1 /*
2 * #%L
3 * SingleDocumentCallback.java - mongodb-async-driver - Allanbank Consulting, Inc.
4 * %%
5 * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.
6 * %%
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * 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, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * #L%
19 */
20
21 package com.allanbank.mongodb.client.callback;
22
23 import com.allanbank.mongodb.Callback;
24 import com.allanbank.mongodb.MongoDbException;
25 import com.allanbank.mongodb.bson.Document;
26 import com.allanbank.mongodb.client.MongoIteratorImpl;
27 import com.allanbank.mongodb.client.message.Reply;
28
29 /**
30 * Callback to convert a {@link Reply} into a single document.
31 *
32 * @api.no This class is <b>NOT</b> part of the drivers API. This class may be
33 * mutated in incompatible ways between any two releases of the driver.
34 * @copyright 2011-2013, Allanbank Consulting, Inc., All Rights Reserved
35 */
36 public final class SingleDocumentCallback extends
37 AbstractReplyCallback<Document> {
38
39 /**
40 * Create a new CursorCallback.
41 *
42 * @param results
43 * The callback to update once the first set of results are
44 * ready.
45 */
46 public SingleDocumentCallback(final Callback<Document> results) {
47 super(results);
48 }
49
50 /**
51 * {@inheritDoc}
52 * <p>
53 * Overridden to construct a {@link MongoIteratorImpl} around the reply.
54 * </p>
55 *
56 * @see AbstractReplyCallback#convert(Reply)
57 */
58 @Override
59 protected Document convert(final Reply reply) throws MongoDbException {
60 if (!reply.getResults().isEmpty()) {
61 return reply.getResults().get(0);
62 }
63 return null;
64 }
65 }