001/* 002 * Copyright (C) 2011 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.cache; 018 019import static com.google.common.base.Preconditions.checkNotNull; 020 021import java.util.concurrent.Executor; 022 023/** 024 * A collection of common removal listeners. 025 * 026 * @author Charles Fry 027 * @since 10.0 028 */ 029public final class RemovalListeners { 030 031 private RemovalListeners() {} 032 033 /** 034 * Returns a {@code RemovalListener} which processes all eviction 035 * notifications using {@code executor}. 036 * 037 * @param listener the backing listener 038 * @param executor the executor with which removal notifications are 039 * asynchronously executed 040 */ 041 public static <K, V> RemovalListener<K, V> asynchronous( 042 final RemovalListener<K, V> listener, final Executor executor) { 043 checkNotNull(listener); 044 checkNotNull(executor); 045 return new RemovalListener<K, V>() { 046 @Override 047 public void onRemoval(final RemovalNotification<K, V> notification) { 048 executor.execute(new Runnable() { 049 @Override 050 public void run() { 051 listener.onRemoval(notification); 052 } 053 }); 054 } 055 }; 056 } 057 058}