com.hazelcast.ringbuffer.OverflowPolicy Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2016, 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.ringbuffer;
/**
* Using this policy one can control the behavior what should to be done when an item is about to be added to the ringbuffer,
* but there is 0 remaining capacity.
*
* Overflowing happens when a time-to-live is set and the oldest item in the ringbuffer (the head) is not old enough to expire.
*
* @see Ringbuffer#addAsync(Object, OverflowPolicy)
* @see Ringbuffer#addAllAsync(java.util.Collection, OverflowPolicy)
*/
public enum OverflowPolicy {
/**
* Using this policy the oldest item is overwritten no matter it is not old enough to retire. Using this policy you are
* sacrificing the time-to-live in favor of being able to write.
*
* Example: if there is a time-to-live of 30 seconds, the buffer is full and the oldest item in the ring has been placed a
* second ago, then there are 29 seconds remaining for that item. Using this policy you are going to overwrite no matter
* what.
*/
OVERWRITE(0),
/**
* Using this policy the call will fail immediately and the oldest item will not be overwritten before it is old enough
* to retire. So this policy sacrificing the ability to write in favor of time-to-live.
*
* The advantage of fail is that the caller can decide what to do since it doesn't trap the thread due to backoff.
*
* Example: if there is a time-to-live of 30 seconds, the buffer is full and the oldest item in the ring has been placed a
* second ago, then there are 29 seconds remaining for that item. Using this policy you are not going to overwrite that
* item for the next 29 seconds.
*/
FAIL(1);
private final int id;
OverflowPolicy(int id) {
this.id = id;
}
/**
* Gets the id for the given OverflowPolicy.
*
* This reason this id is used instead of an the ordinal value is that the ordinal value is more prone to changes due to
* reordering.
*
* @return the id.
*/
public int getId() {
return id;
}
/**
* Returns the OverflowPolicy for the given id.
*
* @return the OverflowPolicy found or null if not found
*/
public static OverflowPolicy getById(final int id) {
for (OverflowPolicy policy : values()) {
if (policy.id == id) {
return policy;
}
}
return null;
}
}