com.hazelcast.map.impl.querycache.event.sequence.PartitionSequencer Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2024, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.map.impl.querycache.event.sequence;
/**
* General contract of a sequence-number provider for a partition.
*
* Each partition has its own sequence-number on publisher-side. For every generated event, this sequence will be
* incremented by one and set to that event before sending it to the subscriber side.
*
* On subscriber side, this sequence is used to keep track of published events; upon arrival of an event, there
* is a pre-condition check to decide whether that the arrived event has the next-expected-sequence-number for the
* relevant partition. If the event has next-sequence, it is applied to the query-cache.
*
* Implementations of this interface should be thread-safe.
*/
public interface PartitionSequencer {
/**
* Returns next number in sequence for the partition.
*
* @return next number in sequence.
*/
long nextSequence();
/**
* Sets the current sequence number for the partition.
*
* @param update new sequence number.
*/
void setSequence(long update);
/**
* Atomically sets the value of sequence number for the partition.
*
* @param expect the expected sequence.
* @param update the new sequence.
* @return {@code true} if Compare-and-Set operation is successful, otherwise returns {@code false}.
*/
boolean compareAndSetSequence(long expect, long update);
/**
* Returns current sequence number of the partition.
*
* @return current sequence number.
*/
long getSequence();
/**
* Resets {@link PartitionSequencer}.
* After this call returns sequence generation will be start from zero.
*/
void reset();
}