
return getEncodingById(encoderId).getEncoder();
}
/**
* Find and return the name of data block encoder for the given id.
* @param encoderId id of data block encoder
* @return name, same as used in options in column family
*/
public static String getNameFromId(short encoderId) {
return getEncodingById(encoderId).toString();
}
/**
* Check if given encoder has this id.
* @param encoder encoder which id will be checked
* @param encoderId id which we except
* @return true if id is right for given encoder, false otherwise
* @exception IllegalArgumentException
* thrown when there is no matching data block encoder
*/
public static boolean isCorrectEncoder(DataBlockEncoder encoder,
short encoderId) {
DataBlockEncoding algorithm = getEncodingById(encoderId);
String encoderCls = encoder.getClass().getName();
return encoderCls.equals(algorithm.encoderCls);
}
public static DataBlockEncoding getEncodingById(short dataBlockEncodingId) {
DataBlockEncoding algorithm = null;
if (dataBlockEncodingId >= 0 && dataBlockEncodingId <= Byte.MAX_VALUE) {
algorithm = idArray[dataBlockEncodingId];
}
if (algorithm == null) {
throw new IllegalArgumentException(String.format(
"There is no data block encoder for given id '%d'",
(int) dataBlockEncodingId));
}
return algorithm;
}
protected static DataBlockEncoder createEncoder(String fullyQualifiedClassName){
try {
return (DataBlockEncoder)Class.forName(fullyQualifiedClassName).newInstance();
} catch (InstantiationException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
} catch (ClassNotFoundException e) {
throw new IllegalArgumentException(e);
}
}
}