/*
* Copyright 2017 OmniFaces
*
* 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 org.omnifaces.util.concurrentlinkedhashmap;
/**
* A listener registered for notification when an entry is evicted. An instance
* may be called concurrently by multiple threads to process entries. An
* implementation should avoid performing blocking calls or synchronizing on
* shared resources.
* <p>
* The listener is invoked by {@link ConcurrentLinkedHashMap} on a caller's
* thread and will not block other threads from operating on the map. An
* implementation should be aware that the caller's thread will not expect
* long execution times or failures as a side effect of the listener being
* notified. Execution safety and a fast turn around time can be achieved by
* performing the operation asynchronously, such as by submitting a task to an
* {@link java.util.concurrent.ExecutorService}.
*
* @author ben.manes@gmail.com (Ben Manes)
* @see <a href="https://github.com/ben-manes/concurrentlinkedhashmap">
* https://github.com/ben-manes/concurrentlinkedhashmap</a>
*/
@ThreadSafe
public interface EvictionListener<K, V> {
/**
* A call-back notification that the entry was evicted.
*
* @param key the entry's key
* @param value the entry's value
*/
void onEviction(K key, V value);
}