/*
* 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.solr.handler;
import java.util.ArrayList;
import java.util.List;
/**
* A state manager which implements an observer pattern to notify observers
* of a state change.
*/
abstract class CdcrStateManager {
private List<CdcrStateObserver> observers = new ArrayList<>();
void register(CdcrStateObserver observer) {
this.observers.add(observer);
}
void callback() {
for (CdcrStateObserver observer : observers) {
observer.stateUpdate();
}
}
interface CdcrStateObserver {
void stateUpdate();
}
}