/*
* Copyright 2014 the original author or authors.
*
* 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 org.springframework.xd.dirt.integration.bus;
/**
* Strategy for determining the partition to which a message should be sent.
*
* @author Gary Russell
*/
public interface PartitionSelectorStrategy {
/**
* Determine the partition based on a key. The partitionCount is 1 greater
* than the maximum value of a valid partition. Typical implementations
* will return {@code someValue % partitionCount}. The caller will apply
* that same modulo operation (as well as enforcing absolute value) if the
* value exceeds partitionCount - 1.
*
* @param key the key
* @param partitionCount the number of partitions
*
* @return the partition
*/
int selectPartition(Object key, int partitionCount);
}