1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27 package org.apache.http.client.cache;
28
29 import java.io.IOException;
30
31 /**
32 * Used for atomically updating entries in a {@link HttpCacheStorage}
33 * implementation. The current entry (if any) is fed into an implementation
34 * of this interface, and the new, possibly updated entry (if any)
35 * should be returned.
36 */
37 public interface HttpCacheUpdateCallback {
38
39 /**
40 * Returns the new cache entry that should replace an existing one.
41 *
42 * @param existing
43 * the cache entry currently in-place in the cache, possibly
44 * {@code null} if nonexistent
45 * @return the cache entry that should replace it, again,
46 * possibly {@code null} if the entry should be deleted
47 *
48 * @since 4.1
49 */
50 HttpCacheEntry/../../../org/apache/http/client/cache/HttpCacheEntry.html#HttpCacheEntry">HttpCacheEntry update(HttpCacheEntry existing) throws IOException;
51
52 }