org.apache.bookkeeper.versioning.Version Maven / Gradle / Ivy
/*
*
* 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.bookkeeper.versioning;
/**
* An interface that allows us to determine if a given version happened before or after another version.
*/
public interface Version {
/**
* Initial version.
*/
Version NEW = new Version() {
@Override
public Occurred compare(Version v) {
if (null == v) {
throw new NullPointerException("Version is not allowed to be null.");
}
if (this == v) {
return Occurred.CONCURRENTLY;
}
return Occurred.BEFORE;
}
};
/**
* Match any version.
*/
Version ANY = v -> {
if (null == v) {
throw new NullPointerException("Version is not allowed to be null.");
}
return Occurred.CONCURRENTLY;
};
/**
* Define the sequence of versions.
*/
enum Occurred {
BEFORE, AFTER, CONCURRENTLY
}
Occurred compare(Version v);
}