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/*
* 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.commons.configuration2.reloading;
/**
*
* An interface to be implemented by objects which can detect whether a reload
* operation is required.
*
*
* This interface is used by a {@link ReloadingController} object. When a
* reloading check is to be performed, it is delegated to a concrete
* implementation. The implementation decides whether (specific) criteria for a
* reload are fulfilled, so that the controller can react accordingly.
*
*
* This interface does not define how a check for a reload is performed. This is
* completely up to a concrete implementation. There is just one method for
* executing the check and one method to notify the {@code ReloadingDetector}
* that the reload actually happened; this method can be used to reset the
* internal state so that the conditions for the next reload can be detected.
*
*
* When used together with {@code ReloadingController} an implementation does
* not have to be thread-safe. The controller takes care for synchronization so
* that an instance is accessed by a single thread only.
*
*
* @version $Id: ReloadingDetector.java 1624601 2014-09-12 18:04:36Z oheger $
* @since 2.0
*/
public interface ReloadingDetector
{
/**
* Checks whether all criteria for a reload operation are fulfilled. This
* method is called by external components to find out when reloading should
* take place.
*
* @return true if a reload operation should be performed,
* false otherwise
*/
boolean isReloadingRequired();
/**
* Notifies this object that a reload operation has been performed. This
* method is called after {@code reloadingRequired()} has returned
* true. It can be used to reset internal state in order to detect
* the next reload operation.
*/
void reloadingPerformed();
}