/**
* 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;
public interface IPartitioner<T extends Token>
{
/**
* @Deprecated: Used by SSTables before version 'e'.
*
* Convert the on disk representation to a DecoratedKey object
* @param key On disk representation
* @return DecoratedKey object
*/
public DecoratedKey<T> convertFromDiskFormat(ByteBuffer key);
/**
* Transform key to object representation of the on-disk format.
*
* @param key the raw, client-facing key
* @return decorated version of key
*/
public DecoratedKey<T> 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 The minimum possible Token in the range that is being partitioned.
*/
public T 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 T getToken(ByteBuffer key);
/**
* @return a randomly generated token
*/
public T 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);
}