/**
* 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.cassandra.dht;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.commons.lang.ArrayUtils;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.Pair;
public abstract class AbstractByteOrderedPartitioner implements IPartitioner<BytesToken>
{
public static final BytesToken MINIMUM = new BytesToken(ArrayUtils.EMPTY_BYTE_ARRAY);
public static final BigInteger BYTE_MASK = new BigInteger("255");
public DecoratedKey<BytesToken> decorateKey(ByteBuffer key)
{
return new DecoratedKey<BytesToken>(getToken(key), key);
}
public DecoratedKey<BytesToken> convertFromDiskFormat(ByteBuffer key)
{
return new DecoratedKey<BytesToken>(getToken(key), key);
}
public BytesToken midpoint(Token ltoken, Token rtoken)
{
int ll,rl;
ByteBuffer lb,rb;
if(ltoken.token instanceof byte[])
{
ll = ((byte[])ltoken.token).length;
lb = ByteBuffer.wrap(((byte[])ltoken.token));
}
else
{
ll = ((ByteBuffer)ltoken.token).remaining();
lb = (ByteBuffer)ltoken.token;
}
if(rtoken.token instanceof byte[])
{
rl = ((byte[])rtoken.token).length;
rb = ByteBuffer.wrap(((byte[])rtoken.token));
}
else
{
rl = ((ByteBuffer)rtoken.token).remaining();
rb = (ByteBuffer)rtoken.token;
}
int sigbytes = Math.max(ll, rl);
BigInteger left = bigForBytes(lb, sigbytes);
BigInteger right = bigForBytes(rb, sigbytes);
Pair<BigInteger,Boolean> midpair = FBUtilities.midpoint(left, right, 8*sigbytes);
return new BytesToken(bytesForBig(midpair.left, sigbytes, midpair.right));
}
/**
* Convert a byte array containing the most significant of 'sigbytes' bytes
* representing a big-endian magnitude into a BigInteger.
*/
private BigInteger bigForBytes(ByteBuffer bytes, int sigbytes)
{
byte[] b = new byte[sigbytes];
Arrays.fill(b, (byte) 0); // append zeros
ByteBufferUtil.arrayCopy(bytes, bytes.position(), b, 0, bytes.remaining());
return new BigInteger(1, b);
}
/**
* Convert a (positive) BigInteger into a byte array representing its magnitude.
* If remainder is true, an additional byte with the high order bit enabled
* will be added to the end of the array
*/
private byte[] bytesForBig(BigInteger big, int sigbytes, boolean remainder)
{
byte[] bytes = new byte[sigbytes + (remainder ? 1 : 0)];
if (remainder)
{
// remaining bit is the most significant in the last byte
bytes[sigbytes] |= 0x80;
}
// bitmask for a single byte
for (int i = 0; i < sigbytes; i++)
{
int maskpos = 8 * (sigbytes - (i + 1));
// apply bitmask and get byte value
bytes[i] = (byte)(big.and(BYTE_MASK.shiftLeft(maskpos)).shiftRight(maskpos).intValue() & 0xFF);
}
return bytes;
}
public BytesToken getMinimumToken()
{
return MINIMUM;
}
public BytesToken getRandomToken()
{
Random r = new Random();
byte[] buffer = new byte[16];
r.nextBytes(buffer);
return new BytesToken(buffer);
}
private final Token.TokenFactory<byte[]> tokenFactory = new Token.TokenFactory<byte[]>() {
public ByteBuffer toByteArray(Token<byte[]> bytesToken)
{
return ByteBuffer.wrap(bytesToken.token);
}
public Token<byte[]> fromByteArray(ByteBuffer bytes)
{
return new BytesToken(bytes);
}
public String toString(Token<byte[]> bytesToken)
{
return FBUtilities.bytesToHex(bytesToken.token);
}
public Token<byte[]> fromString(String string)
{
return new BytesToken(FBUtilities.hexToBytes(string));
}
};
public Token.TokenFactory<byte[]> getTokenFactory()
{
return tokenFactory;
}
public boolean preservesOrder()
{
return true;
}
public abstract BytesToken getToken(ByteBuffer key);
public Map<Token, Float> describeOwnership(List<Token> sortedTokens)
{
// allTokens will contain the count and be returned, sorted_ranges is shorthand for token<->token math.
Map<Token, Float> allTokens = new HashMap<Token, Float>();
List<Range> sortedRanges = new ArrayList<Range>();
// this initializes the counts to 0 and calcs the ranges in order.
Token lastToken = sortedTokens.get(sortedTokens.size() - 1);
for (Token node : sortedTokens)
{
allTokens.put(node, new Float(0.0));
sortedRanges.add(new Range(lastToken, node));
lastToken = node;
}
for (String ks : DatabaseDescriptor.getTables())
{
for (CFMetaData cfmd : DatabaseDescriptor.getKSMetaData(ks).cfMetaData().values())
{
for (Range r : sortedRanges)
{
// Looping over every KS:CF:Range, get the splits size and add it to the count
allTokens.put(r.right, allTokens.get(r.right) + StorageService.instance.getSplits(ks, cfmd.cfName, r, 1).size());
}
}
}
// Sum every count up and divide count/total for the fractional ownership.
Float total = new Float(0.0);
for (Float f : allTokens.values())
total += f;
for (Map.Entry<Token, Float> row : allTokens.entrySet())
allTokens.put(row.getKey(), row.getValue() / total);
return allTokens;
}
}