    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
    017    package com.google.common.cache;
    018
    019    import com.google.common.annotations.Beta;
    020
    021    import java.util.concurrent.Executor;
    022
    023    /**
    024     * A collection of common removal listeners.
    025     *
    026     * @author Charles Fry
    027     * @since 10.0
    028     */
    029    @Beta
    030    public final class RemovalListeners {
    031
    032      private RemovalListeners() {}
    033
    034      /**
    035       * Returns an asynchronous {@code RemovalListener} which processes all
    036       * eviction notifications asynchronously, using {@code executor}.
    037       *
    038       * @param listener the backing listener
    039       * @param executor the executor with which removal notifications are
    040       *     asynchronously executed
    041       */
    042      public static <K, V> RemovalListener<K, V> asynchronous(
    043          final RemovalListener<K, V> listener, final Executor executor) {
    044        return new RemovalListener<K, V>() {
    045          @Override
    046          public void onRemoval(final RemovalNotification<K, V> notification) {
    047            executor.execute(new Runnable() {
    048              @Override
    049              public void run() {
    050                listener.onRemoval(notification);
    051              }
    052            });
    053          }
    054        };
    055      }
    056
    057    }