/** * 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.util.Comparator; import java.util.regex.Pattern; import org.apache.cassandra.config.DatabaseDescriptor; import org.apache.cassandra.db.DecoratedKey; import org.apache.cassandra.utils.FBUtilities; import org.apache.cassandra.utils.GuidGenerator; import org.apache.cassandra.utils.Pair; /** * This class generates a BigIntegerToken using MD5 hash. */ public class RandomPartitioner implements IPartitioner<BigIntegerToken> { public static final BigInteger TWO = new BigInteger("2"); public static final BigIntegerToken MINIMUM = new BigIntegerToken("0"); private static final String DELIMITER = ":"; public DecoratedKey<BigIntegerToken> decorateKey(String key) { return new DecoratedKey<BigIntegerToken>(getToken(key), key); } public DecoratedKey<BigIntegerToken> convertFromDiskFormat(String key) { int splitPoint = key.indexOf(DELIMITER); String first = key.substring(0, splitPoint); String second = key.substring(splitPoint+1); return new DecoratedKey<BigIntegerToken>(new BigIntegerToken(first), second); } public String convertToDiskFormat(DecoratedKey<BigIntegerToken> key) { return key.token + DELIMITER + key.key; } public BigIntegerToken midpoint(BigIntegerToken ltoken, BigIntegerToken rtoken) { Pair<BigInteger,Boolean> midpair = FBUtilities.midpoint(ltoken.token, rtoken.token, 127); // discard the remainder return new BigIntegerToken(midpair.left); } public BigIntegerToken getMinimumToken() { return MINIMUM; } public BigIntegerToken getRandomToken() { String guid = GuidGenerator.guid(); BigInteger token = FBUtilities.hash(guid); if ( token.signum() == -1 ) token = token.multiply(BigInteger.valueOf(-1L)); return new BigIntegerToken(token); } private final Token.TokenFactory<BigInteger> tokenFactory = new Token.TokenFactory<BigInteger>() { public byte[] toByteArray(Token<BigInteger> bigIntegerToken) { return bigIntegerToken.token.toByteArray(); } public Token<BigInteger> fromByteArray(byte[] bytes) { return new BigIntegerToken(new BigInteger(bytes)); } public String toString(Token<BigInteger> bigIntegerToken) { return bigIntegerToken.token.toString(); } public Token<BigInteger> fromString(String string) { return new BigIntegerToken(new BigInteger(string)); } }; public Token.TokenFactory<BigInteger> getTokenFactory() { return tokenFactory; } public boolean preservesOrder() { return false; } public BigIntegerToken getToken(String key) { if (key.isEmpty()) return MINIMUM; return new BigIntegerToken(FBUtilities.hash(key)); } }