package org.apache.cassandra.triggers;
/*
*
* 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.
*
*/
import java.util.Collection;
import org.apache.cassandra.db.Mutation;
import org.apache.cassandra.db.partitions.Partition;
/**
* Trigger interface, For every partition update received by the coordinator {@link #augment(Partition)}
* is called.<p>
*
* <b> Contract:</b><br>
* 1) Implementation of this interface should only have a constructor without parameters <br>
* 2) ITrigger implementation can be instantiated multiple times during the server life time.
* (Depends on the number of times trigger folder is updated.)<br>
* 3) ITrigger implementation should be state-less (avoid dependency on instance variables).<br>
*
* <br><b>The API is still beta and can change.</b>
*/
public interface ITrigger
{
/**
* Called exactly once per CF update, returned mutations are atomically updated.
*
* @param update - update received for the CF
* @return additional modifications to be applied along with the supplied update
*/
public Collection<Mutation> augment(Partition update);
}