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