| /* |
| * 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.nio.ByteBuffer; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.cassandra.db.DecoratedKey; |
| import org.apache.cassandra.db.marshal.AbstractType; |
| |
| public interface IPartitioner |
| { |
| /** |
| * Transform key to object representation of the on-disk format. |
| * |
| * @param key the raw, client-facing key |
| * @return decorated version of key |
| */ |
| public DecoratedKey decorateKey(ByteBuffer key); |
| |
| /** |
| * Calculate a Token representing the approximate "middle" of the given |
| * range. |
| * |
| * @return The approximate midpoint between left and right. |
| */ |
| public Token midpoint(Token left, Token right); |
| |
| /** |
| * @return A Token smaller than all others in the range that is being partitioned. |
| * Not legal to assign to a node or key. (But legal to use in range scans.) |
| */ |
| public Token getMinimumToken(); |
| |
| /** |
| * @return a Token that can be used to route a given key |
| * (This is NOT a method to create a Token from its string representation; |
| * for that, use TokenFactory.fromString.) |
| */ |
| public Token getToken(ByteBuffer key); |
| |
| /** |
| * @return a randomly generated token |
| */ |
| public Token getRandomToken(); |
| |
| public Token.TokenFactory getTokenFactory(); |
| |
| /** |
| * @return True if the implementing class preserves key order in the Tokens |
| * it generates. |
| */ |
| public boolean preservesOrder(); |
| |
| /** |
| * Calculate the deltas between tokens in the ring in order to compare |
| * relative sizes. |
| * |
| * @param sortedTokens a sorted List of Tokens |
| * @return the mapping from 'token' to 'percentage of the ring owned by that token'. |
| */ |
| public Map<Token, Float> describeOwnership(List<Token> sortedTokens); |
| |
| public AbstractType<?> getTokenValidator(); |
| |
| /** |
| * Abstract type that orders the same way as DecoratedKeys provided by this partitioner. |
| * Used by secondary indices. |
| */ |
| public AbstractType<?> partitionOrdering(); |
| } |