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A driver for Apache Cassandra 1.2+ that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol.
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/*
* Copyright (C) 2012 DataStax 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 com.datastax.driver.core;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/*
* It's not an interface because we don't want to expose it
* Note: we may want to expose this later if people use custom partitioner and want to be able to extend that.
* This is way premature however.
*/
abstract class Token implements Comparable {
public static Token.Factory getFactory(String partitionerName) {
if (partitionerName.endsWith("Murmur3Partitioner"))
return M3PToken.FACTORY;
else if (partitionerName.endsWith("RandomPartitioner"))
return RPToken.FACTORY;
else if (partitionerName.endsWith("OrderedPartitioner"))
return OPPToken.FACTORY;
else
return null;
}
public interface Factory {
public Token fromString(String tokenStr);
public Token hash(ByteBuffer partitionKey);
}
// Murmur3Partitioner tokens
static class M3PToken extends Token {
private final long value;
public static final Factory FACTORY = new Factory() {
private long getblock(ByteBuffer key, int offset, int index) {
int i_8 = index << 3;
int blockOffset = offset + i_8;
return ((long) key.get(blockOffset + 0) & 0xff) + (((long) key.get(blockOffset + 1) & 0xff) << 8) +
(((long) key.get(blockOffset + 2) & 0xff) << 16) + (((long) key.get(blockOffset + 3) & 0xff) << 24) +
(((long) key.get(blockOffset + 4) & 0xff) << 32) + (((long) key.get(blockOffset + 5) & 0xff) << 40) +
(((long) key.get(blockOffset + 6) & 0xff) << 48) + (((long) key.get(blockOffset + 7) & 0xff) << 56);
}
private long rotl64(long v, int n) {
return ((v << n) | (v >>> (64 - n)));
}
private long fmix(long k) {
k ^= k >>> 33;
k *= 0xff51afd7ed558ccdL;
k ^= k >>> 33;
k *= 0xc4ceb9fe1a85ec53L;
k ^= k >>> 33;
return k;
}
// This is an adapted version of the MurmurHash.hash3_x64_128 from Cassandra used
// for M3P. Compared to that methods, there's a few inlining of arguments and we
// only return the first 64-bits of the result since that's all M3P uses.
@SuppressWarnings("fallthrough")
private long murmur(ByteBuffer data) {
int offset = data.position();
int length = data.remaining();
int nblocks = length >> 4; // Process as 128-bit blocks.
long h1 = 0;
long h2 = 0;
long c1 = 0x87c37b91114253d5L;
long c2 = 0x4cf5ad432745937fL;
//----------
// body
for(int i = 0; i < nblocks; i++) {
long k1 = getblock(data, offset, i*2+0);
long k2 = getblock(data, offset, i*2+1);
k1 *= c1; k1 = rotl64(k1,31); k1 *= c2; h1 ^= k1;
h1 = rotl64(h1,27); h1 += h2; h1 = h1*5+0x52dce729;
k2 *= c2; k2 = rotl64(k2,33); k2 *= c1; h2 ^= k2;
h2 = rotl64(h2,31); h2 += h1; h2 = h2*5+0x38495ab5;
}
//----------
// tail
// Advance offset to the unprocessed tail of the data.
offset += nblocks * 16;
long k1 = 0;
long k2 = 0;
switch(length & 15) {
case 15: k2 ^= ((long) data.get(offset+14)) << 48;
case 14: k2 ^= ((long) data.get(offset+13)) << 40;
case 13: k2 ^= ((long) data.get(offset+12)) << 32;
case 12: k2 ^= ((long) data.get(offset+11)) << 24;
case 11: k2 ^= ((long) data.get(offset+10)) << 16;
case 10: k2 ^= ((long) data.get(offset+9)) << 8;
case 9: k2 ^= ((long) data.get(offset+8)) << 0;
k2 *= c2; k2 = rotl64(k2,33); k2 *= c1; h2 ^= k2;
case 8: k1 ^= ((long) data.get(offset+7)) << 56;
case 7: k1 ^= ((long) data.get(offset+6)) << 48;
case 6: k1 ^= ((long) data.get(offset+5)) << 40;
case 5: k1 ^= ((long) data.get(offset+4)) << 32;
case 4: k1 ^= ((long) data.get(offset+3)) << 24;
case 3: k1 ^= ((long) data.get(offset+2)) << 16;
case 2: k1 ^= ((long) data.get(offset+1)) << 8;
case 1: k1 ^= ((long) data.get(offset));
k1 *= c1; k1 = rotl64(k1,31); k1 *= c2; h1 ^= k1;
};
//----------
// finalization
h1 ^= length; h2 ^= length;
h1 += h2;
h2 += h1;
h1 = fmix(h1);
h2 = fmix(h2);
h1 += h2;
h2 += h1;
return h1;
}
@Override
public M3PToken fromString(String tokenStr) {
return new M3PToken(Long.parseLong(tokenStr));
}
@Override
public M3PToken hash(ByteBuffer partitionKey) {
long v = murmur(partitionKey);
return new M3PToken(v == Long.MIN_VALUE ? Long.MAX_VALUE : v);
}
};
private M3PToken(long value) {
this.value = value;
}
@Override
public int compareTo(Token other) {
assert other instanceof M3PToken;
long otherValue = ((M3PToken)other).value;
return value < otherValue ? -1 : (value == otherValue) ? 0 : 1;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null || this.getClass() != obj.getClass())
return false;
return value == ((M3PToken)obj).value;
}
@Override
public int hashCode() {
return (int)(value^(value>>>32));
}
}
// OPPartitioner tokens
static class OPPToken extends Token {
private final ByteBuffer value;
public static final Factory FACTORY = new Factory() {
@Override
public OPPToken fromString(String tokenStr) {
return new OPPToken(TypeCodec.StringCodec.utf8Instance.serialize(tokenStr));
}
@Override
public OPPToken hash(ByteBuffer partitionKey) {
return new OPPToken(partitionKey);
}
};
private OPPToken(ByteBuffer value) {
this.value = value;
}
@Override
public int compareTo(Token other) {
assert other instanceof OPPToken;
return value.compareTo(((OPPToken)other).value);
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null || this.getClass() != obj.getClass())
return false;
return value.equals(((OPPToken)obj).value);
}
@Override
public int hashCode() {
return value.hashCode();
}
}
// RandomPartitioner tokens
static class RPToken extends Token {
private final BigInteger value;
public static final Factory FACTORY = new Factory() {
private final ThreadLocal md5Digests = new ThreadLocal() {
@Override
protected MessageDigest initialValue() {
try {
return MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("MD5 doesn't seem to be available on this JVM", e);
}
}
@Override
public MessageDigest get() {
MessageDigest digest = super.get();
digest.reset();
return digest;
}
};
private BigInteger md5(ByteBuffer data) {
MessageDigest digest = md5Digests.get();
digest.update(data.duplicate());
return new BigInteger(digest.digest()).abs();
}
@Override
public RPToken fromString(String tokenStr) {
return new RPToken(new BigInteger(tokenStr));
}
@Override
public RPToken hash(ByteBuffer partitionKey) {
return new RPToken(md5(partitionKey));
}
};
private RPToken(BigInteger value) {
this.value = value;
}
@Override
public int compareTo(Token other) {
assert other instanceof RPToken;
return value.compareTo(((RPToken)other).value);
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null || this.getClass() != obj.getClass())
return false;
return value.equals(((RPToken)obj).value);
}
@Override
public int hashCode() {
return value.hashCode();
}
}
}
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